Re: Configuring for maximum memory usage - Mailing list pgsql-performance

From Joshua D. Drake
Subject Re: Configuring for maximum memory usage
Date
Msg-id 4909D688.1090806@commandprompt.com
Whole thread Raw
In response to Configuring for maximum memory usage  (Christiaan Willemsen <cwillemsen@technocon.com>)
Responses Re: Configuring for maximum memory usage  (Christiaan Willemsen <cwillemsen@technocon.com>)
List pgsql-performance
Christiaan Willemsen wrote:
> Hi there,

> The problem is getting it to use that much. At the moment, it only uses
> almost 9 GB, so by far not enough. The problem is getting it to use
> more... I hope you can help me with working config.

PostgreSQL is only going to use what it needs. It relies on the OS for
much of the caching etc...

>
> Here are the parameters I set in the config file:
>
> shared_buffers = 8192MB

I wouldn't take this any higher.

> work_mem = 128MB

This is quite high but it might be o.k. depending on what you are doing.

> maintenance_work_mem = 2048MB

This is only used during maintenance so you won't see this much.

> max_fsm_pages = 204800
> max_fsm_relations = 2000

This uses very little memory.

>
> Database is about 250 GB in size, so we really need to have as much data
> as possible in memory.
>
> I hope you can help us tweak a few parameters to make sure all memory
> will be used.

You are missing effective_cache_size. Try setting that to 32G.

You also didn't mention checkpoint_segments (which isn't memory but
still important) and default_statistics_target (which isn't memory but
still important).

Joshua D. Drake


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