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Fix record length computation in pg_waldump/xlogdump.

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The current method of computing the record length (excluding the
lenght of full-page images) has been wrong since the WAL format has
been revamped in 2c03216d831160bedd72d45f712601b6f7d03f1c.  Only the
main record's length was counted, but that can be significantly too
little if there's data associated with further blocks.

Fix by computing the record length as total_lenght - fpi_length.

Reported-By: Chen Huajun
Bug: #14687
Reviewed-By: Heikki Linnakangas
Discussion: https://postgr.es/m/20170603165939.1436.58887@wrigleys.postgresql.org
Backpatch: 9.5-
This commit is contained in:
Andres Freund 2017-06-05 15:56:58 -07:00
parent 3e60c6f723
commit c25ed20067
1 changed files with 35 additions and 16 deletions
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51
src/bin/pg_waldump/pg_waldump.c
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@ -362,6 +362,35 @@ XLogDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen,
return count; return count;
} }
/*
* Calculate the size of a record, split into !FPI and FPI parts.
*/
static void
XLogDumpRecordLen(XLogReaderState *record, uint32 *rec_len, uint32 *fpi_len)
{
int block_id;
/*
* Calculate the amount of FPI data in the record.
*
* XXX: We peek into xlogreader's private decoded backup blocks for the
* bimg_len indicating the length of FPI data. It doesn't seem worth it to
* add an accessor macro for this.
*/
*fpi_len = 0;
for (block_id = 0; block_id <= record->max_block_id; block_id++)
{
if (XLogRecHasBlockImage(record, block_id))
*fpi_len += record->blocks[block_id].bimg_len;
}
/*
* Calculate the length of the record as the total length - the length of
* all the block images.
*/
*rec_len = XLogRecGetTotalLen(record) - *fpi_len;
}
/* /*
* Store per-rmgr and per-record statistics for a given record. * Store per-rmgr and per-record statistics for a given record.
*/ */
@ -373,26 +402,12 @@ XLogDumpCountRecord(XLogDumpConfig *config, XLogDumpStats *stats,
uint8 recid; uint8 recid;
uint32 rec_len; uint32 rec_len;
uint32 fpi_len; uint32 fpi_len;
int block_id;
stats->count++; stats->count++;
rmid = XLogRecGetRmid(record); rmid = XLogRecGetRmid(record);
rec_len = XLogRecGetDataLen(record) + SizeOfXLogRecord;
/* XLogDumpRecordLen(record, &rec_len, &fpi_len);
* Calculate the amount of FPI data in the record.
*
* XXX: We peek into xlogreader's private decoded backup blocks for the
* bimg_len indicating the length of FPI data. It doesn't seem worth it to
* add an accessor macro for this.
*/
fpi_len = 0;
for (block_id = 0; block_id <= record->max_block_id; block_id++)
{
if (XLogRecHasBlockImage(record, block_id))
fpi_len += record->blocks[block_id].bimg_len;
}
/* Update per-rmgr statistics */ /* Update per-rmgr statistics */
@ -422,6 +437,8 @@ XLogDumpDisplayRecord(XLogDumpConfig *config, XLogReaderState *record)
{ {
const char *id; const char *id;
const RmgrDescData *desc = &RmgrDescTable[XLogRecGetRmid(record)]; const RmgrDescData *desc = &RmgrDescTable[XLogRecGetRmid(record)];
uint32 rec_len;
uint32 fpi_len;
RelFileNode rnode; RelFileNode rnode;
ForkNumber forknum; ForkNumber forknum;
BlockNumber blk; BlockNumber blk;
@ -429,13 +446,15 @@ XLogDumpDisplayRecord(XLogDumpConfig *config, XLogReaderState *record)
uint8 info = XLogRecGetInfo(record); uint8 info = XLogRecGetInfo(record);
XLogRecPtr xl_prev = XLogRecGetPrev(record); XLogRecPtr xl_prev = XLogRecGetPrev(record);
XLogDumpRecordLen(record, &rec_len, &fpi_len);
id = desc->rm_identify(info); id = desc->rm_identify(info);
if (id == NULL) if (id == NULL)
id = psprintf("UNKNOWN (%x)", info & ~XLR_INFO_MASK); id = psprintf("UNKNOWN (%x)", info & ~XLR_INFO_MASK);
printf("rmgr: %-11s len (rec/tot): %6u/%6u, tx: %10u, lsn: %X/%08X, prev %X/%08X, ", printf("rmgr: %-11s len (rec/tot): %6u/%6u, tx: %10u, lsn: %X/%08X, prev %X/%08X, ",
desc->rm_name, desc->rm_name,
XLogRecGetDataLen(record), XLogRecGetTotalLen(record), rec_len, XLogRecGetTotalLen(record),
XLogRecGetXid(record), XLogRecGetXid(record),
(uint32) (record->ReadRecPtr >> 32), (uint32) record->ReadRecPtr, (uint32) (record->ReadRecPtr >> 32), (uint32) record->ReadRecPtr,
(uint32) (xl_prev >> 32), (uint32) xl_prev); (uint32) (xl_prev >> 32), (uint32) xl_prev);