[jira] [Updated] (IGNITE-27435) Improve commit latency for explicit RW transactions

["Alexey Scherbakov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-27435?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Alexey Scherbakov updated IGNITE-27435:
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    Summary: Improve commit latency for explicit RW transactions  (was: Optimize commit time for explicit RW transactions)

> Improve commit latency for explicit RW transactions
> ---------------------------------------------------
>
>                 Key: IGNITE-27435
>                 URL: https://issues.apache.org/jira/browse/IGNITE-27435
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Alexey Scherbakov
>            Priority: Major
>              Labels: ignite-3
>             Fix For: 3.3
>
>
> Currently explicit transaction is committed as soon as all write inflights are completed.
> This adds additional "tail" latency before beginning to commit.
> This can be optimized in the following way:
> 1. Each inflight addtitionally tracks corresponding key in the tx inflight context. A key is removed from the set as soon as inglight is replicated
> 2. We introduce addtitinal persisted tx state: COMMITTING
> 3. The a tx is started to commit, it synchronously replicates COMMITTING state instead of COMMITED. Committing state additionally includes a list of keys (ack list), which are being inflight just before commit starts.
> 4. Tx commit as acked to the user as soon as COMMITTING state is replicated and all inflights are finished. This is "implicit commit".
> 5. As soon as tx is "implicitly committed", COMMITED state is replicated asynchronously. After this, tx is considered "explicitely committed".
> We need changes in tx recovery. When an abandoned write intent is encountered and tx is in COMMITTING state and corresponding key is in the ack list, we need to check if it is fully replicated. If no, tx is marked as rolled back.



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