Redis中怎么实现慢查询操作

Redis中怎么实现慢查询操作，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

什么是慢查询

和mysql的慢SQL日志分析一样，redis也有类似的功能，来帮助定位一些慢查询操作。

Redis slowlog是Redis用来记录查询执行时间的日志系统。

查询执行时间指的是不包括像客户端响应(talking)、发送回复等IO操作，而单单是执行一个查询命令所耗费的时间。

另外，slow log保存在内存里面，读写速度非常快，因此你可以放心地使用它，不必担心因为开启slow log而损害Redis的速度。

慢查询参数

首先来关注下慢日志分析对应的两个参数：

1、slowlog-log-slower-than：预设阀值，即记录超过多少时间的记录，默认为10000微秒，即10毫秒。

2、slowlog-max-len：记录慢查询的条数，默认为128条，当超过设置的条数时最早进入队列的将被移除。线上建议增大数值，如：1000，这样可减少队列移除的频率。

127.0.0.1:6379> config get slowlog-log-slower-than  1) "slowlog-log-slower-than"  2) "10000"  127.0.0.1:6379> config get slowlog-max-len  1) "slowlog-max-len"  2) "128"

可以用config set对这两个参数进行调整，或者在配置文件中设置。

################################## SLOW LOG ###################################  # The Redis Slow Log is a system to log queries that exceeded a specified  # execution time. The execution time does not include the I/O operations  # like talking with the client, sending the reply and so forth,  # but just the time needed to actually execute the command (this is the only  # stage of command execution where the thread is blocked and can not serve  # other requests in the meantime). #  # You can configure the slow log with two parameters: one tells Redis  # what is the execution time, in microseconds, to exceed in order for the  # command to get logged, and the other parameter is the length of the  # slow log. When a new command is logged the oldest one is removed from the  # queue of logged commands.   # The following time is expressed in microseconds, so 1000000 is equivalent  # to one second. Note that a negative number disables the slow log, while  # a value of zero forces the logging of every command.  slowlog-log-slower-than 10000   # There is no limit to this length. Just be aware that it will consume memory.  # You can reclaim memory used by the slow log with SLOWLOG RESET.  slowlog-max-len 128

慢查询命令

语法：slowlog subcommand [argument]

如，进行查询慢查询、获取慢查询记录的数量、重置慢查询日志等操作：

192.168.10.38:9001> slowlog get  (empty list or set)  192.168.10.38:9001> slowlog get 10  (empty list or set)  192.168.10.38:9001> slowlog len   (integer) 0  192.168.10.38:9001> slowlog reset  OK

看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注行业资讯频道，感谢您对的支持。