Thank you Erik! HDs are OK, a couple of GB free. Not that it's a lot, but I can't imagine it being too low for MySQL..
I'm aware memory is a bit low, but RAMBUS chips are hard to come by. They don't have them in stock anywhere anymore. Also they are quite expensive. It's almost like you could've bought 1/3rd of a new cheap Dell server for 2x512MB RAMBUS. But if a new box for a reasonable price wouldn't be any faster it's no use anyway... Concerning slow queries, it seems there's a couple of different queries that's being logged. This is one, taking 66 seconds: # Query_time: 66 Lock_time: 0 Rows_sent: 0 Rows_examined: 15857680 SELECT word_id FROM phpbb_search_wordmatch GROUP BY word_id HAVING COUNT(word_id) > 263916; Usual time for this seems to be from 12 to 66 seconds. And then there's this, usually taking 10-20 seconds: # Query_time: 12 Lock_time: 0 Rows_sent: 10 Rows_examined: 395960 SELECT t.*, u.username, u.user_id, u2.username as user2, u2.user_id as id2, p.post_username, p2.post_username AS post_username2, p2.post_time, f.forum_name FROM phpbb_topics t, phpbb_users u, phpbb_posts p, phpbb_posts p2, phpbb_users u2, phpbb_forums f WHERE t.topic_poster = u.user_id AND t.forum_id NOT IN (16, 17) AND p.post_id = t.topic_first_post_id AND p2.post_id = t.topic_last_post_id AND t.forum_id = f.forum_id AND u2.user_id = p2.poster_id AND t.topic_status <> 1 AND t.topic_status <> 2 ORDER BY t.topic_last_post_id DESC LIMIT 10; In the evenings there seems to be 10-20 slow queries every hour, time between them varying from seconds to usually 5-10 minutes. Cheers, Gunnar On fre, januar 4, 2008, 05:55, Erik Giberti wrote: > Gunnar, > > us = user (things like MySQL/PHP/Apache) > sy = system (memory management / swap space / threading / kernel > processes and so on) > ni = nice (apps running only when nothing else needs the resource) > id = idle (extra cpu cycles being wasted) > wa = wait state (io wait for disk/network/memory) > hi & si - interrupts > > Generally acceptable load should be < #processors (so in your case 2 > is okay - machine is performing well - 4 somethings being over > utilized somewhere) > Also in top 100% = 100% of one processor, so in a dual processor (or > core) setup, you can actually go to 200% > > Your userland apps are taking up 61.3 + 57.0 (118.3% of 200% or 59% > overall) of system resources. > Your system processes are taking up 66.2% (of 200% or 33% overall) > and it's leaving about 14% (of 200% - so 7% overall) of the system idle. > The remainders are I/O waits etc (your numbers look pretty good there, > but IO wait can spike and so may be misleading without using other > tools. > > You may be encountering a thrashing problem with the amount of memory > left or any number of things, but I would look at memory use on this > box, because your load is pretty high and your performance is > suffering if it's staying there. Your memory is at about 92% utilized > too... while 91Mb seems like a lot of memory - it's easily consumed by > a couple of large queries, sorts and so on which then goes right to > disk swapping for virtual memory - never good for performance. It > might also be impacted by IO and you just can't see it in the one > slice of top we have here. If that number spikes up to 5% and then > falls back down - it might be time spent going to disk with temp > tables etc. > > Also turn on slow query logging (yes, I know it's another performance > hit) and see if there is one query that's particularly problematic, > perhaps optimizing the indexes etc on the table might help with the > performance. > > Also, make sure your HD's aren't full... that will kill performance > very quickly if the needed disk space isn't there. > > Erik > > > On Jan 3, 2008, at 3:44 PM, Gunnar R. wrote: > >> Hello, >> >> Thanks. I read the document, but unfortunately it didn't tell me >> anything >> new.. >> >> One of the things I am a bit confused about is: >> >> top - 22:08:12 up 6 days, 7:23, 1 user, load average: 4.36, 3.30, >> 2.84 >> Tasks: 134 total, 1 running, 133 sleeping, 0 stopped, 0 zombie >> Cpu0 : 61.3% us, 29.1% sy, 0.0% ni, 7.9% id, 0.7% wa, 0.3% hi, >> 0.7% si >> Cpu1 : 57.0% us, 37.1% sy, 0.0% ni, 6.0% id, 0.0% wa, 0.0% hi, >> 0.0% si >> Mem: 1034280k total, 942780k used, 91500k free, 34252k >> buffers >> Swap: 2031608k total, 104k used, 2031504k free, 278788k >> cached >> >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND >> 2410 mysql 15 0 470m 310m 4464 S 99.9 30.8 4200:25 mysqld >> >> How come the CPUs can have idle time even though mysqld is running at >> 99.9%, AND there's a processor queue (4.36)? >> >> Cheers, >> >> Gunnar R. >> >> On ons, januar 2, 2008, 13:07, Andrew Braithwaite wrote: >>> Hi, >>> >>> If you can follow this document: >>> >>> http://www.ufsdump.org/papers/uuasc-june-2006.pdf >>> >>> You should be able to figure out what's happening. >>> >>> Cheers, >>> >>> Andrew >>> >>> -----Original Message----- >>> From: Gunnar R. [mailto:[EMAIL PROTECTED] >>> Sent: Tue, 01 January 2008 23:31 >>> To: mysql@lists.mysql.com >>> Subject: Performance problem - MySQL at 99.9% CPU >>> >>> Hello, >>> >>> I am running a community site mainly based on phpBB. It has about >>> 9.300 >>> registered users, 650.000 posts and about 200.000 visitors/month (12 >>> mill >>> "hits"). The SQL database is about 700MB. >>> >>> It's all running on a couple of years old Dell box with two P4 Xeon >>> 1.7Ghz >>> CPUs, 1GB of RAMBUS memory and SCSI disks, with Linux and Apache. >>> >>> The last year the server has been having huge performance problems, >>> and >>> MySQL (5.0.45) seems to be the problem. It's almost constantly >>> running >>> at >>> 99.9% CPU ("measured" using 'top'). >>> >>> I know the hardware isn't too hot, but either way I am a bit >>> confused by >>> the >>> fact that I can't seem to get MySQL to run smoothly. Is this just too >>> big a >>> database for this kind of box, or could this be a configuration >>> issue? >>> >>> I am thinking about buying a new dual core box (with IDE disks?), >>> but I >>> have >>> to make sure this really is a hardware issue before I spend >>> thousands of >>> bucks. >>> >>> Any help will be hugely appreciated! >>> >>> Cheers, >>> >>> Gunnar >>> >>> >>> >>> -- >>> MySQL General Mailing List >>> For list archives: http://lists.mysql.com/mysql >>> To unsubscribe: >>> http://lists.mysql.com/[EMAIL PROTECTED] >>> >>> >>> >>> LOVEFiLM International Limited is a company registered in England and >>> Wales. Registered Number: 04392195. Registered Office: No.9, 6 >>> Portal Way, >>> London W3 6RU, United Kingdom. >>> >>> This e-mail is confidential to the ordinary user of the e-mail >>> address to >>> which it was addressed. If you have received it in error, please >>> delete it >>> from your system and notify the sender immediately. >>> >>> This message has been scanned for viruses by BlackSpider >>> MailControl - >>> www.blackspider.com >>> >>> -- >>> MySQL General Mailing List >>> For list archives: http://lists.mysql.com/mysql >>> To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] >>> >>> >> >> >> >> -- >> MySQL General Mailing List >> For list archives: http://lists.mysql.com/mysql >> To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] >> > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]