Re: pg_dump and thousands of schemas - Mailing list pgsql-performance

From Jeff Janes
Subject Re: pg_dump and thousands of schemas
Date
Msg-id CAMkU=1y_juK5VW8tp0HB009H8oWXzXdCFf6tu2AK=QB6FLwvwQ@mail.gmail.com
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In response to Re: pg_dump and thousands of schemas  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
On Fri, May 25, 2012 at 9:56 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Jeff Janes <jeff.janes@gmail.com> writes:
>
>> For dumping entire databases, It looks like the biggest problem is
>> going to be LockReassignCurrentOwner in the server.  And that doesn't
>> seem to be easy to fix, as any change to it to improve pg_dump will
>> risk degrading normal use cases.
>
> I didn't try profiling the server side, but pg_dump doesn't use
> subtransactions so it's not clear to me why LockReassignCurrentOwner
> would get called at all ...

I thought that every select statement in a repeatable read transaction
ran in a separate "portal", and that a portal is a flavor of
subtransaction.  Anyway, it does show up at the top of a profile of
the server, so it is getting called somehow.

Cheers,

Jeff

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