- Pass prepared statement size to the helper class to prevent runtime resizing.
- Rename CheckValidIndex -> AssertValidIndex
- Cached prepared size on the worker pool as it's shared among all connections
- Cached query data only for each connection, done lookup in map instead of possibly creating a new element
- Kill the prepared statement map, and store raw sql string on the MySQLPreparedStatement class
(This info is only used for logging, and there is no need of keeping a second container just for it)
(cherrypicked from affee140c6)
