Re: partitioned table set and indexes

Rick Otten <rottenwindfish(at)gmail(dot)com> wrote:

> I'm using PostgreSQL 9.5 Beta 2.
>
> I am working with a partitioned table set.
>
> The first thing I noticed, when creating indexes on the 20 or so partitions,
> was that if I create them too fast they don't all succeed.  I have to do a few
> at a time, let them breathe for a few seconds, and then do a few more.   I had
> been simply generating all of the create index commands in a text editor, and
> then cutting and pasting the lot of them into psql all at once or running them
> by using psql '-f'.  Most would get created, but not all.  It seems almost
> random.  There were no obvious error messages.  When I do a few at a time, it
> is never an issue.

Sure? Have you checked that?

> If I do a simple query with a where clause on a specific column from the parent
> table, I can see it index scan each of the children.  This is what I want it to
> do, so no complaints there.
>
> However, if I try to (inner) join another table with that column, the planner
> sequence scans each of the children instead of using the indexes.  I saw
> someone had posted a similar question to this list back in January, however I
> didn't see the answer.

Show us the output from explain analyse <your query>

> FWIW, the column in question is a UUID column and is the primary key for each
> of the child tables.

PostgreSQL using a cost-modell, so maybe there are not enough rows in
the table. That's just a guess, you can see that with explain analyse
...

Andreas
--
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