From a463d37a3112419a95585ed8dcb7c8a45cd04941 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Thu, 6 Feb 2025 08:26:26 +0000 Subject: [PATCH v3 3/4] Allow EXPLAIN to track WAL buffers full Now that wal_buffers_full is part of the WalUsage struct, let's report it in explain/auto_explain when the WAL option/auto_explain.log_wal is enabled. In passing, simplifying the test in show_wal_usage() as the other checks in the original condition can't be true without having wal_bytes > 0. --- doc/src/sgml/ref/explain.sgml | 5 +++-- src/backend/commands/explain.c | 8 ++++++-- 2 files changed, 9 insertions(+), 4 deletions(-) 51.9% doc/src/sgml/ref/ 48.0% src/backend/commands/ diff --git a/doc/src/sgml/ref/explain.sgml b/doc/src/sgml/ref/explain.sgml index 6361a14e65d..652ece7213a 100644 --- a/doc/src/sgml/ref/explain.sgml +++ b/doc/src/sgml/ref/explain.sgml @@ -242,8 +242,9 @@ ROLLBACK; Include information on WAL record generation. Specifically, include the - number of records, number of full page images (fpi) and the amount of WAL - generated in bytes. In text format, only non-zero values are printed. + number of records, number of full page images (fpi), the amount of WAL + generated in bytes and the number of times the WAL buffers became full. + In text format, only non-zero values are printed. This parameter may only be used when ANALYZE is also enabled. It defaults to FALSE. diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index c24e66f82e1..25a43f9d40a 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -4241,8 +4241,7 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) if (es->format == EXPLAIN_FORMAT_TEXT) { /* Show only positive counter values. */ - if ((usage->wal_records > 0) || (usage->wal_fpi > 0) || - (usage->wal_bytes > 0)) + if (usage->wal_bytes > 0) { ExplainIndentText(es); appendStringInfoString(es->str, "WAL:"); @@ -4256,6 +4255,9 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) if (usage->wal_bytes > 0) appendStringInfo(es->str, " bytes=" UINT64_FORMAT, usage->wal_bytes); + if (usage->wal_buffers_full > 0) + appendStringInfo(es->str, " buffers_full=%lld", + (long long) usage->wal_buffers_full); appendStringInfoChar(es->str, '\n'); } } @@ -4267,6 +4269,8 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) usage->wal_fpi, es); ExplainPropertyUInteger("WAL Bytes", NULL, usage->wal_bytes, es); + ExplainPropertyInteger("WAL Buffers Full", NULL, + usage->wal_buffers_full, es); } } -- 2.34.1