[nycbug-talk] MySQL and FreeBSD 6.0

[Francisco Reyes]

Hans Zaunere writes:

> This is 4.1 so these features aren't in use.  I'm afraid we're hitting some
> threading issues, per previous links.

What loads in the machihe?
You mentioned crashes on high concurrency.. how many connections?

I have a 6.1 Stable (May 2006) running Mysql 4.1.13 with no problems.
Large number of selects, with a decent amount of inserts (primarily from a 
greylisting DB) .

Number of connections per seconds, as reported by mtop, is between 200 and 
600 during regular business hours. Just checked right now (saturday 6pm) and 
it was 170 to 200 queries per second.. Weekends are considerably slower..

This is a dedicated machine that does only mysql and absolutely nothing 
else. Have 1 slave running off this machine. 2GB of RAM, 2 Raptors in RAID 
1. Using MyISAM tables. From what I see in top/vmstat/iostat... usually the 
data is coming from memory and not much disk I/O in the machine. 


 No crashes, no issues.

The only issue I have ever had is with the replication. Ocassionaly the 
replication will just stop working on the slave.. and a few times had to 
redo the entire replication setup. Often times just doing a skip on the 
problem transaction solves the problem. If the master gets really busy 
(usually in the 600 queries per second) the slave will stop replication.. 
and just have to "start slave" to get it going again.   

I still would much rather move as much work as possible to postgresql, but 
there is so much legacy code with Mysql that it was not very practical to 
try and convert it all. Most new work we do is postgresql.