mysql_error:Error starting thread: Resource temporarily unavailable
121031 18:53:17 InnoDB: Unable to open the first data file InnoDB: Error in opening ./ibdata1 121031 18:53:17 InnoDB: Operating system error number 11 in a file operation. InnoDB: Error number 11 means 'Resource temporarily unavailable'. InnoDB: Some operating system error numbers are described at InnoDB: http://dev.mysql.com/doc/refman/5.5/en/operating-system-error-codes.html 121031 18:53:17 InnoDB: Could not open or create data files. 121031 18:53:17 InnoDB: If you tried to add new data files, and it failed here, 121031 18:53:17 InnoDB: you should now edit innodb_data_file_path in my.cnf back 121031 18:53:17 InnoDB: to what it was, and remove the new ibdata files InnoDB created 121031 18:53:17 InnoDB: in this failed attempt. InnoDB only wrote those files full of 121031 18:53:17 InnoDB: zeros, but did not yet use them in any way. But be careful: do not 121031 18:53:17 InnoDB: remove old data files which contain your precious data! 121031 18:53:17 [ERROR] Plugin 'InnoDB' init function returned error. 121031 18:53:17 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 121031 18:53:17 [ERROR] Unknown/unsupported storage engine: INNODB 121031 18:53:17 [ERROR] Aborting 121031 18:53:17 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete 121031 18:53:17 mysqld_safe mysqld from pid file /data/mysql/mysql_3301/mysql_3301.pid ended 121031 18:54:29 mysqld_safe Starting mysqld daemon with databases from /data/mysql/mysql_3301 121031 18:54:29 [Warning] The syntax '--log-slow-queries' is deprecated and will be removed in a future release. Please use '--slow- query-log'/'--slow-query-log-file' instead. 121031 18:54:29 InnoDB: The InnoDB memory heap is disabled 121031 18:54:29 InnoDB: Mutexes and rw_locks use GCC atomic builtins 121031 18:54:29 InnoDB: Compressed tables use zlib 1.2.3 121031 18:54:30 InnoDB: Initializing buffer pool, size = 2.9G 121031 18:54:30 InnoDB: Completed initialization of buffer pool InnoDB: Unable to lock ./ibdata1, error: 11 InnoDB: Check that you do not already have another mysqld process InnoDB: using the same InnoDB data or log files. 121031 18:54:30 InnoDB: Retrying to lock the first data file InnoDB: Unable to lock ./ibdata1, error: 11 InnoDB: Check that you do not already have another mysqld process InnoDB: using the same InnoDB data or log files. 121031 18:54:30 InnoDB: Retrying to lock the first data file InnoDB: Unable to lock ./ibdata1, error: 11 InnoDB: Check that you do not already have another mysqld process InnoDB: using the same InnoDB data or log files. InnoDB: Unable to lock ./ibdata1, error: 11 InnoDB: Check that you do not already have another mysqld process InnoDB: using the same InnoDB data or log files. InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Error number 11 means 'Resource temporarily unavailable'.
Error starting thread: Resource temporarily unavailable
经过深入查询，排除了内存，句柄数等问题. 并且切换至root用户打开大量线程时没有问题。试着调整ulimit各项参数,最后发现是"max user processes "参数有问题，通过root用户调整大小至 12000,线程数也随着增大.
Java代码
root@blog:/home/badqiu# ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 143360
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 2048
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 2046
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
在linux系统内生效。
vi /etc/security/limits.conf
Java代码
* soft nproc 12000
* hard nproc 12000
nproc就是"max user processes"，完整描述是: nproc - max number of processes
参数含义:
单个用户可以启动的线程数，因为进程也会启动一个线程，所以也间接对进程数有限制。
注意：
该参数只对普通用户有用，root用户不在此限制。 所以用root用户可以启动几万个线程，无法重现这个问题.