[jira] [Assigned] (IGNITE-21759) Prepare general txn vacuum logic by introducing TxnResourceVacuumTask

["Alexander Lapin (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-21759?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Alexander Lapin reassigned IGNITE-21759:
----------------------------------------

    Assignee: Denis Chudov

> Prepare general txn vacuum logic by introducing TxnResourceVacuumTask
> ---------------------------------------------------------------------
>
>                 Key: IGNITE-21759
>                 URL: https://issues.apache.org/jira/browse/IGNITE-21759
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Alexander Lapin
>            Assignee: Denis Chudov
>            Priority: Major
>              Labels: ignite-3
>
> h3. Motivation
> Within one of Txn cursros cleanup sub tickets cursor cleanup scheduler was introduced. Now it's turn to generalize it to handle txn resource vacuum task. Thus it's expected that TxnResourceVacuumTask will be introduced with following logic inside (this logic will be adjusted later on in other jiras):
>  # TxnResourceVacuumTask evaluates vacuumObservationTimestamp as System.currentTimeMillis(). There's no sense in using hybrid clock in order not to increase the contention level on the clock.
>  # TxnResourceVacuumTask scans txnStateVolatileMap and for each finished (COMMITED or ABORTED) transactions it
>  ## Removes it from txnStateVolatileMap if txnResourcesTTL == 0 (more details a bit later) or if txnState.initialVacuumObservationTimestamp + txnResourcesTTL < vacuumObservationTimestamp.
>  ## Updates txnState.initialVacuumObservationTimestamp by setting it to vacuumObservationTimestamp if it's not already initialized.
> txnResourcesTTL is a new cluster configuration property that defines the *minimum* lifetime of a transaction state in milliseconds. Real txnResourcesTTL lifetime will also depend on cleanupTimer intervals which of course not suitable for test purposes thus we should introduce manual ability to run TxnResourceVacuumTask immediately. At least we will use it within tests.
> h3. Definition of Done
>  * New configuration property txnResourceTTL is introduced with default of 30_000 milliseconds.
>  * TxnResourceVacuumTask is introduced with aforementioned logic. Given task should be tread safe.
>  * Cleanup scheduler is generalized and adjusted to run TxnResourceVacuumTask on every iteration. 
>  * Cleanup scheduler along with subclasses and helpers is renamed to <>Vacuum<>
>  ** Cleanup is part of tx finish flow.
>  ** Vacuum is for removing obsolete resources. Let's be consistent with naming.
>  * Special trigger for TxnResourceVacuumTask introduced within TxManager, at least for testing purposes.



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