MySQL InnoDB 崩溃事后分析

如何解决MySQL InnoDB 崩溃事后分析

我有好消息，也有坏消息。好消息是，您的文件系统和 mysql 很可能没问题……但请检查 /var/log/syslog 或等效项，以查看 10:21:05 之前系统上发生的其他情况。

当您发布的第一条消息被记录时，您的 mysql 服务器已经死了。

120927 10:21:05 mysqld_safe Number of processes running now: 0

所以，假设你没有忽略 mysql 错误日志中的任何内容，我会说它没有崩溃和死亡——它实际上被杀死了。

当 mysqld_safe （它是一个包装器，而不是服务器本身）意识到服务器没有运行，并且服务器没有正常终止时，它会为你重新启动它......

120927 10:21:06 mysqld_safe mysqld restarted

…然后服务器守护进程记录了一些正常的启动消息…

120927 10:21:12 [Note] Plugin 'FEDERATED' is disabled.
120927 10:21:12 InnoDB: The InnoDB memory heap is disabled
120927 10:21:12 InnoDB: Mutexes and rw_locks use GCC atomic builtins
120927 10:21:12 InnoDB: Compressed tables use zlib 1.2.3
120927 10:21:12 InnoDB: Using Linux native AIO

…但是当 mysqld 要求操作系统为 InnoDB 缓冲池分配 4GB 内存时…

120927 10:21:13 InnoDB: Initializing buffer pool, size = 4.0G

…内核说“不”。

InnoDB: mmap(4395630592 bytes) failed; errno 12

检查内核源代码以确保：

#define ENOMEM      12  /* Out of memory */

是的。因此，应该忽略“失败；errno 12”行下方的每条消息——它们都是这条消息的副作用。

但同样，所有这些事情都发生在第一次崩溃之后。

我最好的猜测是，极低的内存条件导致您的内核最初杀死 mysqld 以试图稳定系统。

自然，导致内存不足的任何原因在重新启动后都消失了。mysql 服务器能够为 InnoDB 缓冲池分配 4GB，并且一切都应该很好，直到导致内存不足的原因再次导致它。

第一个猜测：apache 子进程运行异常。

解决方法

MySQL今天早上在我身上崩溃了。

除了标准的 MySQL 包含的数据库之外，我使用的一切都是 InnoDB。

我试图重新启动 MySQL 守护程序，但它失败了两次。

然后我重新启动了整个服务器，MySQL 正确启动并且从那以后一直运行良好。

初始崩溃的 mysqld 日志文件包含以下内容：

120927 10:21:05 mysqld_safe Number of processes running now: 0
120927 10:21:06 mysqld_safe mysqld restarted
120927 10:21:12 [Note] Plugin 'FEDERATED' is disabled.
120927 10:21:12 InnoDB: The InnoDB memory heap is disabled
120927 10:21:12 InnoDB: Mutexes and rw_locks use GCC atomic builtins
120927 10:21:12 InnoDB: Compressed tables use zlib 1.2.3
120927 10:21:12 InnoDB: Using Linux native AIO
120927 10:21:13 InnoDB: Initializing buffer pool,size = 4.0G
InnoDB: mmap(4395630592 bytes) failed; errno 12
120927 10:21:13 InnoDB: Completed initialization of buffer pool
120927 10:21:13 InnoDB: Fatal error: cannot allocate memory for the buffer pool
120927 10:21:13 [ERROR] Plugin 'InnoDB' init function returned error.
120927 10:21:13 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120927 10:21:13 [ERROR] Unknown/unsupported storage engine: InnoDB
120927 10:21:13 [ERROR] Aborting

120927 10:21:13 [Note] /usr/libexec/mysqld: Shutdown complete

120927 10:21:13 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

尝试重新启动守护程序时，mysqld 日志文件包含：

120927 10:43:44 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120927 10:43:44 [Note] Plugin 'FEDERATED' is disabled.
120927 10:43:44 InnoDB: The InnoDB memory heap is disabled
120927 10:43:44 InnoDB: Mutexes and rw_locks use GCC atomic builtins
120927 10:43:44 InnoDB: Compressed tables use zlib 1.2.3
120927 10:43:44 InnoDB: Using Linux native AIO
120927 10:43:44 InnoDB: Initializing buffer pool,size = 4.0G
InnoDB: mmap(4395630592 bytes) failed; errno 12
120927 10:43:44 InnoDB: Completed initialization of buffer pool
120927 10:43:44 InnoDB: Fatal error: cannot allocate memory for the buffer pool
120927 10:43:44 [ERROR] Plugin 'InnoDB' init function returned error.
120927 10:43:44 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120927 10:43:44 [ERROR] Unknown/unsupported storage engine: InnoDB
120927 10:43:44 [ERROR] Aborting

120927 10:43:44 [Note] /usr/libexec/mysqld: Shutdown complete

120927 10:43:44 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

服务器重新启动后，mysqld 日志文件包含：

120927 10:46:11 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120927 10:46:11 [Note] Plugin 'FEDERATED' is disabled.
120927 10:46:11 InnoDB: The InnoDB memory heap is disabled
120927 10:46:11 InnoDB: Mutexes and rw_locks use GCC atomic builtins
120927 10:46:11 InnoDB: Compressed tables use zlib 1.2.3
120927 10:46:11 InnoDB: Using Linux native AIO
120927 10:46:11 InnoDB: Initializing buffer pool,size = 4.0G
120927 10:46:11 InnoDB: Completed initialization of buffer pool
120927 10:46:12 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
120927 10:46:12  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
120927 10:46:15  InnoDB: Waiting for the background threads to start
120927 10:46:16 InnoDB: 1.1.8 started; log sequence number 57665645675
120927 10:46:16 [Note] Event Scheduler: Loaded 0 events
120927 10:46:16 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.21-cll'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MySQL Community Server (GPL) by Atomicorp

我从来没有尝试解密崩溃的 MySQL 日志文件。

我正在使用版本：5.5.21-cll MySQL Community Server (GPL) by Atomicorp

关于我应该从哪里开始的任何想法？

更新：根据@Michael-sqlbot 的建议，我提取了系统日志并发现了这一点：

Sep 27 10:20:58 ip-97-74-197-181 kernel: pcscd invoked oom-killer: gfp_mask=0xd0,order=0,oomkilladj=0
Sep 27 10:21:00 ip-97-74-197-181 kernel:
Sep 27 10:21:00 ip-97-74-197-181 kernel: Call Trace:
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff800c9f35>] out_of_memory+0x8e/0x2f3
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8002dfc7>] __wake_up+0x38/0x4f
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8000f67d>] __alloc_pages+0x27f/0x308
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff80017a84>] cache_grow+0x139/0x3c7
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8005be28>] cache_alloc_refill+0x138/0x188
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8000ad2e>] kmem_cache_alloc+0x6c/0x76
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff80012877>] getname+0x25/0x1c2
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8001a04b>] do_sys_open+0x17/0xbe
Sep 27 10:21:00 ip-97-74-197-181 kernel:  [<ffffffff8005d28d>] tracesys+0xd5/0xe0
Sep 27 10:21:00 ip-97-74-197-181 kernel:
Sep 27 10:21:11 ip-97-74-197-181 kernel: Mem-info:
Sep 27 10:21:20 ip-97-74-197-181 kernel: Node 0 DMA per-cpu:
Sep 27 10:21:27 ip-97-74-197-181 kernel: cpu 0 hot: high 0,batch 1 used:0
Sep 27 10:21:38 ip-97-74-197-181 kernel: cpu 0 cold: high 0,batch 1 used:0
Sep 27 10:21:49 ip-97-74-197-181 kernel: cpu 1 hot: high 0,batch 1 used:0
Sep 27 10:21:49 ip-97-74-197-181 kernel: cpu 1 cold: high 0,batch 1 used:0
Sep 27 10:21:49 ip-97-74-197-181 kernel: cpu 2 hot: high 0,batch 1 used:0
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 2 cold: high 0,batch 1 used:0
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 hot: high 0,batch 1 used:0
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 cold: high 0,batch 1 used:0
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 DMA32 per-cpu:
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 0 hot: high 186,batch 31 used:60
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 0 cold: high 62,batch 15 used:57
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 1 hot: high 186,batch 31 used:139
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 1 cold: high 62,batch 15 used:61
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 2 hot: high 186,batch 31 used:47
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 2 cold: high 62,batch 15 used:57
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 hot: high 186,batch 31 used:52
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 cold: high 62,batch 15 used:53
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 Normal per-cpu:
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 0 hot: high 186,batch 31 used:29
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 0 cold: high 62,batch 15 used:17
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 1 hot: high 186,batch 31 used:178
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 1 cold: high 62,batch 15 used:52
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 2 hot: high 186,batch 31 used:22
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 2 cold: high 62,batch 15 used:59
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 hot: high 186,batch 31 used:71
Sep 27 10:21:52 ip-97-74-197-181 kernel: cpu 3 cold: high 62,batch 15 used:54
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 HighMem per-cpu: empty
Sep 27 10:21:52 ip-97-74-197-181 kernel: Free pages:       41728kB (0kB HighMem)
Sep 27 10:21:52 ip-97-74-197-181 kernel: Active:1031140 inactive:970428 dirty:0 writeback:0 unstable:0 free:10432 slab:4277 mapped-file:801 mapped-anon:1993003 pagetables:11636
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 DMA free:10096kB min:12kB low:12kB high:16kB active:0kB inactive:0kB present:9700kB pages_scanned:0 all_unreclaimable? yes
Sep 27 10:21:52 ip-97-74-197-181 kernel: lowmem_reserve[]: 0 2965 8015 8015
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 DMA32 free:24424kB min:4236kB low:5292kB high:6352kB active:1544164kB inactive:1428756kB present:3037024kB pages_scanned:7185900 all_unreclaimable? yes
Sep 27 10:21:52 ip-97-74-197-181 kernel: lowmem_reserve[]: 0 0 5050 5050
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 Normal free:7208kB min:7212kB low:9012kB high:10816kB active:2580172kB inactive:2453052kB present:5171200kB pages_scanned:12935183 all_unreclaimable? yes
Sep 27 10:21:52 ip-97-74-197-181 kernel: lowmem_reserve[]: 0 0 0 0
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 HighMem free:0kB min:128kB low:128kB high:128kB active:0kB inactive:0kB present:0kB pages_scanned:0 all_unreclaimable? no
Sep 27 10:21:52 ip-97-74-197-181 kernel: lowmem_reserve[]: 0 0 0 0
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 DMA: 6*4kB 3*8kB 4*16kB 4*32kB 4*64kB 5*128kB 1*256kB 1*512kB 0*1024kB 0*2048kB 2*4096kB = 10096kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 DMA32: 24*4kB 3*8kB 1*16kB 1*32kB 1*64kB 3*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 5*4096kB = 24424kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 Normal: 0*4kB 13*8kB 8*16kB 0*32kB 19*64kB 1*128kB 2*256kB 0*512kB 1*1024kB 0*2048kB 1*4096kB = 7208kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: Node 0 HighMem: empty
Sep 27 10:21:52 ip-97-74-197-181 kernel: 9391 pagecache pages
Sep 27 10:21:52 ip-97-74-197-181 kernel: Swap cache: add 5745145,delete 5744809,find 81873079/82270945,race 0+63
Sep 27 10:21:52 ip-97-74-197-181 kernel: Free swap  = 0kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: Total swap = 2096472kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: Free swap:            0kB
Sep 27 10:21:52 ip-97-74-197-181 kernel: 2359296 pages of RAM
Sep 27 10:21:52 ip-97-74-197-181 kernel: 324458 reserved pages
Sep 27 10:21:52 ip-97-74-197-181 kernel: 21388 pages shared
Sep 27 10:21:52 ip-97-74-197-181 kernel: 336 pages swap cached
Sep 27 10:21:52 ip-97-74-197-181 kernel: Out of memory: Killed process 3044,UID 27,(mysqld).