[GitHub] [hbase] ndimiduk commented on a change in pull request #2596: Backport "HBASE-24419 Normalizer merge plans should consider more than 2 region…" to branch-2

[GitBox <gi...@apache.org>]

ndimiduk commented on a change in pull request #2596:
URL: https://github.com/apache/hbase/pull/2596#discussion_r657261818



##########
File path: hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/SimpleRegionNormalizer.java
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@@ -315,35 +316,60 @@ private boolean skipForMerge(final RegionStates regionStates, final RegionInfo r
    * towards target average or target region count.
    */
   private List<NormalizationPlan> computeMergeNormalizationPlans(final NormalizeContext ctx) {
-    if (ctx.getTableRegions().size() < minRegionCount) {
+    if (isEmpty(ctx.getTableRegions()) || ctx.getTableRegions().size() < minRegionCount) {
       LOG.debug("Table {} has {} regions, required min number of regions for normalizer to run"
         + " is {}, not computing merge plans.", ctx.getTableName(), ctx.getTableRegions().size(),
         minRegionCount);
       return Collections.emptyList();
     }
 
-    final double avgRegionSizeMb = ctx.getAverageRegionSizeMb();
+    final long avgRegionSizeMb = (long) ctx.getAverageRegionSizeMb();
+    if (avgRegionSizeMb < mergeMinRegionSizeMb) {

Review comment:
       I'd have to look back through the original JIRA and PR, but I believe there was a concern that normalizer would merge away the splits made on table creation, between the time when the table was created and when the operator got around to loading it with data. The "minimum table size" configuration was designed to prevent this. This behavior pre-dated HBASE-24419 ; the functionality was preserved when this optimization was implemented.
   
   I personally am not a fan, and prefer the "minimum table age" configuration for handling of this concern.




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