19c8dc839b
functions into one ReadBufferExtended function, that takes the strategy and mode as argument. There's three modes, RBM_NORMAL which is the default used by plain ReadBuffer(), RBM_ZERO, which replaces ZeroOrReadBuffer, and a new mode RBM_ZERO_ON_ERROR, which allows callers to read corrupt pages without throwing an error. The FSM needs the new mode to recover from corrupt pages, which could happend if we crash after extending an FSM file, and the new page is "torn". Add fork number to some error messages in bufmgr.c, that still lacked it.
1042 lines
30 KiB
C
1042 lines
30 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* vacuumlazy.c
|
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* Concurrent ("lazy") vacuuming.
|
|
*
|
|
*
|
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* The major space usage for LAZY VACUUM is storage for the array of dead
|
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* tuple TIDs, with the next biggest need being storage for per-disk-page
|
|
* free space info. We want to ensure we can vacuum even the very largest
|
|
* relations with finite memory space usage. To do that, we set upper bounds
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* on the number of tuples and pages we will keep track of at once.
|
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*
|
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* We are willing to use at most maintenance_work_mem memory space to keep
|
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* track of dead tuples. We initially allocate an array of TIDs of that size,
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* with an upper limit that depends on table size (this limit ensures we don't
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* allocate a huge area uselessly for vacuuming small tables). If the array
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* threatens to overflow, we suspend the heap scan phase and perform a pass of
|
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* index cleanup and page compaction, then resume the heap scan with an empty
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* TID array.
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*
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* If we're processing a table with no indexes, we can just vacuum each page
|
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* as we go; there's no need to save up multiple tuples to minimize the number
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* of index scans performed. So we don't use maintenance_work_mem memory for
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* the TID array, just enough to hold as many heap tuples as fit on one page.
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*
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*
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* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
|
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
|
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* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.109 2008/10/31 15:05:00 heikki Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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|
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#include <math.h>
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|
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#include "access/genam.h"
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#include "access/heapam.h"
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#include "access/transam.h"
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#include "commands/dbcommands.h"
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#include "commands/vacuum.h"
|
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "postmaster/autovacuum.h"
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#include "storage/bufmgr.h"
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#include "storage/freespace.h"
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|
#include "storage/lmgr.h"
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#include "utils/lsyscache.h"
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|
#include "utils/memutils.h"
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#include "utils/pg_rusage.h"
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|
#include "utils/tqual.h"
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|
|
|
|
|
/*
|
|
* Space/time tradeoff parameters: do these need to be user-tunable?
|
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*
|
|
* To consider truncating the relation, we want there to be at least
|
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* REL_TRUNCATE_MINIMUM or (relsize / REL_TRUNCATE_FRACTION) (whichever
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* is less) potentially-freeable pages.
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*/
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#define REL_TRUNCATE_MINIMUM 1000
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#define REL_TRUNCATE_FRACTION 16
|
|
|
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/*
|
|
* Guesstimation of number of dead tuples per page. This is used to
|
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* provide an upper limit to memory allocated when vacuuming small
|
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* tables.
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|
*/
|
|
#define LAZY_ALLOC_TUPLES MaxHeapTuplesPerPage
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|
|
|
typedef struct LVRelStats
|
|
{
|
|
/* hasindex = true means two-pass strategy; false means one-pass */
|
|
bool hasindex;
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/* Overall statistics about rel */
|
|
BlockNumber rel_pages;
|
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double rel_tuples;
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|
BlockNumber pages_removed;
|
|
double tuples_deleted;
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|
BlockNumber nonempty_pages; /* actually, last nonempty page + 1 */
|
|
/* List of TIDs of tuples we intend to delete */
|
|
/* NB: this list is ordered by TID address */
|
|
int num_dead_tuples; /* current # of entries */
|
|
int max_dead_tuples; /* # slots allocated in array */
|
|
ItemPointer dead_tuples; /* array of ItemPointerData */
|
|
int num_index_scans;
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} LVRelStats;
|
|
|
|
|
|
/* A few variables that don't seem worth passing around as parameters */
|
|
static int elevel = -1;
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|
|
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static TransactionId OldestXmin;
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static TransactionId FreezeLimit;
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|
|
|
static BufferAccessStrategy vac_strategy;
|
|
|
|
|
|
/* non-export function prototypes */
|
|
static void lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
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Relation *Irel, int nindexes);
|
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static void lazy_vacuum_heap(Relation onerel, LVRelStats *vacrelstats);
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static void lazy_vacuum_index(Relation indrel,
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IndexBulkDeleteResult **stats,
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|
LVRelStats *vacrelstats);
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static void lazy_cleanup_index(Relation indrel,
|
|
IndexBulkDeleteResult *stats,
|
|
LVRelStats *vacrelstats);
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static int lazy_vacuum_page(Relation onerel, BlockNumber blkno, Buffer buffer,
|
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int tupindex, LVRelStats *vacrelstats);
|
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static void lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats);
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static BlockNumber count_nondeletable_pages(Relation onerel,
|
|
LVRelStats *vacrelstats);
|
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static void lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks);
|
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static void lazy_record_dead_tuple(LVRelStats *vacrelstats,
|
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ItemPointer itemptr);
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static bool lazy_tid_reaped(ItemPointer itemptr, void *state);
|
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static int vac_cmp_itemptr(const void *left, const void *right);
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|
|
|
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/*
|
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* lazy_vacuum_rel() -- perform LAZY VACUUM for one heap relation
|
|
*
|
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* This routine vacuums a single heap, cleans out its indexes, and
|
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* updates its relpages and reltuples statistics.
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|
*
|
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* At entry, we have already established a transaction and opened
|
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* and locked the relation.
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|
*/
|
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void
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|
lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
|
|
BufferAccessStrategy bstrategy)
|
|
{
|
|
LVRelStats *vacrelstats;
|
|
Relation *Irel;
|
|
int nindexes;
|
|
BlockNumber possibly_freeable;
|
|
PGRUsage ru0;
|
|
TimestampTz starttime = 0;
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|
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|
pg_rusage_init(&ru0);
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|
|
|
/* measure elapsed time iff autovacuum logging requires it */
|
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if (IsAutoVacuumWorkerProcess() && Log_autovacuum_min_duration > 0)
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starttime = GetCurrentTimestamp();
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if (vacstmt->verbose)
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elevel = INFO;
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else
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elevel = DEBUG2;
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vac_strategy = bstrategy;
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|
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vacuum_set_xid_limits(vacstmt->freeze_min_age, onerel->rd_rel->relisshared,
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&OldestXmin, &FreezeLimit);
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|
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vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
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|
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|
vacrelstats->num_index_scans = 0;
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|
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|
/* Open all indexes of the relation */
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|
vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel);
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vacrelstats->hasindex = (nindexes > 0);
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|
|
|
/* Do the vacuuming */
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lazy_scan_heap(onerel, vacrelstats, Irel, nindexes);
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|
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/* Done with indexes */
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|
vac_close_indexes(nindexes, Irel, NoLock);
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|
|
|
/*
|
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* Optionally truncate the relation.
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|
*
|
|
* Don't even think about it unless we have a shot at releasing a goodly
|
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* number of pages. Otherwise, the time taken isn't worth it.
|
|
*/
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|
possibly_freeable = vacrelstats->rel_pages - vacrelstats->nonempty_pages;
|
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if (possibly_freeable >= REL_TRUNCATE_MINIMUM ||
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possibly_freeable >= vacrelstats->rel_pages / REL_TRUNCATE_FRACTION)
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lazy_truncate_heap(onerel, vacrelstats);
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|
|
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/* Vacuum the Free Space Map */
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|
FreeSpaceMapVacuum(onerel);
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|
|
|
/* Update statistics in pg_class */
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|
vac_update_relstats(RelationGetRelid(onerel),
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|
vacrelstats->rel_pages,
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|
vacrelstats->rel_tuples,
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|
vacrelstats->hasindex,
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|
FreezeLimit);
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|
|
|
/* report results to the stats collector, too */
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|
pgstat_report_vacuum(RelationGetRelid(onerel), onerel->rd_rel->relisshared,
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vacstmt->analyze, vacrelstats->rel_tuples);
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/* and log the action if appropriate */
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if (IsAutoVacuumWorkerProcess() && Log_autovacuum_min_duration >= 0)
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{
|
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if (Log_autovacuum_min_duration == 0 ||
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TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
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|
Log_autovacuum_min_duration))
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|
ereport(LOG,
|
|
(errmsg("automatic vacuum of table \"%s.%s.%s\": index scans: %d\n"
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|
"pages: %d removed, %d remain\n"
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|
"tuples: %.0f removed, %.0f remain\n"
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|
"system usage: %s",
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|
get_database_name(MyDatabaseId),
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get_namespace_name(RelationGetNamespace(onerel)),
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RelationGetRelationName(onerel),
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vacrelstats->num_index_scans,
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vacrelstats->pages_removed, vacrelstats->rel_pages,
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vacrelstats->tuples_deleted, vacrelstats->rel_tuples,
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pg_rusage_show(&ru0))));
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}
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}
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|
|
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/*
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* lazy_scan_heap() -- scan an open heap relation
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*
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|
* This routine sets commit status bits, builds lists of dead tuples
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* and pages with free space, and calculates statistics on the number
|
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* of live tuples in the heap. When done, or when we run low on space
|
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* for dead-tuple TIDs, invoke vacuuming of indexes and heap.
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|
*
|
|
* If there are no indexes then we just vacuum each dirty page as we
|
|
* process it, since there's no point in gathering many tuples.
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|
*/
|
|
static void
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|
lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
|
|
Relation *Irel, int nindexes)
|
|
{
|
|
BlockNumber nblocks,
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|
blkno;
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|
HeapTupleData tuple;
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|
char *relname;
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|
BlockNumber empty_pages,
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|
vacuumed_pages;
|
|
double num_tuples,
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|
tups_vacuumed,
|
|
nkeep,
|
|
nunused;
|
|
IndexBulkDeleteResult **indstats;
|
|
int i;
|
|
PGRUsage ru0;
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|
|
|
pg_rusage_init(&ru0);
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|
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relname = RelationGetRelationName(onerel);
|
|
ereport(elevel,
|
|
(errmsg("vacuuming \"%s.%s\"",
|
|
get_namespace_name(RelationGetNamespace(onerel)),
|
|
relname)));
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|
|
|
empty_pages = vacuumed_pages = 0;
|
|
num_tuples = tups_vacuumed = nkeep = nunused = 0;
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|
|
|
indstats = (IndexBulkDeleteResult **)
|
|
palloc0(nindexes * sizeof(IndexBulkDeleteResult *));
|
|
|
|
nblocks = RelationGetNumberOfBlocks(onerel);
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|
vacrelstats->rel_pages = nblocks;
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vacrelstats->nonempty_pages = 0;
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|
|
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lazy_space_alloc(vacrelstats, nblocks);
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|
|
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for (blkno = 0; blkno < nblocks; blkno++)
|
|
{
|
|
Buffer buf;
|
|
Page page;
|
|
OffsetNumber offnum,
|
|
maxoff;
|
|
bool tupgone,
|
|
hastup;
|
|
int prev_dead_count;
|
|
OffsetNumber frozen[MaxOffsetNumber];
|
|
int nfrozen;
|
|
Size freespace;
|
|
|
|
vacuum_delay_point();
|
|
|
|
/*
|
|
* If we are close to overrunning the available space for dead-tuple
|
|
* TIDs, pause and do a cycle of vacuuming before we tackle this page.
|
|
*/
|
|
if ((vacrelstats->max_dead_tuples - vacrelstats->num_dead_tuples) < MaxHeapTuplesPerPage &&
|
|
vacrelstats->num_dead_tuples > 0)
|
|
{
|
|
/* Remove index entries */
|
|
for (i = 0; i < nindexes; i++)
|
|
lazy_vacuum_index(Irel[i],
|
|
&indstats[i],
|
|
vacrelstats);
|
|
/* Remove tuples from heap */
|
|
lazy_vacuum_heap(onerel, vacrelstats);
|
|
/* Forget the now-vacuumed tuples, and press on */
|
|
vacrelstats->num_dead_tuples = 0;
|
|
vacrelstats->num_index_scans++;
|
|
}
|
|
|
|
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
|
|
RBM_NORMAL, vac_strategy);
|
|
|
|
/* We need buffer cleanup lock so that we can prune HOT chains. */
|
|
LockBufferForCleanup(buf);
|
|
|
|
page = BufferGetPage(buf);
|
|
|
|
if (PageIsNew(page))
|
|
{
|
|
/*
|
|
* An all-zeroes page could be left over if a backend extends the
|
|
* relation but crashes before initializing the page. Reclaim such
|
|
* pages for use.
|
|
*
|
|
* We have to be careful here because we could be looking at a
|
|
* page that someone has just added to the relation and not yet
|
|
* been able to initialize (see RelationGetBufferForTuple). To
|
|
* protect against that, release the buffer lock, grab the
|
|
* relation extension lock momentarily, and re-lock the buffer. If
|
|
* the page is still uninitialized by then, it must be left over
|
|
* from a crashed backend, and we can initialize it.
|
|
*
|
|
* We don't really need the relation lock when this is a new or
|
|
* temp relation, but it's probably not worth the code space to
|
|
* check that, since this surely isn't a critical path.
|
|
*
|
|
* Note: the comparable code in vacuum.c need not worry because
|
|
* it's got exclusive lock on the whole relation.
|
|
*/
|
|
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
|
|
LockRelationForExtension(onerel, ExclusiveLock);
|
|
UnlockRelationForExtension(onerel, ExclusiveLock);
|
|
LockBufferForCleanup(buf);
|
|
if (PageIsNew(page))
|
|
{
|
|
ereport(WARNING,
|
|
(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
|
|
relname, blkno)));
|
|
PageInit(page, BufferGetPageSize(buf), 0);
|
|
empty_pages++;
|
|
}
|
|
freespace = PageGetHeapFreeSpace(page);
|
|
MarkBufferDirty(buf);
|
|
UnlockReleaseBuffer(buf);
|
|
|
|
RecordPageWithFreeSpace(onerel, blkno, freespace);
|
|
continue;
|
|
}
|
|
|
|
if (PageIsEmpty(page))
|
|
{
|
|
empty_pages++;
|
|
freespace = PageGetHeapFreeSpace(page);
|
|
UnlockReleaseBuffer(buf);
|
|
RecordPageWithFreeSpace(onerel, blkno, freespace);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Prune all HOT-update chains in this page.
|
|
*
|
|
* We count tuples removed by the pruning step as removed by VACUUM.
|
|
*/
|
|
tups_vacuumed += heap_page_prune(onerel, buf, OldestXmin,
|
|
false, false);
|
|
|
|
/*
|
|
* Now scan the page to collect vacuumable items and check for tuples
|
|
* requiring freezing.
|
|
*/
|
|
nfrozen = 0;
|
|
hastup = false;
|
|
prev_dead_count = vacrelstats->num_dead_tuples;
|
|
maxoff = PageGetMaxOffsetNumber(page);
|
|
for (offnum = FirstOffsetNumber;
|
|
offnum <= maxoff;
|
|
offnum = OffsetNumberNext(offnum))
|
|
{
|
|
ItemId itemid;
|
|
|
|
itemid = PageGetItemId(page, offnum);
|
|
|
|
/* Unused items require no processing, but we count 'em */
|
|
if (!ItemIdIsUsed(itemid))
|
|
{
|
|
nunused += 1;
|
|
continue;
|
|
}
|
|
|
|
/* Redirect items mustn't be touched */
|
|
if (ItemIdIsRedirected(itemid))
|
|
{
|
|
hastup = true; /* this page won't be truncatable */
|
|
continue;
|
|
}
|
|
|
|
ItemPointerSet(&(tuple.t_self), blkno, offnum);
|
|
|
|
/*
|
|
* DEAD item pointers are to be vacuumed normally; but we don't
|
|
* count them in tups_vacuumed, else we'd be double-counting (at
|
|
* least in the common case where heap_page_prune() just freed up
|
|
* a non-HOT tuple).
|
|
*/
|
|
if (ItemIdIsDead(itemid))
|
|
{
|
|
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
|
|
continue;
|
|
}
|
|
|
|
Assert(ItemIdIsNormal(itemid));
|
|
|
|
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
|
|
tuple.t_len = ItemIdGetLength(itemid);
|
|
|
|
tupgone = false;
|
|
|
|
switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
|
|
{
|
|
case HEAPTUPLE_DEAD:
|
|
|
|
/*
|
|
* Ordinarily, DEAD tuples would have been removed by
|
|
* heap_page_prune(), but it's possible that the tuple
|
|
* state changed since heap_page_prune() looked. In
|
|
* particular an INSERT_IN_PROGRESS tuple could have
|
|
* changed to DEAD if the inserter aborted. So this
|
|
* cannot be considered an error condition.
|
|
*
|
|
* If the tuple is HOT-updated then it must only be
|
|
* removed by a prune operation; so we keep it just as if
|
|
* it were RECENTLY_DEAD. Also, if it's a heap-only
|
|
* tuple, we choose to keep it, because it'll be a lot
|
|
* cheaper to get rid of it in the next pruning pass than
|
|
* to treat it like an indexed tuple.
|
|
*/
|
|
if (HeapTupleIsHotUpdated(&tuple) ||
|
|
HeapTupleIsHeapOnly(&tuple))
|
|
nkeep += 1;
|
|
else
|
|
tupgone = true; /* we can delete the tuple */
|
|
break;
|
|
case HEAPTUPLE_LIVE:
|
|
/* Tuple is good --- but let's do some validity checks */
|
|
if (onerel->rd_rel->relhasoids &&
|
|
!OidIsValid(HeapTupleGetOid(&tuple)))
|
|
elog(WARNING, "relation \"%s\" TID %u/%u: OID is invalid",
|
|
relname, blkno, offnum);
|
|
break;
|
|
case HEAPTUPLE_RECENTLY_DEAD:
|
|
|
|
/*
|
|
* If tuple is recently deleted then we must not remove it
|
|
* from relation.
|
|
*/
|
|
nkeep += 1;
|
|
break;
|
|
case HEAPTUPLE_INSERT_IN_PROGRESS:
|
|
/* This is an expected case during concurrent vacuum */
|
|
break;
|
|
case HEAPTUPLE_DELETE_IN_PROGRESS:
|
|
/* This is an expected case during concurrent vacuum */
|
|
break;
|
|
default:
|
|
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
|
|
break;
|
|
}
|
|
|
|
if (tupgone)
|
|
{
|
|
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
|
|
tups_vacuumed += 1;
|
|
}
|
|
else
|
|
{
|
|
num_tuples += 1;
|
|
hastup = true;
|
|
|
|
/*
|
|
* Each non-removable tuple must be checked to see if it needs
|
|
* freezing. Note we already have exclusive buffer lock.
|
|
*/
|
|
if (heap_freeze_tuple(tuple.t_data, FreezeLimit,
|
|
InvalidBuffer))
|
|
frozen[nfrozen++] = offnum;
|
|
}
|
|
} /* scan along page */
|
|
|
|
/*
|
|
* If we froze any tuples, mark the buffer dirty, and write a WAL
|
|
* record recording the changes. We must log the changes to be
|
|
* crash-safe against future truncation of CLOG.
|
|
*/
|
|
if (nfrozen > 0)
|
|
{
|
|
MarkBufferDirty(buf);
|
|
/* no XLOG for temp tables, though */
|
|
if (!onerel->rd_istemp)
|
|
{
|
|
XLogRecPtr recptr;
|
|
|
|
recptr = log_heap_freeze(onerel, buf, FreezeLimit,
|
|
frozen, nfrozen);
|
|
PageSetLSN(page, recptr);
|
|
PageSetTLI(page, ThisTimeLineID);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If there are no indexes then we can vacuum the page right now
|
|
* instead of doing a second scan.
|
|
*/
|
|
if (nindexes == 0 &&
|
|
vacrelstats->num_dead_tuples > 0)
|
|
{
|
|
/* Remove tuples from heap */
|
|
lazy_vacuum_page(onerel, blkno, buf, 0, vacrelstats);
|
|
/* Forget the now-vacuumed tuples, and press on */
|
|
vacrelstats->num_dead_tuples = 0;
|
|
vacuumed_pages++;
|
|
}
|
|
|
|
freespace = PageGetHeapFreeSpace(page);
|
|
|
|
/* Remember the location of the last page with nonremovable tuples */
|
|
if (hastup)
|
|
vacrelstats->nonempty_pages = blkno + 1;
|
|
|
|
UnlockReleaseBuffer(buf);
|
|
|
|
/*
|
|
* If we remembered any tuples for deletion, then the page will be
|
|
* visited again by lazy_vacuum_heap, which will compute and record
|
|
* its post-compaction free space. If not, then we're done with this
|
|
* page, so remember its free space as-is. (This path will always be
|
|
* taken if there are no indexes.)
|
|
*/
|
|
if (vacrelstats->num_dead_tuples == prev_dead_count)
|
|
RecordPageWithFreeSpace(onerel, blkno, freespace);
|
|
}
|
|
|
|
/* save stats for use later */
|
|
vacrelstats->rel_tuples = num_tuples;
|
|
vacrelstats->tuples_deleted = tups_vacuumed;
|
|
|
|
/* If any tuples need to be deleted, perform final vacuum cycle */
|
|
/* XXX put a threshold on min number of tuples here? */
|
|
if (vacrelstats->num_dead_tuples > 0)
|
|
{
|
|
/* Remove index entries */
|
|
for (i = 0; i < nindexes; i++)
|
|
lazy_vacuum_index(Irel[i],
|
|
&indstats[i],
|
|
vacrelstats);
|
|
/* Remove tuples from heap */
|
|
lazy_vacuum_heap(onerel, vacrelstats);
|
|
vacrelstats->num_index_scans++;
|
|
}
|
|
|
|
/* Do post-vacuum cleanup and statistics update for each index */
|
|
for (i = 0; i < nindexes; i++)
|
|
lazy_cleanup_index(Irel[i], indstats[i], vacrelstats);
|
|
|
|
/* If no indexes, make log report that lazy_vacuum_heap would've made */
|
|
if (vacuumed_pages)
|
|
ereport(elevel,
|
|
(errmsg("\"%s\": removed %.0f row versions in %u pages",
|
|
RelationGetRelationName(onerel),
|
|
tups_vacuumed, vacuumed_pages)));
|
|
|
|
ereport(elevel,
|
|
(errmsg("\"%s\": found %.0f removable, %.0f nonremovable row versions in %u pages",
|
|
RelationGetRelationName(onerel),
|
|
tups_vacuumed, num_tuples, nblocks),
|
|
errdetail("%.0f dead row versions cannot be removed yet.\n"
|
|
"There were %.0f unused item pointers.\n"
|
|
"%u pages are entirely empty.\n"
|
|
"%s.",
|
|
nkeep,
|
|
nunused,
|
|
empty_pages,
|
|
pg_rusage_show(&ru0))));
|
|
}
|
|
|
|
|
|
/*
|
|
* lazy_vacuum_heap() -- second pass over the heap
|
|
*
|
|
* This routine marks dead tuples as unused and compacts out free
|
|
* space on their pages. Pages not having dead tuples recorded from
|
|
* lazy_scan_heap are not visited at all.
|
|
*
|
|
* Note: the reason for doing this as a second pass is we cannot remove
|
|
* the tuples until we've removed their index entries, and we want to
|
|
* process index entry removal in batches as large as possible.
|
|
*/
|
|
static void
|
|
lazy_vacuum_heap(Relation onerel, LVRelStats *vacrelstats)
|
|
{
|
|
int tupindex;
|
|
int npages;
|
|
PGRUsage ru0;
|
|
|
|
pg_rusage_init(&ru0);
|
|
npages = 0;
|
|
|
|
tupindex = 0;
|
|
while (tupindex < vacrelstats->num_dead_tuples)
|
|
{
|
|
BlockNumber tblk;
|
|
Buffer buf;
|
|
Page page;
|
|
Size freespace;
|
|
|
|
vacuum_delay_point();
|
|
|
|
tblk = ItemPointerGetBlockNumber(&vacrelstats->dead_tuples[tupindex]);
|
|
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, tblk, RBM_NORMAL,
|
|
vac_strategy);
|
|
LockBufferForCleanup(buf);
|
|
tupindex = lazy_vacuum_page(onerel, tblk, buf, tupindex, vacrelstats);
|
|
|
|
/* Now that we've compacted the page, record its available space */
|
|
page = BufferGetPage(buf);
|
|
freespace = PageGetHeapFreeSpace(page);
|
|
|
|
UnlockReleaseBuffer(buf);
|
|
RecordPageWithFreeSpace(onerel, tblk, freespace);
|
|
npages++;
|
|
}
|
|
|
|
ereport(elevel,
|
|
(errmsg("\"%s\": removed %d row versions in %d pages",
|
|
RelationGetRelationName(onerel),
|
|
tupindex, npages),
|
|
errdetail("%s.",
|
|
pg_rusage_show(&ru0))));
|
|
}
|
|
|
|
/*
|
|
* lazy_vacuum_page() -- free dead tuples on a page
|
|
* and repair its fragmentation.
|
|
*
|
|
* Caller must hold pin and buffer cleanup lock on the buffer.
|
|
*
|
|
* tupindex is the index in vacrelstats->dead_tuples of the first dead
|
|
* tuple for this page. We assume the rest follow sequentially.
|
|
* The return value is the first tupindex after the tuples of this page.
|
|
*/
|
|
static int
|
|
lazy_vacuum_page(Relation onerel, BlockNumber blkno, Buffer buffer,
|
|
int tupindex, LVRelStats *vacrelstats)
|
|
{
|
|
Page page = BufferGetPage(buffer);
|
|
OffsetNumber unused[MaxOffsetNumber];
|
|
int uncnt = 0;
|
|
|
|
START_CRIT_SECTION();
|
|
|
|
for (; tupindex < vacrelstats->num_dead_tuples; tupindex++)
|
|
{
|
|
BlockNumber tblk;
|
|
OffsetNumber toff;
|
|
ItemId itemid;
|
|
|
|
tblk = ItemPointerGetBlockNumber(&vacrelstats->dead_tuples[tupindex]);
|
|
if (tblk != blkno)
|
|
break; /* past end of tuples for this block */
|
|
toff = ItemPointerGetOffsetNumber(&vacrelstats->dead_tuples[tupindex]);
|
|
itemid = PageGetItemId(page, toff);
|
|
ItemIdSetUnused(itemid);
|
|
unused[uncnt++] = toff;
|
|
}
|
|
|
|
PageRepairFragmentation(page);
|
|
|
|
MarkBufferDirty(buffer);
|
|
|
|
/* XLOG stuff */
|
|
if (!onerel->rd_istemp)
|
|
{
|
|
XLogRecPtr recptr;
|
|
|
|
recptr = log_heap_clean(onerel, buffer,
|
|
NULL, 0, NULL, 0,
|
|
unused, uncnt,
|
|
false);
|
|
PageSetLSN(page, recptr);
|
|
PageSetTLI(page, ThisTimeLineID);
|
|
}
|
|
|
|
END_CRIT_SECTION();
|
|
|
|
return tupindex;
|
|
}
|
|
|
|
/*
|
|
* lazy_vacuum_index() -- vacuum one index relation.
|
|
*
|
|
* Delete all the index entries pointing to tuples listed in
|
|
* vacrelstats->dead_tuples, and update running statistics.
|
|
*/
|
|
static void
|
|
lazy_vacuum_index(Relation indrel,
|
|
IndexBulkDeleteResult **stats,
|
|
LVRelStats *vacrelstats)
|
|
{
|
|
IndexVacuumInfo ivinfo;
|
|
PGRUsage ru0;
|
|
|
|
pg_rusage_init(&ru0);
|
|
|
|
ivinfo.index = indrel;
|
|
ivinfo.vacuum_full = false;
|
|
ivinfo.message_level = elevel;
|
|
/* We don't yet know rel_tuples, so pass -1 */
|
|
ivinfo.num_heap_tuples = -1;
|
|
ivinfo.strategy = vac_strategy;
|
|
|
|
/* Do bulk deletion */
|
|
*stats = index_bulk_delete(&ivinfo, *stats,
|
|
lazy_tid_reaped, (void *) vacrelstats);
|
|
|
|
ereport(elevel,
|
|
(errmsg("scanned index \"%s\" to remove %d row versions",
|
|
RelationGetRelationName(indrel),
|
|
vacrelstats->num_dead_tuples),
|
|
errdetail("%s.", pg_rusage_show(&ru0))));
|
|
}
|
|
|
|
/*
|
|
* lazy_cleanup_index() -- do post-vacuum cleanup for one index relation.
|
|
*/
|
|
static void
|
|
lazy_cleanup_index(Relation indrel,
|
|
IndexBulkDeleteResult *stats,
|
|
LVRelStats *vacrelstats)
|
|
{
|
|
IndexVacuumInfo ivinfo;
|
|
PGRUsage ru0;
|
|
|
|
pg_rusage_init(&ru0);
|
|
|
|
ivinfo.index = indrel;
|
|
ivinfo.vacuum_full = false;
|
|
ivinfo.message_level = elevel;
|
|
ivinfo.num_heap_tuples = vacrelstats->rel_tuples;
|
|
ivinfo.strategy = vac_strategy;
|
|
|
|
stats = index_vacuum_cleanup(&ivinfo, stats);
|
|
|
|
if (!stats)
|
|
return;
|
|
|
|
/* now update statistics in pg_class */
|
|
vac_update_relstats(RelationGetRelid(indrel),
|
|
stats->num_pages,
|
|
stats->num_index_tuples,
|
|
false, InvalidTransactionId);
|
|
|
|
ereport(elevel,
|
|
(errmsg("index \"%s\" now contains %.0f row versions in %u pages",
|
|
RelationGetRelationName(indrel),
|
|
stats->num_index_tuples,
|
|
stats->num_pages),
|
|
errdetail("%.0f index row versions were removed.\n"
|
|
"%u index pages have been deleted, %u are currently reusable.\n"
|
|
"%s.",
|
|
stats->tuples_removed,
|
|
stats->pages_deleted, stats->pages_free,
|
|
pg_rusage_show(&ru0))));
|
|
|
|
pfree(stats);
|
|
}
|
|
|
|
/*
|
|
* lazy_truncate_heap - try to truncate off any empty pages at the end
|
|
*/
|
|
static void
|
|
lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
|
|
{
|
|
BlockNumber old_rel_pages = vacrelstats->rel_pages;
|
|
BlockNumber new_rel_pages;
|
|
PGRUsage ru0;
|
|
|
|
pg_rusage_init(&ru0);
|
|
|
|
/*
|
|
* We need full exclusive lock on the relation in order to do truncation.
|
|
* If we can't get it, give up rather than waiting --- we don't want to
|
|
* block other backends, and we don't want to deadlock (which is quite
|
|
* possible considering we already hold a lower-grade lock).
|
|
*/
|
|
if (!ConditionalLockRelation(onerel, AccessExclusiveLock))
|
|
return;
|
|
|
|
/*
|
|
* Now that we have exclusive lock, look to see if the rel has grown
|
|
* whilst we were vacuuming with non-exclusive lock. If so, give up; the
|
|
* newly added pages presumably contain non-deletable tuples.
|
|
*/
|
|
new_rel_pages = RelationGetNumberOfBlocks(onerel);
|
|
if (new_rel_pages != old_rel_pages)
|
|
{
|
|
/* might as well use the latest news when we update pg_class stats */
|
|
vacrelstats->rel_pages = new_rel_pages;
|
|
UnlockRelation(onerel, AccessExclusiveLock);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Scan backwards from the end to verify that the end pages actually
|
|
* contain no tuples. This is *necessary*, not optional, because other
|
|
* backends could have added tuples to these pages whilst we were
|
|
* vacuuming.
|
|
*/
|
|
new_rel_pages = count_nondeletable_pages(onerel, vacrelstats);
|
|
|
|
if (new_rel_pages >= old_rel_pages)
|
|
{
|
|
/* can't do anything after all */
|
|
UnlockRelation(onerel, AccessExclusiveLock);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Okay to truncate.
|
|
*/
|
|
FreeSpaceMapTruncateRel(onerel, new_rel_pages);
|
|
RelationTruncate(onerel, new_rel_pages);
|
|
|
|
/*
|
|
* Note: once we have truncated, we *must* keep the exclusive lock until
|
|
* commit. The sinval message that will be sent at commit (as a result of
|
|
* vac_update_relstats()) must be received by other backends, to cause
|
|
* them to reset their rd_targblock values, before they can safely access
|
|
* the table again.
|
|
*/
|
|
|
|
/* update statistics */
|
|
vacrelstats->rel_pages = new_rel_pages;
|
|
vacrelstats->pages_removed = old_rel_pages - new_rel_pages;
|
|
|
|
ereport(elevel,
|
|
(errmsg("\"%s\": truncated %u to %u pages",
|
|
RelationGetRelationName(onerel),
|
|
old_rel_pages, new_rel_pages),
|
|
errdetail("%s.",
|
|
pg_rusage_show(&ru0))));
|
|
}
|
|
|
|
/*
|
|
* Rescan end pages to verify that they are (still) empty of tuples.
|
|
*
|
|
* Returns number of nondeletable pages (last nonempty page + 1).
|
|
*/
|
|
static BlockNumber
|
|
count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
|
|
{
|
|
BlockNumber blkno;
|
|
|
|
/* Strange coding of loop control is needed because blkno is unsigned */
|
|
blkno = vacrelstats->rel_pages;
|
|
while (blkno > vacrelstats->nonempty_pages)
|
|
{
|
|
Buffer buf;
|
|
Page page;
|
|
OffsetNumber offnum,
|
|
maxoff;
|
|
bool hastup;
|
|
|
|
/*
|
|
* We don't insert a vacuum delay point here, because we have an
|
|
* exclusive lock on the table which we want to hold for as short a
|
|
* time as possible. We still need to check for interrupts however.
|
|
*/
|
|
CHECK_FOR_INTERRUPTS();
|
|
|
|
blkno--;
|
|
|
|
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
|
|
RBM_NORMAL, vac_strategy);
|
|
|
|
/* In this phase we only need shared access to the buffer */
|
|
LockBuffer(buf, BUFFER_LOCK_SHARE);
|
|
|
|
page = BufferGetPage(buf);
|
|
|
|
if (PageIsNew(page) || PageIsEmpty(page))
|
|
{
|
|
/* PageIsNew probably shouldn't happen... */
|
|
UnlockReleaseBuffer(buf);
|
|
continue;
|
|
}
|
|
|
|
hastup = false;
|
|
maxoff = PageGetMaxOffsetNumber(page);
|
|
for (offnum = FirstOffsetNumber;
|
|
offnum <= maxoff;
|
|
offnum = OffsetNumberNext(offnum))
|
|
{
|
|
ItemId itemid;
|
|
|
|
itemid = PageGetItemId(page, offnum);
|
|
|
|
/*
|
|
* Note: any non-unused item should be taken as a reason to keep
|
|
* this page. We formerly thought that DEAD tuples could be
|
|
* thrown away, but that's not so, because we'd not have cleaned
|
|
* out their index entries.
|
|
*/
|
|
if (ItemIdIsUsed(itemid))
|
|
{
|
|
hastup = true;
|
|
break; /* can stop scanning */
|
|
}
|
|
} /* scan along page */
|
|
|
|
UnlockReleaseBuffer(buf);
|
|
|
|
/* Done scanning if we found a tuple here */
|
|
if (hastup)
|
|
return blkno + 1;
|
|
}
|
|
|
|
/*
|
|
* If we fall out of the loop, all the previously-thought-to-be-empty
|
|
* pages still are; we need not bother to look at the last known-nonempty
|
|
* page.
|
|
*/
|
|
return vacrelstats->nonempty_pages;
|
|
}
|
|
|
|
/*
|
|
* lazy_space_alloc - space allocation decisions for lazy vacuum
|
|
*
|
|
* See the comments at the head of this file for rationale.
|
|
*/
|
|
static void
|
|
lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks)
|
|
{
|
|
long maxtuples;
|
|
|
|
if (vacrelstats->hasindex)
|
|
{
|
|
maxtuples = (maintenance_work_mem * 1024L) / sizeof(ItemPointerData);
|
|
maxtuples = Min(maxtuples, INT_MAX);
|
|
maxtuples = Min(maxtuples, MaxAllocSize / sizeof(ItemPointerData));
|
|
|
|
/* curious coding here to ensure the multiplication can't overflow */
|
|
if ((BlockNumber) (maxtuples / LAZY_ALLOC_TUPLES) > relblocks)
|
|
maxtuples = relblocks * LAZY_ALLOC_TUPLES;
|
|
|
|
/* stay sane if small maintenance_work_mem */
|
|
maxtuples = Max(maxtuples, MaxHeapTuplesPerPage);
|
|
}
|
|
else
|
|
{
|
|
maxtuples = MaxHeapTuplesPerPage;
|
|
}
|
|
|
|
vacrelstats->num_dead_tuples = 0;
|
|
vacrelstats->max_dead_tuples = (int) maxtuples;
|
|
vacrelstats->dead_tuples = (ItemPointer)
|
|
palloc(maxtuples * sizeof(ItemPointerData));
|
|
}
|
|
|
|
/*
|
|
* lazy_record_dead_tuple - remember one deletable tuple
|
|
*/
|
|
static void
|
|
lazy_record_dead_tuple(LVRelStats *vacrelstats,
|
|
ItemPointer itemptr)
|
|
{
|
|
/*
|
|
* The array shouldn't overflow under normal behavior, but perhaps it
|
|
* could if we are given a really small maintenance_work_mem. In that
|
|
* case, just forget the last few tuples (we'll get 'em next time).
|
|
*/
|
|
if (vacrelstats->num_dead_tuples < vacrelstats->max_dead_tuples)
|
|
{
|
|
vacrelstats->dead_tuples[vacrelstats->num_dead_tuples] = *itemptr;
|
|
vacrelstats->num_dead_tuples++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* lazy_tid_reaped() -- is a particular tid deletable?
|
|
*
|
|
* This has the right signature to be an IndexBulkDeleteCallback.
|
|
*
|
|
* Assumes dead_tuples array is in sorted order.
|
|
*/
|
|
static bool
|
|
lazy_tid_reaped(ItemPointer itemptr, void *state)
|
|
{
|
|
LVRelStats *vacrelstats = (LVRelStats *) state;
|
|
ItemPointer res;
|
|
|
|
res = (ItemPointer) bsearch((void *) itemptr,
|
|
(void *) vacrelstats->dead_tuples,
|
|
vacrelstats->num_dead_tuples,
|
|
sizeof(ItemPointerData),
|
|
vac_cmp_itemptr);
|
|
|
|
return (res != NULL);
|
|
}
|
|
|
|
/*
|
|
* Comparator routines for use with qsort() and bsearch().
|
|
*/
|
|
static int
|
|
vac_cmp_itemptr(const void *left, const void *right)
|
|
{
|
|
BlockNumber lblk,
|
|
rblk;
|
|
OffsetNumber loff,
|
|
roff;
|
|
|
|
lblk = ItemPointerGetBlockNumber((ItemPointer) left);
|
|
rblk = ItemPointerGetBlockNumber((ItemPointer) right);
|
|
|
|
if (lblk < rblk)
|
|
return -1;
|
|
if (lblk > rblk)
|
|
return 1;
|
|
|
|
loff = ItemPointerGetOffsetNumber((ItemPointer) left);
|
|
roff = ItemPointerGetOffsetNumber((ItemPointer) right);
|
|
|
|
if (loff < roff)
|
|
return -1;
|
|
if (loff > roff)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|