IO - ControlFileWriteUpdate
Waiting for a write to update the control file.
The control file
pg_control is an 8kb binary file which stores information about various aspects of the PostgreSQL server’s internal state, such as the most recent checkpoint, as well as fundamental parameters set by
initdb. It is located in the cluster’s global/ directory.
Updating the control file is fundamental to the normal operation of the database. Check that the server I/O subsystem is performing correctly across the cluster.