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Update plannodes.h's comments about PlanRowMark.

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The reference here to different physical column numbers in inherited
UPDATE/DELETE plans is obsolete as of 86dc90056; remove it.  Also
rework the text about inheritance cases to make it clearer.
This commit is contained in:
Tom Lane 2021-06-02 11:52:35 -04:00
parent 9e3b3ff266
commit 79c50ca578
1 changed files with 4 additions and 5 deletions
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9
src/include/nodes/plannodes.h
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@ -1086,9 +1086,9 @@ typedef enum RowMarkType
* When the planner discovers that a relation is the root of an inheritance * When the planner discovers that a relation is the root of an inheritance
* tree, it sets isParent true, and adds an additional PlanRowMark to the * tree, it sets isParent true, and adds an additional PlanRowMark to the
* list for each child relation (including the target rel itself in its role * list for each child relation (including the target rel itself in its role
* as a child). isParent is also set to true for the partitioned child * as a child, if it is not a partitioned table). Any non-leaf partitioned
* relations, which are not scanned just like the root parent. The child * child relations will also have entries with isParent = true. The child
* entries have rti == child rel's RT index and prti == parent's RT index, * entries have rti == child rel's RT index and prti == top parent's RT index,
* and can therefore be recognized as children by the fact that prti != rti. * and can therefore be recognized as children by the fact that prti != rti.
* The parent's allMarkTypes field gets the OR of (1<<markType) across all * The parent's allMarkTypes field gets the OR of (1<<markType) across all
* its children (this definition allows children to use different markTypes). * its children (this definition allows children to use different markTypes).
@ -1109,8 +1109,7 @@ typedef enum RowMarkType
* means we needn't renumber rowmarkIds when flattening subqueries, which * means we needn't renumber rowmarkIds when flattening subqueries, which
* would require finding and renaming the resjunk columns as well.) * would require finding and renaming the resjunk columns as well.)
* Note this means that all tables in an inheritance hierarchy share the * Note this means that all tables in an inheritance hierarchy share the
* same resjunk column names. However, in an inherited UPDATE/DELETE the * same resjunk column names.
* columns could have different physical column numbers in each subplan.
*/ */
typedef struct PlanRowMark typedef struct PlanRowMark
{ {