database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-04-20 00:42:27 +03:00
Code
postgres/src/backend/commands/vacuum.c
Neil Conway d0b4399d81 Reimplement the linked list data structure used throughout the backend. 
In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.

The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.
2004-05-26 04:41:50 +00:00

3227 lines
90 KiB
C
Raw Blame History

/*-------------------------------------------------------------------------
*
* vacuum.c
* The postgres vacuum cleaner.
*
* This file includes the "full" version of VACUUM, as well as control code
* used by all three of full VACUUM, lazy VACUUM, and ANALYZE. See
* vacuumlazy.c and analyze.c for the rest of the code for the latter two.
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.278 2004/05/26 04:41:12 neilc Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/time.h>
#include <unistd.h>
#include "access/clog.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/xlog.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/namespace.h"
#include "catalog/pg_database.h"
#include "catalog/pg_index.h"
#include "commands/vacuum.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "storage/buf_internals.h"
#include "storage/freespace.h"
#include "storage/sinval.h"
#include "storage/smgr.h"
#include "tcop/pquery.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
#include "pgstat.h"
typedef struct VacPageData
{
BlockNumber blkno; /* BlockNumber of this Page */
Size free; /* FreeSpace on this Page */
uint16 offsets_used; /* Number of OffNums used by vacuum */
uint16 offsets_free; /* Number of OffNums free or to be free */
OffsetNumber offsets[1]; /* Array of free OffNums */
} VacPageData;
typedef VacPageData *VacPage;
typedef struct VacPageListData
{
BlockNumber empty_end_pages; /* Number of "empty" end-pages */
int num_pages; /* Number of pages in pagedesc */
int num_allocated_pages; /* Number of allocated pages in
* pagedesc */
VacPage *pagedesc; /* Descriptions of pages */
} VacPageListData;
typedef VacPageListData *VacPageList;
typedef struct VTupleLinkData
{
ItemPointerData new_tid;
ItemPointerData this_tid;
} VTupleLinkData;
typedef VTupleLinkData *VTupleLink;
typedef struct VTupleMoveData
{
ItemPointerData tid; /* tuple ID */
VacPage vacpage; /* where to move */
bool cleanVpd; /* clean vacpage before using */
} VTupleMoveData;
typedef VTupleMoveData *VTupleMove;
typedef struct VRelStats
{
BlockNumber rel_pages;
double rel_tuples;
Size min_tlen;
Size max_tlen;
bool hasindex;
int num_vtlinks;
VTupleLink vtlinks;
} VRelStats;
static MemoryContext vac_context = NULL;
static int elevel = -1;
static TransactionId OldestXmin;
static TransactionId FreezeLimit;
/* non-export function prototypes */
static List *get_rel_oids(const RangeVar *vacrel, const char *stmttype);
static void vac_update_dbstats(Oid dbid,
TransactionId vacuumXID,
TransactionId frozenXID);
static void vac_truncate_clog(TransactionId vacuumXID,
TransactionId frozenXID);
static bool vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind);
static void full_vacuum_rel(Relation onerel, VacuumStmt *vacstmt);
static void scan_heap(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages);
static void repair_frag(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages,
int nindexes, Relation *Irel);
static void vacuum_heap(VRelStats *vacrelstats, Relation onerel,
VacPageList vacpagelist);
static void vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage);
static void vacuum_index(VacPageList vacpagelist, Relation indrel,
double num_tuples, int keep_tuples);
static void scan_index(Relation indrel, double num_tuples);
static bool tid_reaped(ItemPointer itemptr, void *state);
static bool dummy_tid_reaped(ItemPointer itemptr, void *state);
static void vac_update_fsm(Relation onerel, VacPageList fraged_pages,
BlockNumber rel_pages);
static VacPage copy_vac_page(VacPage vacpage);
static void vpage_insert(VacPageList vacpagelist, VacPage vpnew);
static void *vac_bsearch(const void *key, const void *base,
size_t nelem, size_t size,
int (*compar) (const void *, const void *));
static int vac_cmp_blk(const void *left, const void *right);
static int vac_cmp_offno(const void *left, const void *right);
static int vac_cmp_vtlinks(const void *left, const void *right);
static bool enough_space(VacPage vacpage, Size len);
/****************************************************************************
* *
* Code common to all flavors of VACUUM and ANALYZE *
* *
****************************************************************************
*/
/*
* Primary entry point for VACUUM and ANALYZE commands.
*/
void
vacuum(VacuumStmt *vacstmt)
{
const char *stmttype = vacstmt->vacuum ? "VACUUM" : "ANALYZE";
MemoryContext anl_context = NULL;
TransactionId initialOldestXmin = InvalidTransactionId;
TransactionId initialFreezeLimit = InvalidTransactionId;
bool all_rels,
in_outer_xact,
use_own_xacts;
List *relations;
ListCell *cur;
if (vacstmt->verbose)
elevel = INFO;
else
elevel = DEBUG2;
/*
* We cannot run VACUUM inside a user transaction block; if we were
* inside a transaction, then our commit- and
* start-transaction-command calls would not have the intended effect!
* Furthermore, the forced commit that occurs before truncating the
* relation's file would have the effect of committing the rest of the
* user's transaction too, which would certainly not be the desired
* behavior. (This only applies to VACUUM FULL, though. We could
* in theory run lazy VACUUM inside a transaction block, but we choose
* to disallow that case because we'd rather commit as soon as possible
* after finishing the vacuum. This is mainly so that we can let go the
* AccessExclusiveLock that we may be holding.)
*
* ANALYZE (without VACUUM) can run either way.
*/
if (vacstmt->vacuum)
{
PreventTransactionChain((void *) vacstmt, stmttype);
in_outer_xact = false;
}
else
{
in_outer_xact = IsInTransactionChain((void *) vacstmt);
}
/* Turn vacuum cost accounting on or off */
VacuumCostActive = (VacuumCostNaptime > 0);
VacuumCostBalance = 0;
/*
* Send info about dead objects to the statistics collector
*/
if (vacstmt->vacuum)
pgstat_vacuum_tabstat();
/*
* Create special memory context for cross-transaction storage.
*
* Since it is a child of PortalContext, it will go away eventually even
* if we suffer an error; there's no need for special abort cleanup
* logic.
*/
vac_context = AllocSetContextCreate(PortalContext,
"Vacuum",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* Assume we are processing everything unless one table is mentioned */
all_rels = (vacstmt->relation == NULL);
/* Build list of relations to process (note this lives in vac_context) */
relations = get_rel_oids(vacstmt->relation, stmttype);
if (vacstmt->vacuum && all_rels)
{
/*
* It's a database-wide VACUUM.
*
* Compute the initially applicable OldestXmin and FreezeLimit
* XIDs, so that we can record these values at the end of the
* VACUUM. Note that individual tables may well be processed
* with newer values, but we can guarantee that no
* (non-shared) relations are processed with older ones.
*
* It is okay to record non-shared values in pg_database, even
* though we may vacuum shared relations with older cutoffs,
* because only the minimum of the values present in
* pg_database matters. We can be sure that shared relations
* have at some time been vacuumed with cutoffs no worse than
* the global minimum; for, if there is a backend in some
* other DB with xmin = OLDXMIN that's determining the cutoff
* with which we vacuum shared relations, it is not possible
* for that database to have a cutoff newer than OLDXMIN
* recorded in pg_database.
*/
vacuum_set_xid_limits(vacstmt, false,
&initialOldestXmin,
&initialFreezeLimit);
}
/*
* Decide whether we need to start/commit our own transactions.
*
* For VACUUM (with or without ANALYZE): always do so, so that we
* can release locks as soon as possible. (We could possibly use the
* outer transaction for a one-table VACUUM, but handling TOAST tables
* would be problematic.)
*
* For ANALYZE (no VACUUM): if inside a transaction block, we cannot
* start/commit our own transactions. Also, there's no need to do so
* if only processing one relation. For multiple relations when not
* within a transaction block, use own transactions so we can release
* locks sooner.
*/
if (vacstmt->vacuum)
{
use_own_xacts = true;
}
else
{
Assert(vacstmt->analyze);
if (in_outer_xact)
use_own_xacts = false;
else if (list_length(relations) > 1)
use_own_xacts = true;
else
use_own_xacts = false;
}
/*
* If we are running ANALYZE without per-table transactions, we'll
* need a memory context with table lifetime.
*/
if (!use_own_xacts)
anl_context = AllocSetContextCreate(PortalContext,
"Analyze",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* vacuum_rel expects to be entered with no transaction active; it will
* start and commit its own transaction. But we are called by an SQL
* command, and so we are executing inside a transaction already. We
* commit the transaction started in PostgresMain() here, and start
* another one before exiting to match the commit waiting for us back
* in PostgresMain().
*/
if (use_own_xacts)
{
/* matches the StartTransaction in PostgresMain() */
CommitTransactionCommand();
}
/*
* Loop to process each selected relation.
*/
foreach(cur, relations)
{
Oid relid = lfirst_oid(cur);
if (vacstmt->vacuum)
{
if (!vacuum_rel(relid, vacstmt, RELKIND_RELATION))
all_rels = false; /* forget about updating dbstats */
}
if (vacstmt->analyze)
{
MemoryContext old_context = NULL;
/*
* If using separate xacts, start one for analyze. Otherwise,
* we can use the outer transaction, but we still need to call
* analyze_rel in a memory context that will be cleaned up on
* return (else we leak memory while processing multiple
* tables).
*/
if (use_own_xacts)
{
StartTransactionCommand();
SetQuerySnapshot(); /* might be needed for functions
* in indexes */
}
else
old_context = MemoryContextSwitchTo(anl_context);
/*
* Tell the buffer replacement strategy that vacuum is
* causing the IO
*/
StrategyHintVacuum(true);
analyze_rel(relid, vacstmt);
StrategyHintVacuum(false);
if (use_own_xacts)
CommitTransactionCommand();
else
{
MemoryContextSwitchTo(old_context);
MemoryContextResetAndDeleteChildren(anl_context);
}
}
}
/*
* Finish up processing.
*/
if (use_own_xacts)
{
/* here, we are not in a transaction */
/*
* This matches the CommitTransaction waiting for us in
* PostgresMain().
*/
StartTransactionCommand();
}
if (vacstmt->vacuum)
{
/*
* If it was a database-wide VACUUM, print FSM usage statistics
* (we don't make you be superuser to see these).
*/
if (vacstmt->relation == NULL)
PrintFreeSpaceMapStatistics(elevel);
/*
* If we completed a database-wide VACUUM without skipping any
* relations, update the database's pg_database row with info
* about the transaction IDs used, and try to truncate pg_clog.
*/
if (all_rels)
{
vac_update_dbstats(MyDatabaseId,
initialOldestXmin, initialFreezeLimit);
vac_truncate_clog(initialOldestXmin, initialFreezeLimit);
}
}
/*
* Clean up working storage --- note we must do this after
* StartTransactionCommand, else we might be trying to delete the
* active context!
*/
MemoryContextDelete(vac_context);
vac_context = NULL;
if (anl_context)
MemoryContextDelete(anl_context);
/* Turn off vacuum cost accounting */
VacuumCostActive = false;
}
/*
* Build a list of Oids for each relation to be processed
*
* The list is built in vac_context so that it will survive across our
* per-relation transactions.
*/
static List *
get_rel_oids(const RangeVar *vacrel, const char *stmttype)
{
List *oid_list = NIL;
MemoryContext oldcontext;
if (vacrel)
{
/* Process a specific relation */
Oid relid;
relid = RangeVarGetRelid(vacrel, false);
/* Make a relation list entry for this guy */
oldcontext = MemoryContextSwitchTo(vac_context);
oid_list = lappend_oid(oid_list, relid);
MemoryContextSwitchTo(oldcontext);
}
else
{
/* Process all plain relations listed in pg_class */
Relation pgclass;
HeapScanDesc scan;
HeapTuple tuple;
ScanKeyData key;
ScanKeyInit(&key,
Anum_pg_class_relkind,
BTEqualStrategyNumber, F_CHAREQ,
CharGetDatum(RELKIND_RELATION));
pgclass = heap_openr(RelationRelationName, AccessShareLock);
scan = heap_beginscan(pgclass, SnapshotNow, 1, &key);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
/* Make a relation list entry for this guy */
oldcontext = MemoryContextSwitchTo(vac_context);
oid_list = lappend_oid(oid_list, HeapTupleGetOid(tuple));
MemoryContextSwitchTo(oldcontext);
}
heap_endscan(scan);
heap_close(pgclass, AccessShareLock);
}
return oid_list;
}
/*
* vacuum_set_xid_limits() -- compute oldest-Xmin and freeze cutoff points
*/
void
vacuum_set_xid_limits(VacuumStmt *vacstmt, bool sharedRel,
TransactionId *oldestXmin,
TransactionId *freezeLimit)
{
TransactionId limit;
*oldestXmin = GetOldestXmin(sharedRel);
Assert(TransactionIdIsNormal(*oldestXmin));
if (vacstmt->freeze)
{
/* FREEZE option: use oldest Xmin as freeze cutoff too */
limit = *oldestXmin;
}
else
{
/*
* Normal case: freeze cutoff is well in the past, to wit, about
* halfway to the wrap horizon
*/
limit = GetCurrentTransactionId() - (MaxTransactionId >> 2);
}
/*
* Be careful not to generate a "permanent" XID
*/
if (!TransactionIdIsNormal(limit))
limit = FirstNormalTransactionId;
/*
* Ensure sane relationship of limits
*/
if (TransactionIdFollows(limit, *oldestXmin))
{
ereport(WARNING,
(errmsg("oldest xmin is far in the past"),
errhint("Close open transactions soon to avoid wraparound problems.")));
limit = *oldestXmin;
}
*freezeLimit = limit;
}
/*
* vac_update_relstats() -- update statistics for one relation
*
* Update the whole-relation statistics that are kept in its pg_class
* row. There are additional stats that will be updated if we are
* doing ANALYZE, but we always update these stats. This routine works
* for both index and heap relation entries in pg_class.
*
* We violate no-overwrite semantics here by storing new values for the
* statistics columns directly into the pg_class tuple that's already on
* the page. The reason for this is that if we updated these tuples in
* the usual way, vacuuming pg_class itself wouldn't work very well ---
* by the time we got done with a vacuum cycle, most of the tuples in
* pg_class would've been obsoleted. Of course, this only works for
* fixed-size never-null columns, but these are.
*
* This routine is shared by full VACUUM, lazy VACUUM, and stand-alone
* ANALYZE.
*/
void
vac_update_relstats(Oid relid, BlockNumber num_pages, double num_tuples,
bool hasindex)
{
Relation rd;
HeapTupleData rtup;
HeapTuple ctup;
Form_pg_class pgcform;
Buffer buffer;
/*
* update number of tuples and number of pages in pg_class
*/
rd = heap_openr(RelationRelationName, RowExclusiveLock);
ctup = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(ctup))
elog(ERROR, "pg_class entry for relid %u vanished during vacuuming",
relid);
/* get the buffer cache tuple */
rtup.t_self = ctup->t_self;
ReleaseSysCache(ctup);
if (!heap_fetch(rd, SnapshotNow, &rtup, &buffer, false, NULL))
elog(ERROR, "pg_class entry for relid %u vanished during vacuuming",
relid);
/* ensure no one else does this at the same time */
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/* overwrite the existing statistics in the tuple */
pgcform = (Form_pg_class) GETSTRUCT(&rtup);
pgcform->relpages = (int32) num_pages;
pgcform->reltuples = num_tuples;
pgcform->relhasindex = hasindex;
/*
* If we have discovered that there are no indexes, then there's no
* primary key either. This could be done more thoroughly...
*/
if (!hasindex)
pgcform->relhaspkey = false;
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* Invalidate the tuple in the catcaches; this also arranges to flush
* the relation's relcache entry. (If we fail to commit for some
* reason, no flush will occur, but no great harm is done since there
* are no noncritical state updates here.)
*/
CacheInvalidateHeapTuple(rd, &rtup);
/* Write the buffer */
WriteBuffer(buffer);
heap_close(rd, RowExclusiveLock);
}
/*
* vac_update_dbstats() -- update statistics for one database
*
* Update the whole-database statistics that are kept in its pg_database
* row.
*
* We violate no-overwrite semantics here by storing new values for the
* statistics columns directly into the tuple that's already on the page.
* As with vac_update_relstats, this avoids leaving dead tuples behind
* after a VACUUM; which is good since GetRawDatabaseInfo
* can get confused by finding dead tuples in pg_database.
*
* This routine is shared by full and lazy VACUUM. Note that it is only
* applied after a database-wide VACUUM operation.
*/
static void
vac_update_dbstats(Oid dbid,
TransactionId vacuumXID,
TransactionId frozenXID)
{
Relation relation;
ScanKeyData entry[1];
HeapScanDesc scan;
HeapTuple tuple;
Form_pg_database dbform;
relation = heap_openr(DatabaseRelationName, RowExclusiveLock);
/* Must use a heap scan, since there's no syscache for pg_database */
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(dbid));
scan = heap_beginscan(relation, SnapshotNow, 1, entry);
tuple = heap_getnext(scan, ForwardScanDirection);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for database %u", dbid);
/* ensure no one else does this at the same time */
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_EXCLUSIVE);
dbform = (Form_pg_database) GETSTRUCT(tuple);
/* overwrite the existing statistics in the tuple */
dbform->datvacuumxid = vacuumXID;
dbform->datfrozenxid = frozenXID;
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
/* invalidate the tuple in the cache and write the buffer */
CacheInvalidateHeapTuple(relation, tuple);
WriteNoReleaseBuffer(scan->rs_cbuf);
heap_endscan(scan);
heap_close(relation, RowExclusiveLock);
}
/*
* vac_truncate_clog() -- attempt to truncate the commit log
*
* Scan pg_database to determine the system-wide oldest datvacuumxid,
* and use it to truncate the transaction commit log (pg_clog).
* Also generate a warning if the system-wide oldest datfrozenxid
* seems to be in danger of wrapping around.
*
* The passed XIDs are simply the ones I just wrote into my pg_database
* entry. They're used to initialize the "min" calculations.
*
* This routine is shared by full and lazy VACUUM. Note that it is only
* applied after a database-wide VACUUM operation.
*/
static void
vac_truncate_clog(TransactionId vacuumXID, TransactionId frozenXID)
{
TransactionId myXID;
Relation relation;
HeapScanDesc scan;
HeapTuple tuple;
int32 age;
bool vacuumAlreadyWrapped = false;
bool frozenAlreadyWrapped = false;
myXID = GetCurrentTransactionId();
relation = heap_openr(DatabaseRelationName, AccessShareLock);
scan = heap_beginscan(relation, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Form_pg_database dbform = (Form_pg_database) GETSTRUCT(tuple);
/* Ignore non-connectable databases (eg, template0) */
/* It's assumed that these have been frozen correctly */
if (!dbform->datallowconn)
continue;
if (TransactionIdIsNormal(dbform->datvacuumxid))
{
if (TransactionIdPrecedes(myXID, dbform->datvacuumxid))
vacuumAlreadyWrapped = true;
else if (TransactionIdPrecedes(dbform->datvacuumxid, vacuumXID))
vacuumXID = dbform->datvacuumxid;
}
if (TransactionIdIsNormal(dbform->datfrozenxid))
{
if (TransactionIdPrecedes(myXID, dbform->datfrozenxid))
frozenAlreadyWrapped = true;
else if (TransactionIdPrecedes(dbform->datfrozenxid, frozenXID))
frozenXID = dbform->datfrozenxid;
}
}
heap_endscan(scan);
heap_close(relation, AccessShareLock);
/*
* Do not truncate CLOG if we seem to have suffered wraparound
* already; the computed minimum XID might be bogus.
*/
if (vacuumAlreadyWrapped)
{
ereport(WARNING,
(errmsg("some databases have not been vacuumed in over 2 billion transactions"),
errdetail("You may have already suffered transaction-wraparound data loss.")));
return;
}
/* Truncate CLOG to the oldest vacuumxid */
TruncateCLOG(vacuumXID);
/* Give warning about impending wraparound problems */
if (frozenAlreadyWrapped)
{
ereport(WARNING,
(errmsg("some databases have not been vacuumed in over 1 billion transactions"),
errhint("Better vacuum them soon, or you may have a wraparound failure.")));
}
else
{
age = (int32) (myXID - frozenXID);
if (age > (int32) ((MaxTransactionId >> 3) * 3))
ereport(WARNING,
(errmsg("some databases have not been vacuumed in %d transactions",
age),
errhint("Better vacuum them within %d transactions, "
"or you may have a wraparound failure.",
(int32) (MaxTransactionId >> 1) - age)));
}
}
/****************************************************************************
* *
* Code common to both flavors of VACUUM *
* *
****************************************************************************
*/
/*
* vacuum_rel() -- vacuum one heap relation
*
* Returns TRUE if we actually processed the relation (or can ignore it
* for some reason), FALSE if we failed to process it due to permissions
* or other reasons. (A FALSE result really means that some data
* may have been left unvacuumed, so we can't update XID stats.)
*
* Doing one heap at a time incurs extra overhead, since we need to
* check that the heap exists again just before we vacuum it. The
* reason that we do this is so that vacuuming can be spread across
* many small transactions. Otherwise, two-phase locking would require
* us to lock the entire database during one pass of the vacuum cleaner.
*
* At entry and exit, we are not inside a transaction.
*/
static bool
vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
{
LOCKMODE lmode;
Relation onerel;
LockRelId onerelid;
Oid toast_relid;
bool result;
/* Begin a transaction for vacuuming this relation */
StartTransactionCommand();
SetQuerySnapshot(); /* might be needed for functions in
* indexes */
/*
* Tell the cache replacement strategy that vacuum is causing
* all following IO
*/
StrategyHintVacuum(true);
/*
* Check for user-requested abort. Note we want this to be inside a
* transaction, so xact.c doesn't issue useless WARNING.
*/
CHECK_FOR_INTERRUPTS();
/*
* Race condition -- if the pg_class tuple has gone away since the
* last time we saw it, we don't need to vacuum it.
*/
if (!SearchSysCacheExists(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0))
{
StrategyHintVacuum(false);
CommitTransactionCommand();
return true; /* okay 'cause no data there */
}
/*
* Determine the type of lock we want --- hard exclusive lock for a
* FULL vacuum, but just ShareUpdateExclusiveLock for concurrent
* vacuum. Either way, we can be sure that no other backend is
* vacuuming the same table.
*/
lmode = vacstmt->full ? AccessExclusiveLock : ShareUpdateExclusiveLock;
/*
* Open the class, get an appropriate lock on it, and check
* permissions.
*
* We allow the user to vacuum a table if he is superuser, the table
* owner, or the database owner (but in the latter case, only if it's
* not a shared relation). pg_class_ownercheck includes the superuser
* case.
*
* Note we choose to treat permissions failure as a WARNING and keep
* trying to vacuum the rest of the DB --- is this appropriate?
*/
onerel = relation_open(relid, lmode);
if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
(pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
{
ereport(WARNING,
(errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
RelationGetRelationName(onerel))));
relation_close(onerel, lmode);
StrategyHintVacuum(false);
CommitTransactionCommand();
return false;
}
/*
* Check that it's a plain table; we used to do this in
* get_rel_oids() but seems safer to check after we've locked the
* relation.
*/
if (onerel->rd_rel->relkind != expected_relkind)
{
ereport(WARNING,
(errmsg("skipping \"%s\" --- cannot vacuum indexes, views, or special system tables",
RelationGetRelationName(onerel))));
relation_close(onerel, lmode);
StrategyHintVacuum(false);
CommitTransactionCommand();
return false;
}
/*
* Silently ignore tables that are temp tables of other backends ---
* trying to vacuum these will lead to great unhappiness, since their
* contents are probably not up-to-date on disk. (We don't throw a
* warning here; it would just lead to chatter during a database-wide
* VACUUM.)
*/
if (isOtherTempNamespace(RelationGetNamespace(onerel)))
{
relation_close(onerel, lmode);
StrategyHintVacuum(false);
CommitTransactionCommand();
return true; /* assume no long-lived data in temp
* tables */
}
/*
* Get a session-level lock too. This will protect our access to the
* relation across multiple transactions, so that we can vacuum the
* relation's TOAST table (if any) secure in the knowledge that no one
* is deleting the parent relation.
*
* NOTE: this cannot block, even if someone else is waiting for access,
* because the lock manager knows that both lock requests are from the
* same process.
*/
onerelid = onerel->rd_lockInfo.lockRelId;
LockRelationForSession(&onerelid, lmode);
/*
* Remember the relation's TOAST relation for later
*/
toast_relid = onerel->rd_rel->reltoastrelid;
/*
* Do the actual work --- either FULL or "lazy" vacuum
*/
if (vacstmt->full)
full_vacuum_rel(onerel, vacstmt);
else
lazy_vacuum_rel(onerel, vacstmt);
result = true; /* did the vacuum */
/* all done with this class, but hold lock until commit */
relation_close(onerel, NoLock);
/*
* Complete the transaction and free all temporary memory used.
*/
StrategyHintVacuum(false);
CommitTransactionCommand();
/*
* If the relation has a secondary toast rel, vacuum that too while we
* still hold the session lock on the master table. Note however that
* "analyze" will not get done on the toast table. This is good,
* because the toaster always uses hardcoded index access and
* statistics are totally unimportant for toast relations.
*/
if (toast_relid != InvalidOid)
{
if (!vacuum_rel(toast_relid, vacstmt, RELKIND_TOASTVALUE))
result = false; /* failed to vacuum the TOAST table? */
}
/*
* Now release the session-level lock on the master table.
*/
UnlockRelationForSession(&onerelid, lmode);
return result;
}
/****************************************************************************
* *
* Code for VACUUM FULL (only) *
* *
****************************************************************************
*/
/*
* full_vacuum_rel() -- perform FULL VACUUM for one heap relation
*
* This routine vacuums a single heap, cleans out its indexes, and
* updates its num_pages and num_tuples statistics.
*
* At entry, we have already established a transaction and opened
* and locked the relation.
*/
static void
full_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
{
VacPageListData vacuum_pages; /* List of pages to vacuum and/or
* clean indexes */
VacPageListData fraged_pages; /* List of pages with space enough
* for re-using */
Relation *Irel;
int nindexes,
i;
VRelStats *vacrelstats;
vacuum_set_xid_limits(vacstmt, onerel->rd_rel->relisshared,
&OldestXmin, &FreezeLimit);
/*
* Set up statistics-gathering machinery.
*/
vacrelstats = (VRelStats *) palloc(sizeof(VRelStats));
vacrelstats->rel_pages = 0;
vacrelstats->rel_tuples = 0;
vacrelstats->hasindex = false;
/* scan the heap */
vacuum_pages.num_pages = fraged_pages.num_pages = 0;
scan_heap(vacrelstats, onerel, &vacuum_pages, &fraged_pages);
/* Now open all indexes of the relation */
vac_open_indexes(onerel, &nindexes, &Irel);
if (nindexes > 0)
vacrelstats->hasindex = true;
/* Clean/scan index relation(s) */
if (Irel != NULL)
{
if (vacuum_pages.num_pages > 0)
{
for (i = 0; i < nindexes; i++)
vacuum_index(&vacuum_pages, Irel[i],
vacrelstats->rel_tuples, 0);
}
else
{
/* just scan indexes to update statistic */
for (i = 0; i < nindexes; i++)
scan_index(Irel[i], vacrelstats->rel_tuples);
}
}
if (fraged_pages.num_pages > 0)
{
/* Try to shrink heap */
repair_frag(vacrelstats, onerel, &vacuum_pages, &fraged_pages,
nindexes, Irel);
vac_close_indexes(nindexes, Irel);
}
else
{
vac_close_indexes(nindexes, Irel);
if (vacuum_pages.num_pages > 0)
{
/* Clean pages from vacuum_pages list */
vacuum_heap(vacrelstats, onerel, &vacuum_pages);
}
else
{
/*
* Flush dirty pages out to disk. We must do this even if we
* didn't do anything else, because we want to ensure that all
* tuples have correct on-row commit status on disk (see
* bufmgr.c's comments for FlushRelationBuffers()).
*/
i = FlushRelationBuffers(onerel, vacrelstats->rel_pages);
if (i < 0)
elog(ERROR, "FlushRelationBuffers returned %d", i);
}
}
/* update shared free space map with final free space info */
vac_update_fsm(onerel, &fraged_pages, vacrelstats->rel_pages);
/* update statistics in pg_class */
vac_update_relstats(RelationGetRelid(onerel), vacrelstats->rel_pages,
vacrelstats->rel_tuples, vacrelstats->hasindex);
}
/*
* scan_heap() -- scan an open heap relation
*
* This routine sets commit status bits, constructs vacuum_pages (list
* of pages we need to compact free space on and/or clean indexes of
* deleted tuples), constructs fraged_pages (list of pages with free
* space that tuples could be moved into), and calculates statistics
* on the number of live tuples in the heap.
*/
static void
scan_heap(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages)
{
BlockNumber nblocks,
blkno;
ItemId itemid;
Buffer buf;
HeapTupleData tuple;
OffsetNumber offnum,
maxoff;
bool pgchanged,
tupgone,
notup;
char *relname;
VacPage vacpage,
vacpagecopy;
BlockNumber empty_pages,
empty_end_pages;
double num_tuples,
tups_vacuumed,
nkeep,
nunused;
double free_space,
usable_free_space;
Size min_tlen = MaxTupleSize;
Size max_tlen = 0;
int i;
bool do_shrinking = true;
VTupleLink vtlinks = (VTupleLink) palloc(100 * sizeof(VTupleLinkData));
int num_vtlinks = 0;
int free_vtlinks = 100;
VacRUsage ru0;
vac_init_rusage(&ru0);
relname = RelationGetRelationName(onerel);
ereport(elevel,
(errmsg("vacuuming \"%s.%s\"",
get_namespace_name(RelationGetNamespace(onerel)),
relname)));
empty_pages = empty_end_pages = 0;
num_tuples = tups_vacuumed = nkeep = nunused = 0;
free_space = 0;
nblocks = RelationGetNumberOfBlocks(onerel);
/*
* We initially create each VacPage item in a maximal-sized workspace,
* then copy the workspace into a just-large-enough copy.
*/
vacpage = (VacPage) palloc(sizeof(VacPageData) + MaxOffsetNumber * sizeof(OffsetNumber));
for (blkno = 0; blkno < nblocks; blkno++)
{
Page page,
tempPage = NULL;
bool do_reap,
do_frag;
vacuum_delay_point();
buf = ReadBuffer(onerel, blkno);
page = BufferGetPage(buf);
vacpage->blkno = blkno;
vacpage->offsets_used = 0;
vacpage->offsets_free = 0;
if (PageIsNew(page))
{
ereport(WARNING,
(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
relname, blkno)));
PageInit(page, BufferGetPageSize(buf), 0);
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_space += vacpage->free;
empty_pages++;
empty_end_pages++;
vacpagecopy = copy_vac_page(vacpage);
vpage_insert(vacuum_pages, vacpagecopy);
vpage_insert(fraged_pages, vacpagecopy);
WriteBuffer(buf);
continue;
}
if (PageIsEmpty(page))
{
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_space += vacpage->free;
empty_pages++;
empty_end_pages++;
vacpagecopy = copy_vac_page(vacpage);
vpage_insert(vacuum_pages, vacpagecopy);
vpage_insert(fraged_pages, vacpagecopy);
ReleaseBuffer(buf);
continue;
}
pgchanged = false;
notup = true;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
uint16 sv_infomask;
itemid = PageGetItemId(page, offnum);
/*
* Collect un-used items too - it's possible to have indexes
* pointing here after crash.
*/
if (!ItemIdIsUsed(itemid))
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
nunused += 1;
continue;
}
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple.t_len = ItemIdGetLength(itemid);
ItemPointerSet(&(tuple.t_self), blkno, offnum);
tupgone = false;
sv_infomask = tuple.t_data->t_infomask;
switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin))
{
case HEAPTUPLE_DEAD:
tupgone = true; /* we can delete the tuple */
break;
case HEAPTUPLE_LIVE:
/*
* Tuple is good. Consider whether to replace its
* xmin value with FrozenTransactionId.
*/
if (TransactionIdIsNormal(HeapTupleHeaderGetXmin(tuple.t_data)) &&
TransactionIdPrecedes(HeapTupleHeaderGetXmin(tuple.t_data),
FreezeLimit))
{
HeapTupleHeaderSetXmin(tuple.t_data, FrozenTransactionId);
/* infomask should be okay already */
Assert(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED);
pgchanged = true;
}
/*
* Other 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;
/*
* If we do shrinking and this tuple is updated one
* then remember it to construct updated tuple
* dependencies.
*/
if (do_shrinking &&
!(ItemPointerEquals(&(tuple.t_self),
&(tuple.t_data->t_ctid))))
{
if (free_vtlinks == 0)
{
free_vtlinks = 1000;
vtlinks = (VTupleLink) repalloc(vtlinks,
(free_vtlinks + num_vtlinks) *
sizeof(VTupleLinkData));
}
vtlinks[num_vtlinks].new_tid = tuple.t_data->t_ctid;
vtlinks[num_vtlinks].this_tid = tuple.t_self;
free_vtlinks--;
num_vtlinks++;
}
break;
case HEAPTUPLE_INSERT_IN_PROGRESS:
/*
* This should not happen, since we hold exclusive
* lock on the relation; shouldn't we raise an error?
* (Actually, it can happen in system catalogs, since
* we tend to release write lock before commit there.)
*/
ereport(NOTICE,
(errmsg("relation \"%s\" TID %u/%u: InsertTransactionInProgress %u --- can't shrink relation",
relname, blkno, offnum, HeapTupleHeaderGetXmin(tuple.t_data))));
do_shrinking = false;
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
/*
* This should not happen, since we hold exclusive
* lock on the relation; shouldn't we raise an error?
* (Actually, it can happen in system catalogs, since
* we tend to release write lock before commit there.)
*/
ereport(NOTICE,
(errmsg("relation \"%s\" TID %u/%u: DeleteTransactionInProgress %u --- can't shrink relation",
relname, blkno, offnum, HeapTupleHeaderGetXmax(tuple.t_data))));
do_shrinking = false;
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
/* check for hint-bit update by HeapTupleSatisfiesVacuum */
if (sv_infomask != tuple.t_data->t_infomask)
pgchanged = true;
if (tupgone)
{
ItemId lpp;
/*
* Here we are building a temporary copy of the page with
* dead tuples removed. Below we will apply
* PageRepairFragmentation to the copy, so that we can
* determine how much space will be available after
* removal of dead tuples. But note we are NOT changing
* the real page yet...
*/
if (tempPage == NULL)
{
Size pageSize;
pageSize = PageGetPageSize(page);
tempPage = (Page) palloc(pageSize);
memcpy(tempPage, page, pageSize);
}
/* mark it unused on the temp page */
lpp = PageGetItemId(tempPage, offnum);
lpp->lp_flags &= ~LP_USED;
vacpage->offsets[vacpage->offsets_free++] = offnum;
tups_vacuumed += 1;
}
else
{
num_tuples += 1;
notup = false;
if (tuple.t_len < min_tlen)
min_tlen = tuple.t_len;
if (tuple.t_len > max_tlen)
max_tlen = tuple.t_len;
}
} /* scan along page */
if (tempPage != NULL)
{
/* Some tuples are removable; figure free space after removal */
PageRepairFragmentation(tempPage, NULL);
vacpage->free = ((PageHeader) tempPage)->pd_upper - ((PageHeader) tempPage)->pd_lower;
pfree(tempPage);
do_reap = true;
}
else
{
/* Just use current available space */
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
/* Need to reap the page if it has ~LP_USED line pointers */
do_reap = (vacpage->offsets_free > 0);
}
free_space += vacpage->free;
/*
* Add the page to fraged_pages if it has a useful amount of free
* space. "Useful" means enough for a minimal-sized tuple. But we
* don't know that accurately near the start of the relation, so
* add pages unconditionally if they have >= BLCKSZ/10 free space.
*/
do_frag = (vacpage->free >= min_tlen || vacpage->free >= BLCKSZ / 10);
if (do_reap || do_frag)
{
vacpagecopy = copy_vac_page(vacpage);
if (do_reap)
vpage_insert(vacuum_pages, vacpagecopy);
if (do_frag)
vpage_insert(fraged_pages, vacpagecopy);
}
/*
* Include the page in empty_end_pages if it will be empty after
* vacuuming; this is to keep us from using it as a move
* destination.
*/
if (notup)
{
empty_pages++;
empty_end_pages++;
}
else
empty_end_pages = 0;
if (pgchanged)
WriteBuffer(buf);
else
ReleaseBuffer(buf);
}
pfree(vacpage);
/* save stats in the rel list for use later */
vacrelstats->rel_tuples = num_tuples;
vacrelstats->rel_pages = nblocks;
if (num_tuples == 0)
min_tlen = max_tlen = 0;
vacrelstats->min_tlen = min_tlen;
vacrelstats->max_tlen = max_tlen;
vacuum_pages->empty_end_pages = empty_end_pages;
fraged_pages->empty_end_pages = empty_end_pages;
/*
* Clear the fraged_pages list if we found we couldn't shrink. Else,
* remove any "empty" end-pages from the list, and compute usable free
* space = free space in remaining pages.
*/
if (do_shrinking)
{
Assert((BlockNumber) fraged_pages->num_pages >= empty_end_pages);
fraged_pages->num_pages -= empty_end_pages;
usable_free_space = 0;
for (i = 0; i < fraged_pages->num_pages; i++)
usable_free_space += fraged_pages->pagedesc[i]->free;
}
else
{
fraged_pages->num_pages = 0;
usable_free_space = 0;
}
/* don't bother to save vtlinks if we will not call repair_frag */
if (fraged_pages->num_pages > 0 && num_vtlinks > 0)
{
qsort((char *) vtlinks, num_vtlinks, sizeof(VTupleLinkData),
vac_cmp_vtlinks);
vacrelstats->vtlinks = vtlinks;
vacrelstats->num_vtlinks = num_vtlinks;
}
else
{
vacrelstats->vtlinks = NULL;
vacrelstats->num_vtlinks = 0;
pfree(vtlinks);
}
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"
"Nonremovable row versions range from %lu to %lu bytes long.\n"
"There were %.0f unused item pointers.\n"
"Total free space (including removable row versions) is %.0f bytes.\n"
"%u pages are or will become empty, including %u at the end of the table.\n"
"%u pages containing %.0f free bytes are potential move destinations.\n"
"%s",
nkeep,
(unsigned long) min_tlen, (unsigned long) max_tlen,
nunused,
free_space,
empty_pages, empty_end_pages,
fraged_pages->num_pages, usable_free_space,
vac_show_rusage(&ru0))));
}
/*
* repair_frag() -- try to repair relation's fragmentation
*
* This routine marks dead tuples as unused and tries re-use dead space
* by moving tuples (and inserting indexes if needed). It constructs
* Nvacpagelist list of free-ed pages (moved tuples) and clean indexes
* for them after committing (in hack-manner - without losing locks
* and freeing memory!) current transaction. It truncates relation
* if some end-blocks are gone away.
*/
static void
repair_frag(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages,
int nindexes, Relation *Irel)
{
TransactionId myXID;
CommandId myCID;
Buffer buf,
cur_buffer;
BlockNumber nblocks,
blkno;
BlockNumber last_move_dest_block = 0,
last_vacuum_block;
Page page,
ToPage = NULL;
OffsetNumber offnum,
maxoff,
newoff,
max_offset;
ItemId itemid,
newitemid;
HeapTupleData tuple,
newtup;
TupleDesc tupdesc;
ResultRelInfo *resultRelInfo;
EState *estate;
TupleTable tupleTable;
TupleTableSlot *slot;
VacPageListData Nvacpagelist;
VacPage cur_page = NULL,
last_vacuum_page,
vacpage,
*curpage;
int cur_item = 0;
int i;
Size tuple_len;
int num_moved,
num_fraged_pages,
vacuumed_pages;
int checked_moved,
num_tuples,
keep_tuples = 0;
bool isempty,
dowrite,
chain_tuple_moved;
VacRUsage ru0;
vac_init_rusage(&ru0);
myXID = GetCurrentTransactionId();
myCID = GetCurrentCommandId();
tupdesc = RelationGetDescr(onerel);
/*
* We need a ResultRelInfo and an EState so we can use the regular
* executor's index-entry-making machinery.
*/
estate = CreateExecutorState();
resultRelInfo = makeNode(ResultRelInfo);
resultRelInfo->ri_RangeTableIndex = 1; /* dummy */
resultRelInfo->ri_RelationDesc = onerel;
resultRelInfo->ri_TrigDesc = NULL; /* we don't fire triggers */
ExecOpenIndices(resultRelInfo);
estate->es_result_relations = resultRelInfo;
estate->es_num_result_relations = 1;
estate->es_result_relation_info = resultRelInfo;
/* Set up a dummy tuple table too */
tupleTable = ExecCreateTupleTable(1);
slot = ExecAllocTableSlot(tupleTable);
ExecSetSlotDescriptor(slot, tupdesc, false);
Nvacpagelist.num_pages = 0;
num_fraged_pages = fraged_pages->num_pages;
Assert((BlockNumber) vacuum_pages->num_pages >= vacuum_pages->empty_end_pages);
vacuumed_pages = vacuum_pages->num_pages - vacuum_pages->empty_end_pages;
if (vacuumed_pages > 0)
{
/* get last reaped page from vacuum_pages */
last_vacuum_page = vacuum_pages->pagedesc[vacuumed_pages - 1];
last_vacuum_block = last_vacuum_page->blkno;
}
else
{
last_vacuum_page = NULL;
last_vacuum_block = InvalidBlockNumber;
}
cur_buffer = InvalidBuffer;
num_moved = 0;
vacpage = (VacPage) palloc(sizeof(VacPageData) + MaxOffsetNumber * sizeof(OffsetNumber));
vacpage->offsets_used = vacpage->offsets_free = 0;
/*
* Scan pages backwards from the last nonempty page, trying to move
* tuples down to lower pages. Quit when we reach a page that we have
* moved any tuples onto, or the first page if we haven't moved
* anything, or when we find a page we cannot completely empty (this
* last condition is handled by "break" statements within the loop).
*
* NB: this code depends on the vacuum_pages and fraged_pages lists being
* in order by blkno.
*/
nblocks = vacrelstats->rel_pages;
for (blkno = nblocks - vacuum_pages->empty_end_pages - 1;
blkno > last_move_dest_block;
blkno--)
{
vacuum_delay_point();
/*
* Forget fraged_pages pages at or after this one; they're no
* longer useful as move targets, since we only want to move down.
* Note that since we stop the outer loop at last_move_dest_block,
* pages removed here cannot have had anything moved onto them
* already.
*
* Also note that we don't change the stored fraged_pages list, only
* our local variable num_fraged_pages; so the forgotten pages are
* still available to be loaded into the free space map later.
*/
while (num_fraged_pages > 0 &&
fraged_pages->pagedesc[num_fraged_pages - 1]->blkno >= blkno)
{
Assert(fraged_pages->pagedesc[num_fraged_pages - 1]->offsets_used == 0);
--num_fraged_pages;
}
/*
* Process this page of relation.
*/
buf = ReadBuffer(onerel, blkno);
page = BufferGetPage(buf);
vacpage->offsets_free = 0;
isempty = PageIsEmpty(page);
dowrite = false;
/* Is the page in the vacuum_pages list? */
if (blkno == last_vacuum_block)
{
if (last_vacuum_page->offsets_free > 0)
{
/* there are dead tuples on this page - clean them */
Assert(!isempty);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, last_vacuum_page);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
dowrite = true;
}
else
Assert(isempty);
--vacuumed_pages;
if (vacuumed_pages > 0)
{
/* get prev reaped page from vacuum_pages */
last_vacuum_page = vacuum_pages->pagedesc[vacuumed_pages - 1];
last_vacuum_block = last_vacuum_page->blkno;
}
else
{
last_vacuum_page = NULL;
last_vacuum_block = InvalidBlockNumber;
}
if (isempty)
{
ReleaseBuffer(buf);
continue;
}
}
else
Assert(!isempty);
chain_tuple_moved = false; /* no one chain-tuple was moved
* off this page, yet */
vacpage->blkno = blkno;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple_len = tuple.t_len = ItemIdGetLength(itemid);
ItemPointerSet(&(tuple.t_self), blkno, offnum);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
elog(ERROR, "HEAP_MOVED_IN was not expected");
/*
* If this (chain) tuple is moved by me already then I
* have to check is it in vacpage or not - i.e. is it
* moved while cleaning this page or some previous one.
*/
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
if (HeapTupleHeaderGetXvac(tuple.t_data) != myXID)
elog(ERROR, "invalid XVAC in tuple header");
if (keep_tuples == 0)
continue;
if (chain_tuple_moved) /* some chains was moved
* while */
{ /* cleaning this page */
Assert(vacpage->offsets_free > 0);
for (i = 0; i < vacpage->offsets_free; i++)
{
if (vacpage->offsets[i] == offnum)
break;
}
if (i >= vacpage->offsets_free) /* not found */
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
keep_tuples--;
}
}
else
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
keep_tuples--;
}
continue;
}
elog(ERROR, "HEAP_MOVED_OFF was expected");
}
/*
* If this tuple is in the chain of tuples created in updates
* by "recent" transactions then we have to move all chain of
* tuples to another places.
*
* NOTE: this test is not 100% accurate: it is possible for a
* tuple to be an updated one with recent xmin, and yet not
* have a corresponding tuple in the vtlinks list. Presumably
* there was once a parent tuple with xmax matching the xmin,
* but it's possible that that tuple has been removed --- for
* example, if it had xmin = xmax then
* HeapTupleSatisfiesVacuum would deem it removable as soon as
* the xmin xact completes.
*
* To be on the safe side, we abandon the repair_frag process if
* we cannot find the parent tuple in vtlinks. This may be
* overly conservative; AFAICS it would be safe to move the
* chain.
*/
if (((tuple.t_data->t_infomask & HEAP_UPDATED) &&
!TransactionIdPrecedes(HeapTupleHeaderGetXmin(tuple.t_data),
OldestXmin)) ||
(!(tuple.t_data->t_infomask & (HEAP_XMAX_INVALID |
HEAP_MARKED_FOR_UPDATE)) &&
!(ItemPointerEquals(&(tuple.t_self),
&(tuple.t_data->t_ctid)))))
{
Buffer Cbuf = buf;
bool freeCbuf = false;
bool chain_move_failed = false;
Page Cpage;
ItemId Citemid;
ItemPointerData Ctid;
HeapTupleData tp = tuple;
Size tlen = tuple_len;
VTupleMove vtmove;
int num_vtmove;
int free_vtmove;
VacPage to_vacpage = NULL;
int to_item = 0;
int ti;
if (cur_buffer != InvalidBuffer)
{
WriteBuffer(cur_buffer);
cur_buffer = InvalidBuffer;
}
/* Quick exit if we have no vtlinks to search in */
if (vacrelstats->vtlinks == NULL)
{
elog(DEBUG2, "parent item in update-chain not found --- can't continue repair_frag");
break; /* out of walk-along-page loop */
}
vtmove = (VTupleMove) palloc(100 * sizeof(VTupleMoveData));
num_vtmove = 0;
free_vtmove = 100;
/*
* If this tuple is in the begin/middle of the chain then
* we have to move to the end of chain.
*/
while (!(tp.t_data->t_infomask & (HEAP_XMAX_INVALID |
HEAP_MARKED_FOR_UPDATE)) &&
!(ItemPointerEquals(&(tp.t_self),
&(tp.t_data->t_ctid))))
{
Ctid = tp.t_data->t_ctid;
if (freeCbuf)
ReleaseBuffer(Cbuf);
freeCbuf = true;
Cbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&Ctid));
Cpage = BufferGetPage(Cbuf);
Citemid = PageGetItemId(Cpage,
ItemPointerGetOffsetNumber(&Ctid));
if (!ItemIdIsUsed(Citemid))
{
/*
* This means that in the middle of chain there
* was tuple updated by older (than OldestXmin)
* xaction and this tuple is already deleted by
* me. Actually, upper part of chain should be
* removed and seems that this should be handled
* in scan_heap(), but it's not implemented at the
* moment and so we just stop shrinking here.
*/
elog(DEBUG2, "child itemid in update-chain marked as unused --- can't continue repair_frag");
chain_move_failed = true;
break; /* out of loop to move to chain end */
}
tp.t_datamcxt = NULL;
tp.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tp.t_self = Ctid;
tlen = tp.t_len = ItemIdGetLength(Citemid);
}
if (chain_move_failed)
{
if (freeCbuf)
ReleaseBuffer(Cbuf);
pfree(vtmove);
break; /* out of walk-along-page loop */
}
/*
* Check if all items in chain can be moved
*/
for (;;)
{
Buffer Pbuf;
Page Ppage;
ItemId Pitemid;
HeapTupleData Ptp;
VTupleLinkData vtld,
*vtlp;
if (to_vacpage == NULL ||
!enough_space(to_vacpage, tlen))
{
for (i = 0; i < num_fraged_pages; i++)
{
if (enough_space(fraged_pages->pagedesc[i], tlen))
break;
}
if (i == num_fraged_pages)
{
/* can't move item anywhere */
chain_move_failed = true;
break; /* out of check-all-items loop */
}
to_item = i;
to_vacpage = fraged_pages->pagedesc[to_item];
}
to_vacpage->free -= MAXALIGN(tlen);
if (to_vacpage->offsets_used >= to_vacpage->offsets_free)
to_vacpage->free -= sizeof(ItemIdData);
(to_vacpage->offsets_used)++;
if (free_vtmove == 0)
{
free_vtmove = 1000;
vtmove = (VTupleMove)
repalloc(vtmove,
(free_vtmove + num_vtmove) *
sizeof(VTupleMoveData));
}
vtmove[num_vtmove].tid = tp.t_self;
vtmove[num_vtmove].vacpage = to_vacpage;
if (to_vacpage->offsets_used == 1)
vtmove[num_vtmove].cleanVpd = true;
else
vtmove[num_vtmove].cleanVpd = false;
free_vtmove--;
num_vtmove++;
/* At beginning of chain? */
if (!(tp.t_data->t_infomask & HEAP_UPDATED) ||
TransactionIdPrecedes(HeapTupleHeaderGetXmin(tp.t_data),
OldestXmin))
break;
/* No, move to tuple with prior row version */
vtld.new_tid = tp.t_self;
vtlp = (VTupleLink)
vac_bsearch((void *) &vtld,
(void *) (vacrelstats->vtlinks),
vacrelstats->num_vtlinks,
sizeof(VTupleLinkData),
vac_cmp_vtlinks);
if (vtlp == NULL)
{
/* see discussion above */
elog(DEBUG2, "parent item in update-chain not found --- can't continue repair_frag");
chain_move_failed = true;
break; /* out of check-all-items loop */
}
tp.t_self = vtlp->this_tid;
Pbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&(tp.t_self)));
Ppage = BufferGetPage(Pbuf);
Pitemid = PageGetItemId(Ppage,
ItemPointerGetOffsetNumber(&(tp.t_self)));
/* this can't happen since we saw tuple earlier: */
if (!ItemIdIsUsed(Pitemid))
elog(ERROR, "parent itemid marked as unused");
Ptp.t_datamcxt = NULL;
Ptp.t_data = (HeapTupleHeader) PageGetItem(Ppage, Pitemid);
/* ctid should not have changed since we saved it */
Assert(ItemPointerEquals(&(vtld.new_tid),
&(Ptp.t_data->t_ctid)));
/*
* Read above about cases when !ItemIdIsUsed(Citemid)
* (child item is removed)... Due to the fact that at
* the moment we don't remove unuseful part of
* update-chain, it's possible to get too old parent
* row here. Like as in the case which caused this
* problem, we stop shrinking here. I could try to
* find real parent row but want not to do it because
* of real solution will be implemented anyway, later,
* and we are too close to 6.5 release. - vadim
* 06/11/99
*/
if (!(TransactionIdEquals(HeapTupleHeaderGetXmax(Ptp.t_data),
HeapTupleHeaderGetXmin(tp.t_data))))
{
ReleaseBuffer(Pbuf);
elog(DEBUG2, "too old parent tuple found --- can't continue repair_frag");
chain_move_failed = true;
break; /* out of check-all-items loop */
}
tp.t_datamcxt = Ptp.t_datamcxt;
tp.t_data = Ptp.t_data;
tlen = tp.t_len = ItemIdGetLength(Pitemid);
if (freeCbuf)
ReleaseBuffer(Cbuf);
Cbuf = Pbuf;
freeCbuf = true;
} /* end of check-all-items loop */
if (freeCbuf)
ReleaseBuffer(Cbuf);
freeCbuf = false;
if (chain_move_failed)
{
/*
* Undo changes to offsets_used state. We don't
* bother cleaning up the amount-free state, since
* we're not going to do any further tuple motion.
*/
for (i = 0; i < num_vtmove; i++)
{
Assert(vtmove[i].vacpage->offsets_used > 0);
(vtmove[i].vacpage->offsets_used)--;
}
pfree(vtmove);
break; /* out of walk-along-page loop */
}
/*
* Okay, move the whle tuple chain
*/
ItemPointerSetInvalid(&Ctid);
for (ti = 0; ti < num_vtmove; ti++)
{
VacPage destvacpage = vtmove[ti].vacpage;
/* Get page to move from */
tuple.t_self = vtmove[ti].tid;
Cbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&(tuple.t_self)));
/* Get page to move to */
cur_buffer = ReadBuffer(onerel, destvacpage->blkno);
LockBuffer(cur_buffer, BUFFER_LOCK_EXCLUSIVE);
if (cur_buffer != Cbuf)
LockBuffer(Cbuf, BUFFER_LOCK_EXCLUSIVE);
ToPage = BufferGetPage(cur_buffer);
Cpage = BufferGetPage(Cbuf);
Citemid = PageGetItemId(Cpage,
ItemPointerGetOffsetNumber(&(tuple.t_self)));
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tuple_len = tuple.t_len = ItemIdGetLength(Citemid);
/*
* make a copy of the source tuple, and then mark the
* source tuple MOVED_OFF.
*/
heap_copytuple_with_tuple(&tuple, &newtup);
/*
* register invalidation of source tuple in catcaches.
*/
CacheInvalidateHeapTuple(onerel, &tuple);
/* NO EREPORT(ERROR) TILL CHANGES ARE LOGGED */
START_CRIT_SECTION();
tuple.t_data->t_infomask &= ~(HEAP_XMIN_COMMITTED |
HEAP_XMIN_INVALID |
HEAP_MOVED_IN);
tuple.t_data->t_infomask |= HEAP_MOVED_OFF;
HeapTupleHeaderSetXvac(tuple.t_data, myXID);
/*
* If this page was not used before - clean it.
*
* NOTE: a nasty bug used to lurk here. It is possible
* for the source and destination pages to be the same
* (since this tuple-chain member can be on a page
* lower than the one we're currently processing in
* the outer loop). If that's true, then after
* vacuum_page() the source tuple will have been
* moved, and tuple.t_data will be pointing at
* garbage. Therefore we must do everything that uses
* tuple.t_data BEFORE this step!!
*
* This path is different from the other callers of
* vacuum_page, because we have already incremented
* the vacpage's offsets_used field to account for the
* tuple(s) we expect to move onto the page. Therefore
* vacuum_page's check for offsets_used == 0 is wrong.
* But since that's a good debugging check for all
* other callers, we work around it here rather than
* remove it.
*/
if (!PageIsEmpty(ToPage) && vtmove[ti].cleanVpd)
{
int sv_offsets_used = destvacpage->offsets_used;
destvacpage->offsets_used = 0;
vacuum_page(onerel, cur_buffer, destvacpage);
destvacpage->offsets_used = sv_offsets_used;
}
/*
* Update the state of the copied tuple, and store it
* on the destination page.
*/
newtup.t_data->t_infomask &= ~(HEAP_XMIN_COMMITTED |
HEAP_XMIN_INVALID |
HEAP_MOVED_OFF);
newtup.t_data->t_infomask |= HEAP_MOVED_IN;
HeapTupleHeaderSetXvac(newtup.t_data, myXID);
newoff = PageAddItem(ToPage,
(Item) newtup.t_data,
tuple_len,
InvalidOffsetNumber,
LP_USED);
if (newoff == InvalidOffsetNumber)
{
elog(PANIC, "failed to add item with len = %lu to page %u while moving tuple chain",
(unsigned long) tuple_len, destvacpage->blkno);
}
newitemid = PageGetItemId(ToPage, newoff);
pfree(newtup.t_data);
newtup.t_datamcxt = NULL;
newtup.t_data = (HeapTupleHeader) PageGetItem(ToPage, newitemid);
ItemPointerSet(&(newtup.t_self), destvacpage->blkno, newoff);
/* XLOG stuff */
if (!onerel->rd_istemp)
{
XLogRecPtr recptr =
log_heap_move(onerel, Cbuf, tuple.t_self,
cur_buffer, &newtup);
if (Cbuf != cur_buffer)
{
PageSetLSN(Cpage, recptr);
PageSetSUI(Cpage, ThisStartUpID);
}
PageSetLSN(ToPage, recptr);
PageSetSUI(ToPage, ThisStartUpID);
}
else
{
/*
* No XLOG record, but still need to flag that XID
* exists on disk
*/
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
if (destvacpage->blkno > last_move_dest_block)
last_move_dest_block = destvacpage->blkno;
/*
* Set new tuple's t_ctid pointing to itself for last
* tuple in chain, and to next tuple in chain
* otherwise.
*/
if (!ItemPointerIsValid(&Ctid))
newtup.t_data->t_ctid = newtup.t_self;
else
newtup.t_data->t_ctid = Ctid;
Ctid = newtup.t_self;
num_moved++;
/*
* Remember that we moved tuple from the current page
* (corresponding index tuple will be cleaned).
*/
if (Cbuf == buf)
vacpage->offsets[vacpage->offsets_free++] =
ItemPointerGetOffsetNumber(&(tuple.t_self));
else
keep_tuples++;
LockBuffer(cur_buffer, BUFFER_LOCK_UNLOCK);
if (cur_buffer != Cbuf)
LockBuffer(Cbuf, BUFFER_LOCK_UNLOCK);
/* Create index entries for the moved tuple */
if (resultRelInfo->ri_NumIndices > 0)
{
ExecStoreTuple(&newtup, slot, InvalidBuffer, false);
ExecInsertIndexTuples(slot, &(newtup.t_self),
estate, true);
}
WriteBuffer(cur_buffer);
WriteBuffer(Cbuf);
} /* end of move-the-tuple-chain loop */
cur_buffer = InvalidBuffer;
pfree(vtmove);
chain_tuple_moved = true;
/* advance to next tuple in walk-along-page loop */
continue;
} /* end of is-tuple-in-chain test */
/* try to find new page for this tuple */
if (cur_buffer == InvalidBuffer ||
!enough_space(cur_page, tuple_len))
{
if (cur_buffer != InvalidBuffer)
{
WriteBuffer(cur_buffer);
cur_buffer = InvalidBuffer;
}
for (i = 0; i < num_fraged_pages; i++)
{
if (enough_space(fraged_pages->pagedesc[i], tuple_len))
break;
}
if (i == num_fraged_pages)
break; /* can't move item anywhere */
cur_item = i;
cur_page = fraged_pages->pagedesc[cur_item];
cur_buffer = ReadBuffer(onerel, cur_page->blkno);
LockBuffer(cur_buffer, BUFFER_LOCK_EXCLUSIVE);
ToPage = BufferGetPage(cur_buffer);
/* if this page was not used before - clean it */
if (!PageIsEmpty(ToPage) && cur_page->offsets_used == 0)
vacuum_page(onerel, cur_buffer, cur_page);
}
else
LockBuffer(cur_buffer, BUFFER_LOCK_EXCLUSIVE);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
/* copy tuple */
heap_copytuple_with_tuple(&tuple, &newtup);
/*
* register invalidation of source tuple in catcaches.
*
* (Note: we do not need to register the copied tuple, because we
* are not changing the tuple contents and so there cannot be
* any need to flush negative catcache entries.)
*/
CacheInvalidateHeapTuple(onerel, &tuple);
/* NO EREPORT(ERROR) TILL CHANGES ARE LOGGED */
START_CRIT_SECTION();
/*
* Mark new tuple as MOVED_IN by me.
*/
newtup.t_data->t_infomask &= ~(HEAP_XMIN_COMMITTED |
HEAP_XMIN_INVALID |
HEAP_MOVED_OFF);
newtup.t_data->t_infomask |= HEAP_MOVED_IN;
HeapTupleHeaderSetXvac(newtup.t_data, myXID);
/* add tuple to the page */
newoff = PageAddItem(ToPage, (Item) newtup.t_data, tuple_len,
InvalidOffsetNumber, LP_USED);
if (newoff == InvalidOffsetNumber)
{
elog(PANIC, "failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)",
(unsigned long) tuple_len,
cur_page->blkno, (unsigned long) cur_page->free,
cur_page->offsets_used, cur_page->offsets_free);
}
newitemid = PageGetItemId(ToPage, newoff);
pfree(newtup.t_data);
newtup.t_datamcxt = NULL;
newtup.t_data = (HeapTupleHeader) PageGetItem(ToPage, newitemid);
ItemPointerSet(&(newtup.t_data->t_ctid), cur_page->blkno, newoff);
newtup.t_self = newtup.t_data->t_ctid;
/*
* Mark old tuple as MOVED_OFF by me.
*/
tuple.t_data->t_infomask &= ~(HEAP_XMIN_COMMITTED |
HEAP_XMIN_INVALID |
HEAP_MOVED_IN);
tuple.t_data->t_infomask |= HEAP_MOVED_OFF;
HeapTupleHeaderSetXvac(tuple.t_data, myXID);
/* XLOG stuff */
if (!onerel->rd_istemp)
{
XLogRecPtr recptr =
log_heap_move(onerel, buf, tuple.t_self,
cur_buffer, &newtup);
PageSetLSN(page, recptr);
PageSetSUI(page, ThisStartUpID);
PageSetLSN(ToPage, recptr);
PageSetSUI(ToPage, ThisStartUpID);
}
else
{
/*
* No XLOG record, but still need to flag that XID exists
* on disk
*/
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
cur_page->offsets_used++;
num_moved++;
cur_page->free = ((PageHeader) ToPage)->pd_upper - ((PageHeader) ToPage)->pd_lower;
if (cur_page->blkno > last_move_dest_block)
last_move_dest_block = cur_page->blkno;
vacpage->offsets[vacpage->offsets_free++] = offnum;
LockBuffer(cur_buffer, BUFFER_LOCK_UNLOCK);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/* insert index' tuples if needed */
if (resultRelInfo->ri_NumIndices > 0)
{
ExecStoreTuple(&newtup, slot, InvalidBuffer, false);
ExecInsertIndexTuples(slot, &(newtup.t_self), estate, true);
}
} /* walk along page */
/*
* If we broke out of the walk-along-page loop early (ie, still
* have offnum <= maxoff), then we failed to move some tuple off
* this page. No point in shrinking any more, so clean up and
* exit the per-page loop.
*/
if (offnum < maxoff && keep_tuples > 0)
{
OffsetNumber off;
/*
* Fix vacpage state for any unvisited tuples remaining on
* page
*/
for (off = OffsetNumberNext(offnum);
off <= maxoff;
off = OffsetNumberNext(off))
{
itemid = PageGetItemId(page, off);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED)
continue;
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
elog(ERROR, "HEAP_MOVED_IN was not expected");
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
if (HeapTupleHeaderGetXvac(tuple.t_data) != myXID)
elog(ERROR, "invalid XVAC in tuple header");
/* some chains was moved while */
if (chain_tuple_moved)
{ /* cleaning this page */
Assert(vacpage->offsets_free > 0);
for (i = 0; i < vacpage->offsets_free; i++)
{
if (vacpage->offsets[i] == off)
break;
}
if (i >= vacpage->offsets_free) /* not found */
{
vacpage->offsets[vacpage->offsets_free++] = off;
Assert(keep_tuples > 0);
keep_tuples--;
}
}
else
{
vacpage->offsets[vacpage->offsets_free++] = off;
Assert(keep_tuples > 0);
keep_tuples--;
}
}
else
elog(ERROR, "HEAP_MOVED_OFF was expected");
}
}
if (vacpage->offsets_free > 0) /* some tuples were moved */
{
if (chain_tuple_moved) /* else - they are ordered */
{
qsort((char *) (vacpage->offsets), vacpage->offsets_free,
sizeof(OffsetNumber), vac_cmp_offno);
}
vpage_insert(&Nvacpagelist, copy_vac_page(vacpage));
WriteBuffer(buf);
}
else if (dowrite)
WriteBuffer(buf);
else
ReleaseBuffer(buf);
if (offnum <= maxoff)
break; /* had to quit early, see above note */
} /* walk along relation */
blkno++; /* new number of blocks */
if (cur_buffer != InvalidBuffer)
{
Assert(num_moved > 0);
WriteBuffer(cur_buffer);
}
if (num_moved > 0)
{
/*
* We have to commit our tuple movings before we truncate the
* relation. Ideally we should do Commit/StartTransactionCommand
* here, relying on the session-level table lock to protect our
* exclusive access to the relation. However, that would require
* a lot of extra code to close and re-open the relation, indexes,
* etc. For now, a quick hack: record status of current
* transaction as committed, and continue.
*/
RecordTransactionCommit();
}
/*
* We are not going to move any more tuples across pages, but we still
* need to apply vacuum_page to compact free space in the remaining
* pages in vacuum_pages list. Note that some of these pages may also
* be in the fraged_pages list, and may have had tuples moved onto
* them; if so, we already did vacuum_page and needn't do it again.
*/
for (i = 0, curpage = vacuum_pages->pagedesc;
i < vacuumed_pages;
i++, curpage++)
{
vacuum_delay_point();
Assert((*curpage)->blkno < blkno);
if ((*curpage)->offsets_used == 0)
{
/* this page was not used as a move target, so must clean it */
buf = ReadBuffer(onerel, (*curpage)->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
if (!PageIsEmpty(page))
vacuum_page(onerel, buf, *curpage);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
}
}
/*
* Now scan all the pages that we moved tuples onto and update tuple
* status bits. This is not really necessary, but will save time for
* future transactions examining these tuples.
*
* XXX NOTICE that this code fails to clear HEAP_MOVED_OFF tuples from
* pages that were move source pages but not move dest pages. One
* also wonders whether it wouldn't be better to skip this step and
* let the tuple status updates happen someplace that's not holding an
* exclusive lock on the relation.
*/
checked_moved = 0;
for (i = 0, curpage = fraged_pages->pagedesc;
i < num_fraged_pages;
i++, curpage++)
{
vacuum_delay_point();
Assert((*curpage)->blkno < blkno);
if ((*curpage)->blkno > last_move_dest_block)
break; /* no need to scan any further */
if ((*curpage)->offsets_used == 0)
continue; /* this page was never used as a move dest */
buf = ReadBuffer(onerel, (*curpage)->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
num_tuples = 0;
max_offset = PageGetMaxOffsetNumber(page);
for (newoff = FirstOffsetNumber;
newoff <= max_offset;
newoff = OffsetNumberNext(newoff))
{
itemid = PageGetItemId(page, newoff);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if (!(tuple.t_data->t_infomask & HEAP_MOVED))
elog(ERROR, "HEAP_MOVED_OFF/HEAP_MOVED_IN was expected");
if (HeapTupleHeaderGetXvac(tuple.t_data) != myXID)
elog(ERROR, "invalid XVAC in tuple header");
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
{
tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED;
tuple.t_data->t_infomask &= ~HEAP_MOVED;
num_tuples++;
}
else
tuple.t_data->t_infomask |= HEAP_XMIN_INVALID;
}
}
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
Assert((*curpage)->offsets_used == num_tuples);
checked_moved += num_tuples;
}
Assert(num_moved == checked_moved);
/*
* It'd be cleaner to make this report at the bottom of this routine,
* but then the rusage would double-count the second pass of index
* vacuuming. So do it here and ignore the relatively small amount of
* processing that occurs below.
*/
ereport(elevel,
(errmsg("\"%s\": moved %u row versions, truncated %u to %u pages",
RelationGetRelationName(onerel),
num_moved, nblocks, blkno),
errdetail("%s",
vac_show_rusage(&ru0))));
/*
* Reflect the motion of system tuples to catalog cache here.
*/
CommandCounterIncrement();
if (Nvacpagelist.num_pages > 0)
{
/* vacuum indexes again if needed */
if (Irel != NULL)
{
VacPage *vpleft,
*vpright,
vpsave;
/* re-sort Nvacpagelist.pagedesc */
for (vpleft = Nvacpagelist.pagedesc,
vpright = Nvacpagelist.pagedesc + Nvacpagelist.num_pages - 1;
vpleft < vpright; vpleft++, vpright--)
{
vpsave = *vpleft;
*vpleft = *vpright;
*vpright = vpsave;
}
Assert(keep_tuples >= 0);
for (i = 0; i < nindexes; i++)
vacuum_index(&Nvacpagelist, Irel[i],
vacrelstats->rel_tuples, keep_tuples);
}
/* clean moved tuples from last page in Nvacpagelist list */
if (vacpage->blkno == (blkno - 1) &&
vacpage->offsets_free > 0)
{
OffsetNumber unused[BLCKSZ / sizeof(OffsetNumber)];
int uncnt;
buf = ReadBuffer(onerel, vacpage->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
num_tuples = 0;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
if (HeapTupleHeaderGetXvac(tuple.t_data) != myXID)
elog(ERROR, "invalid XVAC in tuple header");
itemid->lp_flags &= ~LP_USED;
num_tuples++;
}
else
elog(ERROR, "HEAP_MOVED_OFF was expected");
}
}
Assert(vacpage->offsets_free == num_tuples);
START_CRIT_SECTION();
uncnt = PageRepairFragmentation(page, unused);
/* XLOG stuff */
if (!onerel->rd_istemp)
{
XLogRecPtr recptr;
recptr = log_heap_clean(onerel, buf, unused, uncnt);
PageSetLSN(page, recptr);
PageSetSUI(page, ThisStartUpID);
}
else
{
/*
* No XLOG record, but still need to flag that XID exists
* on disk
*/
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
}
/* now - free new list of reaped pages */
curpage = Nvacpagelist.pagedesc;
for (i = 0; i < Nvacpagelist.num_pages; i++, curpage++)
pfree(*curpage);
pfree(Nvacpagelist.pagedesc);
}
/*
* Flush dirty pages out to disk. We do this unconditionally, even if
* we don't need to truncate, because we want to ensure that all
* tuples have correct on-row commit status on disk (see bufmgr.c's
* comments for FlushRelationBuffers()).
*/
i = FlushRelationBuffers(onerel, blkno);
if (i < 0)
elog(ERROR, "FlushRelationBuffers returned %d", i);
/* truncate relation, if needed */
if (blkno < nblocks)
{
RelationTruncate(onerel, blkno);
vacrelstats->rel_pages = blkno; /* set new number of blocks */
}
/* clean up */
pfree(vacpage);
if (vacrelstats->vtlinks != NULL)
pfree(vacrelstats->vtlinks);
ExecDropTupleTable(tupleTable, true);
ExecCloseIndices(resultRelInfo);
FreeExecutorState(estate);
}
/*
* vacuum_heap() -- free dead tuples
*
* This routine marks dead tuples as unused and truncates relation
* if there are "empty" end-blocks.
*/
static void
vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
{
Buffer buf;
VacPage *vacpage;
BlockNumber relblocks;
int nblocks;
int i;
nblocks = vacuum_pages->num_pages;
nblocks -= vacuum_pages->empty_end_pages; /* nothing to do with them */
for (i = 0, vacpage = vacuum_pages->pagedesc; i < nblocks; i++, vacpage++)
{
vacuum_delay_point();
if ((*vacpage)->offsets_free > 0)
{
buf = ReadBuffer(onerel, (*vacpage)->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, *vacpage);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
}
}
/*
* Flush dirty pages out to disk. We do this unconditionally, even if
* we don't need to truncate, because we want to ensure that all
* tuples have correct on-row commit status on disk (see bufmgr.c's
* comments for FlushRelationBuffers()).
*/
Assert(vacrelstats->rel_pages >= vacuum_pages->empty_end_pages);
relblocks = vacrelstats->rel_pages - vacuum_pages->empty_end_pages;
i = FlushRelationBuffers(onerel, relblocks);
if (i < 0)
elog(ERROR, "FlushRelationBuffers returned %d", i);
/* truncate relation if there are some empty end-pages */
if (vacuum_pages->empty_end_pages > 0)
{
ereport(elevel,
(errmsg("\"%s\": truncated %u to %u pages",
RelationGetRelationName(onerel),
vacrelstats->rel_pages, relblocks)));
RelationTruncate(onerel, relblocks);
vacrelstats->rel_pages = relblocks; /* set new number of
* blocks */
}
}
/*
* vacuum_page() -- free dead tuples on a page
* and repair its fragmentation.
*/
static void
vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
{
OffsetNumber unused[BLCKSZ / sizeof(OffsetNumber)];
int uncnt;
Page page = BufferGetPage(buffer);
ItemId itemid;
int i;
/* There shouldn't be any tuples moved onto the page yet! */
Assert(vacpage->offsets_used == 0);
START_CRIT_SECTION();
for (i = 0; i < vacpage->offsets_free; i++)
{
itemid = PageGetItemId(page, vacpage->offsets[i]);
itemid->lp_flags &= ~LP_USED;
}
uncnt = PageRepairFragmentation(page, unused);
/* XLOG stuff */
if (!onerel->rd_istemp)
{
XLogRecPtr recptr;
recptr = log_heap_clean(onerel, buffer, unused, uncnt);
PageSetLSN(page, recptr);
PageSetSUI(page, ThisStartUpID);
}
else
{
/* No XLOG record, but still need to flag that XID exists on disk */
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
}
/*
* scan_index() -- scan one index relation to update statistic.
*
* We use this when we have no deletions to do.
*/
static void
scan_index(Relation indrel, double num_tuples)
{
IndexBulkDeleteResult *stats;
IndexVacuumCleanupInfo vcinfo;
VacRUsage ru0;
vac_init_rusage(&ru0);
/*
* Even though we're not planning to delete anything, we use the
* ambulkdelete call, because (a) the scan happens within the index AM
* for more speed, and (b) it may want to pass private statistics to
* the amvacuumcleanup call.
*/
stats = index_bulk_delete(indrel, dummy_tid_reaped, NULL);
/* Do post-VACUUM cleanup, even though we deleted nothing */
vcinfo.vacuum_full = true;
vcinfo.message_level = elevel;
stats = index_vacuum_cleanup(indrel, &vcinfo, stats);
if (!stats)
return;
/* now update statistics in pg_class */
vac_update_relstats(RelationGetRelid(indrel),
stats->num_pages, stats->num_index_tuples,
false);
ereport(elevel,
(errmsg("index \"%s\" now contains %.0f row versions in %u pages",
RelationGetRelationName(indrel),
stats->num_index_tuples,
stats->num_pages),
errdetail("%u index pages have been deleted, %u are currently reusable.\n"
"%s",
stats->pages_deleted, stats->pages_free,
vac_show_rusage(&ru0))));
/*
* Check for tuple count mismatch. If the index is partial, then it's
* OK for it to have fewer tuples than the heap; else we got trouble.
*/
if (stats->num_index_tuples != num_tuples)
{
if (stats->num_index_tuples > num_tuples ||
!vac_is_partial_index(indrel))
ereport(WARNING,
(errmsg("index \"%s\" contains %.0f row versions, but table contains %.0f row versions",
RelationGetRelationName(indrel),
stats->num_index_tuples, num_tuples),
errhint("Rebuild the index with REINDEX.")));
}
pfree(stats);
}
/*
* vacuum_index() -- vacuum one index relation.
*
* Vpl is the VacPageList of the heap we're currently vacuuming.
* It's locked. Indrel is an index relation on the vacuumed heap.
*
* We don't bother to set locks on the index relation here, since
* the parent table is exclusive-locked already.
*
* Finally, we arrange to update the index relation's statistics in
* pg_class.
*/
static void
vacuum_index(VacPageList vacpagelist, Relation indrel,
double num_tuples, int keep_tuples)
{
IndexBulkDeleteResult *stats;
IndexVacuumCleanupInfo vcinfo;
VacRUsage ru0;
vac_init_rusage(&ru0);
/* Do bulk deletion */
stats = index_bulk_delete(indrel, tid_reaped, (void *) vacpagelist);
/* Do post-VACUUM cleanup */
vcinfo.vacuum_full = true;
vcinfo.message_level = elevel;
stats = index_vacuum_cleanup(indrel, &vcinfo, stats);
if (!stats)
return;
/* now update statistics in pg_class */
vac_update_relstats(RelationGetRelid(indrel),
stats->num_pages, stats->num_index_tuples,
false);
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,
vac_show_rusage(&ru0))));
/*
* Check for tuple count mismatch. If the index is partial, then it's
* OK for it to have fewer tuples than the heap; else we got trouble.
*/
if (stats->num_index_tuples != num_tuples + keep_tuples)
{
if (stats->num_index_tuples > num_tuples + keep_tuples ||
!vac_is_partial_index(indrel))
ereport(WARNING,
(errmsg("index \"%s\" contains %.0f row versions, but table contains %.0f row versions",
RelationGetRelationName(indrel),
stats->num_index_tuples, num_tuples + keep_tuples),
errhint("Rebuild the index with REINDEX.")));
}
pfree(stats);
}
/*
* tid_reaped() -- is a particular tid reaped?
*
* This has the right signature to be an IndexBulkDeleteCallback.
*
* vacpagelist->VacPage_array is sorted in right order.
*/
static bool
tid_reaped(ItemPointer itemptr, void *state)
{
VacPageList vacpagelist = (VacPageList) state;
OffsetNumber ioffno;
OffsetNumber *voff;
VacPage vp,
*vpp;
VacPageData vacpage;
vacpage.blkno = ItemPointerGetBlockNumber(itemptr);
ioffno = ItemPointerGetOffsetNumber(itemptr);
vp = &vacpage;
vpp = (VacPage *) vac_bsearch((void *) &vp,
(void *) (vacpagelist->pagedesc),
vacpagelist->num_pages,
sizeof(VacPage),
vac_cmp_blk);
if (vpp == NULL)
return false;
/* ok - we are on a partially or fully reaped page */
vp = *vpp;
if (vp->offsets_free == 0)
{
/* this is EmptyPage, so claim all tuples on it are reaped!!! */
return true;
}
voff = (OffsetNumber *) vac_bsearch((void *) &ioffno,
(void *) (vp->offsets),
vp->offsets_free,
sizeof(OffsetNumber),
vac_cmp_offno);
if (voff == NULL)
return false;
/* tid is reaped */
return true;
}
/*
* Dummy version for scan_index.
*/
static bool
dummy_tid_reaped(ItemPointer itemptr, void *state)
{
return false;
}
/*
* Update the shared Free Space Map with the info we now have about
* free space in the relation, discarding any old info the map may have.
*/
static void
vac_update_fsm(Relation onerel, VacPageList fraged_pages,
BlockNumber rel_pages)
{
int nPages = fraged_pages->num_pages;
VacPage *pagedesc = fraged_pages->pagedesc;
Size threshold;
PageFreeSpaceInfo *pageSpaces;
int outPages;
int i;
/*
* We only report pages with free space at least equal to the average
* request size --- this avoids cluttering FSM with uselessly-small
* bits of space. Although FSM would discard pages with little free
* space anyway, it's important to do this prefiltering because (a) it
* reduces the time spent holding the FSM lock in
* RecordRelationFreeSpace, and (b) FSM uses the number of pages
* reported as a statistic for guiding space management. If we didn't
* threshold our reports the same way vacuumlazy.c does, we'd be
* skewing that statistic.
*/
threshold = GetAvgFSMRequestSize(&onerel->rd_node);
/* +1 to avoid palloc(0) */
pageSpaces = (PageFreeSpaceInfo *)
palloc((nPages + 1) * sizeof(PageFreeSpaceInfo));
outPages = 0;
for (i = 0; i < nPages; i++)
{
/*
* fraged_pages may contain entries for pages that we later
* decided to truncate from the relation; don't enter them into
* the free space map!
*/
if (pagedesc[i]->blkno >= rel_pages)
break;
if (pagedesc[i]->free >= threshold)
{
pageSpaces[outPages].blkno = pagedesc[i]->blkno;
pageSpaces[outPages].avail = pagedesc[i]->free;
outPages++;
}
}
RecordRelationFreeSpace(&onerel->rd_node, outPages, pageSpaces);
pfree(pageSpaces);
}
/* Copy a VacPage structure */
static VacPage
copy_vac_page(VacPage vacpage)
{
VacPage newvacpage;
/* allocate a VacPageData entry */
newvacpage = (VacPage) palloc(sizeof(VacPageData) +
vacpage->offsets_free * sizeof(OffsetNumber));
/* fill it in */
if (vacpage->offsets_free > 0)
memcpy(newvacpage->offsets, vacpage->offsets,
vacpage->offsets_free * sizeof(OffsetNumber));
newvacpage->blkno = vacpage->blkno;
newvacpage->free = vacpage->free;
newvacpage->offsets_used = vacpage->offsets_used;
newvacpage->offsets_free = vacpage->offsets_free;
return newvacpage;
}
/*
* Add a VacPage pointer to a VacPageList.
*
* As a side effect of the way that scan_heap works,
* higher pages come after lower pages in the array
* (and highest tid on a page is last).
*/
static void
vpage_insert(VacPageList vacpagelist, VacPage vpnew)
{
#define PG_NPAGEDESC 1024
/* allocate a VacPage entry if needed */
if (vacpagelist->num_pages == 0)
{
vacpagelist->pagedesc = (VacPage *) palloc(PG_NPAGEDESC * sizeof(VacPage));
vacpagelist->num_allocated_pages = PG_NPAGEDESC;
}
else if (vacpagelist->num_pages >= vacpagelist->num_allocated_pages)
{
vacpagelist->num_allocated_pages *= 2;
vacpagelist->pagedesc = (VacPage *) repalloc(vacpagelist->pagedesc, vacpagelist->num_allocated_pages * sizeof(VacPage));
}
vacpagelist->pagedesc[vacpagelist->num_pages] = vpnew;
(vacpagelist->num_pages)++;
}
/*
* vac_bsearch: just like standard C library routine bsearch(),
* except that we first test to see whether the target key is outside
* the range of the table entries. This case is handled relatively slowly
* by the normal binary search algorithm (ie, no faster than any other key)
* but it occurs often enough in VACUUM to be worth optimizing.
*/
static void *
vac_bsearch(const void *key, const void *base,
size_t nelem, size_t size,
int (*compar) (const void *, const void *))
{
int res;
const void *last;
if (nelem == 0)
return NULL;
res = compar(key, base);
if (res < 0)
return NULL;
if (res == 0)
return (void *) base;
if (nelem > 1)
{
last = (const void *) ((const char *) base + (nelem - 1) * size);
res = compar(key, last);
if (res > 0)
return NULL;
if (res == 0)
return (void *) last;
}
if (nelem <= 2)
return NULL; /* already checked 'em all */
return bsearch(key, base, nelem, size, compar);
}
/*
* Comparator routines for use with qsort() and bsearch().
*/
static int
vac_cmp_blk(const void *left, const void *right)
{
BlockNumber lblk,
rblk;
lblk = (*((VacPage *) left))->blkno;
rblk = (*((VacPage *) right))->blkno;
if (lblk < rblk)
return -1;
if (lblk == rblk)
return 0;
return 1;
}
static int
vac_cmp_offno(const void *left, const void *right)
{
if (*(OffsetNumber *) left < *(OffsetNumber *) right)
return -1;
if (*(OffsetNumber *) left == *(OffsetNumber *) right)
return 0;
return 1;
}
static int
vac_cmp_vtlinks(const void *left, const void *right)
{
if (((VTupleLink) left)->new_tid.ip_blkid.bi_hi <
((VTupleLink) right)->new_tid.ip_blkid.bi_hi)
return -1;
if (((VTupleLink) left)->new_tid.ip_blkid.bi_hi >
((VTupleLink) right)->new_tid.ip_blkid.bi_hi)
return 1;
/* bi_hi-es are equal */
if (((VTupleLink) left)->new_tid.ip_blkid.bi_lo <
((VTupleLink) right)->new_tid.ip_blkid.bi_lo)
return -1;
if (((VTupleLink) left)->new_tid.ip_blkid.bi_lo >
((VTupleLink) right)->new_tid.ip_blkid.bi_lo)
return 1;
/* bi_lo-es are equal */
if (((VTupleLink) left)->new_tid.ip_posid <
((VTupleLink) right)->new_tid.ip_posid)
return -1;
if (((VTupleLink) left)->new_tid.ip_posid >
((VTupleLink) right)->new_tid.ip_posid)
return 1;
return 0;
}
void
vac_open_indexes(Relation relation, int *nindexes, Relation **Irel)
{
List *indexoidlist;
ListCell *indexoidscan;
int i;
indexoidlist = RelationGetIndexList(relation);
*nindexes = list_length(indexoidlist);
if (*nindexes > 0)
*Irel = (Relation *) palloc(*nindexes * sizeof(Relation));
else
*Irel = NULL;
i = 0;
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
(*Irel)[i] = index_open(indexoid);
i++;
}
list_free(indexoidlist);
}
void
vac_close_indexes(int nindexes, Relation *Irel)
{
if (Irel == NULL)
return;
while (nindexes--)
index_close(Irel[nindexes]);
pfree(Irel);
}
/*
* Is an index partial (ie, could it contain fewer tuples than the heap?)
*/
bool
vac_is_partial_index(Relation indrel)
{
/*
* If the index's AM doesn't support nulls, it's partial for our
* purposes
*/
if (!indrel->rd_am->amindexnulls)
return true;
/* Otherwise, look to see if there's a partial-index predicate */
if (!heap_attisnull(indrel->rd_indextuple, Anum_pg_index_indpred))
return true;
return false;
}
static bool
enough_space(VacPage vacpage, Size len)
{
len = MAXALIGN(len);
if (len > vacpage->free)
return false;
/* if there are free itemid(s) and len <= free_space... */
if (vacpage->offsets_used < vacpage->offsets_free)
return true;
/* noff_used >= noff_free and so we'll have to allocate new itemid */
if (len + sizeof(ItemIdData) <= vacpage->free)
return true;
return false;
}
/*
* Initialize usage snapshot.
*/
void
vac_init_rusage(VacRUsage *ru0)
{
struct timezone tz;
getrusage(RUSAGE_SELF, &ru0->ru);
gettimeofday(&ru0->tv, &tz);
}
/*
* Compute elapsed time since ru0 usage snapshot, and format into
* a displayable string. Result is in a static string, which is
* tacky, but no one ever claimed that the Postgres backend is
* threadable...
*/
const char *
vac_show_rusage(VacRUsage *ru0)
{
static char result[100];
VacRUsage ru1;
vac_init_rusage(&ru1);
if (ru1.tv.tv_usec < ru0->tv.tv_usec)
{
ru1.tv.tv_sec--;
ru1.tv.tv_usec += 1000000;
}
if (ru1.ru.ru_stime.tv_usec < ru0->ru.ru_stime.tv_usec)
{
ru1.ru.ru_stime.tv_sec--;
ru1.ru.ru_stime.tv_usec += 1000000;
}
if (ru1.ru.ru_utime.tv_usec < ru0->ru.ru_utime.tv_usec)
{
ru1.ru.ru_utime.tv_sec--;
ru1.ru.ru_utime.tv_usec += 1000000;
}
snprintf(result, sizeof(result),
"CPU %d.%02ds/%d.%02du sec elapsed %d.%02d sec.",
(int) (ru1.ru.ru_stime.tv_sec - ru0->ru.ru_stime.tv_sec),
(int) (ru1.ru.ru_stime.tv_usec - ru0->ru.ru_stime.tv_usec) / 10000,
(int) (ru1.ru.ru_utime.tv_sec - ru0->ru.ru_utime.tv_sec),
(int) (ru1.ru.ru_utime.tv_usec - ru0->ru.ru_utime.tv_usec) / 10000,
(int) (ru1.tv.tv_sec - ru0->tv.tv_sec),
(int) (ru1.tv.tv_usec - ru0->tv.tv_usec) / 10000);
return result;
}
/*
* vacuum_delay_point --- check for interrupts and cost-based delay.
*
* This should be called in each major loop of VACUUM processing,
* typically once per page processed.
*/
void
vacuum_delay_point(void)
{
/* Always check for interrupts */
CHECK_FOR_INTERRUPTS();
/* Nap if appropriate */
if (VacuumCostActive && !InterruptPending &&
VacuumCostBalance >= VacuumCostLimit)
{
int msec;
msec = VacuumCostNaptime * VacuumCostBalance / VacuumCostLimit;
if (msec > VacuumCostNaptime * 4)
msec = VacuumCostNaptime * 4;
pg_usleep(msec * 1000L);
VacuumCostBalance = 0;
/* Might have gotten an interrupt while sleeping */
CHECK_FOR_INTERRUPTS();
}
}
View Git Blame Copy Permalink