From: | Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> |
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To: | <sharmad(at)goatelecom(dot)com> |
Cc: | <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: Indices |
Date: | 2001-12-11 18:46:32 |
Message-ID: | 20011211104254.K79645-100000@megazone23.bigpanda.com |
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Lists: | pgsql-sql |
On Tue, 11 Dec 2001 sharmad(at)goatelecom(dot)com wrote:
> Hi,
> Having to manny indices to a table,does it effect the performance of a table.Like
> a table having following structure
Generally it'll affect the speed of transactions that write to the table.
>
> Name :
> First name,
> Second Name,
> Third name,
> Age,
> Address.
>
> Is it good here to have multiple indices like on only first name, only second
> name,only third name and all other combination of first ,second and third name
> or the performance increases when we have only 1 indice of all first ,second
> and third name
It mostly depends on what you're searching for in your queries.
PostgreSQL will attempt to use multi-column indexes for prefixing columns
(so an index on (a,b,c) can be used for queries that constrain a, but not
for queries that don't, a query that constrains a and c probably only
uses the index to constrain a, etc...)
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