Re: Creating multiple indexes

From: Nick Pierpoint <>
Date: Thu, 18 Nov 2010 09:12:53 +0000
Message-ID: <1290071573.2687.13.camel_at_rollins>

On Wed, 2010-11-17 at 08:18 +0200, wrote:
> >I'm trying to find the reason why there isn't a
> mechanism to create multiple indexes at the same time - a "create
> indexes" statement or similar.
> > Each create index needs to scan through every row in the table to form the index.
> > i.e. 10 indexes = 10 full scans.
> b-tree initial construction requires sorting
> (
> Let's use a merge-sort algorithm (,
> ok?
> Merge algorithm does scan all rows but it also does more than that.

Are you saying that index creation requires more work than the initial table scan so any benefits derived from creating multiple indexes at the same time with a single scan would be countered by the additional overhead?

I don't see this. I'd have thought that the first "data gathering" stage of index creation would benefit from caching each column as part of a single table scan.


Received on Thu Nov 18 2010 - 03:12:53 CST

Original text of this message