setting knob_rocksdb_block_size does not reflect in rocksdb_metrics stats

[ashwiniraina]

I am running foundationdb on a cluster using the fdb operator. When I change the value of knob_rocksdb_block_cache_size in the custom parameters section and deploy the updated cluster yaml, the storageserver processes on the storage nodes get restarted with the new value as expected. However, the "rocksdb_metrics" in the fdbcli status, still shows the old value under "block_cache_limit".

From code inspection, "rocksdb_metrics" are populated in Status.actor.cpp here.
https://github.com/apple/foundationdb/blob/main/fdbserver/Status.actor.cpp#L630

But block_cache_limit field does not get the latest value for that server knob.

Am I missing something in setting the value for this knob?