From: | Sven Geisler <sgeisler(at)aeccom(dot)com> |
---|---|
To: | Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: single transaction vs multiple transactions |
Date: | 2006-12-05 15:58:30 |
Message-ID: | 45759726.9060004@aeccom.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
Hi,
Many thanks for the fast response.
I will use temporary table with copy.
Other issue I have is the connection between app and db.
I guess, the approach with the copy will also hold down the network I/O
between app and db. Keeping in mind that I produce 10,000+ statements.
Thx
Sven
Heikki Linnakangas schrieb:
> Sven Geisler wrote:
>> I have to insert my arguments to a temporary table first, because the
>> arguments are only known in the application tier.
>> Is a multiple insert to a temporary table and a final 'DELETE FROM x
>> WHERE y IN (SELECT z FROM tmp)' faster than multiple deletes?
>
> If the number of records is high, it most likely is faster. You should
> try it with your data to be sure, but in general doing all the deletes
> in one batch is faster when the number of records is high because it
> allows using efficient merge joins or sequential scans.
>
> Populating the temporary table with no indexes should be quite
> inexpensive if you make sure you don't do it one record at a time. Use
> the COPY command or batched inserts instead.
>
>
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