Rearrange vacuum-related bits in PGPROC as a bitmask, to better support

having several of them.  Add two more flags: whether the process is
executing an ANALYZE, and whether a vacuum is for Xid wraparound (which
is obviously only set by autovacuum).

Sneakily move the worker's recently-acquired PostAuthDelay to a more useful
place.

Author: alvherre

src/backend/access/transam/twophase.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *		$PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.36 2007/09/21 16:32:19 tgl Exp $
+ *		$PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.37 2007/10/24 20:55:36 alvherre Exp $
  *
  * NOTES
  *		Each global transaction is associated with a global transaction
@@ -283,8 +283,7 @@ MarkAsPreparing(TransactionId xid, const char *gid,
 	gxact->proc.databaseId = databaseid;
 	gxact->proc.roleId = owner;
 	gxact->proc.inCommit = false;
-	gxact->proc.inVacuum = false;
-	gxact->proc.isAutovacuum = false;
+	gxact->proc.vacuumFlags = 0;
 	gxact->proc.lwWaiting = false;
 	gxact->proc.lwExclusive = false;
 	gxact->proc.lwWaitLink = NULL;

src/backend/commands/analyze.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.109 2007/09/24 03:12:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.110 2007/10/24 20:55:36 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,6 +31,7 @@
 #include "parser/parse_relation.h"
 #include "pgstat.h"
 #include "postmaster/autovacuum.h"
+#include "storage/proc.h"
 #include "utils/acl.h"
 #include "utils/datum.h"
 #include "utils/lsyscache.h"
@@ -201,6 +202,11 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
 		return;
 	}
 
+	/* let others know what I'm doing */
+	LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+	MyProc->vacuumFlags |= PROC_IN_ANALYZE;
+	LWLockRelease(ProcArrayLock);
+
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && Log_autovacuum_min_duration >= 0)
 	{
@@ -484,6 +490,14 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
 							RelationGetRelationName(onerel),
 							pg_rusage_show(&ru0))));
 	}
+
+	/*
+	 * Reset my PGPROC flag.  Note: we need this here, and not in vacuum_rel,
+	 * because the vacuum flag is cleared by the end-of-xact code.
+	 */
+	LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+	MyProc->vacuumFlags &= ~PROC_IN_ANALYZE;
+	LWLockRelease(ProcArrayLock);
 }
 
 /*

src/backend/commands/vacuum.c

@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.359 2007/09/20 17:56:31 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.360 2007/10/24 20:55:36 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -660,9 +660,9 @@ vacuum_set_xid_limits(int freeze_min_age, bool sharedRel,
  *		fixed-size never-null columns, but these are.
  *
  *		Another reason for doing it this way is that when we are in a lazy
- *		VACUUM and have inVacuum set, we mustn't do any updates --- somebody
- *		vacuuming pg_class might think they could delete a tuple marked with
- *		xmin = our xid.
+ *		VACUUM and have PROC_IN_VACUUM set, we mustn't do any updates ---
+ *		somebody vacuuming pg_class might think they could delete a tuple
+ *		marked with xmin = our xid.
  *
  *		This routine is shared by full VACUUM, lazy VACUUM, and stand-alone
  *		ANALYZE.
@@ -987,22 +987,24 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
 		 * During a lazy VACUUM we do not run any user-supplied functions, and
 		 * so it should be safe to not create a transaction snapshot.
 		 *
-		 * We can furthermore set the inVacuum flag, which lets other
+		 * We can furthermore set the PROC_IN_VACUUM flag, which lets other
 		 * concurrent VACUUMs know that they can ignore this one while
-		 * determining their OldestXmin.  (The reason we don't set inVacuum
+		 * determining their OldestXmin.  (The reason we don't set it
 		 * during a full VACUUM is exactly that we may have to run user-
 		 * defined functions for functional indexes, and we want to make sure
 		 * that if they use the snapshot set above, any tuples it requires
 		 * can't get removed from other tables.  An index function that
 		 * depends on the contents of other tables is arguably broken, but we
 		 * won't break it here by violating transaction semantics.)
 		 *
-		 * Note: the inVacuum flag remains set until CommitTransaction or
+		 * Note: this flag remains set until CommitTransaction or
 		 * AbortTransaction.  We don't want to clear it until we reset
 		 * MyProc->xid/xmin, else OldestXmin might appear to go backwards,
 		 * which is probably Not Good.
 		 */
-		MyProc->inVacuum = true;
+		LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+		MyProc->vacuumFlags |= PROC_IN_VACUUM;
+		LWLockRelease(ProcArrayLock);
 	}
 
 	/*

src/backend/postmaster/autovacuum.c

@@ -55,7 +55,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.62 2007/10/24 19:08:25 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.63 2007/10/24 20:55:36 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -172,6 +172,7 @@ typedef struct autovac_table
 	int			at_freeze_min_age;
 	int			at_vacuum_cost_delay;
 	int			at_vacuum_cost_limit;
+	bool		at_wraparound;
 } autovac_table;
 
 /*-------------
@@ -280,7 +281,7 @@ static autovac_table *table_recheck_autovac(Oid relid);
 static void relation_needs_vacanalyze(Oid relid, Form_pg_autovacuum avForm,
 						  Form_pg_class classForm,
 						  PgStat_StatTabEntry *tabentry, bool *dovacuum,
-						  bool *doanalyze);
+						  bool *doanalyze, bool *wraparound);
 
 static void autovacuum_do_vac_analyze(Oid relid, bool dovacuum,
 						  bool doanalyze, int freeze_min_age,
@@ -1440,9 +1441,6 @@ AutoVacWorkerMain(int argc, char *argv[])
 	/* Identify myself via ps */
 	init_ps_display("autovacuum worker process", "", "", "");
 
-	if (PostAuthDelay)
-		pg_usleep(PostAuthDelay * 1000000L);
-
 	SetProcessingMode(InitProcessing);
 
 	/*
@@ -1601,6 +1599,9 @@ AutoVacWorkerMain(int argc, char *argv[])
 		ereport(DEBUG1,
 				(errmsg("autovacuum: processing database \"%s\"", dbname)));
 
+		if (PostAuthDelay)
+			pg_usleep(PostAuthDelay * 1000000L);
+
 		/* And do an appropriate amount of work */
 		recentXid = ReadNewTransactionId();
 		do_autovacuum();
@@ -2085,6 +2086,14 @@ do_autovacuum(void)
 		/* clean up memory before each iteration */
 		MemoryContextResetAndDeleteChildren(PortalContext);
 
+		/* set the "vacuum for wraparound" flag in PGPROC */
+		if (tab->at_wraparound)
+		{
+			LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+			MyProc->vacuumFlags |= PROC_VACUUM_FOR_WRAPAROUND;
+			LWLockRelease(ProcArrayLock);
+		}
+
 		/*
 		 * We will abort vacuuming the current table if something errors out,
 		 * and continue with the next one in schedule; in particular, this
@@ -2119,6 +2128,7 @@ do_autovacuum(void)
 						   get_rel_name(tab->at_relid));
 			EmitErrorReport();
 
+			/* this resets the PGPROC flags too */
 			AbortOutOfAnyTransaction();
 			FlushErrorState();
 			MemoryContextResetAndDeleteChildren(PortalContext);
@@ -2129,6 +2139,14 @@ do_autovacuum(void)
 		}
 		PG_END_TRY();
 
+		/* reset my PGPROC flag */
+		if (tab->at_wraparound)
+		{
+			LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+			MyProc->vacuumFlags &= ~PROC_VACUUM_FOR_WRAPAROUND;
+			LWLockRelease(ProcArrayLock);
+		}
+
 		/* be tidy */
 		pfree(tab);
 
@@ -2223,9 +2241,10 @@ relation_check_autovac(Oid relid, Form_pg_class classForm,
 {
 	bool	dovacuum;
 	bool	doanalyze;
+	bool	dummy;
 
 	relation_needs_vacanalyze(relid, avForm, classForm, tabentry,
-							  &dovacuum, &doanalyze);
+							  &dovacuum, &doanalyze, &dummy);
 
 	if (classForm->relkind == RELKIND_TOASTVALUE)
 	{
@@ -2272,6 +2291,8 @@ table_recheck_autovac(Oid relid)
 	bool		doit = false;
 	PgStat_StatDBEntry *shared;
 	PgStat_StatDBEntry *dbentry;
+	bool		wraparound,
+				toast_wraparound = false;
 
 	/* use fresh stats */
 	autovac_refresh_stats();
@@ -2298,7 +2319,7 @@ table_recheck_autovac(Oid relid)
 										 shared, dbentry);
 
 	relation_needs_vacanalyze(relid, avForm, classForm, tabentry,
-							  &dovacuum, &doanalyze);
+							  &dovacuum, &doanalyze, &wraparound);
 
 	/* OK, it needs vacuum by itself */
 	if (dovacuum)
@@ -2316,6 +2337,7 @@ table_recheck_autovac(Oid relid)
 		{
 			bool			toast_dovacuum;
 			bool			toast_doanalyze;
+			bool			toast_wraparound;
 			Form_pg_class	toastClassForm;
 			PgStat_StatTabEntry *toasttabentry;
 
@@ -2325,9 +2347,10 @@ table_recheck_autovac(Oid relid)
 													  shared, dbentry);
 
 			/* note we use the pg_autovacuum entry for the main table */
-			relation_needs_vacanalyze(toastrelid, avForm, toastClassForm,
-									  toasttabentry, &toast_dovacuum,
-									  &toast_doanalyze);
+			relation_needs_vacanalyze(toastrelid, avForm,
+									  toastClassForm, toasttabentry,
+									  &toast_dovacuum, &toast_doanalyze,
+									  &toast_wraparound);
 			/* we only consider VACUUM for toast tables */
 			if (toast_dovacuum)
 			{
@@ -2389,6 +2412,7 @@ table_recheck_autovac(Oid relid)
 		tab->at_freeze_min_age = freeze_min_age;
 		tab->at_vacuum_cost_limit = vac_cost_limit;
 		tab->at_vacuum_cost_delay = vac_cost_delay;
+		tab->at_wraparound = wraparound || toast_wraparound;
 	}
 
 	heap_close(avRel, AccessShareLock);
@@ -2403,7 +2427,8 @@ table_recheck_autovac(Oid relid)
  * relation_needs_vacanalyze
  *
  * Check whether a relation needs to be vacuumed or analyzed; return each into
- * "dovacuum" and "doanalyze", respectively.  avForm and tabentry can be NULL,
+ * "dovacuum" and "doanalyze", respectively.  Also return whether the vacuum is
+ * being forced because of Xid wraparound.  avForm and tabentry can be NULL,
  * classForm shouldn't.
  *
  * A table needs to be vacuumed if the number of dead tuples exceeds a
@@ -2437,7 +2462,8 @@ relation_needs_vacanalyze(Oid relid,
 						  PgStat_StatTabEntry *tabentry,
 						  /* output params below */
 						  bool *dovacuum,
-						  bool *doanalyze)
+						  bool *doanalyze,
+						  bool *wraparound)
 {
 	bool		force_vacuum;
 	float4		reltuples;		/* pg_class.reltuples */
@@ -2499,6 +2525,7 @@ relation_needs_vacanalyze(Oid relid,
 	force_vacuum = (TransactionIdIsNormal(classForm->relfrozenxid) &&
 					TransactionIdPrecedes(classForm->relfrozenxid,
 										  xidForceLimit));
+	*wraparound = force_vacuum;
 
 	/* User disabled it in pg_autovacuum?  (But ignore if at risk) */
 	if (avForm && !avForm->enabled && !force_vacuum)

src/backend/storage/ipc/procarray.c

@@ -23,7 +23,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.35 2007/09/23 18:50:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.36 2007/10/24 20:55:36 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -242,7 +242,8 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid)
 		proc->xid = InvalidTransactionId;
 		proc->lxid = InvalidLocalTransactionId;
 		proc->xmin = InvalidTransactionId;
-		proc->inVacuum = false;			/* must be cleared with xid/xmin */
+		/* must be cleared with xid/xmin: */
+		proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
 		proc->inCommit = false;			/* be sure this is cleared in abort */
 
 		/* Clear the subtransaction-XID cache too while holding the lock */
@@ -267,7 +268,8 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid)
 
 		proc->lxid = InvalidLocalTransactionId;
 		proc->xmin = InvalidTransactionId;
-		proc->inVacuum = false;			/* must be cleared with xid/xmin */
+		/* must be cleared with xid/xmin: */
+		proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
 		proc->inCommit = false;			/* be sure this is cleared in abort */
 
 		Assert(proc->subxids.nxids == 0);
@@ -296,8 +298,10 @@ ProcArrayClearTransaction(PGPROC *proc)
 	proc->xid = InvalidTransactionId;
 	proc->lxid = InvalidLocalTransactionId;
 	proc->xmin = InvalidTransactionId;
-	proc->inVacuum = false;			/* redundant, but just in case */
-	proc->inCommit = false;			/* ditto */
+
+	/* redundant, but just in case */
+	proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
+	proc->inCommit = false;
 
 	/* Clear the subtransaction-XID cache too */
 	proc->subxids.nxids = 0;
@@ -546,7 +550,8 @@ TransactionIdIsActive(TransactionId xid)
  * If allDbs is TRUE then all backends are considered; if allDbs is FALSE
  * then only backends running in my own database are considered.
  *
- * If ignoreVacuum is TRUE then backends with inVacuum set are ignored.
+ * If ignoreVacuum is TRUE then backends with the PROC_IN_VACUUM flag set are
+ * ignored.
  *
  * This is used by VACUUM to decide which deleted tuples must be preserved
  * in a table.	allDbs = TRUE is needed for shared relations, but allDbs =
@@ -586,7 +591,7 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
 	{
 		volatile PGPROC	   *proc = arrayP->procs[index];
 
-		if (ignoreVacuum && proc->inVacuum)
+		if (ignoreVacuum && (proc->vacuumFlags & PROC_IN_VACUUM))
 			continue;
 
 		if (allDbs || proc->databaseId == MyDatabaseId)
@@ -723,7 +728,7 @@ GetSnapshotData(Snapshot snapshot, bool serializable)
 		TransactionId xid;
 
 		/* Ignore procs running LAZY VACUUM */
-		if (proc->inVacuum)
+		if (proc->vacuumFlags & PROC_IN_VACUUM)
 			continue;
 
 		/* Update globalxmin to be the smallest valid xmin */
@@ -1193,7 +1198,7 @@ CheckOtherDBBackends(Oid databaseId)
 
 			found = true;
 
-			if (proc->isAutovacuum)
+			if (proc->vacuumFlags & PROC_IS_AUTOVACUUM)
 			{
 				/* an autovacuum --- send it SIGTERM before sleeping */
 				int		autopid = proc->pid;

src/backend/storage/lmgr/proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.194 2007/09/08 20:31:15 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.195 2007/10/24 20:55:36 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -291,8 +291,9 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->inCommit = false;
-	MyProc->inVacuum = false;
-	MyProc->isAutovacuum = IsAutoVacuumWorkerProcess();
+	MyProc->vacuumFlags = 0;
+	if (IsAutoVacuumWorkerProcess())
+		MyProc->vacuumFlags |= PROC_IS_AUTOVACUUM;
 	MyProc->lwWaiting = false;
 	MyProc->lwExclusive = false;
 	MyProc->lwWaitLink = NULL;
@@ -429,8 +430,8 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->inCommit = false;
-	MyProc->inVacuum = false;
-	MyProc->isAutovacuum = IsAutoVacuumLauncherProcess(); /* is this needed? */
+	/* we don't set the "is autovacuum" flag in the launcher */
+	MyProc->vacuumFlags = 0;
 	MyProc->lwWaiting = false;
 	MyProc->lwExclusive = false;
 	MyProc->lwWaitLink = NULL;