a0b7ffb184
NB: This is a speculative experiment and could easily result in a dead-end branch. FossilOrigin-Name: 3d930501a2acb7f20932cfeb4e3fe308b4569cd6
3293 lines
97 KiB
C
3293 lines
97 KiB
C
/*
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** 2011-08-26
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** NORMAL DATABASE FILE FORMAT
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**
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** The following database file format concepts are used by the code in
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** this file to read and write the database file.
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**
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** Pages:
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**
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** A database file is divided into pages. The first 8KB of the file consists
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** of two 4KB meta-pages. The meta-page size is not configurable. The
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** remainder of the file is made up of database pages. The default database
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** page size is 4KB. Database pages are aligned to page-size boundaries,
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** so if the database page size is larger than 8KB there is a gap between
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** the end of the meta pages and the start of the database pages.
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**
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** Database pages are numbered based on their position in the file. Page N
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** begins at byte offset ((N-1)*pgsz). This means that page 1 does not
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** exist - since it would always overlap with the meta pages. If the
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** page-size is (say) 512 bytes, then the first usable page in the database
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** is page 33.
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**
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** It is assumed that the first two meta pages and the data that follows
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** them are located on different disk sectors. So that if a power failure
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** while writing to a meta page there is no risk of damage to the other
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** meta page or any other part of the database file. TODO: This may need
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** to be revisited.
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**
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** Blocks:
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**
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** The database file is also divided into blocks. The default block size is
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** 1MB. When writing to the database file, an attempt is made to write data
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** in contiguous block-sized chunks.
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**
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** The first and last page on each block are special in that they are 4
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** bytes smaller than all other pages. This is because the last four bytes
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** of space on the first and last pages of each block are reserved for
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** pointers to other blocks (i.e. a 32-bit block number).
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**
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** Runs:
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**
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** A run is a sequence of pages that the upper layer uses to store a
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** sorted array of database keys (and accompanying data - values, FC
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** pointers and so on). Given a page within a run, it is possible to
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** navigate to the next page in the run as follows:
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**
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** a) if the current page is not the last in a block, the next page
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** in the run is located immediately after the current page, OR
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**
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** b) if the current page is the last page in a block, the next page
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** in the run is the first page on the block identified by the
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** block pointer stored in the last 4 bytes of the current block.
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**
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** It is possible to navigate to the previous page in a similar fashion,
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** using the block pointer embedded in the last 4 bytes of the first page
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** of each block as required.
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**
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** The upper layer is responsible for identifying by page number the
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** first and last page of any run that it needs to navigate - there are
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** no "end-of-run" markers stored or identified by this layer. This is
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** necessary as clients reading different database snapshots may access
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** different subsets of a run.
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**
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** THE LOG FILE
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**
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** This file opens and closes the log file. But it does not contain any
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** logic related to the log file format. Instead, it exports the following
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** functions that are used by the code in lsm_log.c to read and write the
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** log file:
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**
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** lsmFsOpenLog
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** lsmFsWriteLog
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** lsmFsSyncLog
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** lsmFsReadLog
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** lsmFsTruncateLog
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** lsmFsCloseAndDeleteLog
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**
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** COMPRESSED DATABASE FILE FORMAT
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**
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** The compressed database file format is very similar to the normal format.
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** The file still begins with two 4KB meta-pages (which are never compressed).
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** It is still divided into blocks.
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**
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** The first and last four bytes of each block are reserved for 32-bit
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** pointer values. Similar to the way four bytes are carved from the end of
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** the first and last page of each block in uncompressed databases. From
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** the point of view of the upper layer, all pages are the same size - this
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** is different from the uncompressed format where the first and last pages
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** on each block are 4 bytes smaller than the others.
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**
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** Pages are stored in variable length compressed form, as follows:
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**
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** * 3-byte size field containing the size of the compressed page image
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** in bytes. The most significant bit of each byte of the size field
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** is always set. The remaining 7 bits are used to store a 21-bit
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** integer value (in big-endian order - the first byte in the field
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** contains the most significant 7 bits). Since the maximum allowed
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** size of a compressed page image is (2^17 - 1) bytes, there are
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** actually 4 unused bits in the size field.
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**
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** In other words, if the size of the compressed page image is nSz,
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** the header can be serialized as follows:
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**
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** u8 aHdr[3]
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** aHdr[0] = 0x80 | (u8)(nSz >> 14);
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** aHdr[1] = 0x80 | (u8)(nSz >> 7);
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** aHdr[2] = 0x80 | (u8)(nSz >> 0);
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**
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** * Compressed page image.
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**
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** * A second copy of the 3-byte record header.
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**
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** A page number is a byte offset into the database file. So the smallest
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** possible page number is 8192 (immediately after the two meta-pages).
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** The first and root page of a segment are identified by a page number
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** corresponding to the byte offset of the first byte in the corresponding
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** page record. The last page of a segment is identified by the byte offset
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** of the last byte in its record.
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**
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** Unlike uncompressed pages, compressed page records may span blocks.
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**
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** Sometimes, in order to avoid touching sectors that contain synced data
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** when writing, it is necessary to insert unused space between compressed
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** page records. This can be done as follows:
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**
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** * For less than 6 bytes of empty space, the first and last byte
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** of the free space contain the total number of free bytes. For
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** example:
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**
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** Block of 4 free bytes: 0x04 0x?? 0x?? 0x04
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** Block of 2 free bytes: 0x02 0x02
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** A single free byte: 0x01
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**
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** * For 6 or more bytes of empty space, a record similar to a
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** compressed page record is added to the segment. A padding record
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** is distinguished from a compressed page record by the most
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** significant bit of the second byte of the size field, which is
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** cleared instead of set.
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*/
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#include "lsmInt.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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/*
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** File-system object. Each database connection allocates a single instance
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** of the following structure. It is used for all access to the database and
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** log files.
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**
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** The database file may be accessed via two methods - using mmap() or using
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** read() and write() calls. In the general case both methods are used - a
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** prefix of the file is mapped into memory and the remainder accessed using
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** read() and write(). This is helpful when accessing very large files (or
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** files that may grow very large during the lifetime of a database
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** connection) on systems with 32-bit address spaces. However, it also requires
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** that this object manage two distinct types of Page objects simultaneously -
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** those that carry pointers to the mapped file and those that carry arrays
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** populated by read() calls.
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**
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** pFree:
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** The head of a singly-linked list that containing currently unused Page
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** structures suitable for use as mmap-page handles. Connected by the
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** Page.pFreeNext pointers.
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**
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** pMapped:
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** The head of a singly-linked list that contains all pages that currently
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** carry pointers to the mapped region. This is used if the region is
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** every remapped - the pointers carried by existing pages can be adjusted
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** to account for the remapping. Connected by the Page.pMappedNext pointers.
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**
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** pWaiting:
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** When the upper layer wishes to append a new b-tree page to a segment,
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** it allocates a Page object that carries a malloc'd block of memory -
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** regardless of the mmap-related configuration. The page is not assigned
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** a page number at first. When the upper layer has finished constructing
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** the page contents, it calls lsmFsPagePersist() to assign a page number
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** to it. At this point it is likely that N pages have been written to the
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** segment, the (N+1)th page is still outstanding and the b-tree page is
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** assigned page number (N+2). To avoid writing page (N+2) before page
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** (N+1), the recently completed b-tree page is held in the singly linked
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** list headed by pWaiting until page (N+1) has been written.
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**
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** Function lsmFsFlushWaiting() is responsible for eventually writing
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** waiting pages to disk.
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**
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** apHash/nHash:
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** Hash table used to store all Page objects that carry malloc'd arrays,
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** except those b-tree pages that have not yet been assigned page numbers.
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** Once they have been assigned page numbers - they are added to this
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** hash table.
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**
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** Hash table overflow chains are connected using the Page.pHashNext
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** pointers.
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**
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** pLruFirst, pLruLast:
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** The first and last entries in a doubly-linked list of pages. This
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** list contains all pages with malloc'd data that are present in the
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** hash table and have a ref-count of zero.
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*/
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struct FileSystem {
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lsm_db *pDb; /* Database handle that owns this object */
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lsm_env *pEnv; /* Environment pointer */
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char *zDb; /* Database file name */
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char *zLog; /* Database file name */
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int nMetasize; /* Size of meta pages in bytes */
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int nPagesize; /* Database page-size in bytes */
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int nBlocksize; /* Database block-size in bytes */
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/* r/w file descriptors for both files. */
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LsmFile *pLsmFile; /* Used after lsm_close() to link into list */
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lsm_file *fdDb; /* Database file */
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lsm_file *fdLog; /* Log file */
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int szSector; /* Database file sector size */
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/* If this is a compressed database, a pointer to the compression methods.
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** For an uncompressed database, a NULL pointer. */
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lsm_compress *pCompress;
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u8 *aIBuffer; /* Buffer to compress to */
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u8 *aOBuffer; /* Buffer to uncompress from */
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int nBuffer; /* Allocated size of above buffers in bytes */
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/* mmap() page related things */
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i64 nMapLimit; /* Maximum bytes of file to map */
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void *pMap; /* Current mapping of database file */
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i64 nMap; /* Bytes mapped at pMap */
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Page *pFree; /* Unused Page structures */
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Page *pMapped; /* List of Page structs that point to pMap */
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/* Page cache parameters for non-mmap() pages */
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int nCacheMax; /* Configured cache size (in pages) */
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int nCacheAlloc; /* Current cache size (in pages) */
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Page *pLruFirst; /* Head of the LRU list */
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Page *pLruLast; /* Tail of the LRU list */
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int nHash; /* Number of hash slots in hash table */
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Page **apHash; /* nHash Hash slots */
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Page *pWaiting; /* b-tree pages waiting to be written */
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/* Statistics */
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int nOut; /* Number of outstanding pages */
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int nWrite; /* Total number of pages written */
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int nRead; /* Total number of pages read */
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};
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/*
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** Database page handle.
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**
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** pSeg:
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** When lsmFsSortedAppend() is called on a compressed database, the new
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** page is not assigned a page number or location in the database file
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** immediately. Instead, these are assigned by the lsmFsPagePersist() call
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** right before it writes the compressed page image to disk.
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**
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** The lsmFsSortedAppend() function sets the pSeg pointer to point to the
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** segment that the new page will be a part of. It is unset by
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** lsmFsPagePersist() after the page is written to disk.
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*/
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struct Page {
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u8 *aData; /* Buffer containing page data */
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int nData; /* Bytes of usable data at aData[] */
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Pgno iPg; /* Page number */
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int nRef; /* Number of outstanding references */
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int flags; /* Combination of PAGE_XXX flags */
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Page *pHashNext; /* Next page in hash table slot */
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Page *pLruNext; /* Next page in LRU list */
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Page *pLruPrev; /* Previous page in LRU list */
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FileSystem *pFS; /* File system that owns this page */
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/* Only used in compressed database mode: */
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int nCompress; /* Compressed size (or 0 for uncomp. db) */
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int nCompressPrev; /* Compressed size of prev page */
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Segment *pSeg; /* Segment this page will be written to */
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/* Pointers for singly linked lists */
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Page *pWaitingNext; /* Next page in FileSystem.pWaiting list */
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Page *pFreeNext; /* Next page in FileSystem.pFree list */
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Page *pMappedNext; /* Next page in FileSystem.pMapped list */
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};
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/*
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** Meta-data page handle. There are two meta-data pages at the start of
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** the database file, each FileSystem.nMetasize bytes in size.
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*/
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struct MetaPage {
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int iPg; /* Either 1 or 2 */
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int bWrite; /* Write back to db file on release */
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u8 *aData; /* Pointer to buffer */
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FileSystem *pFS; /* FileSystem that owns this page */
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};
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/*
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** Values for LsmPage.flags
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*/
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#define PAGE_DIRTY 0x00000001 /* Set if page is dirty */
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#define PAGE_FREE 0x00000002 /* Set if Page.aData requires lsmFree() */
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#define PAGE_HASPREV 0x00000004 /* Set if page is first on uncomp. block */
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/*
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** Number of pgsz byte pages omitted from the start of block 1. The start
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** of block 1 contains two 4096 byte meta pages (8192 bytes in total).
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*/
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#define BLOCK1_HDR_SIZE(pgsz) LSM_MAX(1, 8192/(pgsz))
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/*
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** If NDEBUG is not defined, set a breakpoint in function lsmIoerrBkpt()
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** to catch IO errors (any error returned by a VFS method).
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*/
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#ifndef NDEBUG
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static void lsmIoerrBkpt(){
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static int nErr = 0;
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nErr++;
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}
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static int IOERR_WRAPPER(int rc){
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if( rc!=LSM_OK ) lsmIoerrBkpt();
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return rc;
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}
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#else
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# define IOERR_WRAPPER(rc) (rc)
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#endif
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#ifdef NDEBUG
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# define assert_lists_are_ok(x)
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#else
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static Page *fsPageFindInHash(FileSystem *pFS, Pgno iPg, int *piHash);
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static void assert_lists_are_ok(FileSystem *pFS){
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#if 0
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Page *p;
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assert( pFS->nMapLimit>=0 );
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/* Check that all pages in the LRU list have nRef==0, pointers to buffers
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** in heap memory, and corresponding entries in the hash table. */
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for(p=pFS->pLruFirst; p; p=p->pLruNext){
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assert( p==pFS->pLruFirst || p->pLruPrev!=0 );
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assert( p==pFS->pLruLast || p->pLruNext!=0 );
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assert( p->pLruPrev==0 || p->pLruPrev->pLruNext==p );
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assert( p->pLruNext==0 || p->pLruNext->pLruPrev==p );
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assert( p->nRef==0 );
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assert( p->flags & PAGE_FREE );
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assert( p==fsPageFindInHash(pFS, p->iPg, 0) );
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}
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#endif
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}
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#endif
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/*
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** Wrappers around the VFS methods of the lsm_env object:
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**
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** lsmEnvOpen()
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** lsmEnvRead()
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** lsmEnvWrite()
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** lsmEnvSync()
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** lsmEnvSectorSize()
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** lsmEnvClose()
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** lsmEnvTruncate()
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** lsmEnvUnlink()
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** lsmEnvRemap()
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*/
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int lsmEnvOpen(lsm_env *pEnv, const char *zFile, int flags, lsm_file **ppNew){
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return pEnv->xOpen(pEnv, zFile, flags, ppNew);
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}
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static int lsmEnvRead(
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lsm_env *pEnv,
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lsm_file *pFile,
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lsm_i64 iOff,
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void *pRead,
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int nRead
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){
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return IOERR_WRAPPER( pEnv->xRead(pFile, iOff, pRead, nRead) );
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}
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static int lsmEnvWrite(
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lsm_env *pEnv,
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lsm_file *pFile,
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lsm_i64 iOff,
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const void *pWrite,
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int nWrite
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){
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return IOERR_WRAPPER( pEnv->xWrite(pFile, iOff, (void *)pWrite, nWrite) );
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}
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static int lsmEnvSync(lsm_env *pEnv, lsm_file *pFile){
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return IOERR_WRAPPER( pEnv->xSync(pFile) );
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}
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static int lsmEnvSectorSize(lsm_env *pEnv, lsm_file *pFile){
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return pEnv->xSectorSize(pFile);
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}
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int lsmEnvClose(lsm_env *pEnv, lsm_file *pFile){
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return IOERR_WRAPPER( pEnv->xClose(pFile) );
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}
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static int lsmEnvTruncate(lsm_env *pEnv, lsm_file *pFile, lsm_i64 nByte){
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return IOERR_WRAPPER( pEnv->xTruncate(pFile, nByte) );
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}
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static int lsmEnvUnlink(lsm_env *pEnv, const char *zDel){
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return IOERR_WRAPPER( pEnv->xUnlink(pEnv, zDel) );
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}
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static int lsmEnvRemap(
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lsm_env *pEnv,
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lsm_file *pFile,
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i64 szMin,
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void **ppMap,
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i64 *pszMap
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){
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return pEnv->xRemap(pFile, szMin, ppMap, pszMap);
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}
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int lsmEnvLock(lsm_env *pEnv, lsm_file *pFile, int iLock, int eLock){
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if( pFile==0 ) return LSM_OK;
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return pEnv->xLock(pFile, iLock, eLock);
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}
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int lsmEnvTestLock(
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lsm_env *pEnv,
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lsm_file *pFile,
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int iLock,
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int nLock,
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int eLock
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){
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return pEnv->xTestLock(pFile, iLock, nLock, eLock);
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}
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int lsmEnvShmMap(
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lsm_env *pEnv,
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lsm_file *pFile,
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int iChunk,
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int sz,
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void **ppOut
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){
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return pEnv->xShmMap(pFile, iChunk, sz, ppOut);
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}
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void lsmEnvShmBarrier(lsm_env *pEnv){
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return pEnv->xShmBarrier();
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}
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void lsmEnvShmUnmap(lsm_env *pEnv, lsm_file *pFile, int bDel){
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pEnv->xShmUnmap(pFile, bDel);
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}
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void lsmEnvSleep(lsm_env *pEnv, int nUs){
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pEnv->xSleep(pEnv, nUs);
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}
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/*
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** Write the contents of string buffer pStr into the log file, starting at
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** offset iOff.
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*/
|
|
int lsmFsWriteLog(FileSystem *pFS, i64 iOff, LsmString *pStr){
|
|
assert( pFS->fdLog );
|
|
return lsmEnvWrite(pFS->pEnv, pFS->fdLog, iOff, pStr->z, pStr->n);
|
|
}
|
|
|
|
/*
|
|
** fsync() the log file.
|
|
*/
|
|
int lsmFsSyncLog(FileSystem *pFS){
|
|
assert( pFS->fdLog );
|
|
return lsmEnvSync(pFS->pEnv, pFS->fdLog);
|
|
}
|
|
|
|
/*
|
|
** Read nRead bytes of data starting at offset iOff of the log file. Append
|
|
** the results to string buffer pStr.
|
|
*/
|
|
int lsmFsReadLog(FileSystem *pFS, i64 iOff, int nRead, LsmString *pStr){
|
|
int rc; /* Return code */
|
|
assert( pFS->fdLog );
|
|
rc = lsmStringExtend(pStr, nRead);
|
|
if( rc==LSM_OK ){
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdLog, iOff, &pStr->z[pStr->n], nRead);
|
|
pStr->n += nRead;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Truncate the log file to nByte bytes in size.
|
|
*/
|
|
int lsmFsTruncateLog(FileSystem *pFS, i64 nByte){
|
|
if( pFS->fdLog==0 ) return LSM_OK;
|
|
return lsmEnvTruncate(pFS->pEnv, pFS->fdLog, nByte);
|
|
}
|
|
|
|
/*
|
|
** Truncate the db file to nByte bytes in size.
|
|
*/
|
|
int lsmFsTruncateDb(FileSystem *pFS, i64 nByte){
|
|
if( pFS->fdDb==0 ) return LSM_OK;
|
|
return lsmEnvTruncate(pFS->pEnv, pFS->fdDb, nByte);
|
|
}
|
|
|
|
/*
|
|
** Close the log file. Then delete it from the file-system. This function
|
|
** is called during database shutdown only.
|
|
*/
|
|
int lsmFsCloseAndDeleteLog(FileSystem *pFS){
|
|
char *zDel;
|
|
|
|
if( pFS->fdLog ){
|
|
lsmEnvClose(pFS->pEnv, pFS->fdLog );
|
|
pFS->fdLog = 0;
|
|
}
|
|
|
|
zDel = lsmMallocPrintf(pFS->pEnv, "%s-log", pFS->zDb);
|
|
if( zDel ){
|
|
lsmEnvUnlink(pFS->pEnv, zDel);
|
|
lsmFree(pFS->pEnv, zDel);
|
|
}
|
|
return LSM_OK;
|
|
}
|
|
|
|
/*
|
|
** Return true if page iReal of the database should be accessed using mmap.
|
|
** False otherwise.
|
|
*/
|
|
static int fsMmapPage(FileSystem *pFS, Pgno iReal){
|
|
return ((i64)iReal*pFS->nPagesize <= pFS->nMapLimit);
|
|
}
|
|
|
|
/*
|
|
** Given that there are currently nHash slots in the hash table, return
|
|
** the hash key for file iFile, page iPg.
|
|
*/
|
|
static int fsHashKey(int nHash, int iPg){
|
|
return (iPg % nHash);
|
|
}
|
|
|
|
/*
|
|
** This is a helper function for lsmFsOpen(). It opens a single file on
|
|
** disk (either the database or log file).
|
|
*/
|
|
static lsm_file *fsOpenFile(
|
|
FileSystem *pFS, /* File system object */
|
|
int bReadonly, /* True to open this file read-only */
|
|
int bLog, /* True for log, false for db */
|
|
int *pRc /* IN/OUT: Error code */
|
|
){
|
|
lsm_file *pFile = 0;
|
|
if( *pRc==LSM_OK ){
|
|
int flags = (bReadonly ? LSM_OPEN_READONLY : 0);
|
|
const char *zPath = (bLog ? pFS->zLog : pFS->zDb);
|
|
|
|
*pRc = lsmEnvOpen(pFS->pEnv, zPath, flags, &pFile);
|
|
}
|
|
return pFile;
|
|
}
|
|
|
|
/*
|
|
** If it is not already open, this function opens the log file. It returns
|
|
** LSM_OK if successful (or if the log file was already open) or an LSM
|
|
** error code otherwise.
|
|
**
|
|
** The log file must be opened before any of the following may be called:
|
|
**
|
|
** lsmFsWriteLog
|
|
** lsmFsSyncLog
|
|
** lsmFsReadLog
|
|
*/
|
|
int lsmFsOpenLog(lsm_db *db, int *pbOpen){
|
|
int rc = LSM_OK;
|
|
FileSystem *pFS = db->pFS;
|
|
|
|
if( 0==pFS->fdLog ){
|
|
pFS->fdLog = fsOpenFile(pFS, db->bReadonly, 1, &rc);
|
|
|
|
if( rc==LSM_IOERR_NOENT && db->bReadonly ){
|
|
rc = LSM_OK;
|
|
}
|
|
}
|
|
|
|
if( pbOpen ) *pbOpen = (pFS->fdLog!=0);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Close the log file, if it is open.
|
|
*/
|
|
void lsmFsCloseLog(lsm_db *db){
|
|
FileSystem *pFS = db->pFS;
|
|
if( pFS->fdLog ){
|
|
lsmEnvClose(pFS->pEnv, pFS->fdLog);
|
|
pFS->fdLog = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Open a connection to a database stored within the file-system.
|
|
**
|
|
** If parameter bReadonly is true, then open a read-only file-descriptor
|
|
** on the database file. It is possible that bReadonly will be false even
|
|
** if the user requested that pDb be opened read-only. This is because the
|
|
** file-descriptor may later on be recycled by a read-write connection.
|
|
** If the db file can be opened for read-write access, it always is. Parameter
|
|
** bReadonly is only ever true if it has already been determined that the
|
|
** db can only be opened for read-only access.
|
|
**
|
|
** Return LSM_OK if successful or an lsm error code otherwise.
|
|
*/
|
|
int lsmFsOpen(
|
|
lsm_db *pDb, /* Database connection to open fd for */
|
|
const char *zDb, /* Full path to database file */
|
|
int bReadonly /* True to open db file read-only */
|
|
){
|
|
FileSystem *pFS;
|
|
int rc = LSM_OK;
|
|
int nDb = strlen(zDb);
|
|
int nByte;
|
|
|
|
assert( pDb->pFS==0 );
|
|
assert( pDb->pWorker==0 && pDb->pClient==0 );
|
|
|
|
nByte = sizeof(FileSystem) + nDb+1 + nDb+4+1;
|
|
pFS = (FileSystem *)lsmMallocZeroRc(pDb->pEnv, nByte, &rc);
|
|
if( pFS ){
|
|
LsmFile *pLsmFile;
|
|
pFS->zDb = (char *)&pFS[1];
|
|
pFS->zLog = &pFS->zDb[nDb+1];
|
|
pFS->nPagesize = LSM_DFLT_PAGE_SIZE;
|
|
pFS->nBlocksize = LSM_DFLT_BLOCK_SIZE;
|
|
pFS->nMetasize = 4 * 1024;
|
|
pFS->pDb = pDb;
|
|
pFS->pEnv = pDb->pEnv;
|
|
|
|
/* Make a copy of the database and log file names. */
|
|
memcpy(pFS->zDb, zDb, nDb+1);
|
|
memcpy(pFS->zLog, zDb, nDb);
|
|
memcpy(&pFS->zLog[nDb], "-log", 5);
|
|
|
|
/* Allocate the hash-table here. At some point, it should be changed
|
|
** so that it can grow dynamicly. */
|
|
pFS->nCacheMax = 2048*1024 / pFS->nPagesize;
|
|
pFS->nHash = 4096;
|
|
pFS->apHash = lsmMallocZeroRc(pDb->pEnv, sizeof(Page *) * pFS->nHash, &rc);
|
|
|
|
/* Open the database file */
|
|
pLsmFile = lsmDbRecycleFd(pDb);
|
|
if( pLsmFile ){
|
|
pFS->pLsmFile = pLsmFile;
|
|
pFS->fdDb = pLsmFile->pFile;
|
|
memset(pLsmFile, 0, sizeof(LsmFile));
|
|
}else{
|
|
pFS->pLsmFile = lsmMallocZeroRc(pDb->pEnv, sizeof(LsmFile), &rc);
|
|
if( rc==LSM_OK ){
|
|
pFS->fdDb = fsOpenFile(pFS, bReadonly, 0, &rc);
|
|
}
|
|
}
|
|
|
|
if( rc!=LSM_OK ){
|
|
lsmFsClose(pFS);
|
|
pFS = 0;
|
|
}else{
|
|
pFS->szSector = lsmEnvSectorSize(pFS->pEnv, pFS->fdDb);
|
|
}
|
|
}
|
|
|
|
pDb->pFS = pFS;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Configure the file-system object according to the current values of
|
|
** the LSM_CONFIG_MMAP and LSM_CONFIG_SET_COMPRESSION options.
|
|
*/
|
|
int lsmFsConfigure(lsm_db *db){
|
|
FileSystem *pFS = db->pFS;
|
|
if( pFS ){
|
|
lsm_env *pEnv = pFS->pEnv;
|
|
Page *pPg;
|
|
|
|
assert( pFS->nOut==0 );
|
|
assert( pFS->pWaiting==0 );
|
|
assert( pFS->pMapped==0 );
|
|
|
|
/* Reset any compression/decompression buffers already allocated */
|
|
lsmFree(pEnv, pFS->aIBuffer);
|
|
lsmFree(pEnv, pFS->aOBuffer);
|
|
pFS->nBuffer = 0;
|
|
|
|
/* Unmap the file, if it is currently mapped */
|
|
if( pFS->pMap ){
|
|
lsmEnvRemap(pEnv, pFS->fdDb, -1, &pFS->pMap, &pFS->nMap);
|
|
pFS->nMapLimit = 0;
|
|
}
|
|
|
|
/* Free all allocated page structures */
|
|
pPg = pFS->pLruFirst;
|
|
while( pPg ){
|
|
Page *pNext = pPg->pLruNext;
|
|
assert( pPg->flags & PAGE_FREE );
|
|
lsmFree(pEnv, pPg->aData);
|
|
lsmFree(pEnv, pPg);
|
|
pPg = pNext;
|
|
}
|
|
|
|
pPg = pFS->pFree;
|
|
while( pPg ){
|
|
Page *pNext = pPg->pFreeNext;
|
|
lsmFree(pEnv, pPg);
|
|
pPg = pNext;
|
|
}
|
|
|
|
/* Zero pointers that point to deleted page objects */
|
|
pFS->nCacheAlloc = 0;
|
|
pFS->pLruFirst = 0;
|
|
pFS->pLruLast = 0;
|
|
pFS->pFree = 0;
|
|
if( pFS->apHash ){
|
|
memset(pFS->apHash, 0, pFS->nHash*sizeof(pFS->apHash[0]));
|
|
}
|
|
|
|
/* Configure the FileSystem object */
|
|
if( db->compress.xCompress ){
|
|
pFS->pCompress = &db->compress;
|
|
pFS->nMapLimit = 0;
|
|
}else{
|
|
pFS->pCompress = 0;
|
|
if( db->iMmap==1 ){
|
|
/* Unlimited */
|
|
pFS->nMapLimit = (i64)1 << 60;
|
|
}else{
|
|
/* iMmap is a limit in KB. Set nMapLimit to the same value in bytes. */
|
|
pFS->nMapLimit = (i64)db->iMmap * 1024;
|
|
}
|
|
}
|
|
}
|
|
|
|
return LSM_OK;
|
|
}
|
|
|
|
/*
|
|
** Close and destroy a FileSystem object.
|
|
*/
|
|
void lsmFsClose(FileSystem *pFS){
|
|
if( pFS ){
|
|
Page *pPg;
|
|
lsm_env *pEnv = pFS->pEnv;
|
|
|
|
assert( pFS->nOut==0 );
|
|
pPg = pFS->pLruFirst;
|
|
while( pPg ){
|
|
Page *pNext = pPg->pLruNext;
|
|
if( pPg->flags & PAGE_FREE ) lsmFree(pEnv, pPg->aData);
|
|
lsmFree(pEnv, pPg);
|
|
pPg = pNext;
|
|
}
|
|
|
|
pPg = pFS->pFree;
|
|
while( pPg ){
|
|
Page *pNext = pPg->pFreeNext;
|
|
if( pPg->flags & PAGE_FREE ) lsmFree(pEnv, pPg->aData);
|
|
lsmFree(pEnv, pPg);
|
|
pPg = pNext;
|
|
}
|
|
|
|
if( pFS->fdDb ) lsmEnvClose(pFS->pEnv, pFS->fdDb );
|
|
if( pFS->fdLog ) lsmEnvClose(pFS->pEnv, pFS->fdLog );
|
|
lsmFree(pEnv, pFS->pLsmFile);
|
|
lsmFree(pEnv, pFS->apHash);
|
|
lsmFree(pEnv, pFS->aIBuffer);
|
|
lsmFree(pEnv, pFS->aOBuffer);
|
|
lsmFree(pEnv, pFS);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This function is called when closing a database handle (i.e. lsm_close())
|
|
** if there exist other connections to the same database within this process.
|
|
** In that case the file-descriptor open on the database file is not closed
|
|
** when the FileSystem object is destroyed, as this would cause any POSIX
|
|
** locks held by the other connections to be silently dropped (see "man close"
|
|
** for details). Instead, the file-descriptor is stored in a list by the
|
|
** lsm_shared.c module until it is either closed or reused.
|
|
**
|
|
** This function returns a pointer to an object that can be linked into
|
|
** the list described above. The returned object now 'owns' the database
|
|
** file descriptr, so that when the FileSystem object is destroyed, it
|
|
** will not be closed.
|
|
**
|
|
** This function may be called at most once in the life-time of a
|
|
** FileSystem object. The results of any operations involving the database
|
|
** file descriptor are undefined once this function has been called.
|
|
**
|
|
** None of this is necessary on non-POSIX systems. But we do it anyway in
|
|
** the name of using as similar code as possible on all platforms.
|
|
*/
|
|
LsmFile *lsmFsDeferClose(FileSystem *pFS){
|
|
LsmFile *p = pFS->pLsmFile;
|
|
assert( p->pNext==0 );
|
|
p->pFile = pFS->fdDb;
|
|
pFS->fdDb = 0;
|
|
pFS->pLsmFile = 0;
|
|
return p;
|
|
}
|
|
|
|
/*
|
|
** Allocate a buffer and populate it with the output of the xFileid()
|
|
** method of the database file handle. If successful, set *ppId to point
|
|
** to the buffer and *pnId to the number of bytes in the buffer and return
|
|
** LSM_OK. Otherwise, set *ppId and *pnId to zero and return an LSM
|
|
** error code.
|
|
*/
|
|
int lsmFsFileid(lsm_db *pDb, void **ppId, int *pnId){
|
|
lsm_env *pEnv = pDb->pEnv;
|
|
FileSystem *pFS = pDb->pFS;
|
|
int rc;
|
|
int nId = 0;
|
|
void *pId;
|
|
|
|
rc = pEnv->xFileid(pFS->fdDb, 0, &nId);
|
|
pId = lsmMallocZeroRc(pEnv, nId, &rc);
|
|
if( rc==LSM_OK ) rc = pEnv->xFileid(pFS->fdDb, pId, &nId);
|
|
|
|
if( rc!=LSM_OK ){
|
|
lsmFree(pEnv, pId);
|
|
pId = 0;
|
|
nId = 0;
|
|
}
|
|
|
|
*ppId = pId;
|
|
*pnId = nId;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the nominal page-size used by this file-system. Actual pages
|
|
** may be smaller or larger than this value.
|
|
*/
|
|
int lsmFsPageSize(FileSystem *pFS){
|
|
return pFS->nPagesize;
|
|
}
|
|
|
|
/*
|
|
** Return the block-size used by this file-system.
|
|
*/
|
|
int lsmFsBlockSize(FileSystem *pFS){
|
|
return pFS->nBlocksize;
|
|
}
|
|
|
|
/*
|
|
** Configure the nominal page-size used by this file-system. Actual
|
|
** pages may be smaller or larger than this value.
|
|
*/
|
|
void lsmFsSetPageSize(FileSystem *pFS, int nPgsz){
|
|
pFS->nPagesize = nPgsz;
|
|
pFS->nCacheMax = 2048*1024 / pFS->nPagesize;
|
|
}
|
|
|
|
/*
|
|
** Configure the block-size used by this file-system.
|
|
*/
|
|
void lsmFsSetBlockSize(FileSystem *pFS, int nBlocksize){
|
|
pFS->nBlocksize = nBlocksize;
|
|
}
|
|
|
|
/*
|
|
** Return the page number of the first page on block iBlock. Blocks are
|
|
** numbered starting from 1.
|
|
**
|
|
** For a compressed database, page numbers are byte offsets. The first
|
|
** page on each block is the byte offset immediately following the 4-byte
|
|
** "previous block" pointer at the start of each block.
|
|
*/
|
|
static Pgno fsFirstPageOnBlock(FileSystem *pFS, int iBlock){
|
|
Pgno iPg;
|
|
if( pFS->pCompress ){
|
|
if( iBlock==1 ){
|
|
iPg = pFS->nMetasize * 2 + 4;
|
|
}else{
|
|
iPg = pFS->nBlocksize * (Pgno)(iBlock-1) + 4;
|
|
}
|
|
}else{
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
if( iBlock==1 ){
|
|
iPg = 1 + ((pFS->nMetasize*2 + pFS->nPagesize - 1) / pFS->nPagesize);
|
|
}else{
|
|
iPg = 1 + (iBlock-1) * nPagePerBlock;
|
|
}
|
|
}
|
|
return iPg;
|
|
}
|
|
|
|
/*
|
|
** Return the page number of the last page on block iBlock. Blocks are
|
|
** numbered starting from 1.
|
|
**
|
|
** For a compressed database, page numbers are byte offsets. The first
|
|
** page on each block is the byte offset of the byte immediately before
|
|
** the 4-byte "next block" pointer at the end of each block.
|
|
*/
|
|
static Pgno fsLastPageOnBlock(FileSystem *pFS, int iBlock){
|
|
if( pFS->pCompress ){
|
|
return pFS->nBlocksize * (Pgno)iBlock - 1 - 4;
|
|
}else{
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
return iBlock * nPagePerBlock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Return the block number of the block that page iPg is located on.
|
|
** Blocks are numbered starting from 1.
|
|
*/
|
|
static int fsPageToBlock(FileSystem *pFS, Pgno iPg){
|
|
if( pFS->pCompress ){
|
|
return (iPg / pFS->nBlocksize) + 1;
|
|
}else{
|
|
return 1 + ((iPg-1) / (pFS->nBlocksize / pFS->nPagesize));
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Return true if page iPg is the last page on its block.
|
|
**
|
|
** This function is only called in non-compressed database mode.
|
|
*/
|
|
static int fsIsLast(FileSystem *pFS, Pgno iPg){
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
assert( !pFS->pCompress );
|
|
return ( iPg && (iPg % nPagePerBlock)==0 );
|
|
}
|
|
|
|
/*
|
|
** Return true if page iPg is the first page on its block.
|
|
**
|
|
** This function is only called in non-compressed database mode.
|
|
*/
|
|
static int fsIsFirst(FileSystem *pFS, Pgno iPg){
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
assert( !pFS->pCompress );
|
|
return ( (iPg % nPagePerBlock)==1
|
|
|| (iPg<nPagePerBlock && iPg==fsFirstPageOnBlock(pFS, 1))
|
|
);
|
|
}
|
|
|
|
/*
|
|
** Given a page reference, return a pointer to the buffer containing the
|
|
** pages contents. If parameter pnData is not NULL, set *pnData to the size
|
|
** of the buffer in bytes before returning.
|
|
*/
|
|
u8 *lsmFsPageData(Page *pPage, int *pnData){
|
|
if( pnData ){
|
|
*pnData = pPage->nData;
|
|
}
|
|
return pPage->aData;
|
|
}
|
|
|
|
/*
|
|
** Return the page number of a page.
|
|
*/
|
|
Pgno lsmFsPageNumber(Page *pPage){
|
|
/* assert( (pPage->flags & PAGE_DIRTY)==0 ); */
|
|
return pPage ? pPage->iPg : 0;
|
|
}
|
|
|
|
/*
|
|
** Page pPg is currently part of the LRU list belonging to pFS. Remove
|
|
** it from the list. pPg->pLruNext and pPg->pLruPrev are cleared by this
|
|
** operation.
|
|
*/
|
|
static void fsPageRemoveFromLru(FileSystem *pFS, Page *pPg){
|
|
assert( pPg->pLruNext || pPg==pFS->pLruLast );
|
|
assert( pPg->pLruPrev || pPg==pFS->pLruFirst );
|
|
if( pPg->pLruNext ){
|
|
pPg->pLruNext->pLruPrev = pPg->pLruPrev;
|
|
}else{
|
|
pFS->pLruLast = pPg->pLruPrev;
|
|
}
|
|
if( pPg->pLruPrev ){
|
|
pPg->pLruPrev->pLruNext = pPg->pLruNext;
|
|
}else{
|
|
pFS->pLruFirst = pPg->pLruNext;
|
|
}
|
|
pPg->pLruPrev = 0;
|
|
pPg->pLruNext = 0;
|
|
}
|
|
|
|
/*
|
|
** Page pPg is not currently part of the LRU list belonging to pFS. Add it.
|
|
*/
|
|
static void fsPageAddToLru(FileSystem *pFS, Page *pPg){
|
|
assert( pPg->pLruNext==0 && pPg->pLruPrev==0 );
|
|
pPg->pLruPrev = pFS->pLruLast;
|
|
if( pPg->pLruPrev ){
|
|
pPg->pLruPrev->pLruNext = pPg;
|
|
}else{
|
|
pFS->pLruFirst = pPg;
|
|
}
|
|
pFS->pLruLast = pPg;
|
|
}
|
|
|
|
/*
|
|
** Page pPg is currently stored in the apHash/nHash hash table. Remove it.
|
|
*/
|
|
static void fsPageRemoveFromHash(FileSystem *pFS, Page *pPg){
|
|
int iHash;
|
|
Page **pp;
|
|
|
|
iHash = fsHashKey(pFS->nHash, pPg->iPg);
|
|
for(pp=&pFS->apHash[iHash]; *pp!=pPg; pp=&(*pp)->pHashNext);
|
|
*pp = pPg->pHashNext;
|
|
pPg->pHashNext = 0;
|
|
}
|
|
|
|
/*
|
|
** Free a Page object allocated by fsPageBuffer().
|
|
*/
|
|
static void fsPageBufferFree(Page *pPg){
|
|
pPg->pFS->nCacheAlloc--;
|
|
lsmFree(pPg->pFS->pEnv, pPg->aData);
|
|
lsmFree(pPg->pFS->pEnv, pPg);
|
|
}
|
|
|
|
|
|
/*
|
|
** Purge the cache of all non-mmap pages with nRef==0.
|
|
*/
|
|
void lsmFsPurgeCache(FileSystem *pFS){
|
|
Page *pPg;
|
|
|
|
pPg = pFS->pLruFirst;
|
|
while( pPg ){
|
|
Page *pNext = pPg->pLruNext;
|
|
assert( pPg->flags & PAGE_FREE );
|
|
fsPageRemoveFromHash(pFS, pPg);
|
|
fsPageBufferFree(pPg);
|
|
pPg = pNext;
|
|
}
|
|
pFS->pLruFirst = 0;
|
|
pFS->pLruLast = 0;
|
|
|
|
assert( pFS->nCacheAlloc<=pFS->nOut && pFS->nCacheAlloc>=0 );
|
|
}
|
|
|
|
/*
|
|
** Search the hash-table for page iPg. If an entry is round, return a pointer
|
|
** to it. Otherwise, return NULL.
|
|
**
|
|
** Either way, if argument piHash is not NULL set *piHash to the hash slot
|
|
** number that page iPg would be stored in before returning.
|
|
*/
|
|
static Page *fsPageFindInHash(FileSystem *pFS, Pgno iPg, int *piHash){
|
|
Page *p; /* Return value */
|
|
int iHash = fsHashKey(pFS->nHash, iPg);
|
|
|
|
if( piHash ) *piHash = iHash;
|
|
for(p=pFS->apHash[iHash]; p; p=p->pHashNext){
|
|
if( p->iPg==iPg) break;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
/*
|
|
** Allocate and return a non-mmap Page object. If there are already
|
|
** nCacheMax such Page objects outstanding, try to recycle an existing
|
|
** Page instead.
|
|
*/
|
|
static int fsPageBuffer(
|
|
FileSystem *pFS,
|
|
Page **ppOut
|
|
){
|
|
int rc = LSM_OK;
|
|
Page *pPage = 0;
|
|
if( pFS->pLruFirst==0 || pFS->nCacheAlloc<pFS->nCacheMax ){
|
|
/* Allocate a new Page object */
|
|
pPage = lsmMallocZero(pFS->pEnv, sizeof(Page));
|
|
if( !pPage ){
|
|
rc = LSM_NOMEM_BKPT;
|
|
}else{
|
|
pPage->aData = (u8 *)lsmMalloc(pFS->pEnv, pFS->nPagesize);
|
|
if( !pPage->aData ){
|
|
lsmFree(pFS->pEnv, pPage);
|
|
rc = LSM_NOMEM_BKPT;
|
|
pPage = 0;
|
|
}else{
|
|
pFS->nCacheAlloc++;
|
|
}
|
|
}
|
|
}else{
|
|
/* Reuse an existing Page object */
|
|
u8 *aData;
|
|
pPage = pFS->pLruFirst;
|
|
aData = pPage->aData;
|
|
fsPageRemoveFromLru(pFS, pPage);
|
|
fsPageRemoveFromHash(pFS, pPage);
|
|
|
|
memset(pPage, 0, sizeof(Page));
|
|
pPage->aData = aData;
|
|
}
|
|
|
|
if( pPage ){
|
|
pPage->flags = PAGE_FREE;
|
|
}
|
|
*ppOut = pPage;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Assuming *pRc is initially LSM_OK, attempt to ensure that the
|
|
** memory-mapped region is at least iSz bytes in size. If it is not already,
|
|
** iSz bytes in size, extend it and update the pointers associated with any
|
|
** outstanding Page objects.
|
|
**
|
|
** If *pRc is not LSM_OK when this function is called, it is a no-op.
|
|
** Otherwise, *pRc is set to an lsm error code if an error occurs, or
|
|
** left unmodified otherwise.
|
|
**
|
|
** This function is never called in compressed database mode.
|
|
*/
|
|
static void fsGrowMapping(
|
|
FileSystem *pFS, /* File system object */
|
|
i64 iSz, /* Minimum size to extend mapping to */
|
|
int *pRc /* IN/OUT: Error code */
|
|
){
|
|
assert( pFS->pCompress==0 );
|
|
assert( PAGE_HASPREV==4 );
|
|
|
|
if( *pRc==LSM_OK && iSz>pFS->nMap ){
|
|
int rc;
|
|
u8 *aOld = pFS->pMap;
|
|
rc = lsmEnvRemap(pFS->pEnv, pFS->fdDb, iSz, &pFS->pMap, &pFS->nMap);
|
|
if( rc==LSM_OK && pFS->pMap!=aOld ){
|
|
Page *pFix;
|
|
i64 iOff = (u8 *)pFS->pMap - aOld;
|
|
for(pFix=pFS->pMapped; pFix; pFix=pFix->pMappedNext){
|
|
pFix->aData += iOff;
|
|
}
|
|
lsmSortedRemap(pFS->pDb);
|
|
}
|
|
*pRc = rc;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** fsync() the database file.
|
|
*/
|
|
int lsmFsSyncDb(FileSystem *pFS, int nBlock){
|
|
return lsmEnvSync(pFS->pEnv, pFS->fdDb);
|
|
}
|
|
|
|
/*
|
|
** If block iBlk has been redirected according to the redirections in the
|
|
** object passed as the first argument, return the destination block to
|
|
** which it is redirected. Otherwise, return a copy of iBlk.
|
|
*/
|
|
static int fsRedirectBlock(Redirect *p, int iBlk){
|
|
if( p ){
|
|
int i;
|
|
for(i=0; i<p->n; i++){
|
|
if( iBlk==p->a[i].iFrom ) return p->a[i].iTo;
|
|
}
|
|
}
|
|
assert( iBlk!=0 );
|
|
return iBlk;
|
|
}
|
|
|
|
/*
|
|
** If page iPg has been redirected according to the redirections in the
|
|
** object passed as the second argument, return the destination page to
|
|
** which it is redirected. Otherwise, return a copy of iPg.
|
|
*/
|
|
Pgno lsmFsRedirectPage(FileSystem *pFS, Redirect *pRedir, Pgno iPg){
|
|
Pgno iReal = iPg;
|
|
|
|
if( pRedir ){
|
|
const int nPagePerBlock = (
|
|
pFS->pCompress ? pFS->nBlocksize : (pFS->nBlocksize / pFS->nPagesize)
|
|
);
|
|
int iBlk = fsPageToBlock(pFS, iPg);
|
|
int i;
|
|
for(i=0; i<pRedir->n; i++){
|
|
int iFrom = pRedir->a[i].iFrom;
|
|
if( iFrom>iBlk ) break;
|
|
if( iFrom==iBlk ){
|
|
int iTo = pRedir->a[i].iTo;
|
|
iReal = iPg - (Pgno)(iFrom - iTo) * nPagePerBlock;
|
|
if( iTo==1 ){
|
|
iReal += (fsFirstPageOnBlock(pFS, 1)-1);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
assert( iReal!=0 );
|
|
return iReal;
|
|
}
|
|
|
|
/* Required by the circular fsBlockNext<->fsPageGet dependency. */
|
|
static int fsPageGet(FileSystem *, Segment *, Pgno, int, Page **, int *);
|
|
|
|
/*
|
|
** Parameter iBlock is a database file block. This function reads the value
|
|
** stored in the blocks "next block" pointer and stores it in *piNext.
|
|
** LSM_OK is returned if everything is successful, or an LSM error code
|
|
** otherwise.
|
|
*/
|
|
static int fsBlockNext(
|
|
FileSystem *pFS, /* File-system object handle */
|
|
Segment *pSeg, /* Use this segment for block redirects */
|
|
int iBlock, /* Read field from this block */
|
|
int *piNext /* OUT: Next block in linked list */
|
|
){
|
|
int rc;
|
|
int iRead; /* Read block from here */
|
|
|
|
if( pSeg ){
|
|
iRead = fsRedirectBlock(pSeg->pRedirect, iBlock);
|
|
}else{
|
|
iRead = iBlock;
|
|
}
|
|
|
|
assert( pFS->nMapLimit==0 || pFS->pCompress==0 );
|
|
if( pFS->pCompress ){
|
|
i64 iOff; /* File offset to read data from */
|
|
u8 aNext[4]; /* 4-byte pointer read from db file */
|
|
|
|
iOff = (i64)iRead * pFS->nBlocksize - sizeof(aNext);
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aNext, sizeof(aNext));
|
|
if( rc==LSM_OK ){
|
|
*piNext = (int)lsmGetU32(aNext);
|
|
}
|
|
}else{
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
Page *pLast;
|
|
rc = fsPageGet(pFS, 0, iRead*nPagePerBlock, 0, &pLast, 0);
|
|
if( rc==LSM_OK ){
|
|
*piNext = lsmGetU32(&pLast->aData[pFS->nPagesize-4]);
|
|
lsmFsPageRelease(pLast);
|
|
}
|
|
}
|
|
|
|
if( pSeg ){
|
|
*piNext = fsRedirectBlock(pSeg->pRedirect, *piNext);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the page number of the last page on the same block as page iPg.
|
|
*/
|
|
Pgno fsLastPageOnPagesBlock(FileSystem *pFS, Pgno iPg){
|
|
return fsLastPageOnBlock(pFS, fsPageToBlock(pFS, iPg));
|
|
}
|
|
|
|
/*
|
|
** Read nData bytes of data from offset iOff of the database file into
|
|
** buffer aData. If this means reading past the end of a block, follow
|
|
** the block pointer to the next block and continue reading.
|
|
**
|
|
** Offset iOff is an absolute offset - not subject to any block redirection.
|
|
** However any block pointer followed is. Use pSeg->pRedirect in this case.
|
|
**
|
|
** This function is only called in compressed database mode.
|
|
*/
|
|
static int fsReadData(
|
|
FileSystem *pFS, /* File-system handle */
|
|
Segment *pSeg, /* Block redirection */
|
|
i64 iOff, /* Read data from this offset */
|
|
u8 *aData, /* Buffer to read data into */
|
|
int nData /* Number of bytes to read */
|
|
){
|
|
i64 iEob; /* End of block */
|
|
int nRead;
|
|
int rc;
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
iEob = fsLastPageOnPagesBlock(pFS, iOff) + 1;
|
|
nRead = LSM_MIN(iEob - iOff, nData);
|
|
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aData, nRead);
|
|
if( rc==LSM_OK && nRead!=nData ){
|
|
int iBlk;
|
|
|
|
rc = fsBlockNext(pFS, pSeg, fsPageToBlock(pFS, iOff), &iBlk);
|
|
if( rc==LSM_OK ){
|
|
i64 iOff2 = fsFirstPageOnBlock(pFS, iBlk);
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff2, &aData[nRead], nData-nRead);
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Parameter iBlock is a database file block. This function reads the value
|
|
** stored in the blocks "previous block" pointer and stores it in *piPrev.
|
|
** LSM_OK is returned if everything is successful, or an LSM error code
|
|
** otherwise.
|
|
*/
|
|
static int fsBlockPrev(
|
|
FileSystem *pFS, /* File-system object handle */
|
|
Segment *pSeg, /* Use this segment for block redirects */
|
|
int iBlock, /* Read field from this block */
|
|
int *piPrev /* OUT: Previous block in linked list */
|
|
){
|
|
int rc = LSM_OK; /* Return code */
|
|
|
|
assert( pFS->nMapLimit==0 || pFS->pCompress==0 );
|
|
assert( iBlock>0 );
|
|
|
|
if( pFS->pCompress ){
|
|
i64 iOff = fsFirstPageOnBlock(pFS, iBlock) - 4;
|
|
u8 aPrev[4]; /* 4-byte pointer read from db file */
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aPrev, sizeof(aPrev));
|
|
if( rc==LSM_OK ){
|
|
Redirect *pRedir = (pSeg ? pSeg->pRedirect : 0);
|
|
*piPrev = fsRedirectBlock(pRedir, (int)lsmGetU32(aPrev));
|
|
}
|
|
}else{
|
|
assert( 0 );
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Encode and decode routines for record size fields.
|
|
*/
|
|
static void putRecordSize(u8 *aBuf, int nByte, int bFree){
|
|
aBuf[0] = (u8)(nByte >> 14) | 0x80;
|
|
aBuf[1] = ((u8)(nByte >> 7) & 0x7F) | (bFree ? 0x00 : 0x80);
|
|
aBuf[2] = (u8)nByte | 0x80;
|
|
}
|
|
static int getRecordSize(u8 *aBuf, int *pbFree){
|
|
int nByte;
|
|
nByte = (aBuf[0] & 0x7F) << 14;
|
|
nByte += (aBuf[1] & 0x7F) << 7;
|
|
nByte += (aBuf[2] & 0x7F);
|
|
*pbFree = !(aBuf[1] & 0x80);
|
|
return nByte;
|
|
}
|
|
|
|
/*
|
|
** Subtract iSub from database file offset iOff and set *piRes to the
|
|
** result. If doing so means passing the start of a block, follow the
|
|
** block pointer stored in the first 4 bytes of the block.
|
|
**
|
|
** Offset iOff is an absolute offset - not subject to any block redirection.
|
|
** However any block pointer followed is. Use pSeg->pRedirect in this case.
|
|
**
|
|
** Return LSM_OK if successful or an lsm error code if an error occurs.
|
|
*/
|
|
static int fsSubtractOffset(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
i64 iOff,
|
|
int iSub,
|
|
i64 *piRes
|
|
){
|
|
i64 iStart;
|
|
int iBlk = 0;
|
|
int rc;
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
iStart = fsFirstPageOnBlock(pFS, fsPageToBlock(pFS, iOff));
|
|
if( (iOff-iSub)>=iStart ){
|
|
*piRes = (iOff-iSub);
|
|
return LSM_OK;
|
|
}
|
|
|
|
rc = fsBlockPrev(pFS, pSeg, fsPageToBlock(pFS, iOff), &iBlk);
|
|
*piRes = fsLastPageOnBlock(pFS, iBlk) - iSub + (iOff - iStart + 1);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Add iAdd to database file offset iOff and set *piRes to the
|
|
** result. If doing so means passing the end of a block, follow the
|
|
** block pointer stored in the last 4 bytes of the block.
|
|
**
|
|
** Offset iOff is an absolute offset - not subject to any block redirection.
|
|
** However any block pointer followed is. Use pSeg->pRedirect in this case.
|
|
**
|
|
** Return LSM_OK if successful or an lsm error code if an error occurs.
|
|
*/
|
|
static int fsAddOffset(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
i64 iOff,
|
|
int iAdd,
|
|
i64 *piRes
|
|
){
|
|
i64 iEob;
|
|
int iBlk;
|
|
int rc;
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
iEob = fsLastPageOnPagesBlock(pFS, iOff);
|
|
if( (iOff+iAdd)<=iEob ){
|
|
*piRes = (iOff+iAdd);
|
|
return LSM_OK;
|
|
}
|
|
|
|
rc = fsBlockNext(pFS, pSeg, fsPageToBlock(pFS, iOff), &iBlk);
|
|
*piRes = fsFirstPageOnBlock(pFS, iBlk) + iAdd - (iEob - iOff + 1);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** If it is not already allocated, allocate either the FileSystem.aOBuffer (if
|
|
** bWrite is true) or the FileSystem.aIBuffer (if bWrite is false). Return
|
|
** LSM_OK if successful if the attempt to allocate memory fails.
|
|
*/
|
|
static int fsAllocateBuffer(FileSystem *pFS, int bWrite){
|
|
u8 **pp; /* Pointer to either aIBuffer or aOBuffer */
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
/* If neither buffer has been allocated, figure out how large they
|
|
** should be. Store this value in FileSystem.nBuffer. */
|
|
if( pFS->nBuffer==0 ){
|
|
assert( pFS->aIBuffer==0 && pFS->aOBuffer==0 );
|
|
pFS->nBuffer = pFS->pCompress->xBound(pFS->pCompress->pCtx, pFS->nPagesize);
|
|
if( pFS->nBuffer<(pFS->szSector+6) ){
|
|
pFS->nBuffer = pFS->szSector+6;
|
|
}
|
|
}
|
|
|
|
pp = (bWrite ? &pFS->aOBuffer : &pFS->aIBuffer);
|
|
if( *pp==0 ){
|
|
*pp = lsmMalloc(pFS->pEnv, LSM_MAX(pFS->nBuffer, pFS->nPagesize));
|
|
if( *pp==0 ) return LSM_NOMEM_BKPT;
|
|
}
|
|
|
|
return LSM_OK;
|
|
}
|
|
|
|
/*
|
|
** This function is only called in compressed database mode. It reads and
|
|
** uncompresses the compressed data for page pPg from the database and
|
|
** populates the pPg->aData[] buffer and pPg->nCompress field.
|
|
**
|
|
** It is possible that instead of a page record, there is free space
|
|
** at offset pPg->iPgno. In this case no data is read from the file, but
|
|
** output variable *pnSpace is set to the total number of free bytes.
|
|
**
|
|
** LSM_OK is returned if successful, or an LSM error code otherwise.
|
|
*/
|
|
static int fsReadPagedata(
|
|
FileSystem *pFS, /* File-system handle */
|
|
Segment *pSeg, /* pPg is part of this segment */
|
|
Page *pPg, /* Page to read and uncompress data for */
|
|
int *pnSpace /* OUT: Total bytes of free space */
|
|
){
|
|
lsm_compress *p = pFS->pCompress;
|
|
i64 iOff = pPg->iPg;
|
|
u8 aSz[3];
|
|
int rc;
|
|
|
|
assert( p && pPg->nCompress==0 );
|
|
|
|
if( fsAllocateBuffer(pFS, 0) ) return LSM_NOMEM;
|
|
|
|
rc = fsReadData(pFS, pSeg, iOff, aSz, sizeof(aSz));
|
|
|
|
if( rc==LSM_OK ){
|
|
int bFree;
|
|
if( aSz[0] & 0x80 ){
|
|
pPg->nCompress = (int)getRecordSize(aSz, &bFree);
|
|
}else{
|
|
pPg->nCompress = (int)aSz[0] - sizeof(aSz)*2;
|
|
bFree = 1;
|
|
}
|
|
if( bFree ){
|
|
if( pnSpace ){
|
|
*pnSpace = pPg->nCompress + sizeof(aSz)*2;
|
|
}else{
|
|
rc = LSM_CORRUPT_BKPT;
|
|
}
|
|
}else{
|
|
rc = fsAddOffset(pFS, pSeg, iOff, 3, &iOff);
|
|
if( rc==LSM_OK ){
|
|
if( pPg->nCompress>pFS->nBuffer ){
|
|
rc = LSM_CORRUPT_BKPT;
|
|
}else{
|
|
rc = fsReadData(pFS, pSeg, iOff, pFS->aIBuffer, pPg->nCompress);
|
|
}
|
|
if( rc==LSM_OK ){
|
|
int n = pFS->nPagesize;
|
|
rc = p->xUncompress(p->pCtx,
|
|
(char *)pPg->aData, &n,
|
|
(const char *)pFS->aIBuffer, pPg->nCompress
|
|
);
|
|
if( rc==LSM_OK && n!=pPg->pFS->nPagesize ){
|
|
rc = LSM_CORRUPT_BKPT;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return a handle for a database page.
|
|
**
|
|
** If this file-system object is accessing a compressed database it may be
|
|
** that there is no page record at database file offset iPg. Instead, there
|
|
** may be a free space record. In this case, set *ppPg to NULL and *pnSpace
|
|
** to the total number of free bytes before returning.
|
|
**
|
|
** If no error occurs, LSM_OK is returned. Otherwise, an lsm error code.
|
|
*/
|
|
static int fsPageGet(
|
|
FileSystem *pFS, /* File-system handle */
|
|
Segment *pSeg, /* Block redirection to use (or NULL) */
|
|
Pgno iPg, /* Page id */
|
|
int noContent, /* True to not load content from disk */
|
|
Page **ppPg, /* OUT: New page handle */
|
|
int *pnSpace /* OUT: Bytes of free space */
|
|
){
|
|
Page *p;
|
|
int iHash;
|
|
int rc = LSM_OK;
|
|
|
|
/* In most cases iReal is the same as iPg. Except, if pSeg->pRedirect is
|
|
** not NULL, and the block containing iPg has been redirected, then iReal
|
|
** is the page number after redirection. */
|
|
Pgno iReal = lsmFsRedirectPage(pFS, (pSeg ? pSeg->pRedirect : 0), iPg);
|
|
|
|
assert_lists_are_ok(pFS);
|
|
assert( iPg>=fsFirstPageOnBlock(pFS, 1) );
|
|
assert( iReal>=fsFirstPageOnBlock(pFS, 1) );
|
|
*ppPg = 0;
|
|
|
|
/* Search the hash-table for the page */
|
|
p = fsPageFindInHash(pFS, iReal, &iHash);
|
|
|
|
if( p ){
|
|
assert( p->flags & PAGE_FREE );
|
|
if( p->nRef==0 ) fsPageRemoveFromLru(pFS, p);
|
|
}else{
|
|
|
|
if( fsMmapPage(pFS, iReal) ){
|
|
i64 iEnd = (i64)iReal * pFS->nPagesize;
|
|
fsGrowMapping(pFS, iEnd, &rc);
|
|
if( rc!=LSM_OK ) return rc;
|
|
|
|
if( pFS->pFree ){
|
|
p = pFS->pFree;
|
|
pFS->pFree = p->pFreeNext;
|
|
assert( p->nRef==0 );
|
|
}else{
|
|
p = lsmMallocZeroRc(pFS->pEnv, sizeof(Page), &rc);
|
|
if( rc ) return rc;
|
|
p->pFS = pFS;
|
|
}
|
|
p->aData = &((u8 *)pFS->pMap)[pFS->nPagesize * (iReal-1)];
|
|
p->iPg = iReal;
|
|
|
|
/* This page now carries a pointer to the mapping. Link it in to
|
|
** the FileSystem.pMapped list. */
|
|
assert( p->pMappedNext==0 );
|
|
p->pMappedNext = pFS->pMapped;
|
|
pFS->pMapped = p;
|
|
|
|
assert( pFS->pCompress==0 );
|
|
assert( (p->flags & PAGE_FREE)==0 );
|
|
}else{
|
|
rc = fsPageBuffer(pFS, &p);
|
|
if( rc==LSM_OK ){
|
|
int nSpace = 0;
|
|
p->iPg = iReal;
|
|
p->nRef = 0;
|
|
p->pFS = pFS;
|
|
assert( p->flags==0 || p->flags==PAGE_FREE );
|
|
|
|
#ifdef LSM_DEBUG
|
|
memset(p->aData, 0x56, pFS->nPagesize);
|
|
#endif
|
|
assert( p->pLruNext==0 && p->pLruPrev==0 );
|
|
if( noContent==0 ){
|
|
if( pFS->pCompress ){
|
|
rc = fsReadPagedata(pFS, pSeg, p, &nSpace);
|
|
}else{
|
|
int nByte = pFS->nPagesize;
|
|
i64 iOff = (i64)(iReal-1) * pFS->nPagesize;
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, p->aData, nByte);
|
|
}
|
|
pFS->nRead++;
|
|
}
|
|
|
|
/* If the xRead() call was successful (or not attempted), link the
|
|
** page into the page-cache hash-table. Otherwise, if it failed,
|
|
** free the buffer. */
|
|
if( rc==LSM_OK && nSpace==0 ){
|
|
p->pHashNext = pFS->apHash[iHash];
|
|
pFS->apHash[iHash] = p;
|
|
}else{
|
|
fsPageBufferFree(p);
|
|
p = 0;
|
|
if( pnSpace ) *pnSpace = nSpace;
|
|
}
|
|
}
|
|
}
|
|
|
|
assert( (rc==LSM_OK && (p || (pnSpace && *pnSpace)))
|
|
|| (rc!=LSM_OK && p==0)
|
|
);
|
|
}
|
|
|
|
if( rc==LSM_OK && p ){
|
|
if( pFS->pCompress==0 && (fsIsLast(pFS, iReal) || fsIsFirst(pFS, iReal)) ){
|
|
p->nData = pFS->nPagesize - 4;
|
|
if( fsIsFirst(pFS, iReal) && p->nRef==0 ){
|
|
p->aData += 4;
|
|
p->flags |= PAGE_HASPREV;
|
|
}
|
|
}else{
|
|
p->nData = pFS->nPagesize;
|
|
}
|
|
pFS->nOut += (p->nRef==0);
|
|
p->nRef++;
|
|
}
|
|
*ppPg = p;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Read the 64-bit checkpoint id of the checkpoint currently stored on meta
|
|
** page iMeta of the database file. If no error occurs, store the id value
|
|
** in *piVal and return LSM_OK. Otherwise, return an LSM error code and leave
|
|
** *piVal unmodified.
|
|
**
|
|
** If a checkpointer connection is currently updating meta-page iMeta, or an
|
|
** earlier checkpointer crashed while doing so, the value read into *piVal
|
|
** may be garbage. It is the callers responsibility to deal with this.
|
|
*/
|
|
int lsmFsReadSyncedId(lsm_db *db, int iMeta, i64 *piVal){
|
|
FileSystem *pFS = db->pFS;
|
|
int rc = LSM_OK;
|
|
|
|
assert( iMeta==1 || iMeta==2 );
|
|
if( pFS->nMapLimit>0 ){
|
|
fsGrowMapping(pFS, iMeta*LSM_META_PAGE_SIZE, &rc);
|
|
if( rc==LSM_OK ){
|
|
*piVal = (i64)lsmGetU64(&((u8 *)pFS->pMap)[(iMeta-1)*LSM_META_PAGE_SIZE]);
|
|
}
|
|
}else{
|
|
MetaPage *pMeta = 0;
|
|
rc = lsmFsMetaPageGet(pFS, 0, iMeta, &pMeta);
|
|
if( rc==LSM_OK ){
|
|
*piVal = (i64)lsmGetU64(pMeta->aData);
|
|
lsmFsMetaPageRelease(pMeta);
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Return true if the first or last page of segment pRun falls between iFirst
|
|
** and iLast, inclusive, and pRun is not equal to pIgnore.
|
|
*/
|
|
static int fsRunEndsBetween(
|
|
Segment *pRun,
|
|
Segment *pIgnore,
|
|
Pgno iFirst,
|
|
Pgno iLast
|
|
){
|
|
return (pRun!=pIgnore && (
|
|
(pRun->iFirst>=iFirst && pRun->iFirst<=iLast)
|
|
|| (pRun->iLastPg>=iFirst && pRun->iLastPg<=iLast)
|
|
));
|
|
}
|
|
|
|
/*
|
|
** Return true if level pLevel contains a segment other than pIgnore for
|
|
** which the first or last page is between iFirst and iLast, inclusive.
|
|
*/
|
|
static int fsLevelEndsBetween(
|
|
Level *pLevel,
|
|
Segment *pIgnore,
|
|
Pgno iFirst,
|
|
Pgno iLast
|
|
){
|
|
int i;
|
|
|
|
if( fsRunEndsBetween(&pLevel->lhs, pIgnore, iFirst, iLast) ){
|
|
return 1;
|
|
}
|
|
for(i=0; i<pLevel->nRight; i++){
|
|
if( fsRunEndsBetween(&pLevel->aRhs[i], pIgnore, iFirst, iLast) ){
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Block iBlk is no longer in use by segment pIgnore. If it is not in use
|
|
** by any other segment, move it to the free block list.
|
|
*/
|
|
static int fsFreeBlock(
|
|
FileSystem *pFS, /* File system object */
|
|
Snapshot *pSnapshot, /* Worker snapshot */
|
|
Segment *pIgnore, /* Ignore this run when searching */
|
|
int iBlk /* Block number of block to free */
|
|
){
|
|
int rc = LSM_OK; /* Return code */
|
|
int iFirst; /* First page on block iBlk */
|
|
int iLast; /* Last page on block iBlk */
|
|
Level *pLevel; /* Used to iterate through levels */
|
|
|
|
int iIn; /* Used to iterate through append points */
|
|
int iOut = 0; /* Used to output append points */
|
|
Pgno *aApp = pSnapshot->aiAppend;
|
|
|
|
iFirst = fsFirstPageOnBlock(pFS, iBlk);
|
|
iLast = fsLastPageOnBlock(pFS, iBlk);
|
|
|
|
/* Check if any other run in the snapshot has a start or end page
|
|
** within this block. If there is such a run, return early. */
|
|
for(pLevel=lsmDbSnapshotLevel(pSnapshot); pLevel; pLevel=pLevel->pNext){
|
|
if( fsLevelEndsBetween(pLevel, pIgnore, iFirst, iLast) ){
|
|
return LSM_OK;
|
|
}
|
|
}
|
|
|
|
/* Remove any entries that lie on this block from the append-list. */
|
|
for(iIn=0; iIn<LSM_APPLIST_SZ; iIn++){
|
|
if( aApp[iIn]<iFirst || aApp[iIn]>iLast ){
|
|
aApp[iOut++] = aApp[iIn];
|
|
}
|
|
}
|
|
while( iOut<LSM_APPLIST_SZ ) aApp[iOut++] = 0;
|
|
|
|
if( rc==LSM_OK ){
|
|
rc = lsmBlockFree(pFS->pDb, iBlk);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Delete or otherwise recycle the blocks currently occupied by run pDel.
|
|
*/
|
|
int lsmFsSortedDelete(
|
|
FileSystem *pFS,
|
|
Snapshot *pSnapshot,
|
|
int bZero, /* True to zero the Segment structure */
|
|
Segment *pDel
|
|
){
|
|
if( pDel->iFirst ){
|
|
int rc = LSM_OK;
|
|
|
|
int iBlk;
|
|
int iLastBlk;
|
|
|
|
iBlk = fsPageToBlock(pFS, pDel->iFirst);
|
|
iLastBlk = fsPageToBlock(pFS, pDel->iLastPg);
|
|
|
|
/* Mark all blocks currently used by this sorted run as free */
|
|
while( iBlk && rc==LSM_OK ){
|
|
int iNext = 0;
|
|
if( iBlk!=iLastBlk ){
|
|
rc = fsBlockNext(pFS, pDel, iBlk, &iNext);
|
|
}else if( bZero==0 && pDel->iLastPg!=fsLastPageOnBlock(pFS, iLastBlk) ){
|
|
break;
|
|
}
|
|
rc = fsFreeBlock(pFS, pSnapshot, pDel, iBlk);
|
|
iBlk = iNext;
|
|
}
|
|
|
|
if( pDel->pRedirect ){
|
|
assert( pDel->pRedirect==&pSnapshot->redirect );
|
|
pSnapshot->redirect.n = 0;
|
|
}
|
|
|
|
if( bZero ) memset(pDel, 0, sizeof(Segment));
|
|
}
|
|
return LSM_OK;
|
|
}
|
|
|
|
/*
|
|
** aPgno is an array containing nPgno page numbers. Return the smallest page
|
|
** number from the array that falls on block iBlk. Or, if none of the pages
|
|
** in aPgno[] fall on block iBlk, return 0.
|
|
*/
|
|
static Pgno firstOnBlock(FileSystem *pFS, int iBlk, Pgno *aPgno, int nPgno){
|
|
Pgno iRet = 0;
|
|
int i;
|
|
for(i=0; i<nPgno; i++){
|
|
Pgno iPg = aPgno[i];
|
|
if( fsPageToBlock(pFS, iPg)==iBlk && (iRet==0 || iPg<iRet) ){
|
|
iRet = iPg;
|
|
}
|
|
}
|
|
return iRet;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
/*
|
|
** Return true if page iPg, which is a part of segment p, lies on
|
|
** a redirected block.
|
|
*/
|
|
static int fsPageRedirects(FileSystem *pFS, Segment *p, Pgno iPg){
|
|
return (iPg!=0 && iPg!=lsmFsRedirectPage(pFS, p->pRedirect, iPg));
|
|
}
|
|
|
|
/*
|
|
** Return true if the second argument is not NULL and any of the first
|
|
** last or root pages lie on a redirected block.
|
|
*/
|
|
static int fsSegmentRedirects(FileSystem *pFS, Segment *p){
|
|
return (p && (
|
|
fsPageRedirects(pFS, p, p->iFirst)
|
|
|| fsPageRedirects(pFS, p, p->iRoot)
|
|
|| fsPageRedirects(pFS, p, p->iLastPg)
|
|
));
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Argument aPgno is an array of nPgno page numbers. All pages belong to
|
|
** the segment pRun. This function gobbles from the start of the run to the
|
|
** first page that appears in aPgno[] (i.e. so that the aPgno[] entry is
|
|
** the new first page of the run).
|
|
*/
|
|
void lsmFsGobble(
|
|
lsm_db *pDb,
|
|
Segment *pRun,
|
|
Pgno *aPgno,
|
|
int nPgno
|
|
){
|
|
int rc = LSM_OK;
|
|
FileSystem *pFS = pDb->pFS;
|
|
Snapshot *pSnapshot = pDb->pWorker;
|
|
int iBlk;
|
|
|
|
assert( pRun->nSize>0 );
|
|
assert( 0==fsSegmentRedirects(pFS, pRun) );
|
|
assert( nPgno>0 && 0==fsPageRedirects(pFS, pRun, aPgno[0]) );
|
|
|
|
iBlk = fsPageToBlock(pFS, pRun->iFirst);
|
|
pRun->nSize += (pRun->iFirst - fsFirstPageOnBlock(pFS, iBlk));
|
|
|
|
while( rc==LSM_OK ){
|
|
int iNext = 0;
|
|
Pgno iFirst = firstOnBlock(pFS, iBlk, aPgno, nPgno);
|
|
if( iFirst ){
|
|
pRun->iFirst = iFirst;
|
|
break;
|
|
}
|
|
rc = fsBlockNext(pFS, pRun, iBlk, &iNext);
|
|
if( rc==LSM_OK ) rc = fsFreeBlock(pFS, pSnapshot, pRun, iBlk);
|
|
pRun->nSize -= (
|
|
1 + fsLastPageOnBlock(pFS, iBlk) - fsFirstPageOnBlock(pFS, iBlk)
|
|
);
|
|
iBlk = iNext;
|
|
}
|
|
|
|
pRun->nSize -= (pRun->iFirst - fsFirstPageOnBlock(pFS, iBlk));
|
|
assert( pRun->nSize>0 );
|
|
}
|
|
|
|
/*
|
|
** This function is only used in compressed database mode.
|
|
**
|
|
** Argument iPg is the page number (byte offset) of a page within segment
|
|
** pSeg. The page record, including all headers, is nByte bytes in size.
|
|
** Before returning, set *piNext to the page number of the next page in
|
|
** the segment, or to zero if iPg is the last.
|
|
**
|
|
** In other words, do:
|
|
**
|
|
** *piNext = iPg + nByte;
|
|
**
|
|
** But take block overflow and redirection into account.
|
|
*/
|
|
static int fsNextPageOffset(
|
|
FileSystem *pFS, /* File system object */
|
|
Segment *pSeg, /* Segment to move within */
|
|
Pgno iPg, /* Offset of current page */
|
|
int nByte, /* Size of current page including headers */
|
|
Pgno *piNext /* OUT: Offset of next page. Or zero (EOF) */
|
|
){
|
|
Pgno iNext;
|
|
int rc;
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
rc = fsAddOffset(pFS, pSeg, iPg, nByte-1, &iNext);
|
|
if( pSeg && iNext==pSeg->iLastPg ){
|
|
iNext = 0;
|
|
}else if( rc==LSM_OK ){
|
|
rc = fsAddOffset(pFS, pSeg, iNext, 1, &iNext);
|
|
}
|
|
|
|
*piNext = iNext;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is only used in compressed database mode.
|
|
**
|
|
** Argument iPg is the page number of a pagethat appears in segment pSeg.
|
|
** This function determines the page number of the previous page in the
|
|
** same run. *piPrev is set to the previous page number before returning.
|
|
**
|
|
** LSM_OK is returned if no error occurs. Otherwise, an lsm error code.
|
|
** If any value other than LSM_OK is returned, then the final value of
|
|
** *piPrev is undefined.
|
|
*/
|
|
static int fsGetPageBefore(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
Pgno iPg,
|
|
Pgno *piPrev
|
|
){
|
|
u8 aSz[3];
|
|
int rc;
|
|
i64 iRead;
|
|
|
|
assert( pFS->pCompress );
|
|
|
|
rc = fsSubtractOffset(pFS, pSeg, iPg, sizeof(aSz), &iRead);
|
|
if( rc==LSM_OK ) rc = fsReadData(pFS, pSeg, iRead, aSz, sizeof(aSz));
|
|
|
|
if( rc==LSM_OK ){
|
|
int bFree;
|
|
int nSz;
|
|
if( aSz[2] & 0x80 ){
|
|
nSz = getRecordSize(aSz, &bFree) + sizeof(aSz)*2;
|
|
}else{
|
|
nSz = (int)(aSz[2] & 0x7F);
|
|
bFree = 1;
|
|
}
|
|
rc = fsSubtractOffset(pFS, pSeg, iPg, nSz, piPrev);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** The first argument to this function is a valid reference to a database
|
|
** file page that is part of a sorted run. If parameter eDir is -1, this
|
|
** function attempts to locate and load the previous page in the same run.
|
|
** Or, if eDir is +1, it attempts to find the next page in the same run.
|
|
** The results of passing an eDir value other than positive or negative one
|
|
** are undefined.
|
|
**
|
|
** If parameter pRun is not NULL then it must point to the run that page
|
|
** pPg belongs to. In this case, if pPg is the first or last page of the
|
|
** run, and the request is for the previous or next page, respectively,
|
|
** *ppNext is set to NULL before returning LSM_OK. If pRun is NULL, then it
|
|
** is assumed that the next or previous page, as requested, exists.
|
|
**
|
|
** If the previous/next page does exist and is successfully loaded, *ppNext
|
|
** is set to point to it and LSM_OK is returned. Otherwise, if an error
|
|
** occurs, *ppNext is set to NULL and and lsm error code returned.
|
|
**
|
|
** Page references returned by this function should be released by the
|
|
** caller using lsmFsPageRelease().
|
|
*/
|
|
int lsmFsDbPageNext(Segment *pRun, Page *pPg, int eDir, Page **ppNext){
|
|
int rc = LSM_OK;
|
|
FileSystem *pFS = pPg->pFS;
|
|
Pgno iPg = pPg->iPg;
|
|
|
|
assert( 0==fsSegmentRedirects(pFS, pRun) );
|
|
if( pFS->pCompress ){
|
|
int nSpace = pPg->nCompress + 2*3;
|
|
|
|
do {
|
|
if( eDir>0 ){
|
|
rc = fsNextPageOffset(pFS, pRun, iPg, nSpace, &iPg);
|
|
}else{
|
|
if( iPg==pRun->iFirst ){
|
|
iPg = 0;
|
|
}else{
|
|
rc = fsGetPageBefore(pFS, pRun, iPg, &iPg);
|
|
}
|
|
}
|
|
|
|
nSpace = 0;
|
|
if( iPg!=0 ){
|
|
rc = fsPageGet(pFS, pRun, iPg, 0, ppNext, &nSpace);
|
|
assert( (*ppNext==0)==(rc!=LSM_OK || nSpace>0) );
|
|
}else{
|
|
*ppNext = 0;
|
|
}
|
|
}while( nSpace>0 && rc==LSM_OK );
|
|
|
|
}else{
|
|
Redirect *pRedir = pRun ? pRun->pRedirect : 0;
|
|
assert( eDir==1 || eDir==-1 );
|
|
if( eDir<0 ){
|
|
if( pRun && iPg==pRun->iFirst ){
|
|
*ppNext = 0;
|
|
return LSM_OK;
|
|
}else if( fsIsFirst(pFS, iPg) ){
|
|
assert( pPg->flags & PAGE_HASPREV );
|
|
iPg = fsLastPageOnBlock(pFS, lsmGetU32(&pPg->aData[-4]));
|
|
}else{
|
|
iPg--;
|
|
}
|
|
}else{
|
|
if( pRun ){
|
|
if( iPg==pRun->iLastPg ){
|
|
*ppNext = 0;
|
|
return LSM_OK;
|
|
}
|
|
}
|
|
|
|
if( fsIsLast(pFS, iPg) ){
|
|
int iBlk = fsRedirectBlock(
|
|
pRedir, lsmGetU32(&pPg->aData[pFS->nPagesize-4])
|
|
);
|
|
iPg = fsFirstPageOnBlock(pFS, iBlk);
|
|
}else{
|
|
iPg++;
|
|
}
|
|
}
|
|
rc = fsPageGet(pFS, pRun, iPg, 0, ppNext, 0);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is called when creating a new segment to determine if the
|
|
** first part of it can be written following an existing segment on an
|
|
** already allocated block. If it is possible, the page number of the first
|
|
** page to use for the new segment is returned. Otherwise zero.
|
|
**
|
|
** If argument pLvl is not NULL, then this function will not attempt to
|
|
** start the new segment immediately following any segment that is part
|
|
** of the right-hand-side of pLvl.
|
|
*/
|
|
static Pgno findAppendPoint(FileSystem *pFS, Level *pLvl){
|
|
int i;
|
|
Pgno *aiAppend = pFS->pDb->pWorker->aiAppend;
|
|
Pgno iRet = 0;
|
|
|
|
for(i=LSM_APPLIST_SZ-1; iRet==0 && i>=0; i--){
|
|
if( (iRet = aiAppend[i]) ){
|
|
if( pLvl ){
|
|
int iBlk = fsPageToBlock(pFS, iRet);
|
|
int j;
|
|
for(j=0; iRet && j<pLvl->nRight; j++){
|
|
if( fsPageToBlock(pFS, pLvl->aRhs[j].iLastPg)==iBlk ){
|
|
iRet = 0;
|
|
}
|
|
}
|
|
}
|
|
if( iRet ) aiAppend[i] = 0;
|
|
}
|
|
}
|
|
return iRet;
|
|
}
|
|
|
|
/*
|
|
** Append a page to the left-hand-side of pLvl. Set the ref-count to 1 and
|
|
** return a pointer to it. The page is writable until either
|
|
** lsmFsPagePersist() is called on it or the ref-count drops to zero.
|
|
*/
|
|
int lsmFsSortedAppend(
|
|
FileSystem *pFS,
|
|
Snapshot *pSnapshot,
|
|
Level *pLvl,
|
|
int bDefer,
|
|
Page **ppOut
|
|
){
|
|
int rc = LSM_OK;
|
|
Page *pPg = 0;
|
|
*ppOut = 0;
|
|
int iApp = 0;
|
|
int iNext = 0;
|
|
Segment *p = &pLvl->lhs;
|
|
int iPrev = p->iLastPg;
|
|
|
|
assert( p->pRedirect==0 );
|
|
|
|
if( pFS->pCompress || bDefer ){
|
|
/* In compressed database mode the page is not assigned a page number
|
|
** or location in the database file at this point. This will be done
|
|
** by the lsmFsPagePersist() call. */
|
|
rc = fsPageBuffer(pFS, &pPg);
|
|
if( rc==LSM_OK ){
|
|
pPg->pFS = pFS;
|
|
pPg->pSeg = p;
|
|
pPg->iPg = 0;
|
|
pPg->flags |= PAGE_DIRTY;
|
|
pPg->nData = pFS->nPagesize;
|
|
assert( pPg->aData );
|
|
if( pFS->pCompress==0 ) pPg->nData -= 4;
|
|
|
|
pPg->nRef = 1;
|
|
pFS->nOut++;
|
|
}
|
|
}else{
|
|
if( iPrev==0 ){
|
|
iApp = findAppendPoint(pFS, pLvl);
|
|
}else if( fsIsLast(pFS, iPrev) ){
|
|
int iNext;
|
|
rc = fsBlockNext(pFS, 0, fsPageToBlock(pFS, iPrev), &iNext);
|
|
if( rc!=LSM_OK ) return rc;
|
|
iApp = fsFirstPageOnBlock(pFS, iNext);
|
|
}else{
|
|
iApp = iPrev + 1;
|
|
}
|
|
|
|
/* If this is the first page allocated, or if the page allocated is the
|
|
** last in the block, also allocate the next block here. */
|
|
if( iApp==0 || fsIsLast(pFS, iApp) ){
|
|
int iNew; /* New block number */
|
|
|
|
rc = lsmBlockAllocate(pFS->pDb, 0, &iNew);
|
|
if( rc!=LSM_OK ) return rc;
|
|
if( iApp==0 ){
|
|
iApp = fsFirstPageOnBlock(pFS, iNew);
|
|
}else{
|
|
iNext = fsFirstPageOnBlock(pFS, iNew);
|
|
}
|
|
}
|
|
|
|
/* Grab the new page. */
|
|
pPg = 0;
|
|
rc = fsPageGet(pFS, 0, iApp, 1, &pPg, 0);
|
|
assert( rc==LSM_OK || pPg==0 );
|
|
|
|
/* If this is the first or last page of a block, fill in the pointer
|
|
** value at the end of the new page. */
|
|
if( rc==LSM_OK ){
|
|
p->nSize++;
|
|
p->iLastPg = iApp;
|
|
if( p->iFirst==0 ) p->iFirst = iApp;
|
|
pPg->flags |= PAGE_DIRTY;
|
|
|
|
if( fsIsLast(pFS, iApp) ){
|
|
lsmPutU32(&pPg->aData[pFS->nPagesize-4], fsPageToBlock(pFS, iNext));
|
|
}else if( fsIsFirst(pFS, iApp) ){
|
|
lsmPutU32(&pPg->aData[-4], fsPageToBlock(pFS, iPrev));
|
|
}
|
|
}
|
|
}
|
|
|
|
*ppOut = pPg;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Mark the segment passed as the second argument as finished. Once a segment
|
|
** is marked as finished it is not possible to append any further pages to
|
|
** it.
|
|
**
|
|
** Return LSM_OK if successful or an lsm error code if an error occurs.
|
|
*/
|
|
int lsmFsSortedFinish(FileSystem *pFS, Segment *p){
|
|
int rc = LSM_OK;
|
|
if( p && p->iLastPg ){
|
|
assert( p->pRedirect==0 );
|
|
|
|
/* Check if the last page of this run happens to be the last of a block.
|
|
** If it is, then an extra block has already been allocated for this run.
|
|
** Shift this extra block back to the free-block list.
|
|
**
|
|
** Otherwise, add the first free page in the last block used by the run
|
|
** to the lAppend list.
|
|
*/
|
|
if( fsLastPageOnPagesBlock(pFS, p->iLastPg)!=p->iLastPg ){
|
|
int i;
|
|
Pgno *aiAppend = pFS->pDb->pWorker->aiAppend;
|
|
for(i=0; i<LSM_APPLIST_SZ; i++){
|
|
if( aiAppend[i]==0 ){
|
|
aiAppend[i] = p->iLastPg+1;
|
|
break;
|
|
}
|
|
}
|
|
}else if( pFS->pCompress==0 ){
|
|
Page *pLast;
|
|
rc = fsPageGet(pFS, 0, p->iLastPg, 0, &pLast, 0);
|
|
if( rc==LSM_OK ){
|
|
int iBlk = (int)lsmGetU32(&pLast->aData[pFS->nPagesize-4]);
|
|
lsmBlockRefree(pFS->pDb, iBlk);
|
|
lsmFsPageRelease(pLast);
|
|
}
|
|
}else{
|
|
int iBlk = 0;
|
|
rc = fsBlockNext(pFS, p, fsPageToBlock(pFS, p->iLastPg), &iBlk);
|
|
if( rc==LSM_OK ){
|
|
lsmBlockRefree(pFS->pDb, iBlk);
|
|
}
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Obtain a reference to page number iPg.
|
|
**
|
|
** Return LSM_OK if successful, or an lsm error code if an error occurs.
|
|
*/
|
|
int lsmFsDbPageGet(FileSystem *pFS, Segment *pSeg, Pgno iPg, Page **ppPg){
|
|
return fsPageGet(pFS, pSeg, iPg, 0, ppPg, 0);
|
|
}
|
|
|
|
/*
|
|
** Obtain a reference to the last page in the segment passed as the
|
|
** second argument.
|
|
**
|
|
** Return LSM_OK if successful, or an lsm error code if an error occurs.
|
|
*/
|
|
int lsmFsDbPageLast(FileSystem *pFS, Segment *pSeg, Page **ppPg){
|
|
int rc;
|
|
Pgno iPg = pSeg->iLastPg;
|
|
if( pFS->pCompress ){
|
|
int nSpace;
|
|
iPg++;
|
|
do {
|
|
nSpace = 0;
|
|
rc = fsGetPageBefore(pFS, pSeg, iPg, &iPg);
|
|
if( rc==LSM_OK ){
|
|
rc = fsPageGet(pFS, pSeg, iPg, 0, ppPg, &nSpace);
|
|
}
|
|
}while( rc==LSM_OK && nSpace>0 );
|
|
|
|
}else{
|
|
rc = fsPageGet(pFS, pSeg, iPg, 0, ppPg, 0);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return a reference to meta-page iPg. If successful, LSM_OK is returned
|
|
** and *ppPg populated with the new page reference. The reference should
|
|
** be released by the caller using lsmFsPageRelease().
|
|
**
|
|
** Otherwise, if an error occurs, *ppPg is set to NULL and an LSM error
|
|
** code is returned.
|
|
*/
|
|
int lsmFsMetaPageGet(
|
|
FileSystem *pFS, /* File-system connection */
|
|
int bWrite, /* True for write access, false for read */
|
|
int iPg, /* Either 1 or 2 */
|
|
MetaPage **ppPg /* OUT: Pointer to MetaPage object */
|
|
){
|
|
int rc = LSM_OK;
|
|
MetaPage *pPg;
|
|
assert( iPg==1 || iPg==2 );
|
|
|
|
pPg = lsmMallocZeroRc(pFS->pEnv, sizeof(Page), &rc);
|
|
|
|
if( pPg ){
|
|
i64 iOff = (iPg-1) * pFS->nMetasize;
|
|
if( pFS->nMapLimit>0 ){
|
|
fsGrowMapping(pFS, 2*pFS->nMetasize, &rc);
|
|
pPg->aData = (u8 *)(pFS->pMap) + iOff;
|
|
}else{
|
|
pPg->aData = lsmMallocRc(pFS->pEnv, pFS->nMetasize, &rc);
|
|
if( rc==LSM_OK && bWrite==0 ){
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, pPg->aData, pFS->nMetasize);
|
|
}
|
|
#ifndef NDEBUG
|
|
/* pPg->aData causes an uninitialized access via a downstreadm write().
|
|
After discussion on this list, this memory should not, for performance
|
|
reasons, be memset. However, tracking down "real" misuse is more
|
|
difficult with this "false" positive, so it is set when NDEBUG.
|
|
*/
|
|
else if( rc==LSM_OK ){
|
|
memset( pPg->aData, 0x77, pFS->nMetasize );
|
|
}
|
|
#endif
|
|
}
|
|
|
|
if( rc!=LSM_OK ){
|
|
if( pFS->nMapLimit==0 ) lsmFree(pFS->pEnv, pPg->aData);
|
|
lsmFree(pFS->pEnv, pPg);
|
|
pPg = 0;
|
|
}else{
|
|
pPg->iPg = iPg;
|
|
pPg->bWrite = bWrite;
|
|
pPg->pFS = pFS;
|
|
}
|
|
}
|
|
|
|
*ppPg = pPg;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Release a meta-page reference obtained via a call to lsmFsMetaPageGet().
|
|
*/
|
|
int lsmFsMetaPageRelease(MetaPage *pPg){
|
|
int rc = LSM_OK;
|
|
if( pPg ){
|
|
FileSystem *pFS = pPg->pFS;
|
|
|
|
if( pFS->nMapLimit==0 ){
|
|
if( pPg->bWrite ){
|
|
i64 iOff = (pPg->iPg==2 ? pFS->nMetasize : 0);
|
|
int nWrite = pFS->nMetasize;
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, pPg->aData, nWrite);
|
|
}
|
|
lsmFree(pFS->pEnv, pPg->aData);
|
|
}
|
|
|
|
lsmFree(pFS->pEnv, pPg);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to a buffer containing the data associated with the
|
|
** meta-page passed as the first argument. If parameter pnData is not NULL,
|
|
** set *pnData to the size of the meta-page in bytes before returning.
|
|
*/
|
|
u8 *lsmFsMetaPageData(MetaPage *pPg, int *pnData){
|
|
if( pnData ) *pnData = pPg->pFS->nMetasize;
|
|
return pPg->aData;
|
|
}
|
|
|
|
/*
|
|
** Return true if page is currently writable. This is used in assert()
|
|
** statements only.
|
|
*/
|
|
#ifndef NDEBUG
|
|
int lsmFsPageWritable(Page *pPg){
|
|
return (pPg->flags & PAGE_DIRTY) ? 1 : 0;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** This is called when block iFrom is being redirected to iTo. If page
|
|
** number (*piPg) lies on block iFrom, then calculate the equivalent
|
|
** page on block iTo and set *piPg to this value before returning.
|
|
*/
|
|
static void fsMovePage(
|
|
FileSystem *pFS, /* File system object */
|
|
int iTo, /* Destination block */
|
|
int iFrom, /* Source block */
|
|
Pgno *piPg /* IN/OUT: Page number */
|
|
){
|
|
Pgno iPg = *piPg;
|
|
if( iFrom==fsPageToBlock(pFS, iPg) ){
|
|
const int nPagePerBlock = (
|
|
pFS->pCompress ? pFS ->nBlocksize : (pFS->nBlocksize / pFS->nPagesize)
|
|
);
|
|
*piPg = iPg - (Pgno)(iFrom - iTo) * nPagePerBlock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Copy the contents of block iFrom to block iTo.
|
|
**
|
|
** It is safe to assume that there are no outstanding references to pages
|
|
** on block iTo. And that block iFrom is not currently being written. In
|
|
** other words, the data can be read and written directly.
|
|
*/
|
|
int lsmFsMoveBlock(FileSystem *pFS, Segment *pSeg, int iTo, int iFrom){
|
|
Snapshot *p = pFS->pDb->pWorker;
|
|
int rc = LSM_OK;
|
|
int i;
|
|
i64 nMap;
|
|
|
|
i64 iFromOff = (i64)(iFrom-1) * pFS->nBlocksize;
|
|
i64 iToOff = (i64)(iTo-1) * pFS->nBlocksize;
|
|
|
|
assert( iTo!=1 );
|
|
assert( iFrom>iTo );
|
|
|
|
/* Grow the mapping as required. */
|
|
nMap = LSM_MIN(pFS->nMapLimit, (i64)iFrom * pFS->nBlocksize);
|
|
fsGrowMapping(pFS, nMap, &rc);
|
|
|
|
if( rc==LSM_OK ){
|
|
const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
|
|
int nSz = pFS->nPagesize;
|
|
u8 *aBuf = 0;
|
|
u8 *aData = 0;
|
|
|
|
for(i=0; rc==LSM_OK && i<nPagePerBlock; i++){
|
|
i64 iOff = iFromOff + i*nSz;
|
|
|
|
/* Set aData to point to a buffer containing the from page */
|
|
if( (iOff+nSz)<=pFS->nMapLimit ){
|
|
u8 *aMap = (u8 *)(pFS->pMap);
|
|
aData = &aMap[iOff];
|
|
}else{
|
|
if( aBuf==0 ){
|
|
aBuf = (u8 *)lsmMallocRc(pFS->pEnv, nSz, &rc);
|
|
if( aBuf==0 ) break;
|
|
}
|
|
aData = aBuf;
|
|
rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aData, nSz);
|
|
}
|
|
|
|
/* Copy aData to the to page */
|
|
if( rc==LSM_OK ){
|
|
iOff = iToOff + i*nSz;
|
|
if( (iOff+nSz)<=pFS->nMapLimit ){
|
|
u8 *aMap = (u8 *)(pFS->pMap);
|
|
memcpy(&aMap[iOff], aData, nSz);
|
|
}else{
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, aData, nSz);
|
|
}
|
|
}
|
|
}
|
|
lsmFree(pFS->pEnv, aBuf);
|
|
lsmFsPurgeCache(pFS);
|
|
}
|
|
|
|
/* Update append-point list if necessary */
|
|
for(i=0; i<LSM_APPLIST_SZ; i++){
|
|
fsMovePage(pFS, iTo, iFrom, &p->aiAppend[i]);
|
|
}
|
|
|
|
/* Update the Segment structure itself */
|
|
fsMovePage(pFS, iTo, iFrom, &pSeg->iFirst);
|
|
fsMovePage(pFS, iTo, iFrom, &pSeg->iLastPg);
|
|
fsMovePage(pFS, iTo, iFrom, &pSeg->iRoot);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Append raw data to a segment. Return the database file offset that the
|
|
** data is written to (this may be used as the page number if the data
|
|
** being appended is a new page record).
|
|
**
|
|
** This function is only used in compressed database mode.
|
|
*/
|
|
static Pgno fsAppendData(
|
|
FileSystem *pFS, /* File-system handle */
|
|
Segment *pSeg, /* Segment to append to */
|
|
const u8 *aData, /* Buffer containing data to write */
|
|
int nData, /* Size of buffer aData[] in bytes */
|
|
int *pRc /* IN/OUT: Error code */
|
|
){
|
|
Pgno iRet = 0;
|
|
int rc = *pRc;
|
|
assert( pFS->pCompress );
|
|
if( rc==LSM_OK ){
|
|
int nRem;
|
|
int nWrite;
|
|
Pgno iLastOnBlock;
|
|
Pgno iApp = pSeg->iLastPg+1;
|
|
|
|
/* If this is the first data written into the segment, find an append-point
|
|
** or allocate a new block. */
|
|
if( iApp==1 ){
|
|
pSeg->iFirst = iApp = findAppendPoint(pFS, 0);
|
|
if( iApp==0 ){
|
|
int iBlk;
|
|
rc = lsmBlockAllocate(pFS->pDb, 0, &iBlk);
|
|
pSeg->iFirst = iApp = fsFirstPageOnBlock(pFS, iBlk);
|
|
}
|
|
}
|
|
iRet = iApp;
|
|
|
|
/* Write as much data as is possible at iApp (usually all of it). */
|
|
iLastOnBlock = fsLastPageOnPagesBlock(pFS, iApp);
|
|
if( rc==LSM_OK ){
|
|
int nSpace = iLastOnBlock - iApp + 1;
|
|
nWrite = LSM_MIN(nData, nSpace);
|
|
nRem = nData - nWrite;
|
|
assert( nWrite>=0 );
|
|
if( nWrite!=0 ){
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iApp, aData, nWrite);
|
|
}
|
|
iApp += nWrite;
|
|
}
|
|
|
|
/* If required, allocate a new block and write the rest of the data
|
|
** into it. Set the next and previous block pointers to link the new
|
|
** block to the old. */
|
|
assert( nRem<=0 || (iApp-1)==iLastOnBlock );
|
|
if( rc==LSM_OK && (iApp-1)==iLastOnBlock ){
|
|
u8 aPtr[4]; /* Space to serialize a u32 */
|
|
int iBlk; /* New block number */
|
|
|
|
if( nWrite>0 ){
|
|
/* Allocate a new block. */
|
|
rc = lsmBlockAllocate(pFS->pDb, 0, &iBlk);
|
|
|
|
/* Set the "next" pointer on the old block */
|
|
if( rc==LSM_OK ){
|
|
assert( iApp==(fsPageToBlock(pFS, iApp)*pFS->nBlocksize)-4 );
|
|
lsmPutU32(aPtr, iBlk);
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iApp, aPtr, sizeof(aPtr));
|
|
}
|
|
|
|
/* Set the "prev" pointer on the new block */
|
|
if( rc==LSM_OK ){
|
|
Pgno iWrite;
|
|
lsmPutU32(aPtr, fsPageToBlock(pFS, iApp));
|
|
iWrite = fsFirstPageOnBlock(pFS, iBlk);
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iWrite-4, aPtr, sizeof(aPtr));
|
|
if( nRem>0 ) iApp = iWrite;
|
|
}
|
|
}else{
|
|
/* The next block is already allocated. */
|
|
assert( nRem>0 );
|
|
assert( pSeg->pRedirect==0 );
|
|
rc = fsBlockNext(pFS, 0, fsPageToBlock(pFS, iApp), &iBlk);
|
|
iRet = iApp = fsFirstPageOnBlock(pFS, iBlk);
|
|
}
|
|
|
|
/* Write the remaining data into the new block */
|
|
if( rc==LSM_OK && nRem>0 ){
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iApp, &aData[nWrite], nRem);
|
|
iApp += nRem;
|
|
}
|
|
}
|
|
|
|
pSeg->iLastPg = iApp-1;
|
|
*pRc = rc;
|
|
}
|
|
|
|
return iRet;
|
|
}
|
|
|
|
/*
|
|
** This function is only called in compressed database mode. It
|
|
** compresses the contents of page pPg and writes the result to the
|
|
** buffer at pFS->aOBuffer. The size of the compressed data is stored in
|
|
** pPg->nCompress.
|
|
**
|
|
** If buffer pFS->aOBuffer[] has not been allocated then this function
|
|
** allocates it. If this fails, LSM_NOMEM is returned. Otherwise, LSM_OK.
|
|
*/
|
|
static int fsCompressIntoBuffer(FileSystem *pFS, Page *pPg){
|
|
lsm_compress *p = pFS->pCompress;
|
|
|
|
if( fsAllocateBuffer(pFS, 1) ) return LSM_NOMEM;
|
|
assert( pPg->nData==pFS->nPagesize );
|
|
|
|
pPg->nCompress = pFS->nBuffer;
|
|
return p->xCompress(p->pCtx,
|
|
(char *)pFS->aOBuffer, &pPg->nCompress,
|
|
(const char *)pPg->aData, pPg->nData
|
|
);
|
|
}
|
|
|
|
/*
|
|
** Append a new page to segment pSeg. Set output variable *piNew to the
|
|
** page number of the new page before returning.
|
|
**
|
|
** If the new page is the last on its block, then the 'next' block that
|
|
** will be used by the segment is allocated here too. In this case output
|
|
** variable *piNext is set to the block number of the next block.
|
|
**
|
|
** If the new page is the first on its block but not the first in the
|
|
** entire segment, set output variable *piPrev to the block number of
|
|
** the previous block in the segment.
|
|
**
|
|
** LSM_OK is returned if successful, or an lsm error code otherwise. If
|
|
** any value other than LSM_OK is returned, then the final value of all
|
|
** output variables is undefined.
|
|
*/
|
|
static int fsAppendPage(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
Pgno *piNew,
|
|
int *piPrev,
|
|
int *piNext
|
|
){
|
|
Pgno iPrev = pSeg->iLastPg;
|
|
int rc;
|
|
assert( iPrev!=0 );
|
|
|
|
*piPrev = 0;
|
|
*piNext = 0;
|
|
|
|
if( fsIsLast(pFS, iPrev) ){
|
|
/* Grab the first page on the next block (which has already be
|
|
** allocated). In this case set *piPrev to tell the caller to set
|
|
** the "previous block" pointer in the first 4 bytes of the page.
|
|
*/
|
|
int iNext;
|
|
int iBlk = fsPageToBlock(pFS, iPrev);
|
|
assert( pSeg->pRedirect==0 );
|
|
rc = fsBlockNext(pFS, 0, iBlk, &iNext);
|
|
if( rc!=LSM_OK ) return rc;
|
|
*piNew = fsFirstPageOnBlock(pFS, iNext);
|
|
*piPrev = iBlk;
|
|
}else{
|
|
*piNew = iPrev+1;
|
|
if( fsIsLast(pFS, *piNew) ){
|
|
/* Allocate the next block here. */
|
|
int iBlk;
|
|
rc = lsmBlockAllocate(pFS->pDb, 0, &iBlk);
|
|
if( rc!=LSM_OK ) return rc;
|
|
*piNext = iBlk;
|
|
}
|
|
}
|
|
|
|
pSeg->nSize++;
|
|
pSeg->iLastPg = *piNew;
|
|
return LSM_OK;
|
|
}
|
|
|
|
/*
|
|
** Flush all pages in the FileSystem.pWaiting list to disk.
|
|
*/
|
|
void lsmFsFlushWaiting(FileSystem *pFS, int *pRc){
|
|
int rc = *pRc;
|
|
Page *pPg;
|
|
|
|
pPg = pFS->pWaiting;
|
|
pFS->pWaiting = 0;
|
|
|
|
while( pPg ){
|
|
Page *pNext = pPg->pWaitingNext;
|
|
if( rc==LSM_OK ) rc = lsmFsPagePersist(pPg);
|
|
assert( pPg->nRef==1 );
|
|
lsmFsPageRelease(pPg);
|
|
pPg = pNext;
|
|
}
|
|
*pRc = rc;
|
|
}
|
|
|
|
/*
|
|
** If there exists a hash-table entry associated with page iPg, remove it.
|
|
*/
|
|
static void fsRemoveHashEntry(FileSystem *pFS, Pgno iPg){
|
|
Page *p;
|
|
int iHash = fsHashKey(pFS->nHash, iPg);
|
|
|
|
for(p=pFS->apHash[iHash]; p && p->iPg!=iPg; p=p->pHashNext);
|
|
|
|
if( p ){
|
|
assert( p->nRef==0 || (p->flags & PAGE_FREE)==0 );
|
|
fsPageRemoveFromHash(pFS, p);
|
|
p->iPg = 0;
|
|
iHash = fsHashKey(pFS->nHash, 0);
|
|
p->pHashNext = pFS->apHash[iHash];
|
|
pFS->apHash[iHash] = p;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** If the page passed as an argument is dirty, update the database file
|
|
** (or mapping of the database file) with its current contents and mark
|
|
** the page as clean.
|
|
**
|
|
** Return LSM_OK if the operation is a success, or an LSM error code
|
|
** otherwise.
|
|
*/
|
|
int lsmFsPagePersist(Page *pPg){
|
|
int rc = LSM_OK;
|
|
if( pPg && (pPg->flags & PAGE_DIRTY) ){
|
|
FileSystem *pFS = pPg->pFS;
|
|
|
|
if( pFS->pCompress ){
|
|
int iHash; /* Hash key of assigned page number */
|
|
u8 aSz[3]; /* pPg->nCompress as a 24-bit big-endian */
|
|
assert( pPg->pSeg && pPg->iPg==0 && pPg->nCompress==0 );
|
|
|
|
/* Compress the page image. */
|
|
rc = fsCompressIntoBuffer(pFS, pPg);
|
|
|
|
/* Serialize the compressed size into buffer aSz[] */
|
|
putRecordSize(aSz, pPg->nCompress, 0);
|
|
|
|
/* Write the serialized page record into the database file. */
|
|
pPg->iPg = fsAppendData(pFS, pPg->pSeg, aSz, sizeof(aSz), &rc);
|
|
fsAppendData(pFS, pPg->pSeg, pFS->aOBuffer, pPg->nCompress, &rc);
|
|
fsAppendData(pFS, pPg->pSeg, aSz, sizeof(aSz), &rc);
|
|
|
|
/* Now that it has a page number, insert the page into the hash table */
|
|
iHash = fsHashKey(pFS->nHash, pPg->iPg);
|
|
pPg->pHashNext = pFS->apHash[iHash];
|
|
pFS->apHash[iHash] = pPg;
|
|
|
|
pPg->pSeg->nSize += (sizeof(aSz) * 2) + pPg->nCompress;
|
|
|
|
pPg->flags &= ~PAGE_DIRTY;
|
|
pFS->nWrite++;
|
|
}else{
|
|
|
|
if( pPg->iPg==0 ){
|
|
/* No page number has been assigned yet. This occurs with pages used
|
|
** in the b-tree hierarchy. They were not assigned page numbers when
|
|
** they were created as doing so would cause this call to
|
|
** lsmFsPagePersist() to write an out-of-order page. Instead a page
|
|
** number is assigned here so that the page data will be appended
|
|
** to the current segment.
|
|
*/
|
|
Page **pp;
|
|
int iPrev = 0;
|
|
int iNext = 0;
|
|
int iHash;
|
|
|
|
assert( pPg->pSeg->iFirst );
|
|
assert( pPg->flags & PAGE_FREE );
|
|
assert( (pPg->flags & PAGE_HASPREV)==0 );
|
|
assert( pPg->nData==pFS->nPagesize-4 );
|
|
|
|
rc = fsAppendPage(pFS, pPg->pSeg, &pPg->iPg, &iPrev, &iNext);
|
|
if( rc!=LSM_OK ) return rc;
|
|
|
|
assert( pPg->flags & PAGE_FREE );
|
|
iHash = fsHashKey(pFS->nHash, pPg->iPg);
|
|
fsRemoveHashEntry(pFS, pPg->iPg);
|
|
pPg->pHashNext = pFS->apHash[iHash];
|
|
pFS->apHash[iHash] = pPg;
|
|
assert( pPg->pHashNext==0 || pPg->pHashNext->iPg!=pPg->iPg );
|
|
|
|
if( iPrev ){
|
|
assert( iNext==0 );
|
|
memmove(&pPg->aData[4], pPg->aData, pPg->nData);
|
|
lsmPutU32(pPg->aData, iPrev);
|
|
pPg->flags |= PAGE_HASPREV;
|
|
pPg->aData += 4;
|
|
}else if( iNext ){
|
|
assert( iPrev==0 );
|
|
lsmPutU32(&pPg->aData[pPg->nData], iNext);
|
|
}else{
|
|
int nData = pPg->nData;
|
|
pPg->nData += 4;
|
|
lsmSortedExpandBtreePage(pPg, nData);
|
|
}
|
|
|
|
pPg->nRef++;
|
|
for(pp=&pFS->pWaiting; *pp; pp=&(*pp)->pWaitingNext);
|
|
*pp = pPg;
|
|
assert( pPg->pWaitingNext==0 );
|
|
|
|
}else{
|
|
i64 iOff; /* Offset to write within database file */
|
|
|
|
iOff = (i64)pFS->nPagesize * (i64)(pPg->iPg-1);
|
|
if( fsMmapPage(pFS, pPg->iPg)==0 ){
|
|
u8 *aData = pPg->aData - (pPg->flags & PAGE_HASPREV);
|
|
rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, aData, pFS->nPagesize);
|
|
}else if( pPg->flags & PAGE_FREE ){
|
|
fsGrowMapping(pFS, iOff + pFS->nPagesize, &rc);
|
|
if( rc==LSM_OK ){
|
|
u8 *aTo = &((u8 *)(pFS->pMap))[iOff];
|
|
u8 *aFrom = pPg->aData - (pPg->flags & PAGE_HASPREV);
|
|
memcpy(aTo, aFrom, pFS->nPagesize);
|
|
lsmFree(pFS->pEnv, aFrom);
|
|
pFS->nCacheAlloc--;
|
|
pPg->aData = aTo + (pPg->flags & PAGE_HASPREV);
|
|
pPg->flags &= ~PAGE_FREE;
|
|
fsPageRemoveFromHash(pFS, pPg);
|
|
pPg->pMappedNext = pFS->pMapped;
|
|
pFS->pMapped = pPg;
|
|
}
|
|
}
|
|
|
|
lsmFsFlushWaiting(pFS, &rc);
|
|
pPg->flags &= ~PAGE_DIRTY;
|
|
pFS->nWrite++;
|
|
}
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** For non-compressed databases, this function is a no-op. For compressed
|
|
** databases, it adds a padding record to the segment passed as the third
|
|
** argument.
|
|
**
|
|
** The size of the padding records is selected so that the last byte
|
|
** written is the last byte of a disk sector. This means that if a
|
|
** snapshot is taken and checkpointed, subsequent worker processes will
|
|
** not write to any sector that contains checkpointed data.
|
|
*/
|
|
int lsmFsSortedPadding(
|
|
FileSystem *pFS,
|
|
Snapshot *pSnapshot,
|
|
Segment *pSeg
|
|
){
|
|
int rc = LSM_OK;
|
|
if( pFS->pCompress ){
|
|
Pgno iLast2;
|
|
Pgno iLast = pSeg->iLastPg; /* Current last page of segment */
|
|
int nPad; /* Bytes of padding required */
|
|
u8 aSz[3];
|
|
|
|
iLast2 = (1 + iLast/pFS->szSector) * pFS->szSector - 1;
|
|
assert( fsPageToBlock(pFS, iLast)==fsPageToBlock(pFS, iLast2) );
|
|
nPad = iLast2 - iLast;
|
|
|
|
if( iLast2>fsLastPageOnPagesBlock(pFS, iLast) ){
|
|
nPad -= 4;
|
|
}
|
|
assert( nPad>=0 );
|
|
|
|
if( nPad>=6 ){
|
|
pSeg->nSize += nPad;
|
|
nPad -= 6;
|
|
putRecordSize(aSz, nPad, 1);
|
|
fsAppendData(pFS, pSeg, aSz, sizeof(aSz), &rc);
|
|
memset(pFS->aOBuffer, 0, nPad);
|
|
fsAppendData(pFS, pSeg, pFS->aOBuffer, nPad, &rc);
|
|
fsAppendData(pFS, pSeg, aSz, sizeof(aSz), &rc);
|
|
}else if( nPad>0 ){
|
|
u8 aBuf[5] = {0,0,0,0,0};
|
|
aBuf[0] = (u8)nPad;
|
|
aBuf[nPad-1] = (u8)nPad;
|
|
fsAppendData(pFS, pSeg, aBuf, nPad, &rc);
|
|
}
|
|
|
|
assert( rc!=LSM_OK
|
|
|| pSeg->iLastPg==fsLastPageOnPagesBlock(pFS, pSeg->iLastPg)
|
|
|| ((pSeg->iLastPg + 1) % pFS->szSector)==0
|
|
);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Increment the reference count on the page object passed as the first
|
|
** argument.
|
|
*/
|
|
void lsmFsPageRef(Page *pPg){
|
|
if( pPg ){
|
|
pPg->nRef++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Release a page-reference obtained using fsPageGet().
|
|
*/
|
|
int lsmFsPageRelease(Page *pPg){
|
|
int rc = LSM_OK;
|
|
if( pPg ){
|
|
assert( pPg->nRef>0 );
|
|
pPg->nRef--;
|
|
if( pPg->nRef==0 ){
|
|
FileSystem *pFS = pPg->pFS;
|
|
rc = lsmFsPagePersist(pPg);
|
|
pFS->nOut--;
|
|
|
|
assert( pPg->pFS->pCompress
|
|
|| fsIsFirst(pPg->pFS, pPg->iPg)==0
|
|
|| (pPg->flags & PAGE_HASPREV)
|
|
);
|
|
pPg->aData -= (pPg->flags & PAGE_HASPREV);
|
|
pPg->flags &= ~PAGE_HASPREV;
|
|
|
|
if( (pPg->flags & PAGE_FREE)==0 ){
|
|
/* Removed from mapped list */
|
|
Page **pp;
|
|
for(pp=&pFS->pMapped; (*pp)!=pPg; pp=&(*pp)->pMappedNext);
|
|
*pp = pPg->pMappedNext;
|
|
pPg->pMappedNext = 0;
|
|
|
|
/* Add to free list */
|
|
pPg->pFreeNext = pFS->pFree;
|
|
pFS->pFree = pPg;
|
|
}else{
|
|
fsPageAddToLru(pFS, pPg);
|
|
}
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the total number of pages read from the database file.
|
|
*/
|
|
int lsmFsNRead(FileSystem *pFS){ return pFS->nRead; }
|
|
|
|
/*
|
|
** Return the total number of pages written to the database file.
|
|
*/
|
|
int lsmFsNWrite(FileSystem *pFS){ return pFS->nWrite; }
|
|
|
|
/*
|
|
** Return a copy of the environment pointer used by the file-system object.
|
|
*/
|
|
lsm_env *lsmFsEnv(FileSystem *pFS){
|
|
return pFS->pEnv;
|
|
}
|
|
|
|
/*
|
|
** Return a copy of the environment pointer used by the file-system object
|
|
** to which this page belongs.
|
|
*/
|
|
lsm_env *lsmPageEnv(Page *pPg) {
|
|
return pPg->pFS->pEnv;
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to the file-system object associated with the Page
|
|
** passed as the only argument.
|
|
*/
|
|
FileSystem *lsmPageFS(Page *pPg){
|
|
return pPg->pFS;
|
|
}
|
|
|
|
/*
|
|
** Return the sector-size as reported by the log file handle.
|
|
*/
|
|
int lsmFsSectorSize(FileSystem *pFS){
|
|
return pFS->szSector;
|
|
}
|
|
|
|
/*
|
|
** Helper function for lsmInfoArrayStructure().
|
|
*/
|
|
static Segment *startsWith(Segment *pRun, Pgno iFirst){
|
|
return (iFirst==pRun->iFirst) ? pRun : 0;
|
|
}
|
|
|
|
/*
|
|
** Return the segment that starts with page iFirst, if any. If no such segment
|
|
** can be found, return NULL.
|
|
*/
|
|
static Segment *findSegment(Snapshot *pWorker, Pgno iFirst){
|
|
Level *pLvl; /* Used to iterate through db levels */
|
|
Segment *pSeg = 0; /* Pointer to segment to return */
|
|
|
|
for(pLvl=lsmDbSnapshotLevel(pWorker); pLvl && pSeg==0; pLvl=pLvl->pNext){
|
|
if( 0==(pSeg = startsWith(&pLvl->lhs, iFirst)) ){
|
|
int i;
|
|
for(i=0; i<pLvl->nRight; i++){
|
|
if( (pSeg = startsWith(&pLvl->aRhs[i], iFirst)) ) break;
|
|
}
|
|
}
|
|
}
|
|
|
|
return pSeg;
|
|
}
|
|
|
|
/*
|
|
** This function implements the lsm_info(LSM_INFO_ARRAY_STRUCTURE) request.
|
|
** If successful, *pzOut is set to point to a nul-terminated string
|
|
** containing the array structure and LSM_OK is returned. The caller should
|
|
** eventually free the string using lsmFree().
|
|
**
|
|
** If an error occurs, *pzOut is set to NULL and an LSM error code returned.
|
|
*/
|
|
int lsmInfoArrayStructure(
|
|
lsm_db *pDb,
|
|
int bBlock, /* True for block numbers only */
|
|
Pgno iFirst,
|
|
char **pzOut
|
|
){
|
|
int rc = LSM_OK;
|
|
Snapshot *pWorker; /* Worker snapshot */
|
|
Segment *pArray = 0; /* Array to report on */
|
|
int bUnlock = 0;
|
|
|
|
*pzOut = 0;
|
|
if( iFirst==0 ) return LSM_ERROR;
|
|
|
|
/* Obtain the worker snapshot */
|
|
pWorker = pDb->pWorker;
|
|
if( !pWorker ){
|
|
rc = lsmBeginWork(pDb);
|
|
if( rc!=LSM_OK ) return rc;
|
|
pWorker = pDb->pWorker;
|
|
bUnlock = 1;
|
|
}
|
|
|
|
/* Search for the array that starts on page iFirst */
|
|
pArray = findSegment(pWorker, iFirst);
|
|
|
|
if( pArray==0 ){
|
|
/* Could not find the requested array. This is an error. */
|
|
rc = LSM_ERROR;
|
|
}else{
|
|
FileSystem *pFS = pDb->pFS;
|
|
LsmString str;
|
|
int iBlk;
|
|
int iLastBlk;
|
|
|
|
iBlk = fsPageToBlock(pFS, pArray->iFirst);
|
|
iLastBlk = fsPageToBlock(pFS, pArray->iLastPg);
|
|
|
|
lsmStringInit(&str, pDb->pEnv);
|
|
if( bBlock ){
|
|
lsmStringAppendf(&str, "%d", iBlk);
|
|
while( iBlk!=iLastBlk ){
|
|
fsBlockNext(pFS, pArray, iBlk, &iBlk);
|
|
lsmStringAppendf(&str, " %d", iBlk);
|
|
}
|
|
}else{
|
|
lsmStringAppendf(&str, "%d", pArray->iFirst);
|
|
while( iBlk!=iLastBlk ){
|
|
lsmStringAppendf(&str, " %d", fsLastPageOnBlock(pFS, iBlk));
|
|
fsBlockNext(pFS, pArray, iBlk, &iBlk);
|
|
lsmStringAppendf(&str, " %d", fsFirstPageOnBlock(pFS, iBlk));
|
|
}
|
|
lsmStringAppendf(&str, " %d", pArray->iLastPg);
|
|
}
|
|
|
|
*pzOut = str.z;
|
|
}
|
|
|
|
if( bUnlock ){
|
|
int rcwork = LSM_BUSY;
|
|
lsmFinishWork(pDb, 0, &rcwork);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
int lsmFsSegmentContainsPg(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
Pgno iPg,
|
|
int *pbRes
|
|
){
|
|
Redirect *pRedir = pSeg->pRedirect;
|
|
int rc = LSM_OK;
|
|
int iBlk;
|
|
int iLastBlk;
|
|
int iPgBlock; /* Block containing page iPg */
|
|
|
|
iPgBlock = fsPageToBlock(pFS, pSeg->iFirst);
|
|
iBlk = fsRedirectBlock(pRedir, fsPageToBlock(pFS, pSeg->iFirst));
|
|
iLastBlk = fsRedirectBlock(pRedir, fsPageToBlock(pFS, pSeg->iLastPg));
|
|
|
|
while( iBlk!=iLastBlk && iBlk!=iPgBlock && rc==LSM_OK ){
|
|
rc = fsBlockNext(pFS, pSeg, iBlk, &iBlk);
|
|
}
|
|
|
|
*pbRes = (iBlk==iPgBlock);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function implements the lsm_info(LSM_INFO_ARRAY_PAGES) request.
|
|
** If successful, *pzOut is set to point to a nul-terminated string
|
|
** containing the array structure and LSM_OK is returned. The caller should
|
|
** eventually free the string using lsmFree().
|
|
**
|
|
** If an error occurs, *pzOut is set to NULL and an LSM error code returned.
|
|
*/
|
|
int lsmInfoArrayPages(lsm_db *pDb, Pgno iFirst, char **pzOut){
|
|
int rc = LSM_OK;
|
|
Snapshot *pWorker; /* Worker snapshot */
|
|
Segment *pSeg = 0; /* Array to report on */
|
|
int bUnlock = 0;
|
|
|
|
*pzOut = 0;
|
|
if( iFirst==0 ) return LSM_ERROR;
|
|
|
|
/* Obtain the worker snapshot */
|
|
pWorker = pDb->pWorker;
|
|
if( !pWorker ){
|
|
rc = lsmBeginWork(pDb);
|
|
if( rc!=LSM_OK ) return rc;
|
|
pWorker = pDb->pWorker;
|
|
bUnlock = 1;
|
|
}
|
|
|
|
/* Search for the array that starts on page iFirst */
|
|
pSeg = findSegment(pWorker, iFirst);
|
|
|
|
if( pSeg==0 ){
|
|
/* Could not find the requested array. This is an error. */
|
|
rc = LSM_ERROR;
|
|
}else{
|
|
Page *pPg = 0;
|
|
FileSystem *pFS = pDb->pFS;
|
|
LsmString str;
|
|
|
|
lsmStringInit(&str, pDb->pEnv);
|
|
rc = lsmFsDbPageGet(pFS, pSeg, iFirst, &pPg);
|
|
while( rc==LSM_OK && pPg ){
|
|
Page *pNext = 0;
|
|
lsmStringAppendf(&str, " %lld", lsmFsPageNumber(pPg));
|
|
rc = lsmFsDbPageNext(pSeg, pPg, 1, &pNext);
|
|
lsmFsPageRelease(pPg);
|
|
pPg = pNext;
|
|
}
|
|
|
|
if( rc!=LSM_OK ){
|
|
lsmFree(pDb->pEnv, str.z);
|
|
}else{
|
|
*pzOut = str.z;
|
|
}
|
|
}
|
|
|
|
if( bUnlock ){
|
|
int rcwork = LSM_BUSY;
|
|
lsmFinishWork(pDb, 0, &rcwork);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** The following macros are used by the integrity-check code. Associated with
|
|
** each block in the database is an 8-bit bit mask (the entry in the aUsed[]
|
|
** array). As the integrity-check meanders through the database, it sets the
|
|
** following bits to indicate how each block is used.
|
|
**
|
|
** INTEGRITY_CHECK_FIRST_PG:
|
|
** First page of block is in use by sorted run.
|
|
**
|
|
** INTEGRITY_CHECK_LAST_PG:
|
|
** Last page of block is in use by sorted run.
|
|
**
|
|
** INTEGRITY_CHECK_USED:
|
|
** At least one page of the block is in use by a sorted run.
|
|
**
|
|
** INTEGRITY_CHECK_FREE:
|
|
** The free block list contains an entry corresponding to this block.
|
|
*/
|
|
#define INTEGRITY_CHECK_FIRST_PG 0x01
|
|
#define INTEGRITY_CHECK_LAST_PG 0x02
|
|
#define INTEGRITY_CHECK_USED 0x04
|
|
#define INTEGRITY_CHECK_FREE 0x08
|
|
|
|
/*
|
|
** Helper function for lsmFsIntegrityCheck()
|
|
*/
|
|
static void checkBlocks(
|
|
FileSystem *pFS,
|
|
Segment *pSeg,
|
|
int bExtra, /* If true, count the "next" block if any */
|
|
int nUsed,
|
|
u8 *aUsed
|
|
){
|
|
if( pSeg ){
|
|
if( pSeg && pSeg->nSize>0 ){
|
|
int rc;
|
|
int iBlk; /* Current block (during iteration) */
|
|
int iLastBlk; /* Last block of segment */
|
|
int iFirstBlk; /* First block of segment */
|
|
int bLastIsLastOnBlock; /* True iLast is the last on its block */
|
|
|
|
assert( 0==fsSegmentRedirects(pFS, pSeg) );
|
|
iBlk = iFirstBlk = fsPageToBlock(pFS, pSeg->iFirst);
|
|
iLastBlk = fsPageToBlock(pFS, pSeg->iLastPg);
|
|
|
|
bLastIsLastOnBlock = (fsLastPageOnBlock(pFS, iLastBlk)==pSeg->iLastPg);
|
|
assert( iBlk>0 );
|
|
|
|
do {
|
|
/* iBlk is a part of this sorted run. */
|
|
aUsed[iBlk-1] |= INTEGRITY_CHECK_USED;
|
|
|
|
/* If the first page of this block is also part of the segment,
|
|
** set the flag to indicate that the first page of iBlk is in use.
|
|
*/
|
|
if( fsFirstPageOnBlock(pFS, iBlk)==pSeg->iFirst || iBlk!=iFirstBlk ){
|
|
assert( (aUsed[iBlk-1] & INTEGRITY_CHECK_FIRST_PG)==0 );
|
|
aUsed[iBlk-1] |= INTEGRITY_CHECK_FIRST_PG;
|
|
}
|
|
|
|
/* Unless the sorted run finishes before the last page on this block,
|
|
** the last page of this block is also in use. */
|
|
if( iBlk!=iLastBlk || bLastIsLastOnBlock ){
|
|
assert( (aUsed[iBlk-1] & INTEGRITY_CHECK_LAST_PG)==0 );
|
|
aUsed[iBlk-1] |= INTEGRITY_CHECK_LAST_PG;
|
|
}
|
|
|
|
/* Special case. The sorted run being scanned is the output run of
|
|
** a level currently undergoing an incremental merge. The sorted
|
|
** run ends on the last page of iBlk, but the next block has already
|
|
** been allocated. So mark it as in use as well. */
|
|
if( iBlk==iLastBlk && bLastIsLastOnBlock && bExtra ){
|
|
int iExtra = 0;
|
|
rc = fsBlockNext(pFS, pSeg, iBlk, &iExtra);
|
|
assert( rc==LSM_OK );
|
|
|
|
assert( aUsed[iExtra-1]==0 );
|
|
aUsed[iExtra-1] |= INTEGRITY_CHECK_USED;
|
|
aUsed[iExtra-1] |= INTEGRITY_CHECK_FIRST_PG;
|
|
aUsed[iExtra-1] |= INTEGRITY_CHECK_LAST_PG;
|
|
}
|
|
|
|
/* Move on to the next block in the sorted run. Or set iBlk to zero
|
|
** in order to break out of the loop if this was the last block in
|
|
** the run. */
|
|
if( iBlk==iLastBlk ){
|
|
iBlk = 0;
|
|
}else{
|
|
rc = fsBlockNext(pFS, pSeg, iBlk, &iBlk);
|
|
assert( rc==LSM_OK );
|
|
}
|
|
}while( iBlk );
|
|
}
|
|
}
|
|
}
|
|
|
|
typedef struct CheckFreelistCtx CheckFreelistCtx;
|
|
struct CheckFreelistCtx {
|
|
u8 *aUsed;
|
|
int nBlock;
|
|
};
|
|
static int checkFreelistCb(void *pCtx, int iBlk, i64 iSnapshot){
|
|
CheckFreelistCtx *p = (CheckFreelistCtx *)pCtx;
|
|
|
|
assert( iBlk>=1 );
|
|
assert( iBlk<=p->nBlock );
|
|
assert( p->aUsed[iBlk-1]==0 );
|
|
p->aUsed[iBlk-1] = INTEGRITY_CHECK_FREE;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** This function checks that all blocks in the database file are accounted
|
|
** for. For each block, exactly one of the following must be true:
|
|
**
|
|
** + the block is part of a sorted run, or
|
|
** + the block is on the free-block list
|
|
**
|
|
** This function also checks that there are no references to blocks with
|
|
** out-of-range block numbers.
|
|
**
|
|
** If no errors are found, non-zero is returned. If an error is found, an
|
|
** assert() fails.
|
|
*/
|
|
int lsmFsIntegrityCheck(lsm_db *pDb){
|
|
CheckFreelistCtx ctx;
|
|
FileSystem *pFS = pDb->pFS;
|
|
int i;
|
|
int rc;
|
|
Freelist freelist = {0, 0, 0};
|
|
u8 *aUsed;
|
|
Level *pLevel;
|
|
Snapshot *pWorker = pDb->pWorker;
|
|
int nBlock = pWorker->nBlock;
|
|
|
|
#if 0
|
|
static int nCall = 0;
|
|
nCall++;
|
|
printf("%d calls\n", nCall);
|
|
#endif
|
|
|
|
aUsed = lsmMallocZero(pDb->pEnv, nBlock);
|
|
if( aUsed==0 ){
|
|
/* Malloc has failed. Since this function is only called within debug
|
|
** builds, this probably means the user is running an OOM injection test.
|
|
** Regardless, it will not be possible to run the integrity-check at this
|
|
** time, so assume the database is Ok and return non-zero. */
|
|
return 1;
|
|
}
|
|
|
|
for(pLevel=pWorker->pLevel; pLevel; pLevel=pLevel->pNext){
|
|
int i;
|
|
checkBlocks(pFS, &pLevel->lhs, (pLevel->nRight!=0), nBlock, aUsed);
|
|
for(i=0; i<pLevel->nRight; i++){
|
|
checkBlocks(pFS, &pLevel->aRhs[i], 0, nBlock, aUsed);
|
|
}
|
|
}
|
|
|
|
/* Mark all blocks in the free-list as used */
|
|
ctx.aUsed = aUsed;
|
|
ctx.nBlock = nBlock;
|
|
rc = lsmWalkFreelist(pDb, 0, checkFreelistCb, (void *)&ctx);
|
|
|
|
if( rc==LSM_OK ){
|
|
for(i=0; i<nBlock; i++) assert( aUsed[i]!=0 );
|
|
}
|
|
|
|
lsmFree(pDb->pEnv, aUsed);
|
|
lsmFree(pDb->pEnv, freelist.aEntry);
|
|
|
|
return 1;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
/*
|
|
** Return true if pPg happens to be the last page in segment pSeg. Or false
|
|
** otherwise. This function is only invoked as part of assert() conditions.
|
|
*/
|
|
int lsmFsDbPageIsLast(Segment *pSeg, Page *pPg){
|
|
if( pPg->pFS->pCompress ){
|
|
Pgno iNext = 0;
|
|
int rc;
|
|
rc = fsNextPageOffset(pPg->pFS, pSeg, pPg->iPg, pPg->nCompress+6, &iNext);
|
|
return (rc!=LSM_OK || iNext==0);
|
|
}
|
|
return (pPg->iPg==pSeg->iLastPg);
|
|
}
|
|
#endif
|