Resyncs the database session; typically used to make sure the session is
not still in a dangling transaction.
If called while queries/portals are still in-flight, this function
is a no-op.
If called while the connection is in idle state, the function is
lightweight and briefly touches base with the database server to
make sure client and server are in sync.
If issued while inside a transaction, it will rollback the transaction,
close all open cursors, drop all temporary tables and reset all
session variables to their default values.
Sql.pgsql()->reload()