Stephan,
REPLACE is logically handled as a DELETE + INSERT, but
internally it is often handled as an UPDATE. Probably
REPLACE is faster than UPDATE / INSERT, because you
save some communications overhead between the client
and the server.
Regards,
Heikki
>On Mon, Aug 20, 2001 at 11:00:59AM +0200, Stephan wrote:
> Hi all,
>
>> my situation:
>
>> I generate 300 rows at a time - they should be stored in the a mysql>
table.>
>> 99 % of the keys of these rows already exist in the table, so these
>> rows need an update. The remaining 1 % have to be inserted in the> table.>
>> I was wondering if it is a good idea to to this with 300 UPDATE
>> statements and if one of them fails do an INSERT. Or if it's
>> recommendable to use a single REPLACE statement.>
>> My problem with the REPLACE is that the documentation says that a
>> REPLACE always does an DELETE and then an INSERT. In my case a lot
>> of rows (99%) would be deleted in the index that only need an
>> update. Is it a good idea to do that much index manipulations that
>> aren't necessary?
>Hmm. Are you asking for performance reasons or just because one is
>easier to code than the other?
>It shouldn't be hard to benchmark both options. I'd be curious to
>hear what you find.
>
>Jeremy
>--
>Jeremy D. Zawodny, <[EMAIL PROTECTED]>
>Technical Yahoo - Yahoo Finance
>Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936
>MySQL 3.23.41-max: up 3 days, processed 33,485,487 queries (110/sec. avg)
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