Re: remove useless ccache searching - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: remove useless ccache searching
Date
Msg-id CAFj8pRC33hLzd7GZr1CoH22BFb2r_3uETyibOzBguLqpSQPNWw@mail.gmail.com
Whole thread Raw
In response to remove useless ccache searching  (Andy Colson <andy@squeakycode.net>)
List pgsql-hackers
Hello

2011/9/5 Andy Colson <andy@squeakycode.net>:
> This patch:
>
> https://commitfest.postgresql.org/action/patch_view?id=597
>
> caches the cache because, I guess, the cache is slow.
>
> Simon asked, "What is making the first cache so slow?".  Pavel does not
> know, nor how to fix it, and nobody else responded.
>
> So my question is: is someone going to take a look at the cache?  Should
> this be accepted as a short term fix (cuz someone will fix the cache later),
> long term fix (cuz the cache needs to say as-is), or not at all (because
> someone will fix cache right now now)?

A idea so this patch is cache of cache is not exact

Access to array needs lot of metadata related to element type. These
metadata are statics. I can store these data when we first access a
variable with data. ccache is relative fast - hash search, but should
not be faster than just direct access to structure. This technique is
used more time in PL/pgSQL.

Regards

Pavel


>
> -Andy
>
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