I had occurred many times, error like this:
140427 14:11:04 InnoDB: Assertion failure in thread 139751980574464 in file row0sel.c line 4619
InnoDB: Failing assertion: trx->isolation_level == TRX_ISO_READ_UNCOMMITTED
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: [url]http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html[/url]
InnoDB: about forcing recovery.
06:11:04 UTC - mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.
key_buffer_size=33554432
read_buffer_size=131072
max_used_connections=540
max_threads=2000
thread_count=193
connection_count=193
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 4409252 K bytes of memory
Hope that’s ok; if not, decrease some variables in the equation.
Thread pointer: 0x5796d0a0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong…
stack_bottom = 7f1a8b289e60 thread_stack 0x40000
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(my_print_stacktrace+0x35)[0x7d3d45]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(handle_fatal_signal+0x3e1)[0x68fdf1]
/lib64/libpthread.so.0[0x32d260f500]
/lib64/libc.so.6(gsignal+0x35)[0x32d22328a5]
/lib64/libc.so.6(abort+0x175)[0x32d2234085]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x80e0ca]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x7e17bb]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x7e17bb]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_ZN7handler18index_read_idx_mapEPhjPKhm16ha_rkey_function+0x71)[0x690891]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x59f49b]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x5aa82e]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x5ae3a5]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_ZN4JOIN8optimizeEv+0x55d)[0x5b133d]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0xd2)[0x5bb472]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x1ce)[0x5bbeae]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld[0x57905d]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z21mysql_execute_commandP3THD+0x2cde)[0x57c20e]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x3c3)[0x57f9c3]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x14a1)[0x580e81]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z10do_commandP3THD+0x106)[0x581216]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(_Z24do_handle_one_connectionP3THD+0x111)[0x61c611]
/usr/local/Percona-Server-5.5.21-rel25.1-234.Linux.x86_64/bin/mysqld(handle_one_connection+0x54)[0x61c704]
/lib64/libpthread.so.0[0x32d2607851]
/lib64/libc.so.6(clone+0x6d)[0x32d22e890d]