Re: [I] Prefix scan didn't work well when enabling the cluster mode [kvrocks]

["git-hulk (via GitHub)" <gi...@apache.org>]

git-hulk commented on issue #1836:
URL: https://github.com/apache/kvrocks/issues/1836#issuecomment-1770978229

   @EasyProgramming It's a limitation in the scan command when enabling the cluster mode. It'll only look forward N(50) slots when scanning keys, for example:
   
   If we have keys: `aaaa`(slot 0), `bbbb`(slot 10), `cccc`(slot 100), `dddd`(slot 200) and we scan with:
   
   ```
   SCAN "0" MATCH "bb*"
   ```
   it works well since `bbbb` is located at slot 10, and Kvrocks try to look forward next 50 slots. But if you scan with `cc*`:
   
   ```
   SCAN "0" MATCH "cc*"
   ```
   it will return empty array with cursor(`_bbbb`) since `cccc` is located at slot 100.
   
   For the implementation, please refer: https://github.com/apache/kvrocks/blob/unstable/src/storage/redis_db.cc#L365
   
   
   Of course, for this limitation will make the scan command very hard to use. We will try our best to improve this if possible. cc @tisonkun 


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