PHPORM-256: Disable mongoc_client reuse between connections

[alcaeus]

PHPORM-256, fixes #3183

The issue described in the query can happen when multiple connections use the same client config. In that case, MongoDB\Driver\Manager reuses the underlying mongoc_client instance for performance reasons. However, as the query logger relies on APM callbacks which are tied to the mongoc_client, there is no way for us to keep this separate.

Disabling client persistence would solve this problem, but it would potentially introduce performance issues, as the connection would no longer be reused across multiple requests, introducing a delay for connection establishment in every request. However, by using the name of the connection from the config, we can introduce a unique identifier in the driver options, leading to the driver opening separate mongoc_client connections for each Laravel database connection, while at the same time leveraging connection persistence. Since the driver does not yield warnings or errors when encountering unknown driver options, we can safely inject this option that ends up being unused. @jmikola let me know if you can think of a better way to fix this.

The test in this PR fails without the patch, seeing a logged query in $secondConnection before actually running a query through the collection.

[jmikola]

This guarantees correctness for query logging, although I expect it paves the way for some future user inquiry about connection usage. Let's keep that in mind and revisit at a later point to decide if we should add something to the Laravel docs about how the underlying driver handles client persistence.

[GromNaN]

we should add something to the Laravel docs about how the underlying driver handles client persistence.

Is there such documentation for the MongoDB extension or library?

[jmikola]

Is there such documentation for the MongoDB extension or library?

Connection Handling and Persistence covers this in the PHPC docs.

PHPLIB-1278 would add a FAQ entry about using the disableClientPersistence option, but this otherwise isn't something discussed at all within the PHPLIB docs.