Re: [HACKERS] Big IN() clauses etc : feature proposal - Mailing list pgsql-performance

From Zeugswetter Andreas DCP SD
Subject Re: [HACKERS] Big IN() clauses etc : feature proposal
Date
Msg-id E1539E0ED7043848906A8FF995BDA57901053F20@m0143.s-mxs.net
Whole thread Raw
List pgsql-performance
> Something else worth considering is not using the normal
> catalog methods
> for storing information about temp tables, but hacking that together
> would probably be a rather large task.

But the timings suggest, that it cannot be the catalogs in the worst
case
he showed.

> 0.101 ms BEGIN
> 1.451 ms CREATE TEMPORARY TABLE tmp ( a INTEGER NOT NULL, b INTEGER
NOT
> NULL, c TIMESTAMP NOT NULL, d INTEGER NOT NULL ) ON COMMIT DROP

1.4 seconds is not great for create table, is that what we expect ?

> 0.450 ms INSERT INTO tmp SELECT * FROM bookmarks ORDER BY annonce_id
DESC
> LIMIT 20
> 0.443 ms ANALYZE tmp
> 0.365 ms SELECT * FROM tmp
> 0.310 ms DROP TABLE tmp
> 32.918 ms COMMIT
>
>     CREATING the table is OK, but what happens on COMMIT ? I hear
the disk
> seeking frantically.

The 32 seconds for commit can hardly be catalog related. It seems the
file is
fsynced before it is dropped.

Andreas

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