[pgpool-general: 223] Re: More information on relcache_expire

[Sandeep Thakkar]

right, that makes sense. Thanks!

BTW, how do we know that the query result is returned from the cache or not?



________________________________
 From: Tatsuo Ishii <ishii at postgresql.org>
To: sandeeptt at yahoo.com 
Cc: pgpool-general at pgpool.net 
Sent: Tuesday, February 14, 2012 2:11 PM
Subject: Re: [pgpool-general: 221] Re: More information on relcache_expire
 
> I mean, let's say I define the value of relcache_expire as "600" seconds. and the TABLE in cache is ALTERED before that. That means my query will produce the wrong result because the relation cache is not yet updated/expired, right?

Yes.

On what basis one would define the value of relcache_expire in pgpool.conf?

I don't think changing table structure so frequently is a real life
usecase. Rather I think it happens during application development:
table structures are not stable.

If your customer really wants to change table structure every 5
minutes, probably there's something wrong with user's work flow
anyway.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> ________________________________
>  From: Sandeep Thakkar <sandeeptt at yahoo.com>
> To: "pgpool-general at pgpool.net" <pgpool-general at pgpool.net> 
> Sent: Monday, February 13, 2012 1:58 PM
> Subject: [pgpool-general: 220] More information on relcache_expire
>  
> 
> - Add relcache_expire directive to control the expiration of the internal system catalog cache. ALTER TABLE might make these cache values obsoleted and the new directive will make the risk lower(Tatsuo)
>  I would like to know how to make use of this directive? A test case will help.
> 
> Thanks.
> 
> 
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