Overview of the Issue

If you specify a specific shard in your USE statement, such as use commerce/-; and then issue a sql statement with the database name in the query, such as, select * from commerce.corder;, the query fails with an error

ERROR 1049 (42000): target: commerce.-.primary: vttablet: rpc error: code = InvalidArgument desc = Unknown database 'commerce' (errno 1049) (sqlstate 42000) (CallerID: user): Sql: "select * from commerce.corder", BindVars: {}

This makes sense as vtgate just passes through the sql statement to the shard and the underlying database name in the shard is prefexed with vt_ so this fails.
But should this fail? as from end user pov, the database/keyspace name is commerce, so selecting a shard and explicitly specifying the database name in the query should work.

To validate this theory, this query works.

mysql> use commerce/-;
Database changed
mysql> select * from vt_commerce.corder;
Empty set (0.00 sec)

VS

mysql> use commerce/-;
Database changed
mysql> select * from commerce.corder;
ERROR 1049 (42000): target: commerce.-.primary: vttablet: rpc error: code = InvalidArgument desc = Unknown database 'commerce' (errno 1049) (sqlstate 42000) (CallerID: user): Sql: "select * from commerce.corder", BindVars: {}

Reproduction Steps

Follow the steps in https://vitess.io/docs/22.0/get-started/operator/ to create a operator based vitess cluster on main branch.

Binary Version

vtgate --version
vtgate version Version: 22.0.0-SNAPSHOT (Git revision aabf1c9b907691f3c26eab3d75ca123b66735bcc branch 'main') built on Thu Jan  9 10:06:25 UTC 2025 by vitess@buildkitsandbox using go1.23.4 linux/amd64

Operating System and Environment details

ALL

Log Fragments

No response