Ask HN: Optimised scan which returns keys having common prefix in sorted order
I found it hard to get keys in Redis with common prefix in sorted order.
So, I am working on implementing a modified data structure using which we can get sorted keys with a common prefix very fast. The command takes a start index and count as well. Here's how fast it is - I have put 10 ^ 7 keys in Redis and the new tcp server built on top of the data structure which I have created. Keys are of format "user:(number)" where number goes from 1 to 10 ^ 7. On running the following command in Redis
scan 0 match user:66199* count 10000000 It takes 2.62s. I know we should use scan command with less count value and retry command until we get a 0 cursor back.. This is just for getting all data for a common prefix, I have used a bigger count value. On running the following command in new server built on top of the data structure scankeys 0 user:66199 It takes 738.083µs and returns all keys having this "user:66199" as prefix. Both the commands outputs same number of keys which are 111. My question to this community is that - Do you people think its a valid use case to solve? Do you guys want this kind of data structure which has support of GET, SET, MGET, SCAN .. where SCAN takes a prefix and returns keys having common prefix in sorted order. Have you guys encountered this use case/problem for production systems?