From: Heikki Linnakangas <heikki@enterprisedb.com>
To: Steven Flatt <steven.flatt@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Very long SQL strings
Date: Thu, 21 Jun 2007 19:41:55 +0100
Message-ID: <467AC673.6080107@enterprisedb.com> (raw)
In-Reply-To: <357fa7590706211133u2ae43d09id1653ca63d7a7838@mail.gmail.com>
References: <357fa7590706211133u2ae43d09id1653ca63d7a7838@mail.gmail.com>
Steven Flatt wrote:
> It looks like Postgres does not enforce a limit on the length of an SQL
> string. Great. However is there some point at which a query string
> becomes
> ridiculously too long and affects performance? Here's my particular case:
> consider an INSERT statement where you're using the new multi-row VALUES
> clause or SELECT ... UNION ALL to group together tuples. Is it always
> better to group as many together as possible?
I'm sure you'll reach a point of diminishing returns, and eventually a
ceiling where you run out of memory etc, but I don't know what the limit
would be.
The most efficient way to do bulk inserts is to stream the data with COPY.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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To: pgsql-performance@postgresql.org
Cc: heikki@enterprisedb.com, steven.flatt@gmail.com
Subject: Re: Very long SQL strings
In-Reply-To: <467AC673.6080107@enterprisedb.com>
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