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Date: Mon, 7 Jun 2010 17:20:56 -0500
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Subject: Perl/Thrift/Cassandra strangeness
From: Jonathan Shook <jshook@gmail.com>
To: user@cassandra.apache.org
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I have a structure like this:

CF:"Status"
{
  Row("Component42")
  {
    SuperColumn(1275948636203) (epoch millis)
    {
      sub columns...
    }
  }
}

The supercolumns are dropped in periodically by system A, which is using Hector.
System B uses a lightweight perl/Thrift client to reduce process
overhead. (It gets called as a process frequently)
This will go away at some point, but for now it is the de-facto means
for integrating the two systems.

According to the API docs, under get_range_slices, "The empty string
("") can be used as a sentinel value to get the first/last existing
key (or first/last column in the column predicate parameter)"
This seems to conflict directly with the error message that I am
getting: "column name must not be empty", which ISA
Cassandra::InvalidRequestException.

The point is to get the "last" super-column.

I've also tried to set the predicate's slice_range for "all columns,
reversed, limit 1" but it simply returns multiple super columns.

Is the Perl Thrift client problematic, or is there something else that
I am missing?