Remove deprecated methods from the wrapper Connection

[morozov]

Q	A
Type	improvement
BC Break	yes

Summary

1. Calls like $conn->query()->fetch*() have been reworked to $conn->fetch*() before the method removal.
2. The rest of the calls to $conn->query() have been replaced with $conn->executeQuery() and $conn->executeStatement() depending on whether the statement yields rows.
3. Calls to $conn->exec() and $conn->executeUpdate() have been replaced with $conn->executeStatement().
4. The overridden versions of the insert(), update() and delete() methods have been removed form PrimaryReplicaConnection since they all are implemented via executeStatement() in the parent class which ensures connection to the primary instance.

TODO:

• Unlike PrimaryReplicaConnection::query(), PrimaryReplicaConnection::executeQuery() doesn't automatically connect to the primary instance. I have no idea why the method semantics are different in the first place. It looks like a design flaw to me. This should be reflected in the deprecation note in 2.11.x.

  Note that PrimaryReplicaConnection::query() ensures connection to the primary instance while executeQuery() doesn't.

  Depending on the desired behavior:

  • If the statement doesn't have to be executed on the primary instance, use executeQuery().
  • If the statement has to be executed on the primary instance and yields rows (e.g. SELECT), prepend executeQuery() with ensureConnectedToPrimary().
  • Otherwise, use executeStatement().

  Updated the upgrade notes in Additional deprecation note for PrimaryReplicaConnection::query() #4175.

[morozov]

@greg0ire could you take a look please?

[greg0ire]

Sure! Your message ends with three backticks, did you maybe mean to write more?

[greg0ire]

Also, do you mean to fix the todo in another PR?

[morozov]

Your message ends with three backticks, did you maybe mean to write more?

No, it was a code block originally.

Also, do you mean to fix the todo in another PR?

Yes, it will have to be done in 2.11.x.