Deleting keys by prefix in Redis is a common task when working with cache invalidation or data synchronization scenarios. It can be used to remove all keys that match a certain pattern, for example, delete all keys that start with 'user_profile' when user's profile information changes.
Let's assume we're using the
redis-py client for Python.
In this example,
scan_iter is used to iteratively find keys that match the 'user_profile*' pattern. For each such key, we call
delete method to remove it from Redis.
Be mindful of using the delete operation in production applications, as it may affect performance, especially if the number of keys is large.
It's recommended to use scan operations (like
scan_iter) instead of the
keys command for finding keys by pattern, as
keys can block the server when called on large databases.
A common mistake is to accidentally delete keys without ensuring the correct pattern. Always double-check your key patterns before deleting.
keys method instead of
scan_iter could lead to performance issues. The
keys method retrieves all keys and can be slow in large databases.
Q: Can I undo a delete operation in Redis?
A: No, once a key is deleted, it cannot be recovered. Make sure to use the delete operation cautiously.
Q: What's the difference between
keys command retrieves all keys in the database at once and can block the server if the database is large. On the other hand,
scan_iter uses a cursor to iteratively scan through the database, which is more efficient and recommended.