Changes between Version 16 and Version 17 of BluePrintRegionsAndIncidents


Ignore:
Timestamp:
02/18/11 13:30:30 (11 years ago)
Author:
Pat Tressel
Comment:

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  • BluePrintRegionsAndIncidents

    v16 v17  
    9292If the test for whether a location is in a region is expensive (e.g. if it uses polygon overlap), we may want to cache the membership (similar to caching the location's hierarchy path). A location can belong to more than one region, so this would be a list of regions (specified by their region location ids). Would need to record both positive and negative results, i.e. if we test a location against a region and find it's not in that region, we need to record that to avoid redoing the test. The cache would be invalidated if the location's parentage or lon, lat changes.  Invalidating region test results if a region's scope changes (e.g. its border is changed, or a group's membership changes, or if the hierarchy is changed) needs careful consideration to avoid expensive database operations. Fortunately, regions are not expected to be changed frequently.
    9393
    94 We may also want to cache the gis_config currently in effect in the session in any case, not just if it was a region gis_config selected from the menu.
     94We may also want to cache the gis_config currently in effect in the session in any case, not just if it was a region gis_config selected from the menu.  Either way, when a gis_config becomes the current gis_config, any values that now reside in deployment_settings should be copied there, to avoid disrupting existing code.  These are the hierarchy-related values.
    9595
    9696==== Detail on caching region membership ====