Re: Speeding up JSON + TSQUERY + GIN

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On Tue, Feb 28, 2017 at 12:27 AM, Sven R. Kunze <srkunze@xxxxxxx> wrote:
On 27.02.2017 19:22, Jeff Janes wrote:
If by 'permanently', you mean even when you intentionally break things, then no.  You will always be able to intentionally break things.  There is on-going discussion of an auto-prewarm feature.  But that doesn't yet exist; and once it does, a super user will always be able to break it.

Presumably you have a use-case in mind other than intentional sabotage of your caches by root.  But, what is it?  If you reboot the server frequently, maybe you can just throw 'select pg_prewarm...' into an init script?

I didn't express myself well enough. pg_prewarm doesn't help to speed up those queries at all.


Oh.  In my hands, it works very well.  I get 70 seconds to do the {age: 20} query from pure cold caches, versus 1.4 seconds from cold caches which was followed by pg_prewarm('docs','prefetch').

How much RAM do you have?  Maybe you don't have enough to hold the table in RAM.  What kind of IO system?  And what OS?


Cheers,

Jeff

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