A question that came up on an earlier blog post was how to limit the number of revisions on a piece of content. UCM does not inherently enforce any sort of limit on how many revisions you can have. It's unlimited.

In some cases, there may be content that goes through lots of changes, but there just simply isn't a need to keep all of its revisions around. Deleting those revisions through the content information screen can be very cumbersome. And going through the Repository Manager applet can take time as well to filter and find the revisions to get rid of.

But there is an easier way through the Archiver. The Export Query criteria in Archiver includes a very handy field called 'Revision Rank'. With revision labels, they typically go up as new revisions come in (e.g. 1, 2, 3, 4, etc...). But you can't really use this field to tell it to keep the top 5 revisions. Those top 5 revision numbers are always going up. But revision rank goes the opposite direction. The very latest revision is always 0. The previous revision to that is 1. Previous revision to that is 2. And so on and so forth. With revision rank, you can set your query to look for any Revision Rank greater or equal to 5. Now as older revisions move down the line, their revision rank gets higher and higher until they reach that threshold. Then when you run that archive export, you can choose to delete and remove those revisions.

Running that export in Archiver is normally a manual process. But with Idc Command, you can script the process and have it run automatically from the server. Idc Command is a utility that allows you to run any of the content server services via the command line. You basically feed it a text file with the services and parameters defined along with the user to run it as. The Idc Command executable is located within the \bin\ directory:

$ ./IdcCommand -f DeleteOlderRevisions.txt -u sysadmin -l delete_revisions.log

In this example, our IdcCommand file to run the export and do the deletions would look like:

IdcService=EXPORT_ARCHIVE
aArchiveName=DeleteOlderRevisions
aDoDelete=1
IDC_Name=idc
dataSource=RevisionIDs
<<EOD>>

You can then use automated scheduling routines in the OS to run the command and command file at the frequency needed.

Remember that you are deleting the revisions from within UCM, but they are still getting placed within the archive. So you will need to delete those batches to have them fully removed (or re-import if you need to recover them).

For more information about Idc Command, you can find that in the Idc Command Reference Guide.