PostgreSQL is much faster than MySQL, only when...

[Marek Lewczuk]

Hello,
I have changed DB from MySQL to PostgreSQL. When I have run my
application on PostgreSQL it was disaster - it was much slower than
MySQL...

I have tried to change PG configuration file etc.. no luck. After many
long days of thinking what is wrong I have made several tests with
"EXPLAIN" statement, and to my amusement there was many SeqScan - MySQL
didn't show that things. I have made some changes in PG db structure
(new indexes etc) and then I have made another test: PostgreSQL time -
10ms, MySQL time - 1 sec. I've tried to change the structure in MySQL
but it didn't change the results.

So my advise for all users which think that MySQL is faster than PG -
re-check your DB structure, check all your querys using EXPLAIN... maybe
new indexes should be added etc.
Regards,
Marek


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[Martijn van Oosterhout]

And ofcourse, you ran ANALYZE before doing any timings, right?

On Tue, Nov 25, 2003 at 01:08:55PM +0100, Marek Lewczuk wrote:

Hello,
I have changed DB from MySQL to PostgreSQL. When I have run my
application on PostgreSQL it was disaster - it was much slower than
MySQL...

I have tried to change PG configuration file etc.. no luck. After many
long days of thinking what is wrong I have made several tests with
"EXPLAIN" statement, and to my amusement there was many SeqScan - MySQL
didn't show that things. I have made some changes in PG db structure
(new indexes etc) and then I have made another test: PostgreSQL time -
10ms, MySQL time - 1 sec. I've tried to change the structure in MySQL
but it didn't change the results.

So my advise for all users which think that MySQL is faster than PG -
re-check your DB structure, check all your querys using EXPLAIN... maybe
new indexes should be added etc.


Regards,
Marek




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--
Martijn van Oosterhout <kl*****@svana.org> http://svana.org/kleptog/ "All that is needed for the forces of evil to triumph is for enough good
men to do nothing." - Edmond Burke
"The penalty good people pay for not being interested in politics is to be
governed by people worse than themselves." - Plato

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[Marek Lewczuk]

U¿ytkownik Martijn van Oosterhout napisa³:

And ofcourse, you ran ANALYZE before doing any timings, right?

Of course.


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[Randolf Richardson]

Cross-posted to "comp.databases.postgresql.advocacy" because
PostgreSQL could be very helpful to MySQL DBAs who wish to optimize their
databases -- just convert it to PostgreSQL on a test system and use EXPLAIN
and ANALYZE to identify the weaknesses.

Even if these MySQL DBAs don't use PostgreSQL for anything else, at
the very least it will increase awareness of the product. =)

Hello,
I have changed DB from MySQL to PostgreSQL. When I have run my
application on PostgreSQL it was disaster - it was much slower than
MySQL...

I have tried to change PG configuration file etc.. no luck. After many
long days of thinking what is wrong I have made several tests with
"EXPLAIN" statement, and to my amusement there was many SeqScan - MySQL
didn't show that things. I have made some changes in PG db structure
(new indexes etc) and then I have made another test: PostgreSQL time -
10ms, MySQL time - 1 sec. I've tried to change the structure in MySQL
but it didn't change the results.

So my advise for all users which think that MySQL is faster than PG -
re-check your DB structure, check all your querys using EXPLAIN... maybe
new indexes should be added etc.

--
Randolf Richardson - [e-mail]
Vancouver, British Columbia, Canada

Please do not eMail me directly when responding
to my postings in the newsgroups.