Package org.apache.hadoop.hbase.client

Class MetaCacheUtil

java.lang.Object
org.apache.hadoop.hbase.client.MetaCacheUtil
@Private final class MetaCacheUtil extends Object
Util class to DRY common logic between AsyncRegionLocationCache and MetaCache

  • Field Details

    • LOG

      private static final org.slf4j.Logger LOG

  • Constructor Details

  • Method Details

    • cleanProblematicOverlappedRegions

      static void cleanProblematicOverlappedRegions(RegionLocations locations, ConcurrentNavigableMap<byte[],RegionLocations> cache)
      When caching a location, the region may have been the result of a merge. Check to see if the region's boundaries overlap any other cached locations in a problematic way. Those would have been merge parents which no longer exist. We need to proactively clear them out to avoid a case where a merged region which receives no requests never gets cleared. This causes requests to other merged regions after it to see the wrong cached location.

      For example, if we have Start_New < Start_Old < End_Old < End_New, then if we only access within range [End_Old, End_New], then it will always return the old region but it will then find out the row is not in the range, and try to get the new region, and then we get [Start_New, End_New), still fall into the same situation.

      If Start_Old is less than Start_New, even if we have overlap, it is not a problem, as when the row is greater than Start_New, we will locate to the new region, and if the row is less than Start_New, it will fall into the old region's range and we will try to access the region and get a NotServing exception, and then we will clean the cache.

      See HBASE-27650

      Parameters:
      locations - the new location that was just cached