Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables)

2016-08-18 16:33 GMT+02:00 Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>:

> On 08/15/2016 12:23 PM, Pavel Stehule wrote:
>
>>
>>
>> 2016-08-15 12:18 GMT+02:00 Aleksander Alekseev
>> <a(dot)alekseev(at)postgrespro(dot)ru <mailto:a(dot)alekseev(at)postgrespro(dot)ru>>:
>>
>> > The global temporary tables has persistent rows in the catalogue.
>> The
>> > mapping to files can be marked as special and real mapping should be
>> > only in memory.
>> >
>> > So the changes in catalogue related to global temporary tables are
>> > pretty less frequently.
>>
>> I'm afraid I still don't get it. Let say I have an application that
>> does `CREATE TEMP TABLE xx ; DROP TABLE xx` in every session all the
>> time. Naturally there is not only one temp table per session. Could
>> you
>> explain please in more detail how exactly do these persistent rows
>> help?
>>
>>
>> when you use global temporary tables, then you create it only once -
>> like usual tables.
>>
>> you don't drop these tables.
>>
>>
> I share the view that this is a better/simpler solution to the problem. It
> will still require virtual (in-memory) tuples for pg_statistic records, but
> everything else works pretty much as for regular tables. In particular
> there are no problems with dependencies.
>
> The obvious disadvantage is that it requires changes to applications.

sure - as plpgsql developer I can say, the global temp tables are much more
friendly - so rewriting in application is enjoy work.

Regards

Pavel

>
>
> regards
>
> --
> Tomas Vondra http://www.2ndQuadrant.com
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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