better exception handling

Signed-off-by: Varun Bansal <[email protected]>

server/src/main/java/org/opensearch/index/translog/transfer/FileTransferTracker.java

@@ -8,6 +8,8 @@
 
 package org.opensearch.index.translog.transfer;
 
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.logging.Loggers;
 import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.remote.RemoteTranslogTransferTracker;
 import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
@@ -33,11 +35,13 @@ public class FileTransferTracker implements FileTransferListener {
     private final RemoteTranslogTransferTracker remoteTranslogTransferTracker;
     private Map<String, Long> bytesForTlogCkpFileToUpload;
     private long fileTransferStartTime = -1;
+    private final Logger logger;
 
     public FileTransferTracker(ShardId shardId, RemoteTranslogTransferTracker remoteTranslogTransferTracker) {
         this.shardId = shardId;
         this.fileTransferTracker = new ConcurrentHashMap<>();
         this.remoteTranslogTransferTracker = remoteTranslogTransferTracker;
+        this.logger = Loggers.getLogger(getClass(), shardId);
     }
 
     void recordFileTransferStartTime(long uploadStartTime) {
@@ -68,8 +72,14 @@ public void onSuccess(TransferFileSnapshot fileSnapshot) {
             long durationInMillis = (System.nanoTime() - fileTransferStartTime) / 1_000_000L;
             remoteTranslogTransferTracker.addUploadTimeInMillis(durationInMillis);
             remoteTranslogTransferTracker.addUploadBytesSucceeded(bytesForTlogCkpFileToUpload.get(fileSnapshot.getName()));
-            add(fileSnapshot.getName(), TransferState.SUCCESS);
         } catch (Exception ex) {
+            logger.error("Failure to update translog upload success stats", ex);
+        }
+
+        try {
+            // add() gets a dedicated try/catch as its on the critical path
+            add(fileSnapshot.getName(), TransferState.SUCCESS);
+        } catch (IllegalStateException ex) {
             throw new FileTransferException(fileSnapshot, ex);
         }
     }