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

When we need to traverse all the key of Redis or the key of a specified mode, the first thing that comes to mind is the KEYS command, such as: keys *

It is equivalent to select * in a relational database, so using this command in a large Redis database in a production environment can cause performance problems.

Since the Redis2.8 version, officials have provided us with a better command SCAN for traversing KEY.

The syntax is:

SCAN cursor [MATCH pattern] [COUNT count]

For example:

127.0.0.1 scan 6379 > 0 match * 192.168 *

1) "105"

2) 1) "192.168.0.220:6379:CommandCountByMinute"

2) "192.168.0.121:6379:memory"

3) "192.168.0.213:6379:CommandCount:1528190604"

4) "192.168.0.221:6379:KeyCount:1528190601"

5) "192.168.0.226:6379:KeyCount:1528190334"

6) "192.168.0.129:6379:CommandCount:1528121363"

7) "192.168.0.129:6379:KeyCount:1528121366"

Each element returned by the SCAN command is a database key, which has little impact on database performance, so it is recommended for use in production environments.

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