[GitHub] [phoenix] kadirozde commented on a change in pull request #897: PHOENIX-6160 Simplifying concurrent mutation handling for global Indexes

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

kadirozde commented on a change in pull request #897:
URL: https://github.com/apache/phoenix/pull/897#discussion_r502979620



##########
File path: phoenix-core/src/main/java/org/apache/phoenix/hbase/index/IndexRegionObserver.java
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@@ -166,12 +175,36 @@ public static void setFailDataTableUpdatesForTesting(boolean fail) {
       private HashSet<ImmutableBytesPtr> rowsToLock = new HashSet<>();
       // The current and next states of the data rows corresponding to the pending mutations
       private HashMap<ImmutableBytesPtr, Pair<Put, Put>> dataRowStates;
-      // Data table pending mutations
+      // The previous concurrent batch contexts
+      private HashMap<ImmutableBytesPtr, BatchMutateContext> lastConcurrentBatchContext = null;
+      // The latches of the threads waiting for this batch to complete
+      private List<CountDownLatch> waitList = null;
       private Map<ImmutableBytesPtr, MultiMutation> multiMutationMap;
 
       private BatchMutateContext(int clientVersion) {
           this.clientVersion = clientVersion;
       }
+
+      public BatchMutatePhase getCurrentPhase() {
+          return currentPhase;
+      }
+
+      public Put getNextDataRowState(ImmutableBytesPtr rowKeyPtr) {
+          Pair<Put, Put> rowState = dataRowStates.get(rowKeyPtr);
+          if (rowState != null) {
+              return dataRowStates.get(rowKeyPtr).getSecond();

Review comment:
       > > Algorithm makes sense, it's a nice simplification, and just had a few nits on the code. My bigger concern is the potential increase in tail latency on writes to hot rows in write latency-sensitive applications. Would be good to get some perf numbers.
   > 
   > Good suggestion. I will do some perf runs and update the Jira.
   
   @gjacoby126, I have updated the design doc with the performance testing results ( https://docs.google.com/document/d/12H_MwsPtyM0ORiBHclBpBLZWtm4zpY_cc5y_pwtgMUk/edit#heading=h.yt8378ps0k6e)




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