[BUG] dbsize return wrong value

[hellower]

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redis

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127.0.0.1:6379> keys *

1. "a"
2. "tntchecker"
3. "b"
   127.0.0.1:6379> dbsize <========== keys count
   (integer) 3
   127.0.0.1:6379> info keyspace
   -# Keyspace
   db0:keys=3,expires=0,avg_ttl=0 <======== keys=3

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kvrocks

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127.0.0.1:6666> keys *

1. "a"
2. "tntchecker"
3. "b"
   127.0.0.1:6666> dbsize <========== keys count
   (integer) 0 <======= always return 0!!
   127.0.0.1:6666> info keyspace
   -# Keyspace
   -# Last scan db time: Thu Jan 1 00:00:00 1970
   db0:keys=0,expires=0,avg_ttl=0,expired=0 <===== keys 0
   sequence:38283437
   used_db_size:603247462
   max_db_size:0
   used_percent: 0%
   disk_capacity:322110992384
   used_disk_size:161157144576
   used_disk_percent: 50%

[git-hulk]

Thanks for your report, it's not a bug actually, the kvrocks key-values were stored in disk, and find out expired keys was impossible unless we can scan it. So we MUST execute the dbsize scan command to async scan the DB for finding out the key number.

[hellower]

Thanks!
and Thank you for nice KVROCKS open source.

[ShooterIT]

Also welcome you to join in improving kvrocks 😄