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7 | 7 | * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group |
8 | 8 | * Portions Copyright (c) 1994, Regents of the University of California |
9 | 9 | * |
10 | | - * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.86.2.4 2004/08/11 04:09:12 tgl Exp $ |
| 10 | + * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.86.2.5 2005/05/31 19:11:28 tgl Exp $ |
11 | 11 | * |
12 | 12 | *------------------------------------------------------------------------- |
13 | 13 | */ |
@@ -427,8 +427,8 @@ static uint32 readOff = 0; |
427 | 427 | staticchar*readBuf=NULL; |
428 | 428 |
|
429 | 429 | /* State information for XLOG reading */ |
430 | | -staticXLogRecPtrReadRecPtr; |
431 | | -staticXLogRecPtrEndRecPtr; |
| 430 | +staticXLogRecPtrReadRecPtr;/* start of last record read */ |
| 431 | +staticXLogRecPtrEndRecPtr;/* end+1 of last record read */ |
432 | 432 | staticXLogRecord*nextRecord=NULL; |
433 | 433 | staticStartUpIDlastReadSUI; |
434 | 434 |
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@@ -1872,6 +1872,37 @@ got_record:; |
1872 | 1872 | RecPtr->xlogid,RecPtr->xrecoff); |
1873 | 1873 | gotonext_record_is_invalid; |
1874 | 1874 | } |
| 1875 | +if (!nextmode) |
| 1876 | +{ |
| 1877 | +/* |
| 1878 | + * We can't exactly verify the prev-link, but surely it should be |
| 1879 | + * less than the record's own address. |
| 1880 | + */ |
| 1881 | +if (!XLByteLT(record->xl_prev,*RecPtr)) |
| 1882 | +{ |
| 1883 | +elog(emode, |
| 1884 | +"ReadRecord: record with incorrect prev-link %X/%X at %X/%X", |
| 1885 | +record->xl_prev.xlogid,record->xl_prev.xrecoff, |
| 1886 | +RecPtr->xlogid,RecPtr->xrecoff); |
| 1887 | +gotonext_record_is_invalid; |
| 1888 | +} |
| 1889 | +} |
| 1890 | +else |
| 1891 | +{ |
| 1892 | +/* |
| 1893 | + * Record's prev-link should exactly match our previous location. |
| 1894 | + * This check guards against torn WAL pages where a stale but |
| 1895 | + * valid-looking WAL record starts on a sector boundary. |
| 1896 | + */ |
| 1897 | +if (!XLByteEQ(record->xl_prev,ReadRecPtr)) |
| 1898 | +{ |
| 1899 | +elog(emode, |
| 1900 | +"record with incorrect prev-link %X/%X at %X/%X", |
| 1901 | +record->xl_prev.xlogid,record->xl_prev.xrecoff, |
| 1902 | +RecPtr->xlogid,RecPtr->xrecoff); |
| 1903 | +gotonext_record_is_invalid; |
| 1904 | +} |
| 1905 | +} |
1875 | 1906 |
|
1876 | 1907 | /* |
1877 | 1908 | * Compute total length of record including any appended backup |
|