[Bug] `reduce_levels` doesn't work with multiple Column Families

[dieperdev]

In my application, I create SST files for multiple column families to ingest later with RocksDB (through the ldb CLI). The database can be compacted before attempting to reduce the levels, but attempting to reducing the levels (to any number below the default which is 7) will give an error about a column family not being opened. I've tried various parameters but still get the same error. This is a reproducible issue even with small amounts of data (like in my example).

You can see the reproduction here:
https://github.com/dieperdev/rocksdb-sst-repro