At 6:35 PM -0500 9/7/99, Joshua Chamas wrote:
>> I didn't think you could prepare *any* queries with mysql. I thought
>> that DBI::prepare was basically a no-op when using the Mysql driver
>> (well, not quite - it stores the string locally, and does the ?
>> substitution, but that's a local perl-side issue) - and I'd be surprised
>> if it affected query speed much at all. (Unless, of course your
>> overhead is perl, but that'd be surprising)
>>
>> Jules
>>
>
>I don't know what's going on in the background, but between DBD::mysql
>& mysqld, there is a 35% speedup when preparing & caching cursors
>for simple insert statements. Supposedly there are no
>"server-side cursors" so I'm guessing its a client side thing.
What happens if you run your sets of statements in a different order?
You may simply be seeing an effect of OS-level disk cacheing.
>
>Here's a little benchmark that you can run:
>
>use Benchmark;
>
># you supply the $dbi connection
># create a database called spiders with a spider_id auto
># incrementing column
>
>timethis(2000, sub {
> my $isth = $dbi->prepare("insert into spiders (spider_id)
>values (NULL)");
> my $nsth = $dbi->prepare("select last_insert_id()");
> $isth->execute();
> $nsth->execute();
> $nsth->fetchrow_array;
> $nsth->finish;
> });
>timethis(2000, sub {
> my $isth = $dbi->prepare_cached("insert into spiders
>(spider_id) values (NULL)");
> my $nsth = $dbi->prepare_cached("select last_insert_id()");
> $isth->execute();
> $nsth->execute();
> $nsth->fetchrow_array;
> $nsth->finish;
> });
>
>prompt> bench_insert.pl
>timethis 2000: 10 secs (10.32 usr 0.00 sys = 10.32 cpu)
>timethis 2000: 7 secs ( 6.63 usr 0.00 sys = 6.63 cpu)
>
>-- Joshua
>______________________________________________________________________
>Joshua Chamas Chamas Enterprises Inc.
>NODEWORKS - web link monitoring Long Beach, CA USA 1-562-432-2469
>http://www.nodeworks.com http://www.chamas.com
>
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Paul DuBois, paul@stripped
Northern League Chronicles: http://www.snake.net/nl/
