[jira] [Updated] (FLINK-33946) RocksDb sets setAvoidFlushDuringShutdown to true to speed up Task Cancel

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-33946?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated FLINK-33946:
-----------------------------------
    Labels: pull-request-available  (was: )

> RocksDb sets setAvoidFlushDuringShutdown to true to speed up Task Cancel
> ------------------------------------------------------------------------
>
>                 Key: FLINK-33946
>                 URL: https://issues.apache.org/jira/browse/FLINK-33946
>             Project: Flink
>          Issue Type: Improvement
>          Components: Runtime / State Backends
>    Affects Versions: 1.19.0
>            Reporter: Yue Ma
>            Assignee: Yue Ma
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.19.0
>
>
> When a Job fails, the task needs to be canceled and re-deployed. RocksDBStatebackend will call RocksDB.close when disposing.
> {code:java}
> if (!shutting_down_.load(std::memory_order_acquire) &&
>     has_unpersisted_data_.load(std::memory_order_relaxed) &&
>     !mutable_db_options_.avoid_flush_during_shutdown) {
>   if (immutable_db_options_.atomic_flush) {
>     autovector<ColumnFamilyData*> cfds;
>     SelectColumnFamiliesForAtomicFlush(&cfds);
>     mutex_.Unlock();
>     Status s =
>         AtomicFlushMemTables(cfds, FlushOptions(), FlushReason::kShutDown);
>     s.PermitUncheckedError();  //**TODO: What to do on error?
>     mutex_.Lock();
>   } else {
>     for (auto cfd : *versions_->GetColumnFamilySet()) {
>       if (!cfd->IsDropped() && cfd->initialized() && !cfd->mem()->IsEmpty()) {
>         cfd->Ref();
>         mutex_.Unlock();
>         Status s = FlushMemTable(cfd, FlushOptions(), FlushReason::kShutDown);
>         s.PermitUncheckedError();  //**TODO: What to do on error?
>         mutex_.Lock();
>         cfd->UnrefAndTryDelete();
>       }
>     }
>   } {code}
> By default (avoid_flush_during_shutdown=false) RocksDb requires FlushMemtable when Close. When the disk pressure is high or the Memtable is large, this process will be more time-consuming, which will cause the Task to get stuck in the Canceling stage and affect the speed of job Failover.
> In fact, it is completely unnecessary to Flush memtable when Flink Task is Close, because the data can be replayed from Checkpoint. So we can set avoid_flush_during_shutdown to true to speed up Task Failover



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