Re: Composite Index question - Mailing list pgsql-general

From Rob Sargent
Subject Re: Composite Index question
Date
Msg-id 4CBF88A1.6090904@gmail.com
Whole thread Raw
In response to Re: Composite Index question  (DM <dm.aeqa@gmail.com>)
List pgsql-general
Sorry, I cannot prove or disprove any penalty.  I don't currently have
access to any postgres db of any serious magnitude.

On 10/20/2010 06:23 PM, DM wrote:
> I know there is no benfit of having duplicate indexes.
> Inorder for me to make change on production it requires lot of approvals
> and stuff.
>
> I wnat to know if there is any major performance drawback for having
> duplicate composite index, so that i can push hard for the change. Let
> me know.
>
> thanks for your looking into this.
>
>
> On Wed, Oct 20, 2010 at 5:10 PM, Rob Sargent <robjsargent@gmail.com
> <mailto:robjsargent@gmail.com>> wrote:
>
>     If you can think of one benefit from having the redundant index then by
>     all means keep it.  It certainly eludes me.  Seems to me, removing an
>     un-necessary index on a huge table can only be a good thing.
>
>     On 10/20/2010 06:02 PM, DM wrote:
>     > Its a huge table in production, i dont want to take any risk.
>     >
>     > I can simulate and test this but i was to checking to see If any one
>     > knows off hand about this.
>     >
>     >
>     >
>     > I can simulate it but
>     > On Wed, Oct 20, 2010 at 4:57 PM, Rob Sargent
>     <robjsargent@gmail.com <mailto:robjsargent@gmail.com>
>     > <mailto:robjsargent@gmail.com <mailto:robjsargent@gmail.com>>> wrote:
>     >
>     >     Hm. Run some queries; drop the second version of the index
>     definition;
>     >     re-run the same queries; report to the group.  The redundant
>     index isn't
>     >     helping, that much is certain.
>     >
>     >     On 10/20/2010 05:43 PM, DM wrote:
>     >     > Composite Index question:
>     >     >
>     >     > I have composite index on 3 columns on a table, by mistake the
>     >     composite
>     >     > index was created twice on the table.
>     >     >
>     >     > Will there any performance issues on this table because of
>     the 2 same
>     >     > composite indexes?
>     >     >
>     >     > Thanks
>     >     > Deepak
>     >
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>
>

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