The SELECT with the INNER JOIN is executed with one of the two tables being
optimized as a constant table, which is pre-read.  Spider nevertheless attempts
to push down the join to the data node.  The crash occurs because the constant
table is excluded from the optimized query that Spider attempts to push down.

In order for Spider to be able to push down a join, the following conditions
need to be met:
- All of the tables involved in the join need to be included in the optimized
  query that Spider pushes down.  When any of the tables involved in the join
  is a constant table, it is excluded from the optimized query that Spider
  attempts to push down.
- All fields involved in the query need to be members of tables included in the
  optimized query.

I fixed the problem by preventing Spider from pushing down queries that include
a field that is not a member of a table included in the optimized query.  This
solution fixes the reported problem and also fixes other potential problems.

Author:
  Jacob Mathew.

Reviewer:
  Kentoku Shiba.