| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | Geoff Winkless <pgsqladmin(at)geoff(dot)dj> |
| Cc: | Kevin Grittner <kgrittn(at)gmail(dot)com>, Postgres General <pgsql-general(at)postgresql(dot)org>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com> |
| Subject: | Re: multicolumn index and setting effective_cache_size using human-readable-numbers |
| Date: | 2016-03-02 02:52:21 |
| Message-ID: | CAMkU=1zRntiALMEsiK5H6qXshw3t7GGOJE6MQYu4GPQpdseAsA@mail.gmail.com |
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| Lists: | pgsql-general |
On Mon, Feb 29, 2016 at 3:02 PM, Geoff Winkless <pgsqladmin(at)geoff(dot)dj> wrote:
>
> Perhaps I'm not being clear. Index 1 has field a and is used in the join no
> matter how small I set effective_cache_size (even 32mb). Index 2 has fields
> a,b but will not be used at ecs of 3gb, 6gb, whatever up til 8gb, when it's
> suddenly used.
>
> For the variation in size of the two indexes (say 20%?) that just doesn't
> add up.
What version of PostgreSQL are you using? Any chance you can share a
data-generator which reproduces this problem?
Cheers,
Jeff
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