RE: [Patch] change the default value of shared_buffers in postgresql.conf.sample - Mailing list pgsql-hackers

From zhangjie2@fujitsu.com
Subject RE: [Patch] change the default value of shared_buffers in postgresql.conf.sample
Date
Msg-id TYWPR01MB7678D3AE538F6BBAAD11D757F9069@TYWPR01MB7678.jpnprd01.prod.outlook.com
Whole thread Raw
In response to Re: [Patch] change the default value of shared_buffers in postgresql.conf.sample  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> On the whole this seems pretty cosmetic so I'm inclined to leave it alone.  But if we were going to do anything I
thinkthat adjusting both initdb.c and guc.c to use 128MB might be the most appropriate thing.
 

Thank you for your suggestions. initdb.c and guc.c have been modified together.

Best Regards!
Zhangjie

-----Original Message-----
From: Tom Lane <tgl@sss.pgh.pa.us> 
Sent: Thursday, June 24, 2021 11:50 PM
To: Zhang, Jie/张 杰 <zhangjie2@fujitsu.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: [Patch] change the default value of shared_buffers in postgresql.conf.sample

"zhangjie2@fujitsu.com" <zhangjie2@fujitsu.com> writes:
> In PostgreSQL 14, The default value of shared_buffers is 128MB, but in postgresql.conf.sample, the default value of
shared_buffersis 32MB.
 
> I think the following changes should be made.

> File: postgresql\src\backend\utils\misc\ postgresql.conf.sample 
> #shared_buffers = 32MB  =>  #shared_buffers = 128MB

As submitted, this patch breaks initdb, which is looking for the exact string "#shared_buffers = 32MB".

We could adjust that too of course, but I'm dubious first that any change is needed, and second that this is the right
one:

1. Since initdb will replace that string, users will never see this entry as-is in live databases.  So is it worth
doinganything?
 

2. The *actual*, hard-wired, default in guc.c is 1024 (8MB), not either of these numbers.  So maybe the sample file
oughtto use that instead.  Or maybe we should change that value too ... it's surely as obsolete as can be.
 

On the whole this seems pretty cosmetic so I'm inclined to leave it alone.  But if we were going to do anything I think
thatadjusting both initdb.c and guc.c to use 128MB might be the most appropriate thing.
 

            regards, tom lane

Attachment

pgsql-hackers by date:

Previous
From: Peter Eisentraut
Date:
Subject: Re: Remove redundant variable pageSize in gistinitpage
Next
From: Amit Kapila
Date:
Subject: Allow streaming the changes after speculative aborts.