View Redis slow log
On the Databases > Slowlog page, you can view Slow Log details for Redis Enterprise Software databases.
Redis Slow Log is one of the best tools for debugging and tracing your Redis database, especially if you experience high latency and high CPU usage with Redis operations. Because Redis is based on a single threaded architecture, Redis Slow Log can be much more useful than slow log mechanisms of multi-threaded database systems such as MySQL Slow Query Log.
Unlike tools that introduce lock overhead (which complicates the debugging process), Redis Slow Log is highly effective at showing the actual processing time of each command.
Redis Enterprise Software includes enhancements to the standard Redis Slow Log capabilities that allow you to analyze the execution time complexity of each command. This enhancement can help you better analyze Redis operations, allowing you to compare the differences between execution times of the same command, observe spikes in CPU usage, and more.
This is especially useful with complex commands such as ZUNIONSTORE, ZINTERSTORE and ZRANGEBYSCORE.
The enhanced Redis Enterprise Software Slow Log adds the Complexity info field to the output data.
View the complexity info data by its respective command in the table below:
| Command | Value of interest | Complexity |
|---|---|---|
| LINSERT | N - list len | O(N) |
| LREM | N - list len | O(N) |
| LTRIM | N - number of removed elements | O(N) |
| PUBLISH | N - number of channel subscribersM - number of subscribed patterns | O(N+M) |
| PSUBSCRIBE | N - number of patterns client is subscribed toargc - number of arguments passed to the command | O(argc*N) |
| PUNSUBSCRIBE | N - number of patterns client is subscribed toM - total number of subscribed patternsargc - number of arguments passed to the command | O(argc*(N+M)) |
| SDIFF | N - total number of elements in all sets | O(N) |
| SDIFFSTORE | N - total number of elements in all sets | O(N) |
| SINTER | N - number of elements in smallest setargc - number of arguments passed to the command | O(argc*N) |
| SINTERSTORE | N - number of elements in smallest setargc - number of arguments passed to the command | O(argc*N) |
| SMEMBERS | N - number of elements in a set | O(N) |
| SORT | N - number of elements in the when no sorting list/set/zsetM - number of elements in result | O(N+M*log(M))O(N) |
| SUNION | N - number of elements in all sets | O(N) |
| SUNIONSTORE | N - number of elements in all sets | O(N) |
| UNSUBSCRIBE | N - total number of clients subscribed to all channels | O(N) |
| ZADD | N - number of elements in the zset | O(log(N)) |
| ZCOUNT | N - number of elements in the zsetM - number of elements between min and max | O(log(N)+M) |
| ZINCRBY | N - number of elements in the zset | O(log(N)) |
| ZINTERSTORE | N – number of elements in the smallest zsetK – number of zsetsM – number of elements in the results set | O(N*K)+O(M*log(M)) |
| ZRANGE | N – number of elements in the zsetM – number of results | O(log(N)+M) |
| ZRANGEBYSCORE | N – number of elements in the zsetM – number of results | O(log(N)+M) |
| ZRANK | N – number of elements in the zset | O(log(N)) |
| ZREM | N – number of elements in the zsetargc – number of arguments passed to the command | O(argc*log(N)) |
| ZREMRANGEBYRANK | N – number of elements in the zsetargc – number of arguments passed to the command | O(log(N)+M) |
| ZREMRANGEBYSCORE | N – number of elements in the zsetM – number of elements removed | O(log(N)+M) |
| ZREVRANGE | N – number of elements in the zsetM – number of results | O(log(N)+M) |
| ZREVRANK | N – number of elements in the zset | O(log(N)) |
| ZUNIONSTORE | N – sum of element counts of all zsetsM – element count of result | O(N)+O(M*log(M)) |