Observe array length in HaveVirtualXIDsDelayingChkpt().

nmisch · nmisch · commit fb435f40d5e3 · 2013-06-12T19:50:14.000-04:00
Since commit f21bb9c, this function ignores the caller-provided length and loops until it finds a terminator, which GetVirtualXIDsDelayingChkpt() never adds. Restore the previous loop control logic. In passing, revert the addition of an unused variable by the same commit, presumably a debugging relic.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -6984,12 +6984,9 @@ CreateCheckPoint(int flags)
 	vxids = GetVirtualXIDsDelayingChkpt(&nvxids);
 	if (nvxids > 0)
 	{
-		uint32		nwaits = 0;
-
 		do
 		{
 			pg_usleep(10000L);	/* wait for 10 msec */
-			nwaits++;
 		} while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids));
 	}
 	pfree(vxids);
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
@@ -1849,32 +1849,30 @@ HaveVirtualXIDsDelayingChkpt(VirtualTransactionId *vxids, int nvxids)
 
 	LWLockAcquire(ProcArrayLock, LW_SHARED);
 
-	while (VirtualTransactionIdIsValid(*vxids))
+	for (index = 0; index < arrayP->numProcs; index++)
 	{
-		for (index = 0; index < arrayP->numProcs; index++)
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+		VirtualTransactionId vxid;
+
+		GET_VXID_FROM_PGPROC(vxid, *proc);
+
+		if (pgxact->delayChkpt && VirtualTransactionIdIsValid(vxid))
 		{
-			int			pgprocno = arrayP->pgprocnos[index];
-			volatile PGPROC *proc = &allProcs[pgprocno];
-			volatile PGXACT *pgxact = &allPgXact[pgprocno];
-			VirtualTransactionId vxid;
+			int			i;
 
-			GET_VXID_FROM_PGPROC(vxid, *proc);
-			if (VirtualTransactionIdIsValid(vxid))
+			for (i = 0; i < nvxids; i++)
 			{
-				if (VirtualTransactionIdEquals(vxid, *vxids) &&
-					pgxact->delayChkpt)
+				if (VirtualTransactionIdEquals(vxid, vxids[i]))
 				{
 					result = true;
 					break;
 				}
 			}
+			if (result)
+				break;
 		}
-
-		if (result)
-			break;
-
-		/* The virtual transaction is gone now, wait for the next one */
-		vxids++;
 	}
 
 	LWLockRelease(ProcArrayLock);

Original file line number	Diff line number	Diff line change
`@@ -6984,12 +6984,9 @@ CreateCheckPoint(int flags)`
`6984`	`6984`	`vxids = GetVirtualXIDsDelayingChkpt(&nvxids);`
`6985`	`6985`	`if (nvxids > 0)`
`6986`	`6986`	`{`
`6987`		`- uint32 nwaits = 0;`
`6988`		`-`
`6989`	`6987`	`do`
`6990`	`6988`	`{`
`6991`	`6989`	`pg_usleep(10000L); /* wait for 10 msec */`
`6992`		`- nwaits++;`
`6993`	`6990`	`} while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids));`
`6994`	`6991`	`}`
`6995`	`6992`	`pfree(vxids);`
Original file line number	Diff line number	Diff line change
`@@ -1849,32 +1849,30 @@ HaveVirtualXIDsDelayingChkpt(VirtualTransactionId *vxids, int nvxids)`
`1849`	`1849`
`1850`	`1850`	`LWLockAcquire(ProcArrayLock, LW_SHARED);`
`1851`	`1851`
`1852`		`- while (VirtualTransactionIdIsValid(*vxids))`
	`1852`	`+ for (index = 0; index < arrayP->numProcs; index++)`
`1853`	`1853`	`{`
`1854`		`- for (index = 0; index < arrayP->numProcs; index++)`
	`1854`	`+ int pgprocno = arrayP->pgprocnos[index];`
	`1855`	`+ volatile PGPROC *proc = &allProcs[pgprocno];`
	`1856`	`+ volatile PGXACT *pgxact = &allPgXact[pgprocno];`
	`1857`	`+ VirtualTransactionId vxid;`
	`1858`	`+`
	`1859`	`+ GET_VXID_FROM_PGPROC(vxid, *proc);`
	`1860`	`+`
	`1861`	`+ if (pgxact->delayChkpt && VirtualTransactionIdIsValid(vxid))`
`1855`	`1862`	`{`
`1856`		`- int pgprocno = arrayP->pgprocnos[index];`
`1857`		`- volatile PGPROC *proc = &allProcs[pgprocno];`
`1858`		`- volatile PGXACT *pgxact = &allPgXact[pgprocno];`
`1859`		`- VirtualTransactionId vxid;`
	`1863`	`+ int i;`
`1860`	`1864`
`1861`		`- GET_VXID_FROM_PGPROC(vxid, *proc);`
`1862`		`- if (VirtualTransactionIdIsValid(vxid))`
	`1865`	`+ for (i = 0; i < nvxids; i++)`
`1863`	`1866`	`{`
`1864`		`- if (VirtualTransactionIdEquals(vxid, *vxids) &&`
`1865`		`- pgxact->delayChkpt)`
	`1867`	`+ if (VirtualTransactionIdEquals(vxid, vxids[i]))`
`1866`	`1868`	`{`
`1867`	`1869`	`result = true;`
`1868`	`1870`	`break;`
`1869`	`1871`	`}`
`1870`	`1872`	`}`
	`1873`	`+ if (result)`
	`1874`	`+ break;`
`1871`	`1875`	`}`
`1872`		`-`
`1873`		`- if (result)`
`1874`		`- break;`
`1875`		`-`
`1876`		`- /* The virtual transaction is gone now, wait for the next one */`
`1877`		`- vxids++;`
`1878`	`1876`	`}`
`1879`	`1877`
`1880`	`1878`	`LWLockRelease(ProcArrayLock);`