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From:tcobb Date:June 28 1999 10:20am
Subject:RE: Re[2]: mysqld (3.22.23b) dumps core (segmentation violation)
under h igh load after upgrading to FreeBSD 3.2
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>   tscn> We've recently been seeing this on other FreeBSD 3.2 
>   systems, also.
>   tscn> After tracking it down for a while, it is definitely a problem
>   tscn> in the FreeBSD 3.2 libc_r.so, and namely appears to be
>   tscn> caused by some changes in thread priority handling in that
>   tscn> library between 3.1 and 3.2.
>   
>   So this is FreeBSD bug?  Have you notified them about it?

Yes, it appears to be a FreeBSD bug.  We just discovered it last
Friday, so I have not yet notified them of it.  It is rather difficult
to reproduce except under quite heavy load.
   
>   tscn> Most, but not quite all, of the queries causing our 
>   sig 11s were 
>   tscn> also using unix_timestamp calls, and failing in a thread_mutex
>   tscn> call (after localtime_r) in libc_r.
>   
>   What would be you recommendations for now?  Shell I downgrade to
>   FreeBSD 3.1 or build static mysql on FreeBSD 3.1 and run it 
>   on 3.2? Any
>   advise would be very appreciated!

We worked around the problem by using a static mysqld built on 3.1.
That worked quite well.


-Troy Cobb
 Circle Net, Inc.
 http://www.circle.net
   
>   Sergey Gershtein
>   
>   
>   tscn> -Troy Cobb
>   tscn>  Circle Net, Inc.
>   tscn>  http://www.circle.net
>   
>   >>   -----Original Message-----
>   >>   From: Sergey Gershtein [mailto:sg@stripped]
>   >>   Sent: Monday, June 28, 1999 2:58 AM
>   >>   To: mysql@stripped
>   >>   Subject: mysqld (3.22.23b) dumps core (segmentation 
>   violation) under
>   >>   high load after upgrading to FreeBSD 3.2
>   >>   
>   >>   
>   >>   >Description:
>   >>   
>   >>   I've been using mysql for a long time and it used to work very
>   >>   stable until lately. Recently after uprgading from 
>   FreeBSD 3.1 to
>   >>   FreeBSD 3.2 mysqld started dumping core regularly with 
>   signal 11
>   >>   (segmentation violation) at moments of high load. There seems
>   >>   to be no particular query that is garanteed to kills 
>   >>   mysqld, although
>   >>   it often (but not always) dies during the query 
>   specified below.
>   >>   
>   >>   The specifics of usage is that mysql gets a lot of 
>   'replace delayed'
>   >>   queries (up to 7-10 queries a second) on one table 
>   while different
>   >>   selects are done on other tables. Till the very death mysql
>   >>   performs very well, giving fast answers and taking 
>   only 1-3% of cpu
>   >>   load. The death itself is instant and unpredictable.  There is
>   >>   nothing left in any log files about it.
>   >>   
>   >>   All connetions to mysql are done from perl scripts via
>   >>   Msql-Mysql-modules-1.2014 using dynamic link library
>   >>   libmysqlclient.so.6.0
>   >>   
>   >>   I tried to compile mysql with --with-debug, but I was 
>   unable to get
>   >>   it working. The daemon would start and accept connections, but
>   >>   would not reply to any queries, including even 'mysqladmin 
>   >>   status' or
>   >>   'mysqladmin version'.
>   >>           
>   >>   >How-To-Repeat:
>   >>   
>   >>   Here is the query that most often kills mysql. This query 
>   >>   is executed
>   >>   repeatedly in a program and the table 'urlcheck' is 
>   modified between
>   >>   the queries. Usually the query succiedes several times 
>   (3 to 10) and
>   >>   then mysql server dies during this query.
>   >>   
>   >>       select
>   >>               id,
>   >>               min(unix_timestamp(now())-
>   >>               
>   unix_timestamp(ifnull(checktime,'1980-01-01 00:00:00')))
>   >>               as dtime
>   >>       from
>   >>               resource left join urlcheck on id=res_id
>   >>       where
>   >>               include = '1'
>   >>       group by id
>   >>       order by dtime desc
>   >>       limit 1
>   >>   
>   >>   Here's the structures of the tables mentioned:
>   >>   
>   >>       create table urlcheck (
>   >>               res_id    integer not null,
>   >>               checktime timestamp not null,
>   >>               time_win  integer,
>   >>               time_koi  integer,
>   >>               time_eng  integer,
>   >>               err_win   integer,
>   >>               err_koi   integer,
>   >>               err_eng   integer,
>   >>               index index_res_id( res_id ),
>   >>               index index_checktime( checktime )
>   >>       );
>   >>       
>   >>   create table resource (
>   >>       id        integer not null auto_increment primary key,
>   >>       login     char[20] not null,
>   >>       url_win   varchar(200),
>   >>       url_koi   varchar(200),
>   >>       url_eng   varchar(200),
>   >>       title     varchar(80) not null,
>   >>       keywords  text,
>   >>       description text,
>   >>       cmt_user  text,
>   >>       email     varchar(80),
>   >>           person    varchar(80),
>   >>           phone     varchar(80),
>   >>           host          varchar(80),
>   >>           street    text,
>   >>           city      varchar(80),
>   >>           region        enum( 'svrd','perm','chel','oren',
>   >>                           'kurg','tumn','other','-') not null 
>   >>   default '-',
>   >>           country   varchar(80),
>   >>           regdate       date not null,
>   >>           apprdate  date,
>   >>           apprby        varchar(30),
>   >>           include   enum("0","1","-") not null,
>   >>           cmt_admin text,
>   >>           index idx_include( include ),
>   >>           unique idx_login( login ),
>   >>           index idx_region( region )
>   >>   );
>   >>   
>   >>   
>   >>   >Fix:
>   >>   
>   >>       Unknown
>   >>       
>   >>   >Submitter-Id:      <submitter ID>
>   >>   >Originator:        Sergey Gershtein <sg@stripped>
>   >>   >Organization:  Ural Relcom Ltd, Ekaterinburg, Russia
>   >>   >MySQL support: none
>   >>   >Synopsis:      mysqld dump core (segmentation violation) 
>   >>   under high load after upgrade to FreeBSD 3.2
>   >>   >Severity:  serious
>   >>   >Priority:  high
>   >>   >Category:  mysql
>   >>   >Class:             sw-bug
>   >>   >Release:   mysql-3.22.23b (Source distribution)
>   >>   
>   >>   >Environment:
>   >>   System: FreeBSD dream.mplik.ru 3.2-STABLE FreeBSD 
>   >>   3.2-STABLE #1: Thu Jun 24 14:55:03 YEKST 1999     
>   >>   sg@stripped:/usr/src/sys/compile/DREAM  i386
>   >>   Some paths:  /usr/bin/perl /usr/bin/make 
>   >>   /usr/local/bin/gmake /usr/bin/gcc /usr/bin/cc
>   >>   GCC: gcc version 2.7.2.1
>   >>   Compilation info: CC='gcc'  CFLAGS='-O6 -m486 
>   >>   -D_THREAD_SAFE'  CXX='gcc'  CXXFLAGS='-O6 -m486 
>   >>   -D_THREAD_SAFE'  LDFLAGS=''
>   >>   Perl: This is perl, version 5.005_02 built for i386-freebsd
>   >>   Configure command:
>   >>               ./configure --prefix=/usr/servers/mysql-3.22.23b \
>   >>               --localstatedir=/usr/servers/mysql-3.22.23b/data \
>   >>               
>   --with-unix-socket-path=/usr/servers/mysql/mysql.sock \
>   >>               --without-bench \
>   >>               --without-perl \
>   >>               --with-charset=koi8_ru \
>   >>               --with-make=gmake \
>   >>               --without-debug \
>   >>               --without-readline \
>   >>               --with-mit-threads=no
>   >>   
>   >>   ------------------------------------------------------------
>   >>   ---------
>   >>   Please check 
>   >>   >   "http://www.mysql.com/Manual_chapter/manual_toc.ht>   ml" 
>   >>   
>   >>   before
>   >>   posting. To request this thread, e-mail 
>   >>   mysql-thread6033@stripped
>   >>   
>   >>   To unsubscribe, send a message to the address shown in the
>   >>   List-Unsubscribe header of this message. If you cannot see it,
>   >>   e-mail mysql-unsubscribe@stripped instead.
>   >>   
>   
>   
Thread
RE: Re[2]: mysqld (3.22.23b) dumps core (segmentation violation) under h igh load after upgrading to FreeBSD 3.2tcobb28 Jun
  • Re: mysqld (3.22.23b) dumps core (segmentation violation) under h igh load after upgrading to FreeBSD 3.2Dan Nelson29 Jun