Re: MySQL 5 comparison - Mailing list pgsql-advocacy
From | Robert Treat |
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Subject | Re: MySQL 5 comparison |
Date | |
Msg-id | 1105022535.31694.1286.camel@camel Whole thread Raw |
In response to | Re: MySQL 5 comparison (Hans-Jürgen Schönig <postgres@cybertec.at>) |
Responses |
Re: MySQL 5 comparison
|
List | pgsql-advocacy |
On Thu, 2005-01-06 at 05:03, Hans-Jürgen Schönig wrote: > For all those who think of comparing PostgreSQL - maybe this story > should be added. > I HAD to do benchmark a benchmark comparing MySQL and Slony replication. > > a. if you create a table as Innodb it MIGHT become ISAM without warning > (depending on a nicely hidden config parameter). > b. it seems as if BEGIN / COMMIT are silently accepted in ISAM tables ... > c. when dumping a master database it will not necessarily restore on the > slave database; we got a primary key violation on a unique > column a couple of times. > d. then we did a replication scenario: > > lucent@schankserver:~/replication_tests/query$ cat 05.sql > BEGIN; > UPDATE t_one SET intvalue = id WHERE id = 'RANDOMINT'; > UPDATE t_one SET intvalue = id WHERE id = 'RANDOMINT'; > COMMIT; > > BEGIN; > DELETE FROM t_one WHERE id = 'RANDOMINT'; > ROLLBACK; > > myisam -> innodb replication: > when doing this script above (30 concurrent users, 50 runs / user) > > > After the run PostgreSQL still had 500.000 records in the table - mysql > had only 499.950 (rest was ignored because MyISAM cannot do rollback). > But if I do 30 user * 50 runs = 1500 delete statements; why do only 50 > records miss? > > What do you think? Is a database allowed to eat data and issue as > WARNING instead of a hyper-fatal error? > > MySQL benchmark with replication; 2 concurrent users; 10000 repetitions > real 2m06.893s > > MySQL benchmark with replication; 40 concurrent users; 500 repetitions > real 6m40.474s > > In case of just two concurrent users MySQL is truly fast – it is very > unlikely that two users will hit the same random data area. However, the > situation changes dramatically when the number of concurrent users is > risen. Although we execute the same number of statements MySQL will be 2 > ½ times slower (with Innodb). In case of MyISAM we have seen MySQL being > 5 times slower than PostgreSQL. > PostgreSQL with replication; 2 concurrent users; 10000 repetitions > real 2m4.317s > PostgreSQL with replication; 40 concurrent users; 500 repetitions > real 2m53.324s > > In contrast to MySQL, PostgreSQL will perform really well in case of > multiple concurrent users. The time needed is increasing but those > changes are not that dramatical. We think that at least 10 seconds could > be shaved off by doing further tweaks inside the background writer process. > > > > Any more questions? Is it still worth to compare? I think we can agree > that MySQL is crap ... > Mind if i ask which versions of postgresql(&slony)/my$ql these were tested against and on what OS ? Robert Treat -- Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
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