Re: pgBufferUsage.blk_{read|write}_time are zero although there are pgBufferUsage.local_blks_{read|written}

Melanie Plageman <melanieplageman@gmail.com>

From: Melanie Plageman <melanieplageman@gmail.com>

To: Nazir Bilal Yavuz <byavuz81@gmail.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2023-09-15T13:30:24Z

Lists: pgsql-hackers

Commits

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Fix description of I/O timing info for shared buffers in EXPLAIN (BUFFERS)
- 8dd70828b460 15.6 landed
- db69101a1d00 16.2 landed
pg_stat_statements: Add local_blk_{read|write}_time
- 5147ab1dd34a 17.0 landed
Add local_blk_{read|write}_time I/O timing statistics for local blocks
- 295c36c0c1fa 17.0 landed
Rename I/O timing statistics columns to shared_blk_{read|write}_time
- 13d00729d422 17.0 landed
Count write times when extending relation files for shared buffers
- 2308f18c0733 16.1 landed
- d17ffc734dad 17.0 landed
Add JIT deform_counter
- 5a3423ad8ee1 17.0 cited

On Fri, Sep 15, 2023 at 9:24 AM Nazir Bilal Yavuz <byavuz81@gmail.com> wrote:
> I found that pgBufferUsage.blk_{read|write}_time are zero although there are pgBufferUsage.local_blks_{read|written}

Yes, good catch. This is a bug. I will note that at least in 15 and
likely before, pgBufferUsage.local_blks_written is incremented for
local buffers but pgBufferUsage.blk_write_time is only added to for
shared buffers (in FlushBuffer()). I think it makes sense to propose a
bug fix to stable branches counting blk_write_time for local buffers
as well.

- Melanie