How to delete cache in redis

There are four methods to delete cache in Redis: direct deletion (DEL command), batch deletion (KEYS UNLINK command), fuzzy deletion (SCAN UNLINK command) and time-based expiration (TTL).

How to delete the cache in Redis

Delete directly

Use the DEL command to directly delete the cache of the specified key.

<code>DEL key_name</code>

Batch deletion

Use the KEYS command to get the keys matching a specific pattern, and then use the UNLINK command to delete these in batches key.

For example: Delete all keys starting with product_*:

<code>KEYS product_*
UNLINK $(keyspace_keys ...)</code>

Fuzzy delete

Use the SCAN command to iterate over all keys and use the fnmatch module in a scripting language such as Python to match keys. Matching keys can be deleted using the UNLINK command.

Example: Delete all keys containing the string user_ID:

<code class="python">import redis
import fnmatch

r = redis.Redis()
for key in r.scan_iter():
    if fnmatch.fnmatch(key, "*user_ID*"):
        r.unlink(key)</code>

Time-based expiration (TTL)

If a TTL is set for a key, the key will be automatically deleted upon expiration.

For example: Set the TTL of key user_info to 10 minutes:

<code>EXPIRE user_info 600</code>

Notes

• Be careful with security when deleting cache as this may result in data loss.
• Use fuzzy delete with caution as it may accidentally delete other keys.
• Regularly clear caches that are no longer needed to optimize Redis performance.

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