diff options
Diffstat (limited to 'src/backend/access/transam/xlogreader.c')
| -rw-r--r-- | src/backend/access/transam/xlogreader.c | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3a86f3497eb..a7953f323b6 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -27,8 +27,6 @@ static bool allocate_recordbuf(XLogReaderState *state, uint32 reclength); -static bool ValidXLogPageHeader(XLogReaderState *state, XLogRecPtr recptr, - XLogPageHeader hdr); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, @@ -533,7 +531,6 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen) */ if (targetSegNo != state->readSegNo && targetPageOff != 0) { - XLogPageHeader hdr; XLogRecPtr targetSegmentPtr = pageptr - targetPageOff; readLen = state->read_page(state, targetSegmentPtr, XLOG_BLCKSZ, @@ -545,9 +542,8 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen) /* we can be sure to have enough WAL available, we scrolled back */ Assert(readLen == XLOG_BLCKSZ); - hdr = (XLogPageHeader) state->readBuf; - - if (!ValidXLogPageHeader(state, targetSegmentPtr, hdr)) + if (!XLogReaderValidatePageHeader(state, targetSegmentPtr, + state->readBuf)) goto err; } @@ -584,7 +580,7 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen) /* * Now that we know we have the full header, validate it. */ - if (!ValidXLogPageHeader(state, pageptr, hdr)) + if (!XLogReaderValidatePageHeader(state, pageptr, (char *) hdr)) goto err; /* update read state information */ @@ -709,15 +705,19 @@ ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr) } /* - * Validate a page header + * Validate a page header. + * + * Check if 'phdr' is valid as the header of the XLog page at position + * 'recptr'. */ -static bool -ValidXLogPageHeader(XLogReaderState *state, XLogRecPtr recptr, - XLogPageHeader hdr) +bool +XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, + char *phdr) { XLogRecPtr recaddr; XLogSegNo segno; int32 offset; + XLogPageHeader hdr = (XLogPageHeader) phdr; Assert((recptr % XLOG_BLCKSZ) == 0); @@ -805,6 +805,11 @@ ValidXLogPageHeader(XLogReaderState *state, XLogRecPtr recptr, return false; } + /* + * Check that the address on the page agrees with what we expected. + * This check typically fails when an old WAL segment is recycled, + * and hasn't yet been overwritten with new data yet. + */ if (hdr->xlp_pageaddr != recaddr) { char fname[MAXFNAMELEN]; |