MS RFC 47: Move IGNORE_MISSING_DATA to run-time configuration

Author:Paul Ramsey
Contact:pramsey at
Last Edited:2008/10/15
Status:Adopted on 2008-10-15 - Completed
Version:MapServer 5.4


Making the options for ignoring missing data in tile-indexed layers and WMS client layers more flexible, and configurable at run-time via the map file.

Technical Solution

Currently MapServer has only compile-time (./configure –ignore-missing-data) control of behavior when files referenced in tile indexes are missing, via the IGNORE_MISSING_DATA define, and that behavior is applied globally.

Under this RFC, the missing data behavior will be defined:

  • at run time
  • globally for a map file

As well, the option to “fail on a missing layer” will be added to the WMS client code, which currently defaults to “ignore on a missing layer”.

All changes will preserve the current default behavior in cases where new behavior is not requested by the user: missing data in tileindexes will continue to cause failure and missing WMS layers will continue to be ignored, unless MapServer is compiled with –ignore-missing-data.

A map-level configuration option will be added, CONFIG “ON_MISSING_DATA” “[ACTION]”, with the following valid actions: “IGNORE”, “LOG”, “FAIL”. The default map-level behavior will be “FAIL”, unless MapServer is compiled with –ignore-missing-data, in which case it will be “LOG”. This will preserve the current behavior for all legacy mapfiles and compile set-ups.

In the case of “LOG” behavior, the logging will only occur if the mapfile is set up for logging: DEBUG is set and MS_ERRORFILE is set. Documentation must note that DEBUG and MS_ERRORFILE need to be set.

At the same time, this ticket (#2722) can probably be tracked down and resolved.

Mapscript Implications


Files Affected

  • Documentation will be updated to reflect the new feature
    • MapServer Mapfile Reference

Backwards Compatibility Issues

None. Legacy mapfiles and compile setups should retain existing behavior in the presence of this new code.

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