I found some problematic queries which locks mysql server any further processing. I'm using mysql-4.0.18
from FreeBSD ports collection. I'm using FreeBSD-5.2-CURRENT.
Some of the queries like :
select sum(total_amount) pbc from customers.payment where contract_id>=0 and contract_id<=4999 and from_unixtime(time_stamp,'%Y-%m')='2004-03';
Above query is not using any index. It locks mysql server and all other following queries go into queue until I kill locked mysqld thread.
After killing locked mysqld thread everything goes back to function normally.
I made composite index on contract_id,time_stamp,total_amount and let's see what will happen.
In the meantime, can somebody explain me what the problem is?
I already sent email to freebsd-current and freebsd-ports mailing list about this problem.
Does somebody have this problem before? Let me know if there is any solution.
I know I should use FreeBSD 4.9 stable since it doesn't have any problem with this issue. However I need to solve
this problem on FreeBSD-5.2-CURRENT.
thanks in advance,
Ganbold
At 01:36 PM 05.04.2004, you wrote:
yes, we resolved the issue it looks like. I wanted to hold off on announcing this until i was sure, but it's been running for about 24 hours now without a lockup.
options MAXDSIZ="(1024*1024*1024)" # change max from 512M to 1G add that to your kernel config.
basically whats happening ( and i'm probably wrong with the technicals on this, but bear with me :D ) is that mysqld would aquire a lock (on a table more then likely) and then try to allocate above the FBSD 5.2 max default memory size (512M). when it did this, it crashed and left the lock on the table. from there it just froze.
making that change seems to have fixed it. it was never evident before because we had a slower webserver that wasn't loading the sql server all that much. now it is, and we started developing problems. :).
as you can tell with this link: http://sql.tribalwar.com/before-ps.txt the mysqld proc wen't above 512M.
check your sql.err log, if you're getting a malloc error, then this is more then likely your problem.
Thanks to everyone for the help in tracking this down.
Let me know if this fixes the problem for you. Also, are you running -CURRENT in production? or testing? I had given some thought to upgrading the box to -CURRENT after the commit for the network stack settled. But I first need to get serial console enabled on it :).
Daryl
--- Ganbold <[EMAIL PROTECTED]> wrote: > Hi Daryl, > > I have exactly same problem as you. I have FreeBSD > 5.2-CURRENT (did cvsup > on March 23) with mysql-4.0.18 from ports > collection. > It is compiled with linuxthreads. Mysql is working > fine, except it > sometimes freezes, sometimes one or two tables get > corrupted. > Usually freezes once per day. Just freezes and I had > to kill mysql process > and start. > > Did you solve your problem? I also downloaded latest > snapshot from > mysql.com web site and installed, but nothing > changes. > Let me know if you find something. > > TIA, > > Ganbold > > > At 12:48 PM 03.04.2004, you wrote: > >ah! thanks :) > > > >It just happened again and I was able to collect > the > >data again. > > > >Before I did mysqladmin shutdown/killall -11 mysqld > >http://sql.tribalwar.com/before-ps.txt > > > >a few times the 3 giant processes would show as -, > but > >then it got to the point where they weren't > changing > >one bit (staying at Giant) > > > >after I did mysqladmin shutdown/killall -11 mysqld > >http://sql.tribalwar.com/after-ps.txt > > > >this eventually cleared up after a minute or so. > > > >I've given some serious thought to upgrading to > >-CURRENT, but with the network stack commit comming > >soon (or happening now), I don't want to get caught > in > >the middle of it and have severe problems. Perhaps > I > >should use a tag for the time right around the > sysctl > >change for the mp stack? > > > >The guy running the site just wants me to (have > >someone at the colo) format the machine and go back > to > >4.9. > > > >Oh, I now have witness in the kernel...no deadlocks > >from what I've seen. > > > >HTH, > >Daryl > > > >--- Doug White <[EMAIL PROTECTED]> wrote: > > > On Fri, 2 Apr 2004, Daryl Chance wrote: > > > > > > > Thanks for your response. It just happened a > few > > > > minutes ago and i was able to capture all the > > > output > > > > into a text file. > > > > > > > > http://sql.tribalwar.com/ps.txt > > > > > > oops, sorry, I get those confused. You want 'ps > > > axlwww'. WCHAN will be a > > > string like "select". > > > > > > > I have WITNESS* options compiled into the > kernel > > > and > > > > am going to reboot soon. Do you think it > would > > > help > > > > in debugging this to see if there are any > > > deadlocks? > > > > > > Potentially, although I get 100% cpu loops with > kde > > > that won't trigger any > > > witness or invariants checks. > > > > > > -- > > > Doug White | FreeBSD: The > Power > > > to Serve > > > [EMAIL PROTECTED] | www.FreeBSD.org > > > > > >__________________________________ > >Do you Yahoo!? > >Yahoo! Small Business $15K Web Design Giveaway > >http://promotions.yahoo.com/design_giveaway/ > >_______________________________________________ > >[EMAIL PROTECTED] mailing list > >http://lists.freebsd.org/mailman/listinfo/freebsd-current > >To unsubscribe, send any mail to > "[EMAIL PROTECTED]" >
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