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From lars hofhansl <lhofha...@yahoo.com>
Subject Re: HTable.flushCommits and ordering
Date Mon, 16 Jan 2012 07:25:35 GMT
It's late... Never mind... Everything is timestamped... So order does not matter.



----- Original Message -----
From: lars hofhansl <lhofhansl@yahoo.com>
To: hbase-dev <dev@hbase.apache.org>
Cc: 
Sent: Sunday, January 15, 2012 11:01 PM
Subject: HTable.flushCommits and ordering

Here's another strange client behavior:
When autoFlush is set to false on HTable (or HTable.batch is used), this triggers a Multi
action at the RegionServer.

However, the RegionServer collects all Puts and executes those after all other action (presumably
to make use of
batching for Puts). If the batch contains Deletes that is not correct, since the order of
Deletes w.r.t. Puts is significant.

I am adding the option to force execution in the provided order (default false), which would
retain the order of Puts/Deletes/etc, but
comes with a performance penalty at the server (it is still a single roundtrip, though, which
is good).
I'll attach a patch for this (as part of a bigger change) to HBASE-5203 soon. Please provide
your comments.

Thanks.

-- Lars

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