>Description:
I started using BDB tables in a php program with mysql-3.23.36 that comes with
redhat7.1.
The php program uses a database of 3 myISAM tables to read the schema of the
BDB tables and dynamicaly
generate select/update/insert queries on the BDB tables. The BDB tables form
another database.
The concept of a transaction is important to my app because the number of
queries and the number of tables
to be modified during a particular transaction is not easy to calculate. It is
obtained from the result of
the queries to the myISAM tables. If for some reason, one query cannot be
fulfilled, all queries of the transaction
are undone by calling ROLLBACK. The transaction model makes my app much
simlper and more flexible.
It is important to state that some data is inserted into the database without
transactions. This occurs when
"humans" are populating the database by using graphical mysql clients
(phpMyAdmin).
The app is finished but because of the problems experienced has still not
been put in the production environment.
What happens is that mysqld crashes ,almost always bringing down the server
when I was using 3.23.36 .
After I installed 3.23.42 and then 3.23.46 the server does not usually come
down but mysql.log shows that
one of the mysqld threads crashed, prints a backtrace and then resumes
operations. The problem was much more
frequent with 3.23.36 than it is with 3.23.42 and 3.23.46. In the newer
versions it still happens once/twice every two days.
This does not usually happen when I am testing/programing the app and
therefore gerating a lot
of transactions but during moments when other users are just browsing the app
and therefore generating
mainly selects. I have dificulty reproducing the test because of this.
It is interesting to note that the query that usually crashes the server is of
the form
select tblRelac.id as id from tblRelac where tblRelac.classL = 'page' and
tblRelac.idL = '33' and tblRelac.prior > '0' order by tblRelac.prior
and I really cant remember it happening on a table diferent than tblRelac. THe
app has some 20 tables. There is nothing special
about table relac expcept that it is used alot.
After restarting the server (3.23.36) or running [ mysqladmin shutdown ;
service mysqld start ] (3.23.46) things start working again.
I have never experienced data corruption.
An interesting thing that happens is that the above query always fails after
the crash but before the restart with the message
No Records Found
This is wrong, the query should at least return one row.
When I run
Select * from tblRelac ;
the query returns correctly all the rows in the database correctly
After restarting , all is normal.
This suggests to me that the problem could be on an index for the table or on
index code.
It also suggests that the problem is in memory, because after the restart,
everything comes back normally.
I have put on the end of this email, tblRelac's schema alogn with the
backtrace and other error messages.
It seems to me that the offending code is run in
berkeley_cmp_packed_key__FP4__dbPC8__db_dbtT1 + 118
Thank you,
Miguel Feitosa
>How-To-Repeat:
I dont know.
I added --log to my server now.
>Fix:
I dont know
>Submitter-Id: <submitter ID>
>Originator: root
>Organization:
VMN Consulting - Sao Paulo - Brasil
>MySQL support: none
>Synopsis: mysqld crash with BDB
>Severity: serious
>Priority: high
>Category: mysql
>Class: sw-bug
>Release: mysql-3.23.36 (Source distribution)
>Server: /usr/bin/mysqladmin Ver 8.18 Distrib 3.23.36, for redhat-linux-gnu
on i386
Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL license
Server version 3.23.46
Protocol version 10
Connection Localhost via UNIX socket
UNIX socket /var/lib/mysql/mysql.sock
Uptime: 29 min 44 sec
Threads: 27 Questions: 52530 Slow queries: 0 Opens: 72 Flush tables: 1
Open tables: 64 Queries per second avg: 29.445
>Environment:
<machine, os, target, libraries (multiple lines)>
System: Linux diadorim.vmn.com.br 2.4.9-12 #1 Tue Oct 30 18:33:49 EST 2001
i686 unknown
Architecture: i686
Some paths: /usr/bin/perl /usr/bin/make /usr/bin/gmake /usr/bin/gcc
/usr/bin/cc
GCC: Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs
gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-85)
Compilation info: CC='gcc' CFLAGS='-O2 -march=i386 -mcpu=i686' CXX='c++'
CXXFLAGS='-O2 -march=i386 -mcpu=i686' LDFLAGS=''
LIBC:
lrwxrwxrwx 1 root root 13 Nov 29 19:02 /lib/libc.so.6 ->
libc-2.2.4.so
-rwxr-xr-x 2 root root 1283580 Oct 3 15:10 /lib/libc-2.2.4.so
-rw-r--r-- 1 root root 27314604 Oct 3 14:52 /usr/lib/libc.a
-rw-r--r-- 1 root root 178 Oct 3 14:52 /usr/lib/libc.so
Configure command: ./configure i386-redhat-linux --prefix=/usr
--exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
--datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib
--libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/usr/com
--mandir=/usr/share/man --infodir=/usr/share/info --without-debug
--without-readline --enable-shared --with-extra-charsets=complex --with-bench
--localstatedir=/var/lib/mysql
--with-unix-socket-path=/var/lib/mysql/mysql.sock --with-mysqld-user=mysql
--with-extra-charsets=all --with-berkeley-db
To install 3.23.46, I recompiled mysqld from source with
#!/bin/bash
rm -f config.cache; ./configure --prefix=/usr/local/mysql --with-innodb
--with-berkeley-db --with-low-memory --with-mysqld-user=mysql && make clean
&& make && make install
#--enable-static
After the recompile, I copied mysqld to /usr/libexec
Schema of tblRelac
I DROP TABLE IF EXISTS tblRelac;
CREATE TABLE tblRelac (
id int(11) auto_increment PRIMARY KEY,
classL varchar(200) NOT NULL default '',
classR varchar(200) NOT NULL default '',
idL int(11) NOT NULL DEFAULT 0,
idR int(11) NOT NULL DEFAULT 0,
prior int(11) NOT NULL DEFAULT 0,
KEY classL_key (classL),
KEY classR_key (classR),
KEY idL_key (idL),
KEY idR_key (idR),
KEY prior_key (prior),
altera timestamp(14) NOT NULL
)TYPE=BDB;
Note: prior is usually 1
BackTrace
0x80be116 handle_segfault__Fi + 406
0x40029a85 _end + 936416829
0x810139a berkeley_cmp_packed_key__FP4__dbPC8__db_dbtT1 + 118
0x814e8dc __bam_cmp + 148
0x8192802 __bam_search + 886
0x818834d __bam_c_search + 1633
0x8185eb1 __bam_c_get + 1305
0x81626a8 __db_c_get + 840
0x815e7b3 __db_get + 323
0x8103e68 rnd_pos__11ha_berkeleyPcT1 + 216
0x80fad58 rr_from_pointers__FP14st_read_record + 52
0x80e27bf join_init_read_record__FP13st_join_table + 75
0x80dd9ea sub_select__FP4JOINP13st_join_tableb + 78
0x80dd79d do_select__FP4JOINPt4List1Z4ItemP8st_tableP9Procedure + 393
0x80d6bc6
mysql_select__FP3THDP13st_table_listRt4List1Z4ItemP4ItemP8st_orderT4T3T4UiP13select_result
+ 7170
0x80c47c5 mysql_execute_command__Fv + 733
0x80c762f mysql_parse__FP3THDPcUi + 211
0x80c3c46 do_command__FP3THD + 1286
0x80c316c handle_one_connection__FPv + 608
--------------------Another stack trace
Query
select tblRelac.id as id from tblRelac where tblRelac.classL = 'page' and
tblRelac.idL = '31' and tblRelac.prior > '0' order by tblRelac.prior
StackTrace
0x80bdfc2 handle_segfault__Fi + 406
0x4004c935 _end + 936562381
0x810107c berkeley_cmp_packed_key__FP4__dbPC8__db_dbtT1 + 72
0x814e4ac __bam_cmp + 148
0x81923d2 __bam_search + 886
0x8187f1d __bam_c_search + 1633
0x8185a81 __bam_c_get + 1305
0x8162278 __db_c_get + 840
0x815e383 __db_get + 323
0x8103b59 rnd_pos__11ha_berkeleyPcT1 + 213
0x80faad9 rr_from_pointers__FP14st_read_record + 49
0x80e25db join_init_read_record__FP13st_join_table + 75
0x80dd8d2 sub_select__FP4JOINP13st_join_tableb + 78
0x80dd685 do_select__FP4JOINPt4List1Z4ItemP8st_tableP9Procedure + 393
0x80d6a6e
mysql_select__FP3THDP13st_table_listRt4List1Z4ItemP4ItemRt4List1Z15Item_func_matchP8st_orderT5T3T5UiP13select_result
+ 7278
0x80c4673 mysql_execute_command__Fv + 735
0x80c74e3 mysql_parse__FP3THDPcUi + 211
0x80c3af2 do_command__FP3THD + 1286
0x80c3018 handle_one_connection__FPv + 608
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