Skip site navigation (1) Skip section navigation (2)

Re: Slow execution time when querying view with WHERE clause

From: Mike Mascari <mascarm(at)mascari(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Slow execution time when querying view with WHERE clause
Date: 2004-11-24 22:51:13
Message-ID: 41A51061.30805@mascari.com (view raw or flat)
Thread:
Lists: pgsql-performance
Tom Lane wrote:
> Um ... doh ... analyze.c about line 1550:
> 
>     /* We can only compute valid stats if we found some non-null values. */
>     if (nonnull_cnt > 0)
>        ...
> 
> There's a bit of an epistemological issue here: if we didn't actually
> find any nonnull values in our sample, is it legitimate to assume that
> the column is entirely null?  On the other hand, if we find only "3" in
> our sample we will happily assume the column contains only "3", so I
> dunno why we are discriminating against null.  This seems like a case
> that just hasn't come up before.

Will this discriminatory policy toward null end for 8.0?

Mike Mascari



In response to

pgsql-performance by date

Next:From: Steinar H. GundersonDate: 2004-11-25 01:18:23
Subject: Re: Postgres vs. MySQL
Previous:From: gnariDate: 2004-11-24 19:12:41
Subject: Re: FW: Index usage

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group