Re: create table in memory

[Seref Arikan <serefarikan@xxxxxxxxx>]

Hi Merlin, 
See below please

On Tue, Nov 27, 2012 at 3:29 PM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote:

On Fri, Nov 23, 2012 at 4:09 AM, Peter Kroon <plakroon@xxxxxxxxx> wrote:
> I've put up a small test case for creating TEMP and UNLOGGED tables.
> DROP TABLE IF EXISTS test CASCADE;
> CREATE TEMP TABLE test(
> id serial,
> the_value text
> );
> Exec time: 54ms
>
> DROP TABLE IF EXISTS test CASCADE;
> CREATE UNLOGGED TABLE test(
> id serial,
> the_value text
> );
> Exec time: 198ms
>
> There is a significant difference.
>
> Also I need those tables per session, so creating and dropping with TEMP
> tables appear to be faster.

Performance of creating tables is going to be storage bound. what are
your performance requirements?  Even if the temp table itself is moved
to ramdisk you have catalog updating.  Usually from performance
standpoint, creation of temp tables is not interesting -- but there
are exceptions.   If you need extremely fast creation/drop of tempe
tables, you probably need to reorganize into permanent table with
session local records using various tricks.

I am very interested in what you've written in the last sentence above, since it is exactly what my requirement is. Could you explain that a bit more?

Best regards
Seref
 

merlin

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