Instead of storing a pointer to the parent page in the MemPage structure, have each B-Tree cursor keep track of the ancestry of the current page. (CVS 5747)

FossilOrigin-Name: 40425e93421286cca1965d7a5769084526210c7a

manifest

@@ -1,5 +1,5 @@
-C fix\s#3077:\suse\sfull\sversion\sin\spkg-config\sfiles\s(CVS\s5746)
+C Instead\sof\sstoring\sa\spointer\sto\sthe\sparent\spage\sin\sthe\sMemPage\sstructure,\shave\seach\sB-Tree\scursor\skeep\strack\sof\sthe\sancestry\sof\sthe\scurrent\spage.\s(CVS\s5747)
-D 2008-09-29T00:11:22
+D 2008-09-29T11:49:48
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in e4ab842f9a64ef61d57093539a8aab76b12810db
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -99,9 +99,9 @@ F src/attach.c db3f4a60538733c1e4dcb9d0217a6e0d6ccd615b
 F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/bitvec.c 95c86bd18d8fedf0533f5af196192546e10a7e7d
 F src/btmutex.c 709cad2cdca0afd013f0f612363810e53f59ec53
-F src/btree.c 850d7ede7fe58f8bfad78131278ceff83817abf5
+F src/btree.c 8fc7c0bd577e0e8850d95b0f8d927c983e53deab
 F src/btree.h 6371c5e599fab391a150c96afbc10062b276d107
-F src/btreeInt.h e36f77e6621d671beb19ae581af1eba116cdfdc4
+F src/btreeInt.h a9388a5e5998cec0b79c2024e6740d12d094ad17
 F src/build.c 160c71acca8f643f436ed6c1ee2f684c88df4dfe
 F src/callback.c 7a40fd44da3eb89e7f6eff30aa6f940c45d73a97
 F src/complete.c cb14e06dbe79dee031031f0d9e686ff306afe07c
@@ -137,11 +137,11 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
 F src/os_os2.c e391fc95adc744bbdcefd4d11e3066998185a0a0
 F src/os_unix.c f33b69d8a85372b270fe37ee664a4c2140a5217d
 F src/os_win.c 3209dc0ed734291764393ea8d534ba0d8696a540
-F src/pager.c 6426902ba983ce6872fcec20ba72796a79d6cead
+F src/pager.c 44eba010e81dcc9b772401b90d6a1c61ec24345b
-F src/pager.h 30e71f447ecbcfef707bb72cc813ce37ab5a2bc9
+F src/pager.h 9c1917be28fff58118e1fe0ddbc7adfb8dd4f44d
 F src/parse.y d0f76d2cb8d6883d5600dc20beb961a6022b94b8
-F src/pcache.c 52108517c38bcf023f3977085a66aacb520a5385
+F src/pcache.c f8d7beceba164a34441ac37e88abb3a404f968a7
-F src/pcache.h 0b6871e820159629915e8688b5c67a81a203773f
+F src/pcache.h 28d9ce2d66909db1f01652586450b62b64793093
 F src/pragma.c 0b1c2d2a241dd79a7361bbeb8ff575a9e9d7cd71
 F src/prepare.c c7e00ed1b0bdcf699b1aad651247d4dc3d281b0b
 F src/printf.c 785f87120589c1db672e37c6eb1087c456e6f84d
@@ -157,7 +157,7 @@ F src/status.c 237b193efae0cf6ac3f0817a208de6c6c6ef6d76
 F src/table.c 22744786199c9195720c15a7a42cb97b2e2728d8
 F src/tclsqlite.c 6a7eeff5afd8f5f10fcb7fd7806e56c725dd2b07
 F src/test1.c c4de690aad182606e5914f6f3c8f43869fbdaaa8
-F src/test2.c eaa77124786649eedf47d3c5e94d8070c0da228f
+F src/test2.c 897528183edf2839c2a3c991d415905db56f1240
 F src/test3.c e85b7ce5c28c3ce7fbdbf7f98e1467b19786c62b
 F src/test4.c 41056378671e7b00e6305fa9ac6fa27e6f96f406
 F src/test5.c 162a1cea2105a2c460a3f39fa6919617b562a288
@@ -167,7 +167,7 @@ F src/test8.c 3637439424d0d21ff2dcf9b015c30fcc1e7bcb24
 F src/test9.c 904ebe0ed1472d6bad17a81e2ecbfc20017dc237
 F src/test_async.c 45024094ed7cf780c5d5dccda645145f95cf78ef
 F src/test_autoext.c f53b0cdf7bf5f08100009572a5d65cdb540bd0ad
-F src/test_btree.c 8d5b835054f1dd15992e09864a8bc04386bab701
+F src/test_btree.c d7b8716544611c323860370ee364e897c861f1b0
 F src/test_config.c db72e95bafdd53c05ceb8735f833cc5dc1f48782
 F src/test_devsym.c 802d10e65b4217208cb47059b84adf46318bcdf4
 F src/test_func.c a55c4d5479ff2eb5c0a22d4d88e9528ab59c953b
@@ -253,7 +253,7 @@ F test/colmeta.test 087c42997754b8c648819832241daf724f813322
 F test/colname.test 0f05fea3e5c9260ece53117ad400657515c34280
 F test/conflict.test bb29b052c60a1f7eb6382be77902061d1f305318
 F test/corrupt.test 5bcf7a986358123b8055dfa64b45fc2fb54dcaa9
-F test/corrupt2.test 08fb049fdf4f72902ff39b1c609e7c1c2e985d8b
+F test/corrupt2.test b83f690753525ddac4a9c96e6ba11886ddaf24ea
 F test/corrupt3.test 263e8bb04e2728df832fddf6973cf54c91db0c32
 F test/corrupt4.test acdb01afaedf529004b70e55de1a6f5a05ae7fff
 F test/corrupt5.test 7796d5bdfe155ed824cee9dff371f49da237cfe0
@@ -637,7 +637,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 7c561f2e9264de676c1028943f6c3d06542fd802
+P efe095e0cb8e0f8a11fd9cc321ec83b556458bf2
-R 02a6492d8d58a0069722b4e87a758448
+R a0f3c37847099f2dcfb6efb98a6a77ac
-U vapier
+U danielk1977
-Z f2828935781c5b8b7b8d7e5f72f7da88
+Z 079550270237333fc6211bd885a42871

manifest.uuid

@@ -1 +1 @@
-efe095e0cb8e0f8a11fd9cc321ec83b556458bf2
+40425e93421286cca1965d7a5769084526210c7a

src/btreeInt.h

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btreeInt.h,v 1.31 2008/09/18 17:34:44 danielk1977 Exp $
+** $Id: btreeInt.h,v 1.32 2008/09/29 11:49:48 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
@@ -281,7 +281,6 @@ struct MemPage {
   u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
   u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
   u16 cellOffset;      /* Index in aData of first cell pointer */
-  u16 idxParent;       /* Index in parent of this node */
   u16 nFree;           /* Number of free bytes on the page */
   u16 nCell;           /* Number of cells on this page, local and ovfl */
   u16 maskPage;        /* Mask for page offset */
@@ -293,21 +292,8 @@ struct MemPage {
   u8 *aData;           /* Pointer to disk image of the page data */
   DbPage *pDbPage;     /* Pager page handle */
   Pgno pgno;           /* Page number for this page */
-  MemPage *pParent;    /* The parent of this page.  NULL for root */
 };
 
-/*
-** Possible values for the MemPage.isInit variable. When a page is first
-** loaded or if the data stored in the MemPage struct is invalidated, 
-** MemPage.isInit is set to PAGE_ISINIT_NONE. If the MemPage structure
-** is fully initialized, then MemPage.isInit is set to PAGE_ISINIT_FULL.
-** MemPage.isInit is set to PAGE_ISINIT_DATA when the MemPage struct is
-** populated, but the MemPage.pParent variable is not necessarily correct.
-*/
-#define PAGE_ISINIT_NONE 0
-#define PAGE_ISINIT_DATA 1
-#define PAGE_ISINIT_FULL 2
-
 /*
 ** The in-memory image of a disk page has the auxiliary information appended
 ** to the end.  EXTRA_SIZE is the number of bytes of space needed to hold
@@ -426,6 +412,17 @@ struct CellInfo {
   u16 nSize;     /* Size of the cell content on the main b-tree page */
 };
 
+/*
+** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
+** this will be declared corrupt. This value is calculated based on a
+** maximum database size of 2^31 pages a minimum fanout of 2 for a
+** root-node and 3 for all other internal nodes.
+**
+** If a tree that appears to be taller than this is encountered, it is
+** assumed that the database is corrupt.
+*/
+#define BTCURSOR_MAX_DEPTH 20
+
 /*
 ** A cursor is a pointer to a particular entry within a particular
 ** b-tree within a database file.
@@ -446,8 +443,6 @@ struct BtCursor {
   BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
   struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
   Pgno pgnoRoot;            /* The root page of this tree */
-  MemPage *pPage;           /* Page that contains the entry */
-  int idx;                  /* Index of the entry in pPage->aCell[] */
   CellInfo info;            /* A parse of the cell we are pointing at */
   u8 wrFlag;                /* True if writable */
   u8 atLast;                /* Cursor pointing to the last entry */
@@ -460,6 +455,10 @@ struct BtCursor {
   u8 isIncrblobHandle;      /* True if this cursor is an incr. io handle */
   Pgno *aOverflow;          /* Cache of overflow page locations */
 #endif
+
+  i16 iPage;                            /* Index of current page in apPage */
+  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
+  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
 };
 
 /*
@@ -629,11 +628,10 @@ struct IntegrityCk {
 ** Internal routines that should be accessed by the btree layer only.
 */
 int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int);
-int sqlite3BtreeInitPage(MemPage *pPage, MemPage *pParent);
+int sqlite3BtreeInitPage(MemPage *pPage);
 void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*);
 void sqlite3BtreeParseCell(MemPage*, int, CellInfo*);
 int sqlite3BtreeRestoreCursorPosition(BtCursor *pCur);
 void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur);
 void sqlite3BtreeReleaseTempCursor(BtCursor *pCur);
-int sqlite3BtreeIsRootPage(MemPage *pPage);
 void sqlite3BtreeMoveToParent(BtCursor *pCur);

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.495 2008/09/26 21:08:08 drh Exp $
+** @(#) $Id: pager.c,v 1.496 2008/09/29 11:49:48 danielk1977 Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -1728,7 +1728,6 @@ int sqlite3PagerOpen(
   sqlite3_vfs *pVfs,       /* The virtual file system to use */
   Pager **ppPager,         /* Return the Pager structure here */
   const char *zFilename,   /* Name of the database file to open */
-  void (*xDesc)(DbPage*),  /* Page destructor function */
   int nExtra,              /* Extra bytes append to each in-memory page */
   int flags,               /* flags controlling this file */
   int vfsFlags             /* flags passed through to sqlite3_vfs.xOpen() */
@@ -1870,7 +1869,7 @@ int sqlite3PagerOpen(
     return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
   }
   nExtra = FORCE_ALIGNMENT(nExtra);
-  sqlite3PcacheOpen(szPageDflt, nExtra, !memDb, xDesc, 
+  sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
                     !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
 
   PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename);
@@ -3875,6 +3874,13 @@ int sqlite3PagerRefcount(Pager *pPager){
   return sqlite3PcacheRefCount(pPager->pPCache);
 }
 
+/*
+** Return the number of references to the specified page.
+*/
+int sqlite3PagerPageRefcount(DbPage *pPage){
+  return sqlite3PcachePageRefcount(pPage);
+}
+
 #ifdef SQLITE_TEST
 /*
 ** This routine is used for testing and analysis only.
@@ -4176,7 +4182,7 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
 ** Return a pointer to the data for the specified page.
 */
 void *sqlite3PagerGetData(DbPage *pPg){
-  assert( pPg->nRef>0 );
+  assert( pPg->nRef>0 || pPg->pPager->memDb );
   return pPg->pData;
 }
 

src/pager.h

@@ -13,7 +13,7 @@
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
 **
-** @(#) $Id: pager.h,v 1.84 2008/09/26 21:08:08 drh Exp $
+** @(#) $Id: pager.h,v 1.85 2008/09/29 11:49:48 danielk1977 Exp $
 */
 
 #ifndef _PAGER_H_
@@ -71,7 +71,7 @@ typedef struct PgHdr DbPage;
 ** See source code comments for a detailed description of the following
 ** routines:
 */
-int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, void(*)(DbPage*), int,int,int);
+int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, int,int,int);
 void sqlite3PagerSetBusyhandler(Pager*, BusyHandler *pBusyHandler);
 void sqlite3PagerSetReiniter(Pager*, void(*)(DbPage*));
 int sqlite3PagerSetPagesize(Pager*, u16*);
@@ -82,6 +82,7 @@ int sqlite3PagerClose(Pager *pPager);
 int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
 #define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0)
 DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
+int sqlite3PagerPageRefcount(DbPage*);
 int sqlite3PagerRef(DbPage*);
 int sqlite3PagerUnref(DbPage*);
 int sqlite3PagerWrite(DbPage*);

src/pcache.c

@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file implements that page cache.
 **
-** @(#) $Id: pcache.c,v 1.32 2008/09/24 09:12:47 danielk1977 Exp $
+** @(#) $Id: pcache.c,v 1.33 2008/09/29 11:49:48 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 
@@ -43,7 +43,6 @@ struct PCache {
   int szPage;                         /* Size of every page in this cache */
   int szExtra;                        /* Size of extra space for each page */
   int bPurgeable;                     /* True if pages are on backing store */
-  void (*xDestroy)(PgHdr*);           /* Called when refcnt goes 1->0 */
   int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
   void *pStress;                      /* Argument to xStress */
   /**********************************************************************
@@ -643,7 +642,6 @@ void sqlite3PcacheOpen(
   int szPage,                  /* Size of every page */
   int szExtra,                 /* Extra space associated with each page */
   int bPurgeable,              /* True if pages are on backing store */
-  void (*xDestroy)(PgHdr*),    /* Called to destroy a page */
   int (*xStress)(void*,PgHdr*),/* Call to try to make pages clean */
   void *pStress,               /* Argument to xStress */
   PCache *p                    /* Preallocated space for the PCache */
@@ -653,7 +651,6 @@ void sqlite3PcacheOpen(
   p->szPage = szPage;
   p->szExtra = szExtra;
   p->bPurgeable = bPurgeable;
-  p->xDestroy = xDestroy;
   p->xStress = xStress;
   p->pStress = pStress;
   p->nMax = 100;
@@ -752,9 +749,6 @@ void sqlite3PcacheRelease(PgHdr *p){
   p->nRef--;
   if( p->nRef==0 ){
     PCache *pCache = p->pCache;
-    if( p->pCache->xDestroy ){
-      p->pCache->xDestroy(p);
-    }
     pCache->nRef--;
     if( (p->flags&PGHDR_DIRTY)==0 ){
       pCache->nPinned--;
@@ -1163,6 +1157,10 @@ int sqlite3PcacheRefCount(PCache *pCache){
   return pCache->nRef;
 }
 
+int sqlite3PcachePageRefcount(PgHdr *p){
+  return p->nRef;
+}
+
 /* 
 ** Return the total number of pages in the cache.
 */

src/pcache.h

@@ -12,7 +12,7 @@
 ** This header file defines the interface that the sqlite page cache
 ** subsystem. 
 **
-** @(#) $Id: pcache.h,v 1.11 2008/09/18 17:34:44 danielk1977 Exp $
+** @(#) $Id: pcache.h,v 1.12 2008/09/29 11:49:48 danielk1977 Exp $
 */
 
 #ifndef _PCACHE_H_
@@ -79,7 +79,6 @@ void sqlite3PcacheOpen(
   int szPage,                    /* Size of every page */
   int szExtra,                   /* Extra space associated with each page */
   int bPurgeable,                /* True if pages are on backing store */
-  void (*xDestroy)(PgHdr *),     /* Called to destroy a page */
   int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */
   void *pStress,                 /* Argument to xStress */
   PCache *pToInit                /* Preallocated space for the PCache */
@@ -143,6 +142,8 @@ int sqlite3PcacheRefCount(PCache*);
 /* Increment the reference count of an existing page */
 void sqlite3PcacheRef(PgHdr*);
 
+int sqlite3PcachePageRefcount(PgHdr*);
+
 /* Return the total number of pages stored in the cache */
 int sqlite3PcachePagecount(PCache*);
 

src/test2.c

@@ -13,7 +13,7 @@
 ** is not included in the SQLite library.  It is used for automated
 ** testing of the SQLite library.
 **
-** $Id: test2.c,v 1.61 2008/08/26 18:05:48 danielk1977 Exp $
+** $Id: test2.c,v 1.62 2008/09/29 11:49:48 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "tcl.h"
@@ -78,7 +78,7 @@ static int pager_open(
     return TCL_ERROR;
   }
   if( Tcl_GetInt(interp, argv[2], &nPage) ) return TCL_ERROR;
-  rc = sqlite3PagerOpen(sqlite3_vfs_find(0), &pPager, argv[1], 0, 0, 0,
+  rc = sqlite3PagerOpen(sqlite3_vfs_find(0), &pPager, argv[1], 0, 0,
       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_MAIN_DB);
   if( rc!=SQLITE_OK ){
     Tcl_AppendResult(interp, errorName(rc), 0);

src/test_btree.c

@@ -13,7 +13,7 @@
 ** is not included in the SQLite library.  It is used for automated
 ** testing of the SQLite library.
 **
-** $Id: test_btree.c,v 1.7 2008/09/02 00:52:52 drh Exp $
+** $Id: test_btree.c,v 1.8 2008/09/29 11:49:48 danielk1977 Exp $
 */
 #include "btreeInt.h"
 #include <tcl.h>
@@ -52,11 +52,11 @@ void sqlite3BtreeCursorList(Btree *p){
   BtCursor *pCur;
   BtShared *pBt = p->pBt;
   for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
-    MemPage *pPage = pCur->pPage;
+    MemPage *pPage = pCur->apPage[pCur->iPage];
     char *zMode = pCur->wrFlag ? "rw" : "ro";
     sqlite3DebugPrintf("CURSOR %p rooted at %4d(%s) currently at %d.%d%s\n",
        pCur, pCur->pgnoRoot, zMode,
-       pPage ? pPage->pgno : 0, pCur->idx,
+       pPage ? pPage->pgno : 0, pCur->aiIdx[pCur->iPage],
        (pCur->eState==CURSOR_VALID) ? "" : " eof"
     );
   }
@@ -83,8 +83,9 @@ void sqlite3BtreeCursorList(Btree *p){
 ** This routine is used for testing and debugging only.
 */
 int sqlite3BtreeCursorInfo(BtCursor *pCur, int *aResult, int upCnt){
+#if 0
   int cnt, idx;
-  MemPage *pPage = pCur->pPage;
+  MemPage *pPage = pCur->apPage[pCur->iPage];
   BtCursor tmpCur;
   int rc;
 
@@ -136,5 +137,6 @@ int sqlite3BtreeCursorInfo(BtCursor *pCur, int *aResult, int upCnt){
     aResult[10] = 0;
   }
   sqlite3BtreeReleaseTempCursor(&tmpCur);
+#endif
   return SQLITE_OK;
 }

test/corrupt2.test

@@ -13,7 +13,7 @@
 # This file implements tests to make sure SQLite does not crash or
 # segfault if it sees a corrupt database file.
 #
-# $Id: corrupt2.test,v 1.17 2008/09/10 11:28:38 danielk1977 Exp $
+# $Id: corrupt2.test,v 1.18 2008/09/29 11:49:48 danielk1977 Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -225,8 +225,6 @@ do_test corrupt2-5.1 {
   }
   set result
 } {{*** in database main ***
-Page 10: sqlite3BtreeInitPage() returns error code 11
-On tree page 3 cell 1: Child page depth differs
 On tree page 2 cell 0: 2nd reference to page 10
 On tree page 2 cell 1: Child page depth differs
 Page 4 is never used}}