Hello, I'm author and maintainer of ZABBIX and the manual. I would like to add some comments to the thread. First of all, ZABBIX supports three database engines: MySQL, Oracle and PostgreSQL. It uses absolutely standard SQL, same for all three database engines. We have absolutely no intention to push or recommend one of those. I'm big fan of PostgreSQL and having a choice I would choose PostgreSQL for anything except ZABBIX. Unfortunately PostgreSQL performs much slower than MySQL doing large number of updates for one single table. By its nature ZABBIX requires to execute hundreds of updates per second for large installations. PostgreSQL cannot handle this nicely. Do a simple test to see my point: 1. create table test (id int4, aaa int4, primary key (id)); 2. insert into test values (0,1); 3. Execute "update test set aaa=1 where id=0;" in an endless loop I just did the test on PostgreSQL 7.4.12 and MySQL 5.0.22 (MyISAM, sorry had no configured InnoDB). Ubuntu 6.0.6, AMD64, 2GB, default database settings. MySQL performs very well, approximately 15000-20000 updates per second with no degradation of performance. PostgreSQL does approximately 1600 records per second for the first 10000, then 200rps for the first 100k records, and then slower and slower downgrading to 10-20 rps(!!!) when reaching 300k. The manual states that PostgreSQL works ten times slower for ZABBIX, in reality it is much worser. Yes, I'm aware of autovacuuming, etc. But it eats resources and I cannot handle to run it periodically because I want steady performance from my application. I do not want to see ZABBIX performing slower just because of database housekeeper. Several years ago I contacted PostgreSQL developers but unfortunately the only answer was "Run vacuum. We won't change PostgreSQL to reuse unused tuples for updates". Perhaps something has changed in recent releases of PostgreSQL, I don't think so. Please correct me if I'm wrong. Kind regards, Alexei
