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https://issues.apache.org/jira/browse/IGNITE-20033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17758575#comment-17758575
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Denis Chudov commented on IGNITE-20033:
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PR [2483|https://github.com/apache/ignite-3/pull/2483] is ready for review.
> Implement local txnStateMap
> ---------------------------
>
> Key: IGNITE-20033
> URL: https://issues.apache.org/jira/browse/IGNITE-20033
> Project: Ignite
> Issue Type: Improvement
> Reporter: Alexander Lapin
> Assignee: Denis Chudov
> Priority: Major
> Labels: ignite-3, transaction3_recovery, transactions
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> h3. Motivation
> For some purposes, in addition to persistent txnState in commit partition,
> it's required to have a txn meta on every transactional actor: txn
> coordinator, commit partition (both primary and all backups) and all enlisted
> partitions (both primary and backups).
> [IEP-91|https://cwiki.apache.org/confluence/display/IGNITE/IEP-91%3A+Transaction+protocol#IEP91:Transactionprotocol-Txnstatemap]
> names such meta holder as txn state map and specifies following structure
> {code:java}
> txId -> (txState, txCoordAddr, commitTs){code}
> Such map is originally designed to provide required information for
> writeIntentResolution: txState for local write intent resolution and
> txCoordAddr for coordinator-path one, but that's not all it's good for, so it
> definitely worth to implement it as soon as possible in order to unblock
> further activities.
> -Why we have this ticket in "commit partition recovery" pack?
> -Because in order to implement proper handling of a commit partition primary
> replica change (which is definitely a part of the "commit partition pack")
> it's required to:
> # Support local txnStateMap, in order to
> # Implement writeIntentResolution coordinator path, in order to
> # Calculate commitTimestamp on txn coordtinator istead of commit partition,
> where we do it now.
> h3. Definition of Done
> Every transactional actor
> * Txn Coordinator.
> * CommitPartition, both primary and all backups.
> * All enlisted partitions, both primary and all backups.
> should have volatile txnStateMap with following suggested structure 'txId ->
> (txState, txCoordAddr, commitTs)'.
>
> Given map should be adjusted before any further transactional actions within
> node in a following way:
> * Transaction coordinator.
> ** On transaction start with state PENDING.
> ** On transaction commit, right after commitTimestamp calucalttion with
> state FINISHING.
> ** On txFinishReplicaResponse with either COMMITED or ABORTED.
> * Commit partition.
> ** On replica touch with state PENDING.
> ** After succefull finishTxCommand application on majoirty with either
> COMMITED or ABORTED.
> ** Seems that we don't need FINISHING state here, so let's skip it for now.
> * Enlisted replica.
> ** Primary
> *** On replica touch with state PENDING.
> *** On TxCleanupCommand COMMITED or ABORTED.
> ** Backup
> *** On touch replication PENDING.
> *** On TxCleanupCommand COMMITED or ABORTED, same as for primary.
> h3. Implementation Notes
> There are some open questions:
> * Where to put this txnStateMap? TxManager?
> * Properly handle same map multiple updates, based on the fact that Commit
> Partition is also an enlisted partition. To be honest I believe it's not that
> important. We may extent possible state change application rules to assume
> that null > PENDING, PENDING > FINISHING, PENDING > COMMITED, PENDING >
> ABORTED, PENDING > PENDING, COMMITED > COMMITED and ABORTED > ABORTED are all
> possible.
> * Eliminate excessive map updates in case of "one-phase commit".
> https://issues.apache.org/jira/browse/IGNITE-15927
> * Substitute org.apache.ignite.internal.tx.impl.TxManagerImpl#states with
> txnStateMap.
> * Definte "touch".
> * It's reasonbale to use non-consistent node id as txCoordAddr because
> currently there's no sense in sending TxStateReq to the node that lost it's
> local txnStateMap because of node restart.
>
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