Re: Index Backward Scan fast / Index Scan slow ! - Mailing list pgsql-performance

From Pailloncy Jean-Gérard
Subject Re: Index Backward Scan fast / Index Scan slow !
Date
Msg-id 77EC9C09-8D3B-11D8-A5A0-000A95DE2550@ifrance.com
Whole thread Raw
In response to Re: Index Backward Scan fast / Index Scan slow !  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Index Backward Scan fast / Index Scan slow !
List pgsql-performance
> Hm, this is odd.  That says you've got 349519 live index entries in
> only
> 463 actively-used index pages, or an average of 754 per page, which
> AFAICS could not fit in an 8K page.  Are you using a nondefault value
> of
> BLCKSZ?  If so what?
Sorry, I forgot to specify I use BLCKSZ of 32768, the same blokck's
size for newfs, the same for RAID slice's size.
I test the drive sometimes ago, and found a speed win if the slice size
the disk block size and the read block size was the same.

I do not think that a different BLCKSZ should exhibit a slowdown as the
one I found.

> If you *are* using default BLCKSZ then this index must be corrupt, and
> what you probably need to do is REINDEX it.  But before you do that,
> could you send me a copy of the index file?
Do you want the index file now, or may I try something before?

Cordialement,
Jean-Gérard Pailloncy


pgsql-performance by date:

Previous
From: Ken Geis
Date:
Subject: Tracking down performance issue
Next
From: Tom Lane
Date:
Subject: Re: Index Backward Scan fast / Index Scan slow !