Postgres: allow ShouldPrepareCommands to be false to work with npgsql driver Multiplexing

[samcarton]

Here the code is hard-coding DatabaseConnection.ShouldPrepareCommands to true:

DistributedLock/src/DistributedLock.Postgres/PostgresDatabaseConnection.cs

Line 36 in ce4a071

public override bool ShouldPrepareCommands => true;

However we have npgsql's multiplexing enabled on the connection string, which doesn't allow explicit preparation (see related comment in issue). It results in a Explicit preparation not supported with multiplexing NotSupportedException.

• The current workaround is to remove npgsql-Multiplexing from the connection string when passing it to the PostgresDistributedSynchronizationProvider.
• If ShouldPrepareCommands could be set to false via options, then I assume we could also opt-out of the DistributedLock-multiplexing and rely on npgsql-Multiplexing instead. Do you see any issues with this?

[madelson]

Ideally it would just work, meaning that either we always set should prepare to false for Postgres (how important is it with the current driver?) or we default it based on whether the connection is multiplexing.

That said, I’m curious as to whether distributed locking works with a multiplexed Postgres connection. Is it still able to know which session is holding the lock?