[jira] [Updated] (IGNITE-17261) Implement a coordinator path write intent resolution logic for RO reads

["Sergey Uttsel (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-17261?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sergey Uttsel updated IGNITE-17261:
-----------------------------------
    Summary: Implement a coordinator path write intent resolution logic for RO reads  (was: Implement write intent resolution logic for RO reads)

> Implement a coordinator path write intent resolution logic for RO reads
> -----------------------------------------------------------------------
>
>                 Key: IGNITE-17261
>                 URL: https://issues.apache.org/jira/browse/IGNITE-17261
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Alexander Lapin
>            Priority: Major
>              Labels: ignite-3, transaction3_ro
>         Attachments: Screenshot from 2022-07-06 17-00-26.png
>
>
> Because of lock-free nature, RO reads might interact with writeIntents, meaning that such intents should be either evaluated as committed, aborted or pending. In order to perform writeIntent resolution it's required to
>  * Checks a local txn state map for committed or aborted state - allow read if the state is committed and commitTs <= readTs.
>  * If not possible, send a TxStateReq  to the txn coordinator - this initiates the {*}coordinator path{*}. Coordinator address is fetched from the [txn state map|https://docs.google.com/document/d/1PndaylEfK7CPUN7Kv9RYPKASN299s2qlbnMA5xIOFXo/edit#heading=h.wx3zf7jlf156].
>  * If a coordinator path was not able to resolve the intent, one of the following has happened - the coordinator is dead or txn state is not available in the cache. Calculate a commit partition and send the TxStateReq to its primary replica - this initiates the {*}commit partition path{*}.
>  * Retry commit partition path until a success or timeout.
> On receiving TxStateReq on the coordinator:
>  * If the local txn is finished, return the response with the outcome: commit or abort. The txn state is stored in a local cache, mentioned in the RW section.
>  * If the local txn is finishing (waiting for finish state replication), wait for outcome and return response with the outcome: commit or abort
>  * If the outcome is to commit, additional timestamp check is required: a commit timestamp must be <= readTs. If the condition is not held, the outcome is changed to commit .
>  * If local txn is active, adjust the txn coordinator node HLC according to readTs to make sure the txn commit timestamp is above the read timestamp. The read timestamp must be installed before txn is started to commit, so commit timestamp is assigned after the read timestamp. This must be achieved by some sort of concurrency control, preferably non-blocking. In this case we must ignore the write intent, so the outcome is to abort.
>  * If txn state is not found in a local cache and txn is not active, return NULL.
>  
> There's an open question about MvPartitionStorage api feature: https://issues.apache.org/jira/browse/IGNITE-17627



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