[GitHub] [kafka] jsancio commented on a change in pull request #10431: KAFKA-12543: Change RawSnapshotReader ownership model

[GitBox]

jsancio commented on a change in pull request #10431:
URL: https://github.com/apache/kafka/pull/10431#discussion_r628559894



##########
File path: core/src/main/scala/kafka/raft/KafkaMetadataLog.scala
##########
@@ -242,85 +246,116 @@ final class KafkaMetadataLog private (
   }
 
   override def readSnapshot(snapshotId: OffsetAndEpoch): 
Optional[RawSnapshotReader] = {
-    try {
-      if (snapshotIds.contains(snapshotId)) {
-        Optional.of(FileRawSnapshotReader.open(log.dir.toPath, snapshotId))
-      } else {
-        Optional.empty()
+    snapshots synchronized {
+      val reader = snapshots.get(snapshotId) match {
+        case None =>
+          // Snapshot doesn't exists
+          None
+        case Some(None) =>
+          // Snapshot exists but has never been read before
+          try {
+            val snapshotReader = 
Some(FileRawSnapshotReader.open(log.dir.toPath, snapshotId))
+            snapshots.put(snapshotId, snapshotReader)
+            snapshotReader

Review comment:
       Correct.




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