Small fixes for CHECKPOINT FLUSH_UNLOGGED

Chao Li <li.evan.chao@gmail.com>

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From: Chao Li <li.evan.chao@gmail.com>

To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Cc: Nathan Bossart <nathandbossart@gmail.com>, Christoph Berg <myon@debian.org>

Date: 2026-05-25T07:07:38Z

Lists: pgsql-hackers

Attachments

v1-0002-doc-Clarify-CHECKPOINT-handling-of-unlogged-buffe.patch (application/octet-stream)
v1-0001-psql-Complete-boolean-values-for-CHECKPOINT-FLUSH.patch (application/octet-stream)

Hi,

I just tested “Add FLUSH_UNLOGGED option to CHECKPOINT command”, and found no functional issue. I only noticed a couple of small issues.

1. Tab-completion for FLUSH_UNLOGGED misses its boolean value

FLUSH_UNLOGGED can take a boolean value, but tab completion does not suggest ON/OFF for it. For comparison, REPACK does:
```
evantest=# checkpoint (FLUSH_UNLOGGED o

evantest=# repack (concurrently O
OFF ON
```The fix just follows the existing code for REPACK. After the fix:
```
evantest=# checkpoint (flush_unlogged O
OFF ON
```

2. The CHECKPOINT doc still says “All data files will be flushed to disk”

After introducing FLUSH_UNLOGGED, CHECKPOINT by default no longer flushes dirty buffers of unlogged relations, but checkpoint.sgml still says “All data files will be flushed to disk.” That seems stale, so I updated the doc.

These are two small changes, but to make the patch easier to process, I split them into two commits.

Best reagards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/