From: Simon Riggs <simon@2ndQuadrant.com>
Date: Thu, 1 Oct 2009 16:39:28 +0000 (+0100)
Subject: TransactionIdIsInProgress() must check KnownAssignedXids.
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=88b50b6656bb82414ed97a1666bd47b4366781a8;p=users%2Fsimon%2Fpostgres.git

TransactionIdIsInProgress() must check KnownAssignedXids.
---

diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index cc552d81b5..4cb0bc9a2c 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -137,6 +137,7 @@ static void KnownAssignedXidsAdd(TransactionId xid, int nsubxids,
 											TransactionId *subxid);
 static void KnownAssignedXidsRemove(TransactionId xid, bool report_error);
 static void KnownAssignedXidsRemoveMany(TransactionId xid);
+static bool KnownAssignedXidsFind(TransactionId xid);
 static void KnownAssignedXidsDisplay(int trace_level);
 
 /*
@@ -608,6 +609,7 @@ TransactionIdIsInProgress(TransactionId xid)
 	TransactionId topxid;
 	int			i,
 				j;
+	bool found;
 
 	/*
 	 * Don't bother checking a transaction older than RecentXmin; it could not
@@ -729,6 +731,22 @@ TransactionIdIsInProgress(TransactionId xid)
 			xids[nxids++] = pxid;
 	}
 
+	/*
+	 * Check if the transaction id known assigned or whether it is
+	 * completed.
+	 */
+	if (RecoveryInProgress())
+	{
+		found = FindKnownAssignedTransactionId(xid);
+
+		if (found)
+		{
+			LWLockRelease(ProcArrayLock);
+			xc_by_main_xid_inc();	/* we don't know whether its child or main */
+			return true;
+		}
+	}
+
 	LWLockRelease(ProcArrayLock);
 
 	/*
@@ -760,17 +778,33 @@ TransactionIdIsInProgress(TransactionId xid)
 	 * held ProcArrayLock).
 	 */
 	topxid = SubTransGetTopmostTransaction(xid);
-	Assert(TransactionIdIsValid(topxid));
-	if (!TransactionIdEquals(topxid, xid))
+	if (!RecoveryInProgress())
 	{
-		for (i = 0; i < nxids; i++)
+		Assert(TransactionIdIsValid(topxid));
+		if (!TransactionIdEquals(topxid, xid))
 		{
-			if (TransactionIdEquals(xids[i], topxid))
-				return true;
+			for (i = 0; i < nxids; i++)
+			{
+				if (TransactionIdEquals(xids[i], topxid))
+					return true;
+			}
 		}
+
+		return false;
 	}
+	else
+	{
+		/*
+		 * We weren't sure which xids were top-level or not, so 
+		 * we don't have space to record them in the work area.
+		 * So we must re-acquire lock and re-check KnownAssignedXids.
+		 */
+		LWLockAcquire(ProcArrayLock, LW_SHARED);
+		found = FindKnownAssignedTransactionId(xid);
+		LWLockRelease(ProcArrayLock);
 
-	return false;
+		return found;
+	}
 }
 
 /*
@@ -2303,6 +2337,12 @@ ExpireOldKnownAssignedTransactionIds(TransactionId xid)
 	LWLockRelease(ProcArrayLock);
 }
 
+bool
+FindKnownAssignedTransactionId(TransactionId xid)
+{
+	return KnownAssignedXidsFind(xid);
+}
+
 /*
  * Get an array of KnownAssignedXids, not necessarily in sorted order.
  * 
@@ -2492,6 +2532,16 @@ KnownAssignedXidsRemoveMany(TransactionId xid)
 	}
 }
 
+static bool
+KnownAssignedXidsFind(TransactionId xid)
+{
+	bool found;
+
+	(void) hash_search(KnownAssignedXidsHash, &xid, HASH_FIND, &found);
+
+	return found;
+}
+
 /*
  * xidComparator
  *            qsort comparison function for XIDs
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index 36d5d52ae7..302090398e 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -37,6 +37,7 @@ extern void ExpireOldKnownAssignedTransactionIds(TransactionId xid);
 extern int  GetKnownAssignedTransactions(TransactionId *xarray, 
 										TransactionId *xmin, TransactionId xmax,
 										bool *overflow);
+extern bool FindKnownAssignedTransactionId(TransactionId xid);
 
 extern bool IsRunningXactDataValid(void);
 extern void GetRunningTransactionData(void);