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From Lee Parker <...@socialagency.com>
Subject Re: frequent "unknown result" errors
Date Mon, 12 Apr 2010 15:24:12 GMT
If the connections are being made by individual PHP processes running from
the command line, they shouldn't be using the same connection.  Should my
code close the connections after each query and open a new one?

Here is the flow of what is happening when we get the error:
1. Get a set of items from remote API
2. Insert all of the items into the items CF. (usually anywhere from 2 - 200
items)
3. Query the correct index for all entries within a particular time frame
(which is determined by the timeframe of the results of step 1)
4. Compare keys in index to keys of items inserted in step 2.
5. Insert new index columns for items which aren't already in the index.

I am getting the "unknown result" error during step 3.

Lee

On Mon, Apr 12, 2010 at 10:05 AM, Jonathan Ellis <jbellis@gmail.com> wrote:

> unknown result means thrift is badly confused.  You will get this when
> using the same thrift connection from multiple threads, for instance.
>
> On Mon, Apr 12, 2010 at 10:02 AM, Lee Parker <lee@socialagency.com> wrote:
> > 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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