On Tue, 10 Jan 2023 at 14:43, Dean Rasheed <dean.a.rash...@gmail.com> wrote:
>
> Rebased version attached.
>
Rebased version, following 8eba3e3f02 and 5d29d525ff.
Regards,
Dean
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
new file mode 100644
index b87ad5c..1482ede
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -396,8 +396,8 @@
originally matched appears later in the list of actions.
On the other hand, if the row is concurrently updated or deleted so
that the join condition fails, then <command>MERGE</command> will
- evaluate the condition's <literal>NOT MATCHED</literal> actions next,
- and execute the first one that succeeds.
+ evaluate the condition's <literal>NOT MATCHED [BY TARGET]</literal>
+ actions next, and execute the first one that succeeds.
If <command>MERGE</command> attempts an <command>INSERT</command>
and a unique index is present and a duplicate row is concurrently
inserted, then a uniqueness violation error is raised;
diff --git a/doc/src/sgml/ref/merge.sgml b/doc/src/sgml/ref/merge.sgml
new file mode 100644
index 0995fe0..8ef121a
--- a/doc/src/sgml/ref/merge.sgml
+++ b/doc/src/sgml/ref/merge.sgml
@@ -33,7 +33,8 @@ USING <replaceable class="parameter">dat
<phrase>and <replaceable class="parameter">when_clause</replaceable> is:</phrase>
{ WHEN MATCHED [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_update</replaceable> | <replaceable class="parameter">merge_delete</replaceable> | DO NOTHING } |
- WHEN NOT MATCHED [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_insert</replaceable> | DO NOTHING } }
+ WHEN NOT MATCHED BY SOURCE [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_update</replaceable> | <replaceable class="parameter">merge_delete</replaceable> | DO NOTHING } |
+ WHEN NOT MATCHED [BY TARGET] [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_insert</replaceable> | DO NOTHING } }
<phrase>and <replaceable class="parameter">merge_insert</replaceable> is:</phrase>
@@ -70,7 +71,9 @@ DELETE
from <replaceable class="parameter">data_source</replaceable> to
<replaceable class="parameter">target_table_name</replaceable>
producing zero or more candidate change rows. For each candidate change
- row, the status of <literal>MATCHED</literal> or <literal>NOT MATCHED</literal>
+ row, the status of <literal>MATCHED</literal>,
+ <literal>NOT MATCHED BY SOURCE</literal>,
+ or <literal>NOT MATCHED [BY TARGET]</literal>
is set just once, after which <literal>WHEN</literal> clauses are evaluated
in the order specified. For each candidate change row, the first clause to
evaluate as true is executed. No more than one <literal>WHEN</literal>
@@ -226,16 +229,37 @@ DELETE
At least one <literal>WHEN</literal> clause is required.
</para>
<para>
+ The <literal>WHEN</literal> clause may specify <literal>WHEN MATCHED</literal>,
+ <literal>WHEN NOT MATCHED BY SOURCE</literal>, or
+ <literal>WHEN NOT MATCHED [BY TARGET]</literal>.
+ Note that the <acronym>SQL</acronym> standard only defines
+ <literal>WHEN MATCHED</literal> and <literal>WHEN NOT MATCHED</literal>
+ (which is defined to mean no matching target row).
+ <literal>WHEN NOT MATCHED BY SOURCE</literal> is an extension to the
+ <acronym>SQL</acronym> standard, as is the option to append
+ <literal>BY TARGET</literal> to <literal>WHEN NOT MATCHED</literal>, to
+ make its meaning more explicit.
+ </para>
+ <para>
If the <literal>WHEN</literal> clause specifies <literal>WHEN MATCHED</literal>
- and the candidate change row matches a row in the
+ and the candidate change row matches a row in the source to a row in the
<replaceable class="parameter">target_table_name</replaceable>,
the <literal>WHEN</literal> clause is executed if the
<replaceable class="parameter">condition</replaceable> is
absent or it evaluates to <literal>true</literal>.
</para>
<para>
- Conversely, if the <literal>WHEN</literal> clause specifies
- <literal>WHEN NOT MATCHED</literal>
+ If the <literal>WHEN</literal> clause specifies
+ <literal>WHEN NOT MATCHED BY SOURCE</literal> and the candidate change
+ row represents a row in the
+ <replaceable class="parameter">target_table_name</replaceable> that does
+ not match a source row, the <literal>WHEN</literal> clause is executed
+ if the <replaceable class="parameter">condition</replaceable> is
+ absent or it evaluates to <literal>true</literal>.
+ </para>
+ <para>
+ If the <literal>WHEN</literal> clause specifies
+ <literal>WHEN NOT MATCHED [BY TARGET]</literal>
and the candidate change row does not match a row in the
<replaceable class="parameter">target_table_name</replaceable>,
the <literal>WHEN</literal> clause is executed if the
@@ -257,7 +281,10 @@ DELETE
<para>
A condition on a <literal>WHEN MATCHED</literal> clause can refer to columns
in both the source and the target relations. A condition on a
- <literal>WHEN NOT MATCHED</literal> clause can only refer to columns from
+ <literal>WHEN NOT MATCHED BY SOURCE</literal> clause can only refer to
+ columns from the target relation, since by definition there is no matching
+ source row. A condition on a <literal>WHEN NOT MATCHED [BY TARGET]</literal>
+ clause can only refer to columns from
the source relation, since by definition there is no matching target row.
Only the system attributes from the target table are accessible.
</para>
@@ -382,8 +409,10 @@ DELETE
<literal>WHEN MATCHED</literal> clause, the expression can use values
from the original row in the target table, and values from the
<literal>data_source</literal> row.
- If used in a <literal>WHEN NOT MATCHED</literal> clause, the
- expression can use values from the <literal>data_source</literal>.
+ If used in a <literal>WHEN NOT MATCHED BY SOURCE</literal> clause, the
+ expression can only use values from the original row in the target table.
+ If used in a <literal>WHEN NOT MATCHED [BY TARGET]</literal> clause, the
+ expression can only use values from the <literal>data_source</literal>.
</para>
</listitem>
</varlistentry>
@@ -452,8 +481,9 @@ MERGE <replaceable class="parameter">tot
<orderedlist>
<listitem>
<para>
- Evaluate whether each row is <literal>MATCHED</literal> or
- <literal>NOT MATCHED</literal>.
+ Evaluate whether each row is <literal>MATCHED</literal>,
+ <literal>NOT MATCHED BY SOURCE</literal>, or
+ <literal>NOT MATCHED [BY TARGET]</literal>.
</para>
</listitem>
<listitem>
@@ -528,7 +558,8 @@ MERGE <replaceable class="parameter">tot
<para>
If a <literal>WHEN</literal> clause omits an <literal>AND</literal>
sub-clause, it becomes the final reachable clause of that
- kind (<literal>MATCHED</literal> or <literal>NOT MATCHED</literal>).
+ kind (<literal>MATCHED</literal>, <literal>NOT MATCHED BY SOURCE</literal>,
+ or <literal>NOT MATCHED [BY TARGET]</literal>).
If a later <literal>WHEN</literal> clause of that kind
is specified it would be provably unreachable and an error is raised.
If no final reachable clause is specified of either kind, it is
@@ -619,6 +650,23 @@ WHEN MATCHED THEN
temporary table recently loaded into the database.
</para>
+ <para>
+ Update <literal>wine</literal> based on a replacement wine list, inserting
+ rows for any new stock, updating modified stock entries, and deleting any
+ wines not present in the new list.
+<programlisting>
+MERGE INTO wines w
+USING new_wine_list s
+ON s.winename = w.winename
+WHEN NOT MATCHED BY TARGET THEN
+ INSERT VALUES(s.winename, s.stock)
+WHEN MATCHED AND w.stock != s.stock THEN
+ UPDATE SET stock = s.stock
+WHEN NOT MATCHED BY SOURCE THEN
+ DELETE;
+</programlisting>
+ </para>
+
</refsect1>
<refsect1>
@@ -627,7 +675,10 @@ WHEN MATCHED THEN
This command conforms to the <acronym>SQL</acronym> standard.
</para>
<para>
- The WITH clause and <literal>DO NOTHING</literal> action are extensions to
+ The WITH clause, <literal>BY SOURCE</literal> and
+ <literal>BY TARGET</literal> qualifiers to
+ <literal>WHEN NOT MATCHED</literal>, and
+ <literal>DO NOTHING</literal> action are extensions to
the <acronym>SQL</acronym> standard.
</para>
</refsect1>
diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
new file mode 100644
index 651ad24..005da8d
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -898,8 +898,16 @@ ExecInitPartitionInfo(ModifyTableState *
action_state = makeNode(MergeActionState);
action_state->mas_action = action;
- /* And put the action in the appropriate list */
- if (action->matched)
+ /*
+ * Put the action in the appropriate list.
+ *
+ * Note that the executor treats WHEN NOT MATCHED BY SOURCE
+ * actions in exactly the same way as WHEN MATCHED actions, since
+ * they both match the target (see ExecMerge). Thus both types go
+ * in the "matched" list. Only WHEN NOT MATCHED BY TARGET actions
+ * go in the "not matched" list.
+ */
+ if (action->matchKind != MERGE_WHEN_NOT_MATCHED_BY_TARGET)
list = &leaf_part_rri->ri_matchedMergeAction;
else
list = &leaf_part_rri->ri_notMatchedMergeAction;
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
new file mode 100644
index f419c47..d1f3a19
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -24,13 +24,15 @@
* values plus row-locating info for UPDATE and MERGE cases, or just the
* row-locating info for DELETE cases.
*
- * MERGE runs a join between the source relation and the target
- * table; if any WHEN NOT MATCHED clauses are present, then the
- * join is an outer join. In this case, any unmatched tuples will
- * have NULL row-locating info, and only INSERT can be run. But for
- * matched tuples, then row-locating info is used to determine the
- * tuple to UPDATE or DELETE. When all clauses are WHEN MATCHED,
- * then an inner join is used, so all tuples contain row-locating info.
+ * MERGE runs a join between the source relation and the target table.
+ * If any WHEN NOT MATCHED [BY TARGET] clauses are present, then the join
+ * is an outer join that might output tuples without a matching target
+ * tuple. In this case, any unmatched target tuples will have NULL
+ * row-locating info, and only INSERT can be run. But for matched
+ * target tuples, the row-locating info is used to determine the tuple
+ * to UPDATE or DELETE. When all clauses are WHEN MATCHED or WHEN NOT
+ * MATCHED BY SOURCE, all tuples produced by the join will include a
+ * matching target tuple, so all tuples contain row-locating info.
*
* If the query specifies RETURNING, then the ModifyTable returns a
* RETURNING tuple after completing each row insert, update, or delete.
@@ -2695,6 +2697,20 @@ ExecMerge(ModifyTableContext *context, R
bool matched;
/*-----
+ * Note that as far as the executor is concerned, WHEN NOT MATCHED BY
+ * SOURCE actions are treated exactly the same as WHEN MATCHED actions,
+ * since both match target tuples. They are distinguished from one
+ * another by a qual that tests if the source tuple is NULL, but the
+ * executor knows nothing about the contents of the merge action quals.
+ * Thus WHEN MATCHED and WHEN NOT MATCHED BY SOURCE actions are stored
+ * together in the same "matched" list. In the case of concurrent updates
+ * and rechecks discussed below, the target tuple might be modified, but
+ * not the source tuple, and so there is no danger of a WHEN MATCHED case
+ * becoming a WHEN NOT MATCHED BY SOURCE case, or vice versa. Thus, in
+ * the dicussion that follows "MATCHED" means "matched by target", and
+ * should be taken to include both WHEN MATCHED and WHEN NOT MATCHED BY
+ * SOURCE, while "NOT MATCHED" means NOT MATCHED BY TARGET.
+ *
* If we are dealing with a WHEN MATCHED case (tupleid is valid), we
* execute the first action for which the additional WHEN MATCHED AND
* quals pass. If an action without quals is found, that action is
@@ -3257,8 +3273,14 @@ ExecInitMerge(ModifyTableState *mtstate,
* We create two lists - one for WHEN MATCHED actions and one for
* WHEN NOT MATCHED actions - and stick the MergeActionState into
* the appropriate list.
+ *
+ * Note that the executor treats WHEN NOT MATCHED BY SOURCE
+ * actions in exactly the same way as WHEN MATCHED actions, since
+ * they both match the target (see ExecMerge). Thus both types go
+ * in the "matched" list. Only WHEN NOT MATCHED BY TARGET actions
+ * go in the "not matched" list.
*/
- if (action_state->mas_action->matched)
+ if (action->matchKind != MERGE_WHEN_NOT_MATCHED_BY_TARGET)
list = &resultRelInfo->ri_matchedMergeAction;
else
list = &resultRelInfo->ri_notMatchedMergeAction;
diff --git a/src/backend/nodes/queryjumblefuncs.c b/src/backend/nodes/queryjumblefuncs.c
new file mode 100644
index 1608484..b380c3d
--- a/src/backend/nodes/queryjumblefuncs.c
+++ b/src/backend/nodes/queryjumblefuncs.c
@@ -734,7 +734,7 @@ JumbleExpr(JumbleState *jstate, Node *no
{
MergeAction *mergeaction = (MergeAction *) node;
- APP_JUMB(mergeaction->matched);
+ APP_JUMB(mergeaction->matchKind);
APP_JUMB(mergeaction->commandType);
JumbleExpr(jstate, mergeaction->qual);
JumbleExpr(jstate, (Node *) mergeaction->targetList);
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
new file mode 100644
index 37a7af8..4f53f23
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -142,6 +142,9 @@ transform_MERGE_to_join(Query *parse)
{
RangeTblEntry *joinrte;
JoinExpr *joinexpr;
+ ListCell *lc;
+ bool src_only_tuples;
+ bool tgt_only_tuples;
JoinType jointype;
int joinrti;
List *vars;
@@ -153,12 +156,32 @@ transform_MERGE_to_join(Query *parse)
vars = NIL;
/*
- * When any WHEN NOT MATCHED THEN INSERT clauses exist, we need to use an
- * outer join so that we process all unmatched tuples from the source
- * relation. If none exist, we can use an inner join.
+ * Work out what kind of join is required. If there any WHEN NOT MATCHED
+ * BY SOURCE/TARGET clauses, an outer join is required so that we process
+ * all unmatched tuples from the source and/or target relations.
+ * Otherwise, we can use an inner join.
*/
- if (parse->mergeUseOuterJoin)
+ src_only_tuples = false;
+ tgt_only_tuples = false;
+ foreach(lc, parse->mergeActionList)
+ {
+ MergeAction *action = lfirst_node(MergeAction, lc);
+
+ if (action->commandType != CMD_NOTHING)
+ {
+ if (action->matchKind == MERGE_WHEN_NOT_MATCHED_BY_SOURCE)
+ tgt_only_tuples = true;
+ if (action->matchKind == MERGE_WHEN_NOT_MATCHED_BY_TARGET)
+ src_only_tuples = true;
+ }
+ }
+
+ if (src_only_tuples && tgt_only_tuples)
+ jointype = JOIN_FULL;
+ else if (src_only_tuples)
jointype = JOIN_RIGHT;
+ else if (tgt_only_tuples)
+ jointype = JOIN_LEFT;
else
jointype = JOIN_INNER;
diff --git a/src/backend/optimizer/prep/preptlist.c b/src/backend/optimizer/prep/preptlist.c
new file mode 100644
index c6d747b..027d2be
--- a/src/backend/optimizer/prep/preptlist.c
+++ b/src/backend/optimizer/prep/preptlist.c
@@ -157,15 +157,14 @@ preprocess_targetlist(PlannerInfo *root)
/*
* Add resjunk entries for any Vars used in each action's
* targetlist and WHEN condition that belong to relations other
- * than target. Note that aggregates, window functions and
- * placeholder vars are not possible anywhere in MERGE's WHEN
- * clauses. (PHVs may be added later, but they don't concern us
- * here.)
+ * than target. Note that aggregates and window functions are not
+ * possible anywhere in MERGE's WHEN clauses, but PlaceHolderVars
+ * may have been added by subquery pullup.
*/
vars = pull_var_clause((Node *)
list_concat_copy((List *) action->qual,
action->targetList),
- 0);
+ PVC_INCLUDE_PLACEHOLDERS);
foreach(l2, vars)
{
Var *var = (Var *) lfirst(l2);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
new file mode 100644
index a013838..dbe0089
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -273,6 +273,7 @@ static Node *makeRecursiveViewSelect(cha
struct SelectLimit *selectlimit;
SetQuantifier setquantifier;
struct GroupClause *groupclause;
+ MergeMatchKind mergematch;
MergeWhenClause *mergewhen;
struct KeyActions *keyactions;
struct KeyAction *keyaction;
@@ -512,6 +513,7 @@ static Node *makeRecursiveViewSelect(cha
%type <onconflict> opt_on_conflict
%type <mergewhen> merge_insert merge_update merge_delete
+%type <mergematch> merge_when_tgt_matched merge_when_tgt_not_matched
%type <node> merge_when_clause opt_merge_when_condition
%type <list> merge_when_list
@@ -740,11 +742,11 @@ static Node *makeRecursiveViewSelect(cha
SAVEPOINT SCHEMA SCHEMAS SCROLL SEARCH SECOND_P SECURITY SELECT SEQUENCE SEQUENCES
SERIALIZABLE SERVER SESSION SESSION_USER SET SETS SETOF SHARE SHOW
- SIMILAR SIMPLE SKIP SMALLINT SNAPSHOT SOME SQL_P STABLE STANDALONE_P
+ SIMILAR SIMPLE SKIP SMALLINT SNAPSHOT SOME SOURCE SQL_P STABLE STANDALONE_P
START STATEMENT STATISTICS STDIN STDOUT STORAGE STORED STRICT_P STRIP_P
SUBSCRIPTION SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P SYSTEM_USER
- TABLE TABLES TABLESAMPLE TABLESPACE TEMP TEMPLATE TEMPORARY TEXT_P THEN
+ TABLE TABLES TABLESAMPLE TABLESPACE TARGET TEMP TEMPLATE TEMPORARY TEXT_P THEN
TIES TIME TIMESTAMP TO TRAILING TRANSACTION TRANSFORM
TREAT TRIGGER TRIM TRUE_P
TRUNCATE TRUSTED TYPE_P TYPES_P
@@ -12260,49 +12262,59 @@ merge_when_list:
;
merge_when_clause:
- WHEN MATCHED opt_merge_when_condition THEN merge_update
+ merge_when_tgt_matched opt_merge_when_condition THEN merge_update
{
- $5->matched = true;
- $5->condition = $3;
+ $4->matchKind = $1;
+ $4->condition = $2;
- $$ = (Node *) $5;
+ $$ = (Node *) $4;
}
- | WHEN MATCHED opt_merge_when_condition THEN merge_delete
+ | merge_when_tgt_matched opt_merge_when_condition THEN merge_delete
{
- $5->matched = true;
- $5->condition = $3;
+ $4->matchKind = $1;
+ $4->condition = $2;
- $$ = (Node *) $5;
+ $$ = (Node *) $4;
}
- | WHEN NOT MATCHED opt_merge_when_condition THEN merge_insert
+ | merge_when_tgt_not_matched opt_merge_when_condition THEN merge_insert
{
- $6->matched = false;
- $6->condition = $4;
+ $4->matchKind = $1;
+ $4->condition = $2;
- $$ = (Node *) $6;
+ $$ = (Node *) $4;
}
- | WHEN MATCHED opt_merge_when_condition THEN DO NOTHING
+ | merge_when_tgt_matched opt_merge_when_condition THEN DO NOTHING
{
MergeWhenClause *m = makeNode(MergeWhenClause);
- m->matched = true;
+ m->matchKind = $1;
m->commandType = CMD_NOTHING;
- m->condition = $3;
+ m->condition = $2;
$$ = (Node *) m;
}
- | WHEN NOT MATCHED opt_merge_when_condition THEN DO NOTHING
+ | merge_when_tgt_not_matched opt_merge_when_condition THEN DO NOTHING
{
MergeWhenClause *m = makeNode(MergeWhenClause);
- m->matched = false;
+ m->matchKind = $1;
m->commandType = CMD_NOTHING;
- m->condition = $4;
+ m->condition = $2;
$$ = (Node *) m;
}
;
+merge_when_tgt_matched:
+ WHEN MATCHED { $$ = MERGE_WHEN_MATCHED; }
+ | WHEN NOT MATCHED BY SOURCE { $$ = MERGE_WHEN_NOT_MATCHED_BY_SOURCE; }
+ ;
+
+merge_when_tgt_not_matched:
+ WHEN NOT MATCHED { $$ = MERGE_WHEN_NOT_MATCHED_BY_TARGET; }
+ | WHEN NOT MATCHED BY TARGET { $$ = MERGE_WHEN_NOT_MATCHED_BY_TARGET; }
+ ;
+
opt_merge_when_condition:
AND a_expr { $$ = $2; }
| { $$ = NULL; }
@@ -16961,6 +16973,7 @@ unreserved_keyword:
| SIMPLE
| SKIP
| SNAPSHOT
+ | SOURCE
| SQL_P
| STABLE
| STANDALONE_P
@@ -16979,6 +16992,7 @@ unreserved_keyword:
| SYSTEM_P
| TABLES
| TABLESPACE
+ | TARGET
| TEMP
| TEMPLATE
| TEMPORARY
@@ -17555,6 +17569,7 @@ bare_label_keyword:
| SMALLINT
| SNAPSHOT
| SOME
+ | SOURCE
| SQL_P
| STABLE
| STANDALONE_P
@@ -17578,6 +17593,7 @@ bare_label_keyword:
| TABLES
| TABLESAMPLE
| TABLESPACE
+ | TARGET
| TEMP
| TEMPLATE
| TEMPORARY
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
new file mode 100644
index d886637..fca2bd9
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -43,9 +43,9 @@ static void setNamespaceVisibilityForRTE
* Make appropriate changes to the namespace visibility while transforming
* individual action's quals and targetlist expressions. In particular, for
* INSERT actions we must only see the source relation (since INSERT action is
- * invoked for NOT MATCHED tuples and hence there is no target tuple to deal
- * with). On the other hand, UPDATE and DELETE actions can see both source and
- * target relations.
+ * invoked for NOT MATCHED [BY TARGET] tuples and hence there is no target
+ * tuple to deal with). On the other hand, UPDATE and DELETE actions can see
+ * both source and target relations, unless invoked for NOT MATCH BY SOURCE.
*
* Also, since the internal join node can hide the source and target
* relations, we must explicitly make the respective relation as visible so
@@ -61,7 +61,7 @@ setNamespaceForMergeWhen(ParseState *pst
targetRelRTE = rt_fetch(targetRTI, pstate->p_rtable);
sourceRelRTE = rt_fetch(sourceRTI, pstate->p_rtable);
- if (mergeWhenClause->matched)
+ if (mergeWhenClause->matchKind == MERGE_WHEN_MATCHED)
{
Assert(mergeWhenClause->commandType == CMD_UPDATE ||
mergeWhenClause->commandType == CMD_DELETE ||
@@ -73,11 +73,25 @@ setNamespaceForMergeWhen(ParseState *pst
setNamespaceVisibilityForRTE(pstate->p_namespace,
sourceRelRTE, true, true);
}
- else
+ else if (mergeWhenClause->matchKind == MERGE_WHEN_NOT_MATCHED_BY_SOURCE)
{
/*
- * NOT MATCHED actions can't see target relation, but they can see
- * source relation.
+ * NOT MATCHED BY SOURCE actions can see the target relation, but they
+ * can't see the source relation.
+ */
+ Assert(mergeWhenClause->commandType == CMD_UPDATE ||
+ mergeWhenClause->commandType == CMD_DELETE ||
+ mergeWhenClause->commandType == CMD_NOTHING);
+ setNamespaceVisibilityForRTE(pstate->p_namespace,
+ targetRelRTE, true, true);
+ setNamespaceVisibilityForRTE(pstate->p_namespace,
+ sourceRelRTE, false, false);
+ }
+ else /* mergeWhenClause->matchKind == MERGE_WHEN_NOT_MATCHED_BY_TARGET */
+ {
+ /*
+ * NOT MATCHED [BY TARGET] actions can't see target relation, but they
+ * can see source relation.
*/
Assert(mergeWhenClause->commandType == CMD_INSERT ||
mergeWhenClause->commandType == CMD_NOTHING);
@@ -98,7 +112,8 @@ transformMergeStmt(ParseState *pstate, M
Query *qry = makeNode(Query);
ListCell *l;
AclMode targetPerms = ACL_NO_RIGHTS;
- bool is_terminal[2];
+ bool is_terminal[3];
+ bool tgt_only_tuples;
Index sourceRTI;
List *mergeActionList;
Node *joinExpr;
@@ -125,12 +140,13 @@ transformMergeStmt(ParseState *pstate, M
/*
* Check WHEN clauses for permissions and sanity
*/
- is_terminal[0] = false;
- is_terminal[1] = false;
+ is_terminal[MERGE_WHEN_MATCHED] = false;
+ is_terminal[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
+ is_terminal[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
+ tgt_only_tuples = false;
foreach(l, stmt->mergeWhenClauses)
{
MergeWhenClause *mergeWhenClause = (MergeWhenClause *) lfirst(l);
- int when_type = (mergeWhenClause->matched ? 0 : 1);
/*
* Collect action types so we can check target permissions
@@ -155,12 +171,22 @@ transformMergeStmt(ParseState *pstate, M
/*
* Check for unreachable WHEN clauses
*/
- if (is_terminal[when_type])
+ if (is_terminal[mergeWhenClause->matchKind])
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unreachable WHEN clause specified after unconditional WHEN clause")));
if (mergeWhenClause->condition == NULL)
- is_terminal[when_type] = true;
+ is_terminal[mergeWhenClause->matchKind] = true;
+
+ /*
+ * Test if we have a WHEN NOT MATCHED BY SOURCE action that processes
+ * unmatched tuples from the target relation. If so, additional WHEN
+ * conditions are added below to differentiate the various match
+ * kinds.
+ */
+ if (mergeWhenClause->commandType != CMD_NOTHING &&
+ mergeWhenClause->matchKind == MERGE_WHEN_NOT_MATCHED_BY_SOURCE)
+ tgt_only_tuples = true;
}
/*
@@ -255,11 +281,7 @@ transformMergeStmt(ParseState *pstate, M
action = makeNode(MergeAction);
action->commandType = mergeWhenClause->commandType;
- action->matched = mergeWhenClause->matched;
-
- /* Use an outer join if any INSERT actions exist in the command. */
- if (action->commandType == CMD_INSERT)
- qry->mergeUseOuterJoin = true;
+ action->matchKind = mergeWhenClause->matchKind;
/*
* Set namespace for the specific action. This must be done before
@@ -280,6 +302,51 @@ transformMergeStmt(ParseState *pstate, M
EXPR_KIND_MERGE_WHEN, "WHEN");
/*
+ * If there any WHEN NOT MATCHED BY SOURCE actions that require
+ * unmatched tuples from the target relation to be processed, add
+ * additional WHEN conditions to every action to check that tuples
+ * from the source match or do not match, as necessary.
+ *
+ * This distinguishes NOT MATCHED BY SOURCE actions (identified by a
+ * "source IS NOT DISTINCT FROM NULL" clause) from MATCHED actions
+ * (identified by a "source IS DISTINCT FROM NULL" clause).
+ *
+ * Additionally, a "source IS DISTINCT FROM NULL" clause is required
+ * for NOT MATCHED [BY TARGET] actions in case the executor attempts
+ * to invoke such an action for a concurrently deleted target row that
+ * ends up matching neither source nor target.
+ */
+ if (tgt_only_tuples)
+ {
+ bool src_null;
+ NullTest *ntest;
+
+ /* Make a "source IS [NOT] DISTINCT FROM NULL" clause */
+ src_null = action->matchKind == MERGE_WHEN_NOT_MATCHED_BY_SOURCE;
+
+ ntest = makeNode(NullTest);
+
+ ntest->arg = (Expr *) makeVar(sourceRTI,
+ InvalidAttrNumber,
+ RECORDOID,
+ -1,
+ InvalidOid,
+ 0);
+ ntest->nulltesttype = src_null ? IS_NULL : IS_NOT_NULL;
+ ntest->argisrow = false;
+ ntest->location = -1;
+
+ /* Combine it with the action's WHEN condition */
+ if (action->qual == NULL)
+ action->qual = (Node *) ntest;
+ else
+ action->qual =
+ (Node *) makeBoolExpr(AND_EXPR,
+ list_make2(ntest, action->qual),
+ -1);
+ }
+
+ /*
* Transform target lists for each INSERT and UPDATE action stmt
*/
switch (action->commandType)
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
new file mode 100644
index 5e1882e..e202fcd
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -4237,17 +4237,35 @@ psql_completion(const char *text, int st
TailMatches("USING", MatchAny, MatchAny, "ON", MatchAny, MatchAny, MatchAny, "WHEN"))
COMPLETE_WITH("MATCHED", "NOT MATCHED");
- /* Complete ... WHEN [NOT] MATCHED with THEN/AND */
+ /*
+ * Complete ... WHEN MATCHED and WHEN NOT MATCHED BY SOURCE|TARGET with
+ * THEN/AND
+ */
else if (TailMatches("WHEN", "MATCHED") ||
- TailMatches("WHEN", "NOT", "MATCHED"))
+ TailMatches("WHEN", "NOT", "MATCHED", "BY", "SOURCE|TARGET"))
COMPLETE_WITH("THEN", "AND");
- /* Complete ... WHEN MATCHED THEN with UPDATE SET/DELETE/DO NOTHING */
- else if (TailMatches("WHEN", "MATCHED", "THEN"))
+ /* Complete ... WHEN NOT MATCHED with BY/THEN/AND */
+ else if (TailMatches("WHEN", "NOT", "MATCHED"))
+ COMPLETE_WITH("BY", "THEN", "AND");
+
+ /* Complete ... WHEN NOT MATCHED BY with SOURCE/TARGET */
+ else if (TailMatches("WHEN", "NOT", "MATCHED", "BY"))
+ COMPLETE_WITH("SOURCE", "TARGET");
+
+ /*
+ * Complete ... WHEN MATCHED THEN and WHEN NOT MATCHED BY SOURCE THEN with
+ * UPDATE SET/DELETE/DO NOTHING
+ */
+ else if (TailMatches("WHEN", "MATCHED", "THEN") ||
+ TailMatches("WHEN", "NOT", "MATCHED", "BY", "SOURCE", "THEN"))
COMPLETE_WITH("UPDATE SET", "DELETE", "DO NOTHING");
- /* Complete ... WHEN NOT MATCHED THEN with INSERT/DO NOTHING */
- else if (TailMatches("WHEN", "NOT", "MATCHED", "THEN"))
+ /*
+ * Complete ... WHEN NOT MATCHED [BY TARGET] THEN with INSERT/DO NOTHING
+ */
+ else if (TailMatches("WHEN", "NOT", "MATCHED", "THEN") ||
+ TailMatches("WHEN", "NOT", "MATCHED", "BY", "TARGET", "THEN"))
COMPLETE_WITH("INSERT", "DO NOTHING");
/* NOTIFY --- can be inside EXPLAIN, RULE, etc */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
new file mode 100644
index 89335d9..b6a37f5
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -177,8 +177,6 @@ typedef struct Query
* also USING clause for MERGE */
List *mergeActionList; /* list of actions for MERGE (only) */
- /* whether to use outer join */
- bool mergeUseOuterJoin;
List *targetList; /* target list (of TargetEntry) */
@@ -1636,6 +1634,14 @@ typedef struct CommonTableExpr
((Query *) (cte)->ctequery)->targetList : \
((Query *) (cte)->ctequery)->returningList)
+/* MATCHED/NOT MATCHED specification for WHEN clauses in a MERGE statement */
+typedef enum MergeMatchKind
+{
+ MERGE_WHEN_MATCHED,
+ MERGE_WHEN_NOT_MATCHED_BY_SOURCE,
+ MERGE_WHEN_NOT_MATCHED_BY_TARGET
+} MergeMatchKind;
+
/*
* MergeWhenClause -
* raw parser representation of a WHEN clause in a MERGE statement
@@ -1645,7 +1651,7 @@ typedef struct CommonTableExpr
typedef struct MergeWhenClause
{
NodeTag type;
- bool matched; /* true=MATCHED, false=NOT MATCHED */
+ MergeMatchKind matchKind; /* MATCHED/NOT MATCHED BY SOURCE/TARGET */
CmdType commandType; /* INSERT/UPDATE/DELETE/DO NOTHING */
OverridingKind override; /* OVERRIDING clause */
Node *condition; /* WHEN conditions (raw parser) */
@@ -1661,7 +1667,7 @@ typedef struct MergeWhenClause
typedef struct MergeAction
{
NodeTag type;
- bool matched; /* true=MATCHED, false=NOT MATCHED */
+ MergeMatchKind matchKind; /* MATCHED/NOT MATCHED BY SOURCE/TARGET */
CmdType commandType; /* INSERT/UPDATE/DELETE/DO NOTHING */
/* OVERRIDING clause */
OverridingKind override;
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
new file mode 100644
index bb36213..a398153
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -391,6 +391,7 @@ PG_KEYWORD("skip", SKIP, UNRESERVED_KEYW
PG_KEYWORD("smallint", SMALLINT, COL_NAME_KEYWORD, BARE_LABEL)
PG_KEYWORD("snapshot", SNAPSHOT, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("some", SOME, RESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("source", SOURCE, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("sql", SQL_P, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("stable", STABLE, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("standalone", STANDALONE_P, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -414,6 +415,7 @@ PG_KEYWORD("table", TABLE, RESERVED_KEYW
PG_KEYWORD("tables", TABLES, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("tablesample", TABLESAMPLE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
PG_KEYWORD("tablespace", TABLESPACE, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("target", TARGET, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("temp", TEMP, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("template", TEMPLATE, UNRESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("temporary", TEMPORARY, UNRESERVED_KEYWORD, BARE_LABEL)
diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out
new file mode 100644
index bc53b21..00cdbe9
--- a/src/test/regress/expected/merge.out
+++ b/src/test/regress/expected/merge.out
@@ -71,6 +71,15 @@ WHEN MATCHED THEN
ERROR: syntax error at or near "INSERT"
LINE 5: INSERT DEFAULT VALUES;
^
+-- NOT MATCHED BY SOURCE/INSERT error
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE THEN
+ INSERT DEFAULT VALUES;
+ERROR: syntax error at or near "INSERT"
+LINE 5: INSERT DEFAULT VALUES;
+ ^
-- incorrectly specifying INTO target
MERGE INTO target t
USING source AS s
@@ -107,6 +116,15 @@ WHEN NOT MATCHED THEN
ERROR: syntax error at or near "UPDATE"
LINE 5: UPDATE SET balance = 0;
^
+-- NOT MATCHED BY TARGET/UPDATE
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY TARGET THEN
+ UPDATE SET balance = 0;
+ERROR: syntax error at or near "UPDATE"
+LINE 5: UPDATE SET balance = 0;
+ ^
-- UPDATE tablename
MERGE INTO target t
USING source AS s
@@ -271,6 +289,22 @@ SELECT * FROM target ORDER BY tid;
(4 rows)
ROLLBACK;
+-- DELETE/INSERT not matched by source/target
+BEGIN;
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE THEN
+ DELETE
+WHEN NOT MATCHED BY TARGET THEN
+ INSERT VALUES (s.sid, s.delta);
+SELECT * FROM target ORDER BY tid;
+ tid | balance
+-----+---------
+ 4 | 40
+(1 row)
+
+ROLLBACK;
-- index plans
INSERT INTO target SELECT generate_series(1000,2500), 0;
ALTER TABLE target ADD PRIMARY KEY (tid);
@@ -738,6 +772,19 @@ SELECT * FROM wq_target;
1 | -1
(1 row)
+-- conditions in NOT MATCHED BY SOURCE clause can only refer to target columns
+MERGE INTO wq_target t
+USING wq_source s ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE AND s.balance = 100 THEN
+ DELETE;
+ERROR: invalid reference to FROM-clause entry for table "s"
+LINE 3: WHEN NOT MATCHED BY SOURCE AND s.balance = 100 THEN
+ ^
+DETAIL: There is an entry for table "s", but it cannot be referenced from this part of the query.
+MERGE INTO wq_target t
+USING wq_source s ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE AND t.balance = 100 THEN
+ DELETE;
-- conditions in MATCHED clause can refer to both source and target
SELECT * FROM wq_source;
balance | sid
@@ -923,6 +970,45 @@ SELECT * FROM target ORDER BY tid;
(3 rows)
ROLLBACK;
+-- UPSERT with UPDATE/DELETE when not matched by source
+BEGIN;
+DELETE FROM SOURCE WHERE sid = 2;
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN MATCHED AND t.balance > s.delta THEN
+ UPDATE SET balance = t.balance - s.delta
+WHEN MATCHED THEN
+ UPDATE SET balance = 0
+WHEN NOT MATCHED THEN
+ INSERT VALUES (s.sid, s.delta)
+WHEN NOT MATCHED BY SOURCE AND tid = 1 THEN
+ UPDATE SET balance = 0
+WHEN NOT MATCHED BY SOURCE THEN
+ DELETE;
+NOTICE: BEFORE INSERT STATEMENT trigger
+NOTICE: BEFORE UPDATE STATEMENT trigger
+NOTICE: BEFORE DELETE STATEMENT trigger
+NOTICE: BEFORE UPDATE ROW trigger row: (3,30) -> (3,10)
+NOTICE: BEFORE INSERT ROW trigger row: (4,40)
+NOTICE: BEFORE DELETE ROW trigger row: (2,20)
+NOTICE: BEFORE UPDATE ROW trigger row: (1,10) -> (1,0)
+NOTICE: AFTER UPDATE ROW trigger row: (3,30) -> (3,10)
+NOTICE: AFTER INSERT ROW trigger row: (4,40)
+NOTICE: AFTER DELETE ROW trigger row: (2,20)
+NOTICE: AFTER UPDATE ROW trigger row: (1,10) -> (1,0)
+NOTICE: AFTER DELETE STATEMENT trigger
+NOTICE: AFTER UPDATE STATEMENT trigger
+NOTICE: AFTER INSERT STATEMENT trigger
+SELECT * FROM target ORDER BY tid;
+ tid | balance
+-----+---------
+ 1 | 0
+ 3 | 10
+ 4 | 40
+(3 rows)
+
+ROLLBACK;
-- Test behavior of triggers that turn UPDATE/DELETE into no-ops
create or replace function skip_merge_op() returns trigger
language plpgsql as
@@ -1436,6 +1522,50 @@ WHEN NOT MATCHED AND s.a < 20 THEN
-> Seq Scan on ex_mtarget t (actual rows=49 loops=1)
(12 rows)
+-- not matched by source
+SELECT explain_merge('
+MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a
+WHEN NOT MATCHED BY SOURCE and t.a < 10 THEN
+ DELETE');
+ explain_merge
+----------------------------------------------------------------------
+ Merge on ex_mtarget t (actual rows=0 loops=1)
+ Tuples: skipped=54
+ -> Merge Left Join (actual rows=54 loops=1)
+ Merge Cond: (t.a = s.a)
+ -> Sort (actual rows=54 loops=1)
+ Sort Key: t.a
+ Sort Method: quicksort Memory: xxx
+ -> Seq Scan on ex_mtarget t (actual rows=54 loops=1)
+ -> Sort (actual rows=100 loops=1)
+ Sort Key: s.a
+ Sort Method: quicksort Memory: xxx
+ -> Seq Scan on ex_msource s (actual rows=100 loops=1)
+(12 rows)
+
+-- not matched by source and target
+SELECT explain_merge('
+MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a
+WHEN NOT MATCHED BY SOURCE AND t.a < 10 THEN
+ DELETE
+WHEN NOT MATCHED BY TARGET AND s.a < 20 THEN
+ INSERT VALUES (a, b)');
+ explain_merge
+----------------------------------------------------------------------
+ Merge on ex_mtarget t (actual rows=0 loops=1)
+ Tuples: skipped=100
+ -> Merge Full Join (actual rows=100 loops=1)
+ Merge Cond: (t.a = s.a)
+ -> Sort (actual rows=54 loops=1)
+ Sort Key: t.a
+ Sort Method: quicksort Memory: xxx
+ -> Seq Scan on ex_mtarget t (actual rows=54 loops=1)
+ -> Sort (actual rows=100 loops=1)
+ Sort Key: s.a
+ Sort Method: quicksort Memory: xxx
+ -> Seq Scan on ex_msource s (actual rows=100 loops=1)
+(12 rows)
+
-- nothing
SELECT explain_merge('
MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a AND t.a < -1000
diff --git a/src/test/regress/sql/merge.sql b/src/test/regress/sql/merge.sql
new file mode 100644
index fdbcd70..f5dfb2a
--- a/src/test/regress/sql/merge.sql
+++ b/src/test/regress/sql/merge.sql
@@ -51,6 +51,12 @@ USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
INSERT DEFAULT VALUES;
+-- NOT MATCHED BY SOURCE/INSERT error
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE THEN
+ INSERT DEFAULT VALUES;
-- incorrectly specifying INTO target
MERGE INTO target t
USING source AS s
@@ -75,6 +81,12 @@ USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
UPDATE SET balance = 0;
+-- NOT MATCHED BY TARGET/UPDATE
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY TARGET THEN
+ UPDATE SET balance = 0;
-- UPDATE tablename
MERGE INTO target t
USING source AS s
@@ -213,6 +225,18 @@ WHEN NOT MATCHED THEN
SELECT * FROM target ORDER BY tid;
ROLLBACK;
+-- DELETE/INSERT not matched by source/target
+BEGIN;
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE THEN
+ DELETE
+WHEN NOT MATCHED BY TARGET THEN
+ INSERT VALUES (s.sid, s.delta);
+SELECT * FROM target ORDER BY tid;
+ROLLBACK;
+
-- index plans
INSERT INTO target SELECT generate_series(1000,2500), 0;
ALTER TABLE target ADD PRIMARY KEY (tid);
@@ -497,6 +521,17 @@ WHEN NOT MATCHED AND s.balance = 100 THE
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
+-- conditions in NOT MATCHED BY SOURCE clause can only refer to target columns
+MERGE INTO wq_target t
+USING wq_source s ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE AND s.balance = 100 THEN
+ DELETE;
+
+MERGE INTO wq_target t
+USING wq_source s ON t.tid = s.sid
+WHEN NOT MATCHED BY SOURCE AND t.balance = 100 THEN
+ DELETE;
+
-- conditions in MATCHED clause can refer to both source and target
SELECT * FROM wq_source;
MERGE INTO wq_target t
@@ -624,6 +659,25 @@ WHEN NOT MATCHED THEN
SELECT * FROM target ORDER BY tid;
ROLLBACK;
+-- UPSERT with UPDATE/DELETE when not matched by source
+BEGIN;
+DELETE FROM SOURCE WHERE sid = 2;
+MERGE INTO target t
+USING source AS s
+ON t.tid = s.sid
+WHEN MATCHED AND t.balance > s.delta THEN
+ UPDATE SET balance = t.balance - s.delta
+WHEN MATCHED THEN
+ UPDATE SET balance = 0
+WHEN NOT MATCHED THEN
+ INSERT VALUES (s.sid, s.delta)
+WHEN NOT MATCHED BY SOURCE AND tid = 1 THEN
+ UPDATE SET balance = 0
+WHEN NOT MATCHED BY SOURCE THEN
+ DELETE;
+SELECT * FROM target ORDER BY tid;
+ROLLBACK;
+
-- Test behavior of triggers that turn UPDATE/DELETE into no-ops
create or replace function skip_merge_op() returns trigger
language plpgsql as
@@ -916,6 +970,20 @@ WHEN MATCHED AND t.a >= 30 AND t.a <= 40
WHEN NOT MATCHED AND s.a < 20 THEN
INSERT VALUES (a, b)');
+-- not matched by source
+SELECT explain_merge('
+MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a
+WHEN NOT MATCHED BY SOURCE and t.a < 10 THEN
+ DELETE');
+
+-- not matched by source and target
+SELECT explain_merge('
+MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a
+WHEN NOT MATCHED BY SOURCE AND t.a < 10 THEN
+ DELETE
+WHEN NOT MATCHED BY TARGET AND s.a < 20 THEN
+ INSERT VALUES (a, b)');
+
-- nothing
SELECT explain_merge('
MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a AND t.a < -1000
