Restarts and MINE and APPLY counters

Description

There is a basic difference as to the point from which MINE and APPLY processes start processing after a restart.

  • MINE goes back to the last obsolete redo log, always starting on a redo log boundary.

  • APPLY goes back to the oldest uncommitted transaction.

Explanation

This means that after restart, each process starts from a different point in time. For this reason the reported time may look strange (such as APPLY being in front of MINE) and the counters for this execution will not match.

The counters on the "right" of the "/" are the numbers since the restart and the numbers on the "left" of the "/" are the numbers since the start of the replication. The numbers on the left are also referred to as the "all" numbers.

But only the "all" counters really matter. This "restart" numbers are more of a reference that something is really happening after the restart.

Arjen Visser  August 07, 2013 18:32