今天早上我们发布了MySQL版本，该应用程序没有从数据库中获取响应，而是开始出现问题。
以下是我可以在日志中找到的内容，有人可以向我解释MySQL上发生了什么以及如何避免再次发生此事件吗？，我们之前或之后没有其他日志条目，我看不到当时正在运行什么。
Nov 27 07:44:34 mysqld[19527]: Aborted connection 1271090 to db: 'information_schema' user: 'cmon' host: '' (Got an error reading communication packets)
Nov 27 07:46:55 mysqld[19527]: InnoDB: page_cleaner: 1000ms intended loop took 15077ms. The settings might not be optimal. (flushed=923, during the time.)
Nov 27 07:47:16 mysqld[19527]: InnoDB: page_cleaner: 1000ms intended loop took 19703ms. The settings might not be optimal. (flushed=868, during the time.)
Nov 27 07:48:35 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:49:06 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:49:06 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:49:37 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:49:37 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:50:08 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:50:08 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:50:39 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:50:39 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:51:10 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:51:10 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:51:41 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:51:41 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:51:41 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:12 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:12 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:12 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:43 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:43 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:52:43 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:14 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:14 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:14 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:14 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:45 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:45 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:45 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:53:45 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:16 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:16 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:16 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:16 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:47 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:47 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:47 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:54:47 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 07:55:04 mysqld[19527]: Aborted connection 1449537 to db: 'information_schema' user: 'cmon' host: '' (Got an error reading communication packets)
Nov 27 07:55:04 mysqld[19527]: Aborted connection 1450163 to db: 'information_schema' user: 'cmon' host: '' (Got an error reading communication packets)
Nov 27 07:55:15 mysqld[19527]: InnoDB: page_cleaner: 1000ms intended loop took 4665ms. The settings might not be optimal. (flushed=1009, during the time.)
Nov 27 07:58:00 mysqld[19527]: InnoDB: page_cleaner: 1000ms intended loop took 160462ms. The settings might not be optimal. (flushed=708, during the time.)
Nov 27 08:02:01 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 08:02:32 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 08:02:32 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 08:02:32 mysqld[19527]: InnoDB: A long semaphore wait:
Nov 27 08:02:54 mysqld[19527]: Aborted connection 1450788 to db: 'information_schema' user: 'cmon' host: '' (Got an error reading communication packets)
Nov 27 08:02:54 mysqld[19527]: InnoDB: page_cleaner: 1000ms intended loop took 290741ms. The settings might not be optimal. (flushed=650, during the time.)
答案 0 :(得分：0)
此可以解决“ page_cleaner”的问题：降低此水平：
lru_scan_depth = 50