[CASSANDRA-7378] Protocol: Autoprepare flag for QUERY and BATCH requests

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Won't Fix
• Component/s: Legacy/CQL
• Assignee: Unassigned
• Reporter: Jorge Bay
• Created: 11/Jun/14 12:34
• Updated: 16/Apr/19 09:31
• Resolved: 26/Mar/15 20:57

Description

Currently the flow for executing a prepared statement in the native protocol is:

• PREPARE request
• prepared response (queryid)
• EXECUTE request (using queryid)
• RESULT response
• or UNPREPARED error response

As is today, it is the responsibility of the driver or client to maintain the query id and to send a EXECUTE message using this query id and to expect for UNPREPARED error response in case the query got evicted or the node was restarted.
With the following implications:

• Before making a EXECUTE request, there is no way to know if it got evicted.
• Before sending a PREPARE request, there is no way to know if that query has been already prepared on that host (by another connection), .
• There isn't anything else the client can do with the prepared id (no much use from the client perspective).

It would be nice to have a flag in the QUERY and BATCH requests that when set, the Cassandra node will prepare (if not already prepared) and execute the prepared query. This way we could save a few extra roundtrips and make the protocol flow for prepared statements a little more simple.