Horton

Re: Accommodate startup process in a separate ProcState array slot instead of in MaxBackends slots.

Fujii Masao <masao.fujii@oss.nttdata.com>

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From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-10-12T00:07:52Z
Lists: pgsql-hackers 

On 2021/10/12 4:07, Bharath Rupireddy wrote:
> Hi,
> 
> While working on [1], it is found that currently the ProcState array
> doesn't have entries for auxiliary processes, it does have entries for
> MaxBackends. But the startup process is eating up one slot from
> MaxBackends. We need to increase the size of the ProcState array by 1
> at least for the startup process. The startup process uses ProcState
> slot via InitRecoveryTransactionEnvironment->SharedInvalBackendInit.
> The procState array size is initialized to MaxBackends in
> SInvalShmemSize.
> 
> The consequence of not fixing this issue is that the database may hit
> the error "sorry, too many clients already" soon in
> SharedInvalBackendInit.
> 
> Attaching a patch to fix this issue. Thoughts?

Thanks for making the patch! LGTM.
Barring any objection, I will commit it.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Commits

  1. Explain why the startup process can't cause a shortage of sinval slots.