Event queue files and offline archives

For an introduction to the event queue, see Event queue and Automatic event-queue reset.

In most cases the event queue is PI\dat\pimq0000.dat. However, it is possible to have multiple event queue files. The utility piartool -qs indicates if your system uses multiple queues. If multiple queues are used, the queue naming convention is pimqNNNN.dat, where NNNN is a four-digit integer.

In version 3.3 and earlier, the event queue is pi\dat\pieventq.dat. Version 3.4 and later does not support processing this format. These files should be processed before upgrading.

Data Archive versions 3.4 through 3.4.385 have a primary event queue file named pimapevq.dat. If there is more than one queue file, these are named pimqNNNN.dat, where NNNN is a four-digit integer. If these queue files are present during upgrade to PI Server 2012, they will automatically be upgraded to the current format. If there are event queue files that were moved into a separate directory for reprocessing prior to the upgrade, use the following command for each event queue file to reprocess its events into an archive file:

piarchss -if D:\pi\dat\reprocess\pimq0000.dat -of D:\pi\dat\piarchss100.dat -evq

Note that the -if parameter is now only used with -evq when reprocessing event queue files that were created in versions 3.4 through 3.4.385.

PI Server 2012 event queue files require the use of the -evqpath parameter instead.

The memory-mapped queue in PI Server 2012 has been improved to optimize throughput for reading and writing. These improvements also extend to data recovery. If either the Snapshot or Archive Subsystems terminate uncleanly, the PI Snapshot Subsystem will rigorously inspect the event queue files and their contents to ensure that no corrupt events are present when it is next restarted.