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Fix up planner infrastructure to support LATERAL properly.

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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.
This commit is contained in:
Tom Lane
2012-08-26 22:48:55 -04:00
parent de87d47044
commit 9ff79b9d4e
30 changed files with 818 additions and 183 deletions
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8
src/include/optimizer/pathnode.h
View File

@@ -55,7 +55,7 @@ extern BitmapOrPath *create_bitmap_or_path(PlannerInfo *root,
RelOptInfo *rel,
List *bitmapquals);
extern TidPath *create_tidscan_path(PlannerInfo *root, RelOptInfo *rel,
List *tidquals);
List *tidquals, Relids required_outer);
extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths,
Relids required_outer);
extern MergeAppendPath *create_merge_append_path(PlannerInfo *root,
@@ -73,8 +73,10 @@ extern Path *create_functionscan_path(PlannerInfo *root, RelOptInfo *rel,
Relids required_outer);
extern Path *create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel,
Relids required_outer);
extern Path *create_ctescan_path(PlannerInfo *root, RelOptInfo *rel);
extern Path *create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel);
extern Path *create_ctescan_path(PlannerInfo *root, RelOptInfo *rel,
Relids required_outer);
extern Path *create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel,
Relids required_outer);
extern ForeignPath *create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel,
double rows, Cost startup_cost, Cost total_cost,
List *pathkeys,