Re: SSI slows down over time - Mailing list pgsql-performance

From Ryan Johnson
Subject Re: SSI slows down over time
Date
Msg-id 534BEF32.9060309@cs.utoronto.ca
Whole thread Raw
In response to Re: SSI slows down over time  (Kevin Grittner <kgrittn@ymail.com>)
Responses Re: SSI slows down over time
List pgsql-performance
On 14/04/2014 10:14 AM, Kevin Grittner wrote:
> Ryan Johnson <ryan.johnson@cs.utoronto.ca> wrote:
>
>> every time I shut down a database and bring it back up, SSI seems
>> to go slower.
> There's one thing to rule out up front -- that would be a
> long-lived prepared transaction.
>
> Please post the output of these queries:
>
> select version();
> show max_prepared_transactions;
> select * from pg_prepared_xacts;
Hmm. My machine was rebooted over the weekend for Heartbleed patches, so
I'll have to re-build the database and fire off enough runs to repro.
There are some disadvantages to keeping it in tmpfs...

Meanwhile, a quick question: what factors might cause a prepared
transaction to exist in the first place? I'm running a single-node db,
and I've had only normal database shutdowns, so I wouldn't have expected
any.

Thoughts?
Ryan



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