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Fix up planner infrastructure to support LATERAL properly.
This patch takes care of a number of problems having to do with failure to choose valid join orders and incorrect handling of lateral references pulled up from subqueries. Notable changes: * Add a LateralJoinInfo data structure similar to SpecialJoinInfo, to represent join ordering constraints created by lateral references. (I first considered extending the SpecialJoinInfo structure, but the semantics are different enough that a separate data structure seems better.) Extend join_is_legal() and related functions to prevent trying to form unworkable joins, and to ensure that we will consider joins that satisfy lateral references even if the joins would be clauseless. * Fill in the infrastructure needed for the last few types of relation scan paths to support parameterization. We'd have wanted this eventually anyway, but it is necessary now because a relation that gets pulled up out of a UNION ALL subquery may acquire a reltargetlist containing lateral references, meaning that its paths *have* to be parameterized whether or not we have any code that can push join quals down into the scan. * Compute data about lateral references early in query_planner(), and save in RelOptInfo nodes, to avoid repetitive calculations later. * Assorted corner-case bug fixes. There's probably still some bugs left, but this is a lot closer to being real than it was before.
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@@ -367,6 +367,7 @@ OffsetVarNodes_walker(Node *node, OffsetVarNodes_context *context)
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/* Shouldn't need to handle other planner auxiliary nodes here */
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Assert(!IsA(node, PlanRowMark));
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Assert(!IsA(node, SpecialJoinInfo));
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Assert(!IsA(node, LateralJoinInfo));
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Assert(!IsA(node, PlaceHolderInfo));
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Assert(!IsA(node, MinMaxAggInfo));
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@@ -548,6 +549,7 @@ ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
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}
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/* Shouldn't need to handle other planner auxiliary nodes here */
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Assert(!IsA(node, SpecialJoinInfo));
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Assert(!IsA(node, LateralJoinInfo));
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Assert(!IsA(node, PlaceHolderInfo));
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Assert(!IsA(node, MinMaxAggInfo));
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@@ -816,6 +818,7 @@ rangeTableEntry_used_walker(Node *node,
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Assert(!IsA(node, PlaceHolderVar));
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Assert(!IsA(node, PlanRowMark));
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Assert(!IsA(node, SpecialJoinInfo));
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Assert(!IsA(node, LateralJoinInfo));
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Assert(!IsA(node, AppendRelInfo));
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Assert(!IsA(node, PlaceHolderInfo));
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Assert(!IsA(node, MinMaxAggInfo));
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