Improve sweep away of stale recovery procs, tune prune unobservedxids and use some more informative debug messages.dev_hot_standby

1 files changed, 43 insertions, 8 deletions

diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 04bf18ceec..ebef69671f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -520,16 +520,28 @@ void
 ProcArrayDisplay(int trace_level)
 {
 	ProcArrayStruct *arrayP = procArray;
-	int			index;
+	int			index, i;
+	StringInfoData buf;
 
 	for (index = 0; index < arrayP->numProcs; index++)
 	{
-		PGPROC	*RecoveryProc = arrayP->procs[index];
+		PGPROC	*proc = arrayP->procs[index];
+		TransactionId	xid = proc->xid;
+		int nsubxids = proc->subxids.nxids;
+
+		initStringInfo(&buf);
+		appendStringInfo(&buf, "procarray %d xid %d lsn %X/%X ", 
+							index, xid, 
+							proc->lsn.xlogid, proc->lsn.xrecoff);
+		if (nsubxids > 0)
+		{
+			appendStringInfo(&buf, "nsubxids %u : ", nsubxids);
 
-		if (TransactionIdIsValid(RecoveryProc->xid))
-			elog(trace_level,
-					"proc %d proc->xid %d proc->lsn %X/%X", index, RecoveryProc->xid, 
-								RecoveryProc->lsn.xlogid, RecoveryProc->lsn.xrecoff);
+			for (i = 0;	i < nsubxids; i++)
+				appendStringInfo(&buf, "%u ", proc->subxids.xids[i]);
+		}
+
+		elog(trace_level, "%s", buf.data);
 	}
 
 	UnobservedTransactionsDisplay(trace_level);
@@ -572,6 +584,7 @@ ProcArrayUpdateRecoveryTransactions(XLogRecPtr lsn, xl_xact_running_xacts *xlrec
 	ProcArrayStruct *arrayP = procArray;
 	int				xid_index;	/* main loop */
 	int 			index;
+	TransactionId	oldestRunningXid = xlrec->oldestRunningXid;
 
 	if (TransactionIdPrecedes(latestObservedXid, xlrec->latestRunningXid))
 	{
@@ -584,6 +597,19 @@ ProcArrayUpdateRecoveryTransactions(XLogRecPtr lsn, xl_xact_running_xacts *xlrec
 
 	LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
 
+	ProcArrayDisplay(trace_recovery(DEBUG3));
+
+	/*
+	 * If there was nothing running use latestCompletedXid as the barrier
+	 * value for when we sweep away old transaction entries
+	 */
+	if (!TransactionIdIsValid(oldestRunningXid))
+	{
+		Assert(xlrec->xcnt == 0);
+		oldestRunningXid = xlrec->latestCompletedXid;
+		TransactionIdAdvance(oldestRunningXid);
+	}
+
 	/*
 	 * Scan the proc array for stale recovery PGPROC entries, and
 	 * remove them. This shouldn't happen, except when FATAL error
@@ -596,7 +622,7 @@ ProcArrayUpdateRecoveryTransactions(XLogRecPtr lsn, xl_xact_running_xacts *xlrec
 	{
 		PGPROC	*p = arrayP->procs[index];
 
-		if (TransactionIdPrecedes(p->xid, xlrec->oldestRunningXid) && p->pid == 0)
+		if (TransactionIdPrecedes(p->xid, oldestRunningXid) && p->pid == 0)
 		{
 			elog(LOG, "removing stale proc array entry for transaction %d", p->xid);
 
@@ -732,7 +758,7 @@ ProcArrayUpdateRecoveryTransactions(XLogRecPtr lsn, xl_xact_running_xacts *xlrec
 	procArray->allowStandbySnapshots = true;
 	RunningXactIsValid = true;
 
-	ProcArrayDisplay(trace_recovery(DEBUG5));
+	ProcArrayDisplay(trace_recovery(DEBUG3));
 
 	LWLockRelease(ProcArrayLock);
 
@@ -2796,6 +2822,15 @@ UnobservedTransactionsPruneXids(TransactionId limitXid)
 
 	UnobservedXids = (TransactionId *) &(procArray->procs[procArray->maxProcs]);
 
+	/*
+	 * If there's nothing to do, leave quickly
+	 */
+	if (procArray->numUnobservedXids == 0)
+		return;
+
+	/*
+	 * If we can remove the whole array in one go, do it
+	 */
 	if (TransactionIdFollowsOrEquals(limitXid, UnobservedXids[procArray->numUnobservedXids]))
 	{
 		UnobservedTransactionsClearXids();