Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?

From: Stefan Keller <sfkeller(at)gmail(dot)com>
To: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
Cc: Claudio Freire <klaussfreire(at)gmail(dot)com>, postgres performance list <pgsql-performance(at)postgresql(dot)org>
Subject: Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?
Date: 2012-02-29 15:24:15
Message-ID: CAFcOn28PmJxWAvZXbakvuXnpJ+VZSdqmWzOo3hf5fc4zCsutvg@mail.gmail.com
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2012/2/29 Jeff Janes <jeff(dot)janes(at)gmail(dot)com>:
>> It's quite possible the vacuum full is thrashing your disk cache due
>> to maintainance_work_mem. You can overcome this issue with the tar
>> trick, which is more easily performed as:
>>
>> tar cf /dev/null $PG_DATA/base
>
> But on many implementations, that will not work.  tar detects the
> output is going to the bit bucket, and so doesn't bother to actually
> read the data.

Right.
But what about the commands cp $PG_DATA/base /dev/null or cat
$PG_DATA/base > /dev/null ?
They seem to do something.

-Stefan

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