Details
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Improvement
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Status: Closed
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Major
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Resolution: Not A Problem
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Description
This is a follow up improvement of HBase-8763. After we combined MVCC & LogSeqId, the memstore read point advances in the logSeqId increasing order. The MultiVersionConsistencyControl#writeQueue can be possibly removed.
In order to remove writeQueue, we need to return the disruptor sequence of the last WALEdit with durability >= SYNC_WAL inside disruptor consumer code before assigning log sequence Id. If current WALEdit has durability >= SYNC_WAL, we return the disruptor sequence of current WALEdit.
During syncOrDefer, we always waits for the sequence of the last WALEdit has durability >= SYNC_WAL.
The tricky part is how to return the disruptor sequence of the last WALEdit with durability >= SYNC_WAL cleanly from disruptor consumer.
We could put those info in HLogKey because we always create a new HLogKey object for each change otherwise we have to create a new object for this purpose.