The organization has an Always On availability group technology in place, and we have an open transaction on the primary server, but the secondary server accidentally transfers it to the secondary server. If the secondary server goes down, what happens to the stats log file on the primary server?
Note: Server Replica Node 2 Set Synchronous-commit mode.
From the docs:
If primary's session-timeout period is exceeded by a secondary replica, the primary replica temporarily shifts into asynchronous-commit mode for that secondary replica. When the secondary replica reconnects with the primary replica, they resume synchronous-commit mode.
Differences between availability modes for an Always On availability group
So after the timeout, the failed replica is switched to asynchronous mode, and the primary commits the transaction. The failed replica will eventually reconnect and receive the log record indicating that it should commit the transaction too, followed by all the log records while it was down. After it's caught up, it will switch back to synchronous-commit.
See eg Synchronous Always On Availability Groups Is Not Zero Data Loss
You can opt for having the primary fail to commit by setting REQUIRED_SYNCHRONIZED_SECONDARIES_TO_COMMIT on the AG.
