no need to store the hashSum for view. Calculate on remove vs add

apache · Dec 24, 2024 · fac664b · fac664b
1 parent f126b06
commit fac664b
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Showing 2 changed files with 10 additions and 8 deletions.
diff --git a/src/java/org/apache/cassandra/db/lifecycle/SSTableIntervalTree.java b/src/java/org/apache/cassandra/db/lifecycle/SSTableIntervalTree.java
@@ -59,9 +59,7 @@ public static SSTableIntervalTree build(Iterable<SSTableReader> sstables)
 
     public static SSTableIntervalTree replaceSSTables(SSTableIntervalTree tree, Iterable<SSTableReader> sstables)
     {
-        List<Interval<PartitionPosition, SSTableReader>> intervals = buildIntervals(sstables);
-        SSTableIntervalTree newTree = new SSTableIntervalTree(tree.count, tree.head.copyAndReplace(intervals));
-        return newTree;
+        return new SSTableIntervalTree(tree.count, tree.head.copyAndReplace(buildIntervals(sstables)));
     }
 
     public static List<Interval<PartitionPosition, SSTableReader>> buildIntervals(Iterable<SSTableReader> sstables)

diff --git a/src/java/org/apache/cassandra/db/lifecycle/View.java b/src/java/org/apache/cassandra/db/lifecycle/View.java
@@ -307,16 +307,15 @@ static Function<View, View> updateLiveSet(final Set<SSTableReader> remove, final
             public View apply(View view)
             {
                 Map<SSTableReader, SSTableReader> sstableMap = replace(view.sstablesMap, remove, add);
-                int afterHashSum = getSSTablesHash(sstableMap.keySet());
-                if (view.sstablesHash == afterHashSum)
+                if (isRangesUnchanged(remove, add))
                 {
                     // If the SSTable before and after has the same key range, then there is no need to rebuild the interval tree.
                     // Instead, we find and update the node
                     return new View(view.liveMemtables, view.flushingMemtables, sstableMap, view.compactingMap,
-                                    SSTableIntervalTree.replaceSSTables(view.intervalTree, add), afterHashSum);
+                                    SSTableIntervalTree.replaceSSTables(view.intervalTree, add));
                 }
                 return new View(view.liveMemtables, view.flushingMemtables, sstableMap, view.compactingMap,
-                                SSTableIntervalTree.build(sstableMap.keySet()), afterHashSum);
+                                SSTableIntervalTree.build(sstableMap.keySet()));
             }
         };
     }
@@ -386,7 +385,7 @@ public boolean apply(T t)
         };
     }
 
-    private static int getSSTablesHash(Collection<SSTableReader> readers) {
+    private static int getSSTablesHash(Iterable<SSTableReader> readers) {
         int hashSum = 0;
         for (SSTableReader reader : readers) {
             if (reader != null) {
@@ -395,4 +394,9 @@ private static int getSSTablesHash(Collection<SSTableReader> readers) {
         }
         return hashSum;
     }
+
+    private static boolean isRangesUnchanged(final Set<SSTableReader> remove, final Iterable<SSTableReader> add)
+    {
+        return getSSTablesHash(remove) == getSSTablesHash(add);
+    }
 }