From: Richard Huxton <dev@archonet.com>
To: ken@scottshill.com
Cc: pgsql-sql@postgresql.org
Subject: Re: Column Index vs Record Insert Trade-off?
Date: Thu, 09 Feb 2006 10:25:59 +0000
Message-ID: <43EB18B7.4060006@archonet.com> (raw)
In-Reply-To: <1139450040.15713.3.camel@localhost.localdomain>
References: <1139450040.15713.3.camel@localhost.localdomain>
Ken Hill wrote:
> Is there a performance trade-off between column indexes and record
> inserts?
>
> I know that in MS Access there is such a trade-off. This being indexes
> make SQL queries perform faster at the cost of record insert speed. Put
> another way, the more column indexes in a table, the slower a record
> insert in that table performs.
>
> Is there a similar trade-off in PostgreSQL?
The tradeoff is made in every system. The more indexes you have on a
table, the more indexes need to be updated when you update/insert/delete
rows.
So - a unique constraint automatically implies an index in PostgreSQL
(it's how it implements its unique checks). Other than that, you should
only index those columns where you will want a small number of rows or
quick ordering.
--
Richard Huxton
Archonet Ltd
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, ken@scottshill.com
Subject: Re: Column Index vs Record Insert Trade-off?
In-Reply-To: <43EB18B7.4060006@archonet.com>
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