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Message-ID: <9f175444-6bfc-4c6e-a609-e552d85c45a1@aklaver.com>
Date: Wed, 8 Oct 2025 09:22:27 -0700
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Subject: Re: Alerting on memory use and instance crash
To: sud <suds1434@gmail.com>,
 pgsql-general <pgsql-general@lists.postgresql.org>
References: <CAD=mzVXjx-ULCM-ZdSz2RDSoL8EA1Bsd+0gBxgOCTWV_tC4GDw@mail.gmail.com>
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From: Adrian Klaver <adrian.klaver@aklaver.com>
In-Reply-To: <CAD=mzVXjx-ULCM-ZdSz2RDSoL8EA1Bsd+0gBxgOCTWV_tC4GDw@mail.gmail.com>
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On 10/8/25 08:42, sud wrote:
> Hi Experts,
> 
> It's postgres version 16. I have two questions on alerting as below.
> 
> 1)If we want to have alerting on any node/instance that gets crashed :- 
> In other databases like Oracle the catalog Views like "GV$Instance" used 
> to give information on whether the instances are currently active/down 
> or not. But in postgres it seems all the pg_* views are instance 
> specific and are not showing information on the global/cluster level but 
> are restricted to instance level only. So is there any other way to 
> query the pg_* views to have alerts on the specific instance crash?

1) When you say instance do you mean database?

2) Not all system tables/views are database only.

For instance:
https://www.postgresql.org/docs/current/catalog-pg-database.html
https://www.postgresql.org/docs/current/catalog-pg-auth-members.html
https://www.postgresql.org/docs/current/catalog-pg-authid.html
https://www.postgresql.org/docs/current/view-pg-roles.html


> 2)Is there a way to fetch the data from pg_* view to highlight the 
> specific connection/session/sqls which is using high memory in postgres?
> 
> Appreciate your guidance.
> 
> Regards
> Sud


-- 
Adrian Klaver
adrian.klaver@aklaver.com