The constraint MonadSqlTx db m indicates that m is a monadic context that can run db actions, usually as a SQL transaction. Typically, this means that db needs a connection and m can provide one, e.g. from a connection pool.

Run a Database action with connection stats and tracing

This uses OpenTelemetry and MonadTracer. For callstacks in traces to be useful, ensure you have HasCallStack on functions that call this (and functions that call those, for as far as you require to get to a useful source location).

A SqlBackend represents a handle or connection to a database. It contains functions and values that allow databases to have more optimized implementations, as well as references that benefit performance and sharing.

Instead of using the SqlBackend constructor directly, use the mkSqlBackend function.

A SqlBackend is *not* thread-safe. You should not assume that a SqlBackend can be shared among threads and run concurrent queries. This *will* result in problems. Instead, you should create a Pool SqlBackend, known as a ConnectionPool, and pass that around in multi-threaded applications.

To run actions in the persistent library, you should use the runSqlConn function. If you're using a multithreaded application, use the runSqlPool function.

A monadic context in which a SQL backend is available for running database queries

Generalize from SqlPersistT to MonadSqlBackend

This is generally scoped by Monad stack to do different things