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Re: Lowering the default wal_blocksize to 4K

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Andres Freund <andres@anarazel.de>
Cc: Andy Pogrebnoi <andrew.pogrebnoi@percona.com>, pgsql-hackers@postgresql.org, Heikki Linnakangas <hlinnaka@iki.fi>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>
Date: 2026-02-17T07:26:29Z
Lists: pgsql-hackers 
On Mon, Feb 16, 2026 at 04:13:37PM -0500, Andres Freund wrote:
> On 2026-02-16 10:04:37 +0200, Andy Pogrebnoi wrote:
>> 8Kb XLOG_BLCKSZ
>> ====
>> Threads          tps        kB_wrtn
>> 1             535.34         207288
>> 5            1457.24         591708
>> 10           1441.85         574700
>> 15            823.98         388732
>>
>> 4Kb XLOG_BLCKSZ
>> ====
>> Threads          tps        kB_wrtn
>> 1             542.02         153544
>> 5            1556.83         393444
>> 10           1288.00         339648
>> 15            975.32         255708
> 
> The reduction in bytes written is rather impressive...

It's a pretty nice improvement for a change as simple as that, yes.
+1.
--
Michael

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. During online checkpoints, insert XLOG_CHECKPOINT_REDO at redo point.