Often, you'd want to retrieve keys based on their corresponding values in Redis. This is useful when you are storing data in key-value pairs and need to query via values.
In Redis, there isn't a direct command to get a key by its value. But we can create a workaround in python using the scan_iter
function.
Example 1:
import redis r = redis.Redis() # Let's assume that we're looking for keys that have the value '100' search_value = '100' for key in r.scan_iter(): if r.get(key).decode('utf-8') == search_value: print(f'Key: {key.decode('utf-8')}')
In this example, we connect to Redis, iterate over all keys and print the keys where the value equals our search_value
.
While querying keys based on values might be necessary at times, it's not ideal because Redis doesn't support this functionality natively. It's often recommended to design your data in such a way that you don't need to do this kind of operation, which can be expensive and slow.
One common mistake is to try to use this method on large databases. The method above requires iterating through every key in the database, so it can be very slow on large databases.
Q: Why is there no native command in Redis to get a key by value?
A: Redis is not designed to be queried by value. It's a key-value store, meaning it's optimized for retrieving values based on keys.
Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.