[
https://issues.apache.org/jira/browse/IGNITE-20127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17773264#comment-17773264
]
Alexey Scherbakov edited comment on IGNITE-20127 at 10/9/23 11:44 AM:
----------------------------------------------------------------------
The implementation sends a direct ack message to the txn coordinator for any
async replication command.
The coordinator delays commit until all acks are received.
This currently doesn't work for SQL and needs to be implemented in a separate
ticket.
was (Author: ascherbakov):
The implementation sends a direct ack message to the txn coordinator for any
async replication command.
This currently doesn't work for SQL and needs to be implemented in a separate
ticket.
> Implement 1rtt RW transaction await logic in pre commit
> -------------------------------------------------------
>
> Key: IGNITE-20127
> URL: https://issues.apache.org/jira/browse/IGNITE-20127
> Project: Ignite
> Issue Type: Improvement
> Reporter: Alexander Lapin
> Assignee: Alexey Scherbakov
> Priority: Major
> Labels: ignite-3, transactions
> Time Spent: 8h 20m
> Remaining Estimate: 0h
>
> h3. Motivation
> Our transaction protocol assumes that all required request validations, lock
> acquisitions and similar activities are performed on a primary replica prior
> to command replication, meaning that it's not necessary to await replication
> for every request one by one rather it's required to await them all at once
> in pre-commit phase. Most of what is required for such all at once await has
> already been implemented.
> h3. Definition of Done
> * It's required to do the command replication in an async manner, meaning
> that it's necessary to return the result to the client right after
> replication is triggered. Currently, we return replication result in
> PartitionReplicaListener#applyCmdWithExceptionHandling and await it in
> ReplicaManager#onReplicaMessageReceive
> {code:java}
> CompletableFuture<?> result = replica.processRequest(request);
> result.handle((res, ex) -> {
> ...
> msg = prepareReplicaResponse(requestTimestamp, res);
> ...
> clusterNetSvc.messagingService().respond(senderConsistentId, msg,
> correlationId); {code}
> * And of course it's required to await all commands replication at once in
> pre-commit. We already have such logic in ReadWriteTransactionImpl#finish
> {code:java}
> protected CompletableFuture<Void> finish(boolean commit) {
> ...
> CompletableFuture<Void> mainFinishFut = CompletableFuture
> .allOf(enlistedResults.toArray(new CompletableFuture[0]))
> .thenCompose(
> ...
> return txManager.finish(
> ...{code}
> however, it should use not the result from primary, but the replication
> completion one.
> h3. Implementation Notes
> I believe it's possible to implement it in a following way:
> * ReplicaManager should await only primary related actions like lock
> acquisition and store the replication future in a sort of map. It's possible
> to use safeTime as request Id.
> * Transaction should send replicationAwaitRequest in an async manner right
> after replicationResponse from primary was achieved.
> * enlistedResults should be switched to replicationAwaitResponse.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
