PG_WALSUMMARY(1)

📦 version 17.11, in opensuse-leap 16.0

💅 PG_WALSUMMARY 💅

okay so bestie, you found the PG_WALSUMMARY(1) page — this is the PostgreSQL 17.11 documentation for pg_walsummary, and it's genuinely more chill than it sounds. let me walk you through it 🫶

✨ NAME ✨

pg_walsummary — it prints out the contents of WAL summary files. that's it, that's the whole job. iconic honestly 💅

🌸 SYNOPSIS 🌸

pg_walsummary [option...] [file...]

🦋 DESCRIPTION 🦋

okay so here's the tea ☕ — pg_walsummary prints the contents of WAL summary files. these are binary files, and you'll find them hanging out in the pg_wal/summaries subdirectory of the data directory. this tool converts them to text for you, no cap.

now, lowkey you won't normally need to do this — WAL summary files primarily exist to support incremental backup, so the convert-to-text thing is mostly a debugging vibe. but like, it's there if you need it 💖

so how is a WAL summary file even structured?? it's indexed by tablespace OID, relation OID, and relation fork. for each relation fork it stores the list of blocks that were modified by WAL within the range summarized in the file. and it can also store a "limit block" 👑

  • the limit block is 0 if the relation fork was created or truncated within the relevant WAL range.
  • otherwise, it's the shortest length to which the relation fork was truncated.

and if the relation fork was not created, deleted, or truncated within the relevant WAL range? then the limit block is undefined or infinite, and this tool just won't print it. periodt ✨

💜 OPTIONS 💜

  • -i, --individual — so by default, pg_walsummary prints one line of output for each range of one or more consecutive modified blocks. that keeps things way briefer, bestie: a relation where all blocks from 0 through 999 were modified will produce only one line of output rather than 1000 separate lines 😭. this option requests a separate line of output for every single modified block. every one. no skipping 🙈
  • -q, --quiet — do not print any output, except for errors. super useful when you just wanna know whether a WAL summary file can be successfully parsed and you literally don't care about the contents 🎀
  • -V, --version — display version information, then exit. classic ⭐
  • -?, --help — shows help about pg_walsummary command line arguments, and exits. your little safety net 🧚

🌈 ENVIRONMENT 🌈

the environment variable PG_COLOR specifies whether to use color in diagnostic messages. possible values are always, auto and never. pick your vibe 💅

🔥 SEE ALSO 🔥

💀 real talk: the limit block is undefined or infinite in that one case, so don't go looking for it in the output — it will NOT be printed. iykyk.

and that's the whole page, bestie!! no crumbs left. this was PostgreSQL 17.11 documentation, dated 2026, and it's the PG_WALSUMMARY(1) man page 🎀✨ go read your WAL summaries, slay 💜

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