There are many improvements in client variable usage and administration to correct both defects and architectural problems. Client variable problems on Windows are a common support call.
There are many variations of hangs on production systems related to client variable use with the Windows Registry. The Windows Registry is not supported for production applications.
If clientmanagement="yes" in the Application.cfm/Application.cfc, CFID/CFTOKEN records will still be inserted into the registry or database (and purged during the hourly cycle) even if no client variable assignments are made in code. In the case of registry storage, when the registry fills up (perhaps 20,000 to 100,000 records), the hourly purge cycle can cause 100% CPU utilization and crash a machine.
Many applications that evolve from earlier versions of ColdFusion or perhaps from development to deployment can have unknown configuration issues such as this. This could simply be the result of a missing Application.cfm in a directory or an old cfapplication tag that was never reviewed.
To avoid problems related to the registry, don't use Registry storage for client variables, even in development.
Set the cfapplication tag, clientmanagement="no" explicitly if not using client variables. When using client storage on production systems, do the following:
- In the ColdFusion MX administrator section (client variables), turn OFF "purge" explicitly for Registry.
- In the ColdFusion MX administrator, set the client storage default (if Registry) to "none" and explicitly reference it in the cfapplication tag (don't let it default to the ColdFusion MX admin value).
- Set clientstorage to a specific data source rather than letting the default take precedence in the ColdFusion MX admin.
This is especially important on newly installed hardware and software to avoid problems 60 or 90 days after deployment.
For ColdFusion MX 6.1, apply the 6.1 Updater and the client variable hot fixes as other suggested hot fixes in Recommended supported configurations for ColdFusion MX 6.1 and 7.0 Server.