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Support MERGE into updatable views.

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This allows the target relation of MERGE to be an auto-updatable or
trigger-updatable view, and includes support for WITH CHECK OPTION,
security barrier views, and security invoker views.

A trigger-updatable view must have INSTEAD OF triggers for every type
of action (INSERT, UPDATE, and DELETE) mentioned in the MERGE command.
An auto-updatable view must not have any INSTEAD OF triggers. Mixing
auto-update and trigger-update actions (i.e., having a partial set of
INSTEAD OF triggers) is not supported.

Rule-updatable views are also not supported, since there is no
rewriter support for non-SELECT rules with MERGE operations.

Dean Rasheed, reviewed by Jian He and Alvaro Herrera.

Discussion: https://postgr.es/m/CAEZATCVcB1g0nmxuEc-A+gGB0HnfcGQNGYH7gS=7rq0u0zOBXA@mail.gmail.com
This commit is contained in:
Dean Rasheed
2024-02-29 15:56:59 +00:00
parent 8b29a119fd
commit 5f2e179bd3
23 changed files with 1380 additions and 288 deletions
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20
src/backend/optimizer/prep/prepjointree.c
View File

@@ -198,12 +198,17 @@ transform_MERGE_to_join(Query *parse)
/*
* Create a JOIN between the target and the source relation.
*
* Here the target is identified by parse->mergeTargetRelation. For a
* regular table, this will equal parse->resultRelation, but for a
* trigger-updatable view, it will be the expanded view subquery that we
* need to pull data from.
*/
joinexpr = makeNode(JoinExpr);
joinexpr->jointype = jointype;
joinexpr->isNatural = false;
joinexpr->larg = (Node *) makeNode(RangeTblRef);
((RangeTblRef *) joinexpr->larg)->rtindex = parse->resultRelation;
((RangeTblRef *) joinexpr->larg)->rtindex = parse->mergeTargetRelation;
joinexpr->rarg = linitial(parse->jointree->fromlist); /* original join */
joinexpr->usingClause = NIL;
joinexpr->join_using_alias = NULL;
@@ -215,6 +220,19 @@ transform_MERGE_to_join(Query *parse)
/* Make the new join be the sole entry in the query's jointree */
parse->jointree->fromlist = list_make1(joinexpr);
parse->jointree->quals = NULL;
/*
* If necessary, mark parse->targetlist entries that refer to the target
* as nullable by the join. Normally the targetlist will be empty for a
* MERGE, but if the target is a trigger-updatable view, it will contain a
* whole-row Var referring to the expanded view query.
*/
if (parse->targetList != NIL &&
(jointype == JOIN_RIGHT || jointype == JOIN_FULL))
parse->targetList = (List *)
add_nulling_relids((Node *) parse->targetList,
bms_make_singleton(parse->mergeTargetRelation),
bms_make_singleton(joinrti));
}
/*

3
src/backend/optimizer/util/appendinfo.c
View File

@@ -891,8 +891,7 @@ add_row_identity_columns(PlannerInfo *root, Index rtindex,
Assert(commandType == CMD_UPDATE || commandType == CMD_DELETE || commandType == CMD_MERGE);
if (commandType == CMD_MERGE ||
relkind == RELKIND_RELATION ||
if (relkind == RELKIND_RELATION ||
relkind == RELKIND_MATVIEW ||
relkind == RELKIND_PARTITIONED_TABLE)
{