Thread

Re: Changing the state of data checksums in a running cluster

Daniel Gustafsson <daniel@yesql.se> — 2026-05-01T21:13:16Z

> On 1 May 2026, at 18:57, SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com> wrote:

> While further testing this feature, I realized that ProcessSingleRelationFork() 
> unconditionally called log_newpage_buffer() for every page of every relation 
> during pg_enable_data_checksums(). This included unlogged relations, 
> which by definition never generate WAL for data changes and are reset to their
> init fork on any recovery. 
> 
> Guard the log_newpage_buffer() call with RelationNeedsWAL() so that
> unlogged relations still get their pages dirtied (ensuring the checksum
> is flushed to disk at the next checkpoint) but do not emit WAL.
> 
> Attached a patch to address this and added a test for the same. My current
> test checks if standby has main fork, I could just checked WAL to verify this
> using pg_waldump. Any other test ideas are welcome.

Thanks for the report, I agree that this is an oversight that should be fixed.
Your patch looks good on first glance, I am travelling till Sunday evening so
will take another look when back in the office and will apply it then. Thanks!

--
Daniel Gustafsson