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From rgaimari <rgaim...@gmail.com>
Subject Endpoint and Observer work together?
Date Tue, 01 Oct 2013 19:55:13 GMT

I am using HBase version 0.94.2-cdh4.2.0.  I have a question about

I have two Coprocessors: one is an Endpoint, and the other is an Observer. 
The Endpoint accepts a set of filters, does a scan of a table with them, and
returns the results back to the client.  The Observer overrides
preScannerOpen() and postScannerNext() to examine the return values of a
scan of a table and edit some of them before returning them to the caller.

Both of these Coprocessors work exactly as intended in isolation.  If I
attach the Endpoint to a table, the scan works properly and the correct
results are returned.  If, instead, I attach the Observer to the table and
do a scan from the client, the results are returned properly edited.

However, if I attach both of them to the same table, the Observer no longer
is called.  The scan in the Endpoint happens, but the Observer is never
called to do the editing.  What I assumed would happen is that the Endpoint
would invoke the scan, which would get the Observer into play.  But that
doesn't happen.  If I have both attached to the same table, but don't
involve the Endpoint (do the scan from the client), the Observer works
correctly; so I believe that they are both attached correctly.

I've set the priority of the Observer to 1 (which I believe is the highest),
and the Endpoint to 1001.  Should a scan from within an Endpoint invoke the
Observer?  If so, what might I be doing wrong?  Thanks.

- Bob Gaimari

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