[GitHub] gianm closed pull request #5969: [Backport] Fix inefficient available segment cache population in SQLMetadataSegmentManager

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

gianm closed pull request #5969: [Backport] Fix inefficient available segment cache population in SQLMetadataSegmentManager
URL: https://github.com/apache/incubator-druid/pull/5969
 
 
   

This is a PR merged from a forked repository.
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diff --git a/server/src/main/java/io/druid/client/DruidDataSource.java b/server/src/main/java/io/druid/client/DruidDataSource.java
index ed2594b67c8..af9cb2b18a1 100644
--- a/server/src/main/java/io/druid/client/DruidDataSource.java
+++ b/server/src/main/java/io/druid/client/DruidDataSource.java
@@ -90,6 +90,14 @@ public ImmutableDruidDataSource toImmutableDruidDataSource()
     return new ImmutableDruidDataSource(name, properties, idToSegmentMap);
   }
 
+  // For performance reasons, make sure we check for the existence of a segment using containsSegment(),
+  // which performs a key-based lookup, instead of calling contains() on the collection returned by
+  // dataSource.getSegments(). In Map values collections, the contains() method is a linear scan.
+  public boolean containsSegment(DataSegment segment)
+  {
+    return idToSegmentMap.containsKey(segment.getIdentifier());
+  }
+
   @Override
   public String toString()
   {
diff --git a/server/src/main/java/io/druid/metadata/SQLMetadataSegmentManager.java b/server/src/main/java/io/druid/metadata/SQLMetadataSegmentManager.java
index 6f3f4581991..36f628c55d2 100644
--- a/server/src/main/java/io/druid/metadata/SQLMetadataSegmentManager.java
+++ b/server/src/main/java/io/druid/metadata/SQLMetadataSegmentManager.java
@@ -502,7 +502,10 @@ public DataSegment map(int index, ResultSet r, StatementContext ctx)
           }
         }
 
-        if (!dataSource.getSegments().contains(segment)) {
+        // For performance reasons, make sure we check for the existence of a segment using containsSegment(),
+        // which performs a key-based lookup, instead of calling contains() on the collection returned by
+        // dataSource.getSegments(). In Map values collections, the contains() method is a linear scan.
+        if (!dataSource.containsSegment(segment)) {
           dataSource.addSegment(segment);
         }
       }


 

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