Fix off-by-one bug in xlog reading logic

alvherre · alvherre · commit 8c17144c7555 · 2013-01-18T11:19:53.000-03:00
Bug reported by Michael Paquier

Author: Andres Freund
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -8875,7 +8875,7 @@ XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen,
 	/* See if we need to retrieve more data */
 	if (readFile < 0 ||
 		(readSource == XLOG_FROM_STREAM &&
-		 receivedUpto <= targetPagePtr + reqLen))
+		 receivedUpto < targetPagePtr + reqLen))
 	{
 		if (StandbyMode)
 		{

Original file line number	Diff line number	Diff line change
`@@ -8875,7 +8875,7 @@ XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen,`
`8875`	`8875`	`/* See if we need to retrieve more data */`
`8876`	`8876`	`if (readFile < 0 \|\|`
`8877`	`8877`	`(readSource == XLOG_FROM_STREAM &&`
`8878`		`- receivedUpto <= targetPagePtr + reqLen))`
	`8878`	`+ receivedUpto < targetPagePtr + reqLen))`
`8879`	`8879`	`{`
`8880`	`8880`	`if (StandbyMode)`
`8881`	`8881`	`{`