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Thread: analyse question..

analyse question..

From
Rajesh Kumar Mallah
Date:

Do we need to analyze a table after indexing ?
we observed that an already analyzed table had to be
re-analyzed after index creation for index usage .

is it normal behaviour?


regds
mallah.

-- 
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.

Re: analyse question..

From
Tom Lane
Date:
Rajesh Kumar Mallah <mallah@trade-india.com> writes:
> Do we need to analyze a table after indexing ?

No.

> we observed that an already analyzed table had to be
> re-analyzed after index creation for index usage .

I think you must have made a mistake.  Creating an index doesn't
touch pg_statistic.
        regards, tom lane

Re: analyse question..

From
Rajesh Kumar Mallah
Date:
On Thursday 17 Apr 2003 7:47 pm, Tom Lane wrote:
> Rajesh Kumar Mallah <mallah@trade-india.com> writes:
> > Do we need to analyze a table after indexing ?
>
> No.
>
> > we observed that an already analyzed table had to be
> > re-analyzed after index creation for index usage .
>
> I think you must have made a mistake.  Creating an index doesn't
> touch pg_statistic.

Doesnt' it mean we shud analyze after index creation so that
statiscs are updated? (as u said creating index does not touch pg_statistics).

PS: this is the same table "profile_master" abt with i have posted a different
question.



>
>             regards, tom lane
>
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-- 
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.

Re: analyse question..

From
Tom Lane
Date:
Rajesh Kumar Mallah <mallah@trade-india.com> writes:
> On Thursday 17 Apr 2003 7:47 pm, Tom Lane wrote:
>> Rajesh Kumar Mallah <mallah@trade-india.com> writes:
>>> Do we need to analyze a table after indexing ?
>> 
>> No.

> Doesnt' it mean we shud analyze after index creation so that
> statiscs are updated?

No, because the statistics are independent of whether an index exists or
not.  You can do it in either order and get the same results.
        regards, tom lane