Re: When does CLUSTER occur?

-----Original Message-----
From: Jeff Janes [mailto:jeff(dot)janes(at)gmail(dot)com]
Sent: Thursday, November 29, 2012 11:19 AM
To: Schnabel, Robert D.
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] When does CLUSTER occur?

On Thu, Nov 29, 2012 at 8:11 AM, Schnabel, Robert D.
<schnabelr(at)missouri(dot)edu> wrote:

> My question is whether or not the "ALTER TABLE gen1011 CLUSTER ON
> xgen1011_si_sn" actually clusters the table at that point or if it
> just tells it to use that index for clustering?

It just marks it to use that index if/when it is clustered, it doesn't do the clustering.

Cheers,

Jeff
[Schnabel, Robert D.]
That's what I thought because I just went through this exercise for another table which was previously clustered. The correlation on the column for the index was 1. After I did the drop index, insert data, create index with the cluster command the correlation was <1.

Thanks for the clarification.

Bob