How to view all keys without blocking Redis

Question: How to view all keys without blocking Redis? Answer: Using the SCAN command, accept two parameters: cursor (cursor value) and COUNT (maximum number of keys).

How to view all keys without blocking Redis

Redis is a popular key-value storage database that can obtain all the keys it contains without blocking the database through the SCAN command.

Use the SCAN command

The SCAN command accepts two parameters:

• cursor: cursor value starting from 0, used to traverse key space.
• COUNT: The maximum number of keys to retrieve.

Example

The following example uses the SCAN command to get all keys in Redis:

 <code>SCAN 0 COUNT 100</code>

This command retrieves the first 100 keys in the database and returns a tuple where the first element is a new cursor value that is used to retrieve the next batch of keys and the second element is a list of the first 100 keys.

Iterate key space

To iterate over the entire keyspace in Redis, you can use the following code:

 <code>cursor = 0 while cursor != 0: cursor, keys = redis_client.scan(cursor, count=100) # 处理键</code>

This code will loop through the keyspace, processing 100 keys per batch.

Things to note

It should be noted that the SCAN command runs in the background, so when performing other operations, all keys may not be immediately retrieved. Additionally, if keys are added or removed to the database during SCAN operations, these keys may not be retrieved.

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