Re: Safe vm.overcommit_ratio for Large Multi-Instance PostgreSQL Fleet

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________________________________
From: Bruce Momjian <bruce@momjian.us>
Sent: Tuesday, August 12, 2025 1:49:26 PM
To: Frits Hoogland <frits.hoogland@gmail.com>
Cc: Joe Conway <mail@joeconway.com>; Priya V <mailme0216@gmail.com>; pgsql-performance@lists.postgresql.org <pgsql-performance@lists.postgresql.org>
Subject: Re: Safe vm.overcommit_ratio for Large Multi-Instance PostgreSQL Fleet

Note: This message originated from outside the FIU Faculty/Staff email system.


On Wed, Aug  6, 2025 at 11:14:34PM +0200, Frits Hoogland wrote:
> > As I said, do not disable swap. You don't need a huge amount, but maybe 16 GB or so would do it.
>
> Joe, please, can you state a technical reason for saying this?
> All you are saying is ‘don’t do this’.
>
> I’ve stated my reasons for why this doesn’t make sense, and you don’t give any reason.
>
> The article you cite does seem to point to general usage, not database usage.

Here is a blog entry about it from 2012:

        https://urldefense.com/v3/__https://momjian.us/main/blogs/pgblog/2012.html*July_25_2012__;Iw!!FjuHKAHQs5udqho!KYC_U3_OpOjplPgrQZatREvJ8Ft3U7O30Lh6SH0uGMsTcYagWyupQLofwkNLDhhxgmzWzl6blB1HpFk0oj4$

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  Bruce Momjian  <bruce@momjian.us>        https://urldefense.com/v3/__https://momjian.us__;!!FjuHKAHQs5udqho!KYC_U3_OpOjplPgrQZatREvJ8Ft3U7O30Lh6SH0uGMsTcYagWyupQLofwkNLDhhxgmzWzl6blB1H1-eyJ3I$
  EDB                                      https://urldefense.com/v3/__https://enterprisedb.com__;!!FjuHKAHQs5udqho!KYC_U3_OpOjplPgrQZatREvJ8Ft3U7O30Lh6SH0uGMsTcYagWyupQLofwkNLDhhxgmzWzl6blB1HJNHkhfc$

  Do not let urgent matters crowd out time for investment in the future.