Re: Up to date conventional wisdom re max shared_buffer size?

Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> writes:

> On Tue, Sep 19, 2017 at 4:00 PM, Jerry Sievers <gsievers19(at)comcast(dot)net> wrote:
>
>> Briefly, just curious if legacy max values for shared_buffers have
>> scaled up since 8G was like 25% of RAM?
>>
>> Pg 9.3 on monster 2T/192 CPU Xenial thrashing
>>
>> Upgrade pending but we recently started having $interesting performance
>> issues at times looking like I/O slowness and other times apparently
>> causing CPU spins.
>
> Have you looked at things like zone reclaim mode and transparent huge
> pages? Both of those can cause odd problems. Also it's usually a good
> idea to turn off swap as the linux kernel, presented with lots of ram
> and a small (by comparison) swap file sometimes makes bad life choices
> and starts using swap for things like storing currently unused shared
> buffers or something.

Not sure but we're checking into these items. Thanks

--
Jerry Sievers
Postgres DBA/Development Consulting
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