Shulou(Shulou.com)06/01 Report--

1. Source of problem

This problem may seem strange, but many redis clusters have a unified entry, which acts as a proxy compatible with redis commands. Generally, it is forbidden to use keys commands to obtain key information out of new considerations, but keys can be replaced by scan commands.

two。 The method of using keys

127.0.0.1 a8e620b9-e52e-3498 6379 > KEYS * 1) "_ kombu.binding.test_queue" 2) "a8e620b9-e52e-3498-8a1c-448f35783058" 3) "_ kombu.binding.celery"

3. The method of using scan

127.0.0.1 DBSIZE 6379 > DBSIZE (integer) 3127.0.1 SCAN 0 MATCH * COUNT 31) "5" 2) 1) "a8e620b9-e52e-3498-8a1c-448f35783058" 2) "_ kombu.binding.test_queue" 3) "_ kombu.binding.celery"

Simple explanation

The SCAN command (and the associated SSCAN/HSCAN/ZSCAN, for SET/HASH/ZSET, respectively) is used to incrementally traverse the elements in a collection. Because of its incremental nature (only a small number of elements are returned per use), it can be used instead of KEYS or SMEMBERS commands in production environments (KEYS or SMEMBERS commands may block redis because too many elements are returned)

Therefore, even if the redis service supports the keys command in a production environment, scan should be used instead.

Reference:

1. Https://groups.google.com/forum/#!topic/redis-db/zZeI_PjHF_M

2. Https://redis.io/commands/scan

Summary

The above is the editor introduced to you Redis does not use the keys command to obtain key information related knowledge, hope to help you, if you have any questions welcome to leave a message for me, the editor will reply to you in time!

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