amaliujia commented on a change in pull request #1725:
URL: https://github.com/apache/ozone/pull/1725#discussion_r559798815
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File path:
hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SCMStateMachine.java
##########
@@ -26,27 +26,55 @@
import java.util.concurrent.CompletableFuture;
import com.google.protobuf.InvalidProtocolBufferException;
+import org.apache.hadoop.hdds.scm.exceptions.SCMException;
+import org.apache.hadoop.util.Time;
import org.apache.ratis.protocol.Message;
+import org.apache.ratis.server.protocol.TermIndex;
+import org.apache.ratis.statemachine.SnapshotInfo;
import org.apache.ratis.statemachine.TransactionContext;
import org.apache.ratis.statemachine.impl.BaseStateMachine;
import org.apache.hadoop.hdds.protocol.proto.SCMRatisProtocol.RequestType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static
org.apache.hadoop.hdds.scm.exceptions.SCMException.ResultCodes.SCM_NOT_INITIALIZED;
/**
* TODO.
*/
public class SCMStateMachine extends BaseStateMachine {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(BaseStateMachine.class);
private final Map<RequestType, Object> handlers;
+ private final SCMDBTransactionBuffer transactionBuffer;
- public SCMStateMachine() {
+ public SCMStateMachine(SCMDBTransactionBuffer buffer) throws SCMException {
this.handlers = new EnumMap<>(RequestType.class);
+ this.transactionBuffer = buffer;
+ SCMTransactionInfo latestTrxInfo = buffer.getLatestTrxInfo();
+ if (!latestTrxInfo.isInitialized()) {
+ if (!updateLastAppliedTermIndex(latestTrxInfo.getTerm(),
+ latestTrxInfo.getTransactionIndex())) {
+ throw new SCMException(
+ String.format("Failed to update LastAppliedTermIndex " +
+ "in StateMachine to term:{} index:{}",
+ latestTrxInfo.getTerm(), latestTrxInfo.getTransactionIndex()
+ ), SCM_NOT_INITIALIZED);
+ }
+ }
}
public void registerHandler(RequestType type, Object handler) {
handlers.put(type, handler);
}
+ @Override
+ public SnapshotInfo getLatestSnapshot() {
+ return transactionBuffer.getLatestSnapshot();
+ }
+
@Override
public CompletableFuture<Message> applyTransaction(
Review comment:
I created https://issues.apache.org/jira/browse/HDDS-4684.
After check the Ratis state machine interface, I can see two functions:
```
/**
* Called for transactions that have been committed to the RAFT log. This
step is called
* sequentially in strict serial order that the transactions have been
committed in the log.
* The SM is expected to do only necessary work, and leave the actual
apply operation to the
* applyTransaction calls that can happen concurrently.
* @param trx the transaction state including the log entry that has been
committed to a quorum
* of the raft peers
* @return The Transaction context.
*/
TransactionContext applyTransactionSerial(TransactionContext trx);
/**
* Apply a committed log entry to the state machine. This method can be
called concurrently with
* the other calls, and there is no guarantee that the calls will be
ordered according to the
* log commit order.
* @param trx the transaction state including the log entry that has been
committed to a quorum
* of the raft peers
*/
CompletableFuture<Message> applyTransaction(TransactionContext trx);
```
So there is no API as the following
```
Message applyTransactionSerial(TransactionContext trx);
```
Basically a function to apply transaction in strict serial order where it
returns a Message.
I am planning to send an email to Ratis community to discuss the intention
of only having one applyTransaction that returns Message
(CompletableFuture<Message>) but can be called concurrently.
We can address this API change in HDDS-4684.
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