From 47a131b524fea7213ff51c21efb5665308e3664c Mon Sep 17 00:00:00 2001 From: Shinya Kato Date: Sat, 18 Oct 2025 16:28:05 +0900 Subject: [PATCH v2 2/2] Expose WAL FPI byte totals in EXPLAIN Show the new wal_fpi_bytes counter when EXPLAIN (ANALYZE, WAL) reports per-plan WAL usage, emitting it alongside the existing counters in both text and JSON/YAML output. Extend WalUsage aggregation helpers so the value accumulates correctly. Author: Shinya Kato Reviewed-by: Michael Paquier Discusssion: https://postgr.es/m/CAOzEurQtZEAfg6P0kU3Wa-f9BWQOi0RzJEMPN56wNTOmJLmfaQ@mail.gmail.com --- doc/src/sgml/ref/explain.sgml | 4 +++- src/backend/commands/explain.c | 8 +++++++- src/backend/executor/instrument.c | 2 ++ 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/ref/explain.sgml b/doc/src/sgml/ref/explain.sgml index 6dda680aa0d..ead4017d172 100644 --- a/doc/src/sgml/ref/explain.sgml +++ b/doc/src/sgml/ref/explain.sgml @@ -241,7 +241,9 @@ ROLLBACK; Include information on WAL record generation. Specifically, include the 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. + generated in bytes, the number of times the WAL buffers became full, the + amount of WAL fpi generated in bytes (if wal_compression + is enabled, this reflects the compressed size). 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 e6edae0845c..68c3d20353c 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -4283,7 +4283,8 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) { /* Show only positive counter values. */ if ((usage->wal_records > 0) || (usage->wal_fpi > 0) || - (usage->wal_bytes > 0) || (usage->wal_buffers_full > 0)) + (usage->wal_bytes > 0) || (usage->wal_buffers_full > 0) || + (usage->wal_fpi_bytes > 0)) { ExplainIndentText(es); appendStringInfoString(es->str, "WAL:"); @@ -4300,6 +4301,9 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) if (usage->wal_buffers_full > 0) appendStringInfo(es->str, " buffers full=%" PRId64, usage->wal_buffers_full); + if (usage->wal_fpi_bytes > 0) + appendStringInfo(es->str, " fpi bytes=%" PRIu64, + usage->wal_fpi_bytes); appendStringInfoChar(es->str, '\n'); } } @@ -4313,6 +4317,8 @@ show_wal_usage(ExplainState *es, const WalUsage *usage) usage->wal_bytes, es); ExplainPropertyInteger("WAL Buffers Full", NULL, usage->wal_buffers_full, es); + ExplainPropertyUInteger("WAL FPI Bytes Compressed", NULL, + usage->wal_fpi_bytes, es); } } diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c index 56e635f4700..e5f9ec14ef6 100644 --- a/src/backend/executor/instrument.c +++ b/src/backend/executor/instrument.c @@ -281,6 +281,7 @@ WalUsageAdd(WalUsage *dst, WalUsage *add) dst->wal_records += add->wal_records; dst->wal_fpi += add->wal_fpi; dst->wal_buffers_full += add->wal_buffers_full; + dst->wal_fpi_bytes += add->wal_fpi_bytes; } void @@ -290,4 +291,5 @@ WalUsageAccumDiff(WalUsage *dst, const WalUsage *add, const WalUsage *sub) dst->wal_records += add->wal_records - sub->wal_records; dst->wal_fpi += add->wal_fpi - sub->wal_fpi; dst->wal_buffers_full += add->wal_buffers_full - sub->wal_buffers_full; + dst->wal_fpi_bytes += add->wal_fpi_bytes - sub->wal_fpi_bytes; } -- 2.47.3