How to “EXPIRE” the “HSET” child key in redis?

Question

I need to expire all keys in redis hash, which are older than 1 month.

Answer 1

We had the same problem discussed here.

We have a Redis hash, a key to hash entries (name/value pairs), and we needed to hold individual expiration times on each hash entry.

We implemented this by adding n bytes of prefix data containing encoded expiration information when we write the hash entry values, we also set the key to expire at the time contained in the value being written.

Then, on read, we decode the prefix and check for expiration. This is additional overhead, however, the reads are still O(n) and the entire key will expire when the last hash entry has expired.