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https://issues.apache.org/jira/browse/FLINK-33946?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hangxiang Yu reassigned FLINK-33946:
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Assignee: Hangxiang Yu
> 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: Hangxiang Yu
> Priority: Major
> 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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