leveldb multiple deletes - fragmentation

[Prajakta Dandawate]

If leveldb has continuous writes of huge number of records and to free old data, we delete  old data frequently. Does leveldb gets fragmented?

If yes, Are there any ways to defragment leveldb or avoid fragmentation? 

[Ren Z]

If you are going to do that there will be a lot of work for leveldb in the compaction phase (you'll see big disk IO spikes).
If your old data is continuous chunks of data it's much more efficient to just delete the entire "old" db and start new one.

[Akshata m j]

I wanted to know how do you delete old leveldb data without knowing the key value