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From Lee Parker <...@socialagency.com>
Subject frequent "unknown result" errors
Date Mon, 12 Apr 2010 15:02:52 GMT
I am a newbie with Cassandra.  We are currently migrating a large amount of
data out of MySQL into Cassandra.  I have two ColumnFamilies.  One contains
one row per item and each item has roughly 12 columns.  These are items from
REST APIs like the Twitter API.  Then I have a second ColumnFamily with very
large rows and TimeUUID column names which contain the key of the items in
the other ColumnFamily.  So one ColumnFamily has lots of rows with a low
number of columns per row, and the other has relatively few rows with a
large (~500k) columns per row.

I am getting rather frequent errors with "unknown result" from get_slice and
multiget_slice calls from the index ColumnFamily.  I am using Pandra for the
calls.  I can see that this is a generic exception thrown by the Cassandra
Thrift package when it doesn't know what else to say.  Is there a way to
actually see what the result was in a more raw form from the Thrift
protocol?

One thought I had on why this is happening is that my results might be
larger than the configuration settings.  Does anyone have any good ideas on
how to calculate what the ideal values of SlicedBufferSizeInKB
and ColumnIndexSizeInKB should be?  If these are too low, would i get a more
descriptive error?

Lee Parker

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