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Re: I: About "Our CLUSTER implementation is pessimal" patch

From: Leonardo F <m_lists(at)yahoo(dot)it>
To: Josh Kupershmidt <schmiddy(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: I: About "Our CLUSTER implementation is pessimal" patch
Date: 2010-02-10 18:30:35
Message-ID: 391526.82441.qm@web29015.mail.ird.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-hackers
>Perhaps you could supply a .sql file containing a testcase 
> illustrating the performance benefits you tested with your patch

Sure.


Attached the updated patch (should solve a bug) and a script.
The sql scripts generates a 2M rows table ("orig"); then the
table is copied and the copy clustered using seq + sort (since 
"set enable_seqscan=false;").
Then the table "orig" is copied again, and the copy clustered
using regular index scan (set enable_indexscan=true; set 
enable_seqscan=false).
Then the same thing is done on a 5M rows table, and on a 10M
rows table.

On my system (Sol10 on a dual Opteron 2.8) single disc:


2M:  seq+sort 11secs; regular index scan: 33secs
5M:  seq+sort 39secs; regular index scan: 105secs
10M:seq+sort 83secs; regular index scan: 646secs


Maybe someone could suggest a better/different test?


Leonardo



      

Attachment: cluster_tests.sql
Description: application/octet-stream (2.8 KB)
Attachment: sorted_cluster20100210.patch
Description: application/octet-stream (26.5 KB)

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