/*------------------------------------------------------------------------- * * 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 1.277 2004/05/22 23:14:38 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include #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, *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 (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 = lfirsto(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 = lappendo(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 = lappendo(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, *indexoidscan; int i; indexoidlist = RelationGetIndexList(relation); *nindexes = length(indexoidlist); if (*nindexes > 0) *Irel = (Relation *) palloc(*nindexes * sizeof(Relation)); else *Irel = NULL; i = 0; foreach(indexoidscan, indexoidlist) { Oid indexoid = lfirsto(indexoidscan); (*Irel)[i] = index_open(indexoid); i++; } freeList(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(); } }