hadoop-common-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From GitBox <...@apache.org>
Subject [GitHub] [hadoop] bharatviswa504 commented on a change in pull request #651: HDDS-1339. Implement ratis snapshots on OM
Date Thu, 28 Mar 2019 17:48:44 GMT
bharatviswa504 commented on a change in pull request #651: HDDS-1339. Implement ratis snapshots
on OM
URL: https://github.com/apache/hadoop/pull/651#discussion_r270120787
 
 

 ##########
 File path: hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/ratis/OzoneManagerStateMachine.java
 ##########
 @@ -115,7 +117,60 @@ public TransactionContext startTransaction(
       return ctxt;
     }
     return handleStartTransactionRequests(raftClientRequest, omRequest);
+  }
+
+  /*
+   * Apply a committed log entry to the state machine.
+   */
+  @Override
+  public CompletableFuture<Message> applyTransaction(TransactionContext trx) {
+    try {
+      OMRequest request = OMRatisHelper.convertByteStringToOMRequest(
+          trx.getStateMachineLogEntry().getLogData());
+      long trxLogIndex = trx.getLogEntry().getIndex();
+      CompletableFuture<Message> future = CompletableFuture
+          .supplyAsync(() -> runCommand(request, trxLogIndex));
+      return future;
+    } catch (IOException e) {
+      return completeExceptionally(e);
+    }
+  }
+
+  /**
+   * Query the state machine. The request must be read-only.
+   */
+  @Override
+  public CompletableFuture<Message> query(Message request) {
+    try {
+      OMRequest omRequest = OMRatisHelper.convertByteStringToOMRequest(
+          request.getContent());
+      return CompletableFuture.completedFuture(queryCommand(omRequest));
+    } catch (IOException e) {
+      return completeExceptionally(e);
+    }
+  }
+
+  /**
+   * Take OM Ratis snapshot. Write the snapshot index to file. Snapshot index
+   * is the log index corresponding to the last applied transaction on the OM
+   * State Machine.
+   *
+   * @return the last applied index on the state machine which has been
+   * stored in the snapshot file.
+   */
+  @Override
+  public long takeSnapshot() throws IOException {
+    LOG.info("Saving Ratis snapshot on the OM.");
+    return ozoneManager.saveRatisSnapshot();
 
 Review comment:
   Question: Can we consider this applied and when the snapshot is taken can we consider that
it is completed?
   
   As writing to rocksdb means is it is not written to disk(As we are writing with sync false),
so when we take a snapshot, we should also flush the DB to make sure the applied index transaction
is applied to OM DB.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: common-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: common-issues-help@hadoop.apache.org


Mime
View raw message