| From: | Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
|---|---|
| To: | Steven Flatt <steven(dot)flatt(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Very long SQL strings |
| Date: | 2007-06-21 18:41:55 |
| Message-ID: | 467AC673.6080107@enterprisedb.com |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
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| Lists: | pgsql-performance |
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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