pgsql: Fix test for subplans in force-parallel mode.

Fix test for subplans in force-parallel mode.

We mustn't force parallel mode if the query has any subplans, since
ExecSerializePlan doesn't transmit them to workers. Testing
top_plan->initPlan is inadequate because (1) there might be initPlans
attached to lower plan nodes, and (2) non-initPlan subplans don't
work either. There's certainly room for improvement in those
restrictions, but for the moment that's what we've got.

Amit Kapila, per report from Andreas Seltenreich

Discussion: <8737im6pmh(dot)fsf(at)credativ(dot)de>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f24cf960d7ae3503e21fcb59dca652575619d9d4

Modified Files
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src/backend/optimizer/plan/planner.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)