khannaekta opened a new pull request #476: DL: Avoid constant folding of 
weights in GPDB6 plan
URL: https://github.com/apache/madlib/pull/476
 
 
   For versions >=GPDB6, previously, for queries called with the initial
   weights value passed in, the query plan for it would have create custom
   plans with weights embedded in the plan itself.  This meant that the
   query plan size would also include the size of these weights, bloating
   it up to hit the 1GB limit when dispatching the query plan to segments,
   leading to OOM for large weights.
   
   In GPDB, for PREPARE plans, there is a threshold of 5 attempts to create
   custom plans(constant folding the passed in params) for execution and
   then it uses a generic plan(not constant folding the passed in params)
   for all the subsequent executions.  Therefore, to avoid GPDB6 from
   creating custom plans when passing in weights, the queries(with weights)
   is executed with DUMMY weights for 5 time, prior to calling it with the
   actual weights.
   
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