Identifying slow queries using the SLOWLOG
When there are performance issues in Redis, for example, queries to Redis get timed out frequently, we may want to check why Redis is not able to serve a query request in a timely fashion. One possible reason is that there are some queries or operations that take a very long time to complete.
In this recipe, we will introduce how to use the Redis SLOWLOG feature to identify slow queries or operations.
Getting ready…
You need to finish the installation of the Redis Server as we described in the Downloading and installing Redis recipe in Chapter 1, Getting Started with Redis.
How to do it...
- For the purpose of demonstration, let's set
slowlog-log-slower-thanto a very small value:
127.0.0.1:6379> CONFIG SET slowlog-log-slower-than 5 - Execute a couple of test commands:
127.0.0.1:6379> SET foo bar
OK
127.0.0.1:6379> HGETALL bighash
...
127.0.0.1:6379> HMSET new_hash aaa bbb ccc ddd eee fff
OK - To read all slow logs, use
SLOWLOG GET:
127.0.0.1:6379...
