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From:Michael Widenius Date:May 5 2000 2:24pm
Subject:Potential bug in mysql 3.23.14
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Hi!

Peter> 
Peter> I'm running mysql 3.23.14 on RedHat Linux 6.2
Peter> Today I saw the following in my processlist:
Peter> 
Peter> [pz@geo pz]$ mysqladmin processlist | grep -v Sleep
Peter> +-------+-------+-----------+---------+---------+-------+----------------=
Peter> ------+------------------------------------------------------------------=
Peter> ------------------------------------+
Peter> | Id    | User  | Host      | db      | Command | Time  | State          =
Peter>       | Info                                                             =
Peter>                                     |
Peter> +-------+-------+-----------+---------+---------+-------+----------------=
Peter> ------+------------------------------------------------------------------=
Peter> ------------------------------------+
Peter> | 1     | titan | 10.0.0.2  | counter | Killed  | 39566 | update         =
Peter>       | INSERT INTO st10.g00domip (domip, ip, tz, ts) VALUES ('', =
Peter> 3277775400, 8, '2000-05-04 17:40:01')      |
Peter> | 3     | titan |           | counter | Killed  | 37932 | update         =
Peter>       | INSERT INTO st12.g06pages (page_prot, page_domain, =
Peter> page,query,port,hash) VALUES(1,4008,'page_src.htm |
Peter> | 1997  | titan |           | counter | Query   | 39570 | Copying to tmp =
Peter> table | select sum(lt.hits) as val, domip.domip as dom,hex(domip.ip) as =
Peter> ip from layers_st10.g00layers_stat_v |
Peter> | 4443  | titan |           |         | Query   | 32895 | Locked         =
Peter>       | update st10.g00domip set domip=3D'hstna030-0053.splitrock.net', =
Peter> rt=3Drt+1, fldom=3D161 where ip=3D3523193909 |
Peter> | 11461 | pz    | localhost |         | Refresh | 575   | Flushing =
Peter> tables      |                                                            =
Peter>                                           |
Peter> | 11631 | pz    | localhost |         | Query   | 0     |                =
Peter>       | show processlist                                                 =
Peter>                                     |
Peter> +-------+-------+-----------+---------+---------+-------+----------------=
Peter> ------+------------------------------------------------------------------=
Peter> ------------------------------------+
Peter> [pz@geo pz]$=20
Peter> 
Peter> As You see some queries just hanged and even can't be killed.
Peter> Mysqladmin flush-tables also seems to lock-up during this procedure so =
Peter> it seems to be unpleasent.
Peter> I'll try to repeat this but I'm not shure if I'll be able to do so as I =
Peter> run this type of queries for several millions per day and as I remember =
Peter> had the same problem only once before.
Peter> The Tables were checked just yesterday so it should not be because of =
Peter> dammaged once.
Peter> 
Peter> The processes seems to be just locked (not running in a loop and eating =
Peter> a lot of CPU as I have much of idle one).

The only thing I can think of is if you run out of disk space when
this happened.  It's a pity that Linux doesn't have a pstack command,
like on Solaris;  Just getting an 'pstack' when this happend could
help us find what could be the problem :(

It's howwever apparent that the problem is the query:

select sum(lt.hits) as val, domip.domip as dom,hex(domip.ip)...

Just understanding why this hangs could help us a lot into solving this!

Regards,
Monty
Thread
Potential bug in mysql 3.23.14Peter Zaitsev5 May
  • CalendarKevin Waterson5 May
    • Re: Calendarsinisa5 May
  • Re: Potential bug in mysql 3.23.14sinisa5 May
  • Re: CalendarKevin Waterson5 May
    • Re: Calendarsinisa5 May
  • Potential bug in mysql 3.23.14Michael Widenius5 May
    • Re: Potential bug in mysql 3.23.14Dan Nelson5 May