Duo Zhang created HBASE-17633:
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Summary: Update unflushed sequence id in SequenceIdAccounting
after flush with the minimum sequence id in memstore
Key: HBASE-17633
URL: https://issues.apache.org/jira/browse/HBASE-17633
Project: HBase
Issue Type: Improvement
Reporter: Duo Zhang
Now the tracking work is done by SequenceIdAccounting. And it is a little
tricky when dealing with flush. We should remove the mapping for the given
stores of a region from lowestUnflushedSequenceIds, so that we have space to
store the new lowest unflushed sequence id after flush. But we still need to
keep the old sequence ids in another map as we still need to use these values
when reporting to master to prevent data loss(think of the scenario that we
report the new lowest unflushed sequence id to master and we crashed before
actually flushed the data to disk).
And when reviewing HBASE-17407, I found that for CompactingMemStore, we have
to record the minimum sequence id.in memstore. We could just update the
mappings in SequenceIdAccounting after flush. This means we do not need to
update the lowest unflushed sequence id in SequenceIdAccounting, and also do
not need to make space for the new lowest unflushed when startCacheFlush, and
also do not need the extra map to store the old mappings.
This could simplify our logic a lot. But this is an fundamental change so I
need sometime to implement, especially for modifying tests... And I also need
sometime to check if I miss something.
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