Re: [PHP3] Re: PostgreSQL vs Mysql comparison

Hi!

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The>     Also, please note also that those benchmarks were/are based on
The> what MySQL is capable of, not what the other SQL servers are capable of.
The> For instance, if I take an SQL query that has been "optimized for MySQL"
The> and run it verbatim under PostgreSQL, the difference is a 2sec result for
The> MySQL vs 19sec for PostgreSQL ... if I re-write that query for
The> PostgreSQL's featuers (namely, using subselects), i can get the query down
The> to 1sec *shrug*

Just a note about the above!  The queries we run in the MySQL
benchmarks are NOT optimized for MySQL.  The whole idea is that we
try to test different SQL construct and give an relatively accurate
and fair timeing of these!

Not a single of the tested queries can be made faster with sub
selects.

Note also that most queries don't need sub selects and most that need
sub selects can be made as fast (and sometimes faster) by using two
queries instead!

I agree that we don't have any sub selects tests yet in the MySQL
benchmarks, but we plan to add such in the near future; We have tried
to get someone else writing this, but as no one seem to be interested
in making the MySQL benchmarks even better, this may have to wait
until we have sub queries in MySQL).  We have also tried to get
postgreSQL developers to add other tests to the MySQL benchmarks (which
are GPL), but we haven't found anyone that has been interested in
this!

The>     Would be interesting to see us (PostgreSQL) come up with
The> benchmarks against MySQL...we'd be able to put stuff like "couldn't
The> test under MySQL, since they don't support this SQL construct"...

For the moment the standard MySQL benchmarks already contains a lot of
stuff that we can't test on PostgreSQL, because they don't support
some very common constructs (like LEFT JOIN, HAVING, ALTER TABLE
change of many columns).  There is also a lot of hard limits in PostgreSQL
(like number of columns, query size...) that makes it much harder to
make a good benchmark when comparing MySQL and PostgreSQL.

A last thing that few postgreSQL users seams to release;  We have
spent about 10 times as much time to optimize the MySQL benchmarks for
postgreSQL than for MySQL, just to get some decent results for postgreSQL.

Regards,
Monty