Update some comments that should've covered MERGE

Oversight in 7103ebb7aa.  Backpatch to 15.

Author: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAMbWs48gnDjZXq3-b56dVpQCNUJ5hD9kdtWN4QFwKCEapspNsA@mail.gmail.com
This commit is contained in:
Alvaro Herrera 2022-10-24 12:52:43 +02:00
parent 8328a15f8f
commit 3b2db22fe2
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14 changed files with 42 additions and 34 deletions

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@ -3393,12 +3393,13 @@ check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
* Normally we remove quals that are implied by a partial index's
* predicate from indrestrictinfo, indicating that they need not be
* checked explicitly by an indexscan plan using this index. However, if
* the rel is a target relation of UPDATE/DELETE/SELECT FOR UPDATE, we
* cannot remove such quals from the plan, because they need to be in the
* plan so that they will be properly rechecked by EvalPlanQual testing.
* Some day we might want to remove such quals from the main plan anyway
* and pass them through to EvalPlanQual via a side channel; but for now,
* we just don't remove implied quals at all for target relations.
* the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
* we cannot remove such quals from the plan, because they need to be in
* the plan so that they will be properly rechecked by EvalPlanQual
* testing. Some day we might want to remove such quals from the main
* plan anyway and pass them through to EvalPlanQual via a side channel;
* but for now, we just don't remove implied quals at all for target
* relations.
*/
is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
get_plan_rowmark(root->rowMarks, rel->relid) != NULL);

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@ -266,7 +266,7 @@ query_planner(PlannerInfo *root,
add_other_rels_to_query(root);
/*
* Distribute any UPDATE/DELETE row identity variables to the target
* Distribute any UPDATE/DELETE/MERGE row identity variables to the target
* relations. This can't be done till we've finished expansion of
* appendrels.
*/

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@ -1749,7 +1749,7 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
if (bms_membership(root->all_result_relids) == BMS_MULTIPLE)
{
/* Inherited UPDATE/DELETE */
/* Inherited UPDATE/DELETE/MERGE */
RelOptInfo *top_result_rel = find_base_rel(root,
parse->resultRelation);
int resultRelation = -1;
@ -1876,7 +1876,7 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
}
else
{
/* Single-relation INSERT/UPDATE/DELETE. */
/* Single-relation INSERT/UPDATE/DELETE/MERGE. */
resultRelations = list_make1_int(parse->resultRelation);
if (parse->commandType == CMD_UPDATE)
updateColnosLists = list_make1(root->update_colnos);

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@ -730,7 +730,7 @@ find_appinfos_by_relids(PlannerInfo *root, Relids relids, int *nappinfos)
/*
* add_row_identity_var
* Register a row-identity column to be used in UPDATE/DELETE.
* Register a row-identity column to be used in UPDATE/DELETE/MERGE.
*
* The Var must be equal(), aside from varno, to any other row-identity
* column with the same rowid_name. Thus, for example, "wholerow"
@ -909,8 +909,8 @@ add_row_identity_columns(PlannerInfo *root, Index rtindex,
* distribute_row_identity_vars
*
* After we have finished identifying all the row identity columns
* needed by an inherited UPDATE/DELETE query, make sure that these
* columns will be generated by all the target relations.
* needed by an inherited UPDATE/DELETE/MERGE query, make sure that
* these columns will be generated by all the target relations.
*
* This is more or less like what build_base_rel_tlists() does,
* except that it would not understand what to do with ROWID_VAR Vars.

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@ -609,7 +609,7 @@ expand_single_inheritance_child(PlannerInfo *root, RangeTblEntry *parentrte,
/*
* If we are creating a child of the query target relation (only possible
* in UPDATE/DELETE), add it to all_result_relids, as well as
* in UPDATE/DELETE/MERGE), add it to all_result_relids, as well as
* leaf_result_relids if appropriate, and make sure that we generate
* required row-identity data.
*/

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@ -3630,7 +3630,8 @@ create_lockrows_path(PlannerInfo *root, RelOptInfo *rel,
/*
* create_modifytable_path
* Creates a pathnode that represents performing INSERT/UPDATE/DELETE mods
* Creates a pathnode that represents performing INSERT/UPDATE/DELETE/MERGE
* mods
*
* 'rel' is the parent relation associated with the result
* 'subpath' is a Path producing source data

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@ -1013,7 +1013,7 @@ build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
if (var->varno == ROWID_VAR)
{
/* UPDATE/DELETE row identity vars are always needed */
/* UPDATE/DELETE/MERGE row identity vars are always needed */
RowIdentityVarInfo *ridinfo = (RowIdentityVarInfo *)
list_nth(root->row_identity_vars, var->varattno - 1);

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@ -153,7 +153,7 @@ transformFromClause(ParseState *pstate, List *frmList)
/*
* setTargetTable
* Add the target relation of INSERT/UPDATE/DELETE to the range table,
* Add the target relation of INSERT/UPDATE/DELETE/MERGE to the range table,
* and make the special links to it in the ParseState.
*
* We also open the target relation and acquire a write lock on it.
@ -163,7 +163,9 @@ transformFromClause(ParseState *pstate, List *frmList)
*
* If alsoSource is true, add the target to the query's joinlist and
* namespace. For INSERT, we don't want the target to be joined to;
* it's a destination of tuples, not a source. For UPDATE/DELETE,
* it's a destination of tuples, not a source. MERGE is actually
* both, but we'll add it separately to joinlist and namespace, so
* doing nothing (like INSERT) is correct here. For UPDATE/DELETE,
* we do need to scan or join the target. (NOTE: we do not bother
* to check for namespace conflict; we assume that the namespace was
* initially empty in these cases.)

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@ -1679,8 +1679,8 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
/*
* Check to see if the sublink is in an invalid place within the query. We
* allow sublinks everywhere in SELECT/INSERT/UPDATE/DELETE, but generally
* not in utility statements.
* allow sublinks everywhere in SELECT/INSERT/UPDATE/DELETE/MERGE, but
* generally not in utility statements.
*/
err = NULL;
switch (pstate->p_expr_kind)

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@ -163,7 +163,11 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
errmsg("unreachable WHEN clause specified after unconditional WHEN clause")));
}
/* Set up the MERGE target table. */
/*
* Set up the MERGE target table. The target table is added to the
* namespace below and to joinlist in transform_MERGE_to_join, so don't
* do it here.
*/
qry->resultRelation = setTargetTable(pstate, stmt->relation,
stmt->relation->inh,
false, targetPerms);

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@ -1043,8 +1043,8 @@ typedef struct RangeTblEntry
*
* rellockmode is really LOCKMODE, but it's declared int to avoid having
* to include lock-related headers here. It must be RowExclusiveLock if
* the RTE is an INSERT/UPDATE/DELETE target, else RowShareLock if the RTE
* is a SELECT FOR UPDATE/FOR SHARE target, else AccessShareLock.
* the RTE is an INSERT/UPDATE/DELETE/MERGE target, else RowShareLock if
* the RTE is a SELECT FOR UPDATE/FOR SHARE target, else AccessShareLock.
*
* Note: in some cases, rule expansion may result in RTEs that are marked
* with RowExclusiveLock even though they are not the target of the

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@ -328,11 +328,11 @@ struct PlannerInfo
/*
* all_result_relids is empty for SELECT, otherwise it contains at least
* parse->resultRelation. For UPDATE/DELETE across an inheritance or
* partitioning tree, the result rel's child relids are added. When using
* multi-level partitioning, intermediate partitioned rels are included.
* leaf_result_relids is similar except that only actual result tables,
* not partitioned tables, are included in it.
* parse->resultRelation. For UPDATE/DELETE/MERGE across an inheritance
* or partitioning tree, the result rel's child relids are added. When
* using multi-level partitioning, intermediate partitioned rels are
* included. leaf_result_relids is similar except that only actual result
* tables, not partitioned tables, are included in it.
*/
/* set of all result relids */
Relids all_result_relids;
@ -2792,10 +2792,10 @@ typedef struct AppendRelInfo
} AppendRelInfo;
/*
* Information about a row-identity "resjunk" column in UPDATE/DELETE.
* Information about a row-identity "resjunk" column in UPDATE/DELETE/MERGE.
*
* In partitioned UPDATE/DELETE it's important for child partitions to share
* row-identity columns whenever possible, so as not to chew up too many
* In partitioned UPDATE/DELETE/MERGE it's important for child partitions to
* share row-identity columns whenever possible, so as not to chew up too many
* targetlist columns. We use these structs to track which identity columns
* have been requested. In the finished plan, each of these will give rise
* to one resjunk entry in the targetlist of the ModifyTable's subplan node.

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@ -72,7 +72,7 @@ typedef struct PlannedStmt
List *rtable; /* list of RangeTblEntry nodes */
/* rtable indexes of target relations for INSERT/UPDATE/DELETE */
/* rtable indexes of target relations for INSERT/UPDATE/DELETE/MERGE */
List *resultRelations; /* integer list of RT indexes, or NIL */
List *appendRelations; /* list of AppendRelInfo nodes */
@ -217,7 +217,7 @@ typedef struct ProjectSet
* nominalRelation and rootRelation contain the RT index of the partition
* root, which is not otherwise mentioned in the plan. Otherwise rootRelation
* is zero. However, nominalRelation will always be set, as it's the rel that
* EXPLAIN should claim is the INSERT/UPDATE/DELETE target.
* EXPLAIN should claim is the INSERT/UPDATE/DELETE/MERGE target.
*
* Note that rowMarks and epqParam are presumed to be valid for all the
* table(s); they can't contain any info that varies across tables.

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@ -177,8 +177,8 @@ typedef struct Expr
* is abused to signify references to columns of a custom scan tuple type.)
*
* ROWID_VAR is used in the planner to identify nonce variables that carry
* row identity information during UPDATE/DELETE. This value should never
* be seen outside the planner.
* row identity information during UPDATE/DELETE/MERGE. This value should
* never be seen outside the planner.
*
* In the parser, varnosyn and varattnosyn are either identical to
* varno/varattno, or they specify the column's position in an aliased JOIN