Details
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Type:
Bug
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Status: Closed
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Priority:
Trivial
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Resolution: Fixed
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Affects Version/s: None
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Fix Version/s: 0.94.12
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Component/s: None
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Labels:None
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Hadoop Flags:Reviewed
Description
Currently the Javadoc in HBaseAdmin.flush(...) says that this is an asynchronous operation. Looking at the, however, it is in fact not.
Having this as a synchronous operation open ups some use cases we're interested in. For example doing some ingest via the high level API with WAL disabled and then issue a flush through the HBaseAdmin. When the flush succeeded we know the data is securely in HBase.
(This should work even with intermediary splits, as they also force a flush, but that needs to be verified as well.
So this is just for a trivial Javadoc change.
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Wasn't that fixed in HBASE-6835?
And I had this on my wishlist for a while now HBASE-4198.
Ah, didn't know about HBASE-6835. Will just "backport" that then. In the future we can always add a asyncFlush when needed.
Here's a breathtakingly beautiful and complex patch, changing the javadoc.
As for HBASE-4198. Yeah, definitely need:
- issue the flushes in parallel
- offer a asynchronous version
Will commit this soon unless I hear objections (as we have done the same change in trunk anyway)
Your patch breaks everything... not sure if I can agree with you... but I'll +1 it 
Committed to 0.94 (in 0.95+ already)
HBASE-5783 is also related.
SUCCESS: Integrated in HBase-0.94-security #263 (See https://builds.apache.org/job/HBase-0.94-security/263/)
HBASE-9266 Javadoc: Document that HBaseAdmin.flush(...) is synchronous (larsh: rev 1515676)
- /hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java
SUCCESS: Integrated in HBase-0.94 #1117 (See https://builds.apache.org/job/HBase-0.94/1117/)
HBASE-9266 Javadoc: Document that HBaseAdmin.flush(...) is synchronous (larsh: rev 1515676)
- /hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java
Note: It is fine to promise an asynchronous API and then actually perform the action synchronously. The reverse is not true.
With that in mind I could a new method to HBaseAdmin: syncFlush(...) which guarantees synchronous operation. That way we can make flush() asynchronous in the future, without breaking any expectation in the caller.
Thoughts?