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From:Michael Widenius Date:June 12 2001 5:08pm
Subject:Myql internals
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Hi!

>>>>> "Dip" == Dip  <dds98@stripped> writes:

Dip> Hi All,
Dip> Im running some benchmarking tests on mysql, postgres and interbase
Dip> database servers.

Dip> does anyone know the reasons why or know where i can find out some
Dip> technical reasons why the mysql database server is particularly good in
Dip> relation to the others or just by itself e.g. use of query optimisation
Dip> or indexing etc. I'm only looking at creates, selects, inserts, update
Dip> and delete statements. I've noticed that Mysql is particularly good at
Dip> insertions, deletes and updates but quite poor (in relation to postgres
Dip> and interbase) at performing complex queries such as left, right, inner
Dip> joins with where clauses. Why is this?

The reason is that most of the MySQL core is programmed by one persons
with the goal to make everything as fast as possible; By having a
person that knows all code you can get all code consistent and avoid
duplicated code.

Most of the code has been used and fine tuned in a high volume
production environment for over 20 years.

By not having transactions enabled by default, you can do a lot of
shortcuts and optimizations that are not possible with a standard
SQL database.
The SQL engine in MySQL also includes a lot of optimizations that most
other databases doesn't do.

MySQL also uses threads which in most cases give MySQL a speed advantage.

We have tried to test most types of queries with MySQL and PostgreSQL
and for most cases MySQL has been 2-5 times faster.
(This includes complex queries with left, right and normal joins)

Please check the benchmarks at:

http://www.mysql.com/information/benchmarks.html

You can find a list of the majore differences between MySQL and
PostgreSQL at:

http://www.mysql.com/doc/C/o/Compare_PostgreSQL.html

What kind of queries have you found faster with PostgreSQL ?

Any change you could get time to add a test in our benchmark suite
that shows when PostgreSQL is better ?

Dip> I've tried to look around for this on the net, but all i seem to get is
Dip> a big arguement consisting of the features lacking in mysql that are in
Dip> other databases e.g. ACID!!

You can with MySQL use BDB or InnoDB tables and to get MySQL ACID.

Regards,
Monty
Thread
Myql internalsDip12 Jun
  • Re: Myql internalsSasha Pachev12 Jun
  • Myql internalsMichael Widenius12 Jun
Re: Myql internalsMichael Widenius17 Jun