(improvement) do not fetch * from system.local, but specific columns

Specifically, supported_features took quite some space.
Fetching only what is useful for the client.

In follow-up PRs, will remove some (now) dead code that may have relied on some of those columns.

Refs: scylladb/scylla-drivers#11

Signed-off-by: Yaniv Kaul <[email protected]>

Author: mykaul

cassandra/cluster.py

@@ -3446,7 +3446,7 @@ class ControlConnection(object):
 
     _SELECT_PEERS = "SELECT * FROM system.peers"
     _SELECT_PEERS_NO_TOKENS_TEMPLATE = "SELECT host_id, peer, data_center, rack, rpc_address, {nt_col_name}, release_version, schema_version FROM system.peers"
-    _SELECT_LOCAL = "SELECT * FROM system.local WHERE key='local'"
+    _SELECT_LOCAL = "SELECT broadcast_address, cluster_name, data_center, host_id, listen_address, partitioner, rack, release_version, rpc_address, schema_version, tokens FROM system.local WHERE key='local'"
     _SELECT_LOCAL_NO_TOKENS = "SELECT host_id, cluster_name, data_center, rack, partitioner, release_version, schema_version, rpc_address FROM system.local WHERE key='local'"
     # Used only when token_metadata_enabled is set to False
     _SELECT_LOCAL_NO_TOKENS_RPC_ADDRESS = "SELECT rpc_address FROM system.local WHERE key='local'"