From 4220e06f4c0c597c77e0170b4032c3cd10fb9555 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Tue, 23 Mar 2021 09:53:08 +0900 Subject: [PATCH] pg_waldump: Fix bug in per-record statistics. pg_waldump --stats=record identifies a record by a combination of the RmgrId and the four bits of the xl_info field of the record. But XACT records use the first bit of those four bits for an optional flag variable, and the following three bits for the opcode to identify a record. So previously the same type of XACT record could have different four bits (three bits are the same but the first one bit is different), and which could cause pg_waldump --stats=record to show two lines of per-record statistics for the same XACT record. This is a bug. This commit changes pg_waldump --stats=record so that it processes only XACT record differently, i.e., filters the opcode out of xl_info and uses a combination of the RmgrId and those three bits as the identifier of a record, only for XACT record. For other records, the four bits of the xl_info field are still used. Back-patch to all supported branches. Author: Kyotaro Horiguchi Reviewed-by: Shinya Kato, Fujii Masao Discussion: https://postgr.es/m/2020100913412132258847@highgo.ca --- src/bin/pg_waldump/pg_waldump.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 41dc6fc864..0fee1ebdee 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -509,6 +509,15 @@ XLogDumpCountRecord(XLogDumpConfig *config, XLogDumpStats *stats, recid = XLogRecGetInfo(record) >> 4; + /* + * XACT records need to be handled differently. Those records use the + * first bit of those four bits for an optional flag variable and the + * following three bits for the opcode. We filter opcode out of xl_info + * and use it as the identifier of the record. + */ + if (rmid == RM_XACT_ID) + recid &= 0x07; + stats->record_stats[rmid][recid].count++; stats->record_stats[rmid][recid].rec_len += rec_len; stats->record_stats[rmid][recid].fpi_len += fpi_len;