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Modified files for MERGE
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‎contrib/test_decoding/expected/ddl.out‎

Lines changed: 46 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -192,6 +192,52 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'inc
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COMMIT
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(33 rows)
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195+
-- MERGE support
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BEGIN;
197+
MERGE INTO replication_example t
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USING (SELECT i as id, i as data, i as num FROM generate_series(-20, 5) i) s
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ON t.id = s.id
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WHEN MATCHED AND t.id < 0 THEN
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UPDATE SET somenum = somenum + 1
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WHEN MATCHED AND t.id >= 0 THEN
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DELETE
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WHEN NOT MATCHED THEN
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INSERT VALUES (s.*);
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COMMIT;
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/* display results */
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SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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data
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--------------------------------------------------------------------------------------------------------------------------------------------------
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BEGIN
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table public.replication_example: INSERT: id[integer]:-20 somedata[integer]:-20 somenum[integer]:-20 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: INSERT: id[integer]:-19 somedata[integer]:-19 somenum[integer]:-19 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: INSERT: id[integer]:-18 somedata[integer]:-18 somenum[integer]:-18 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: INSERT: id[integer]:-17 somedata[integer]:-17 somenum[integer]:-17 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: INSERT: id[integer]:-16 somedata[integer]:-16 somenum[integer]:-16 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-15 somedata[integer]:-15 somenum[integer]:-14 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-14 somedata[integer]:-14 somenum[integer]:-13 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-13 somedata[integer]:-13 somenum[integer]:-12 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-12 somedata[integer]:-12 somenum[integer]:-11 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-11 somedata[integer]:-11 somenum[integer]:-10 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-10 somedata[integer]:-10 somenum[integer]:-9 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-9 somedata[integer]:-9 somenum[integer]:-8 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-8 somedata[integer]:-8 somenum[integer]:-7 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-7 somedata[integer]:-7 somenum[integer]:-6 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-6 somedata[integer]:-6 somenum[integer]:-5 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-5 somedata[integer]:-5 somenum[integer]:-4 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-4 somedata[integer]:-4 somenum[integer]:-3 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-3 somedata[integer]:-3 somenum[integer]:-2 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-2 somedata[integer]:-2 somenum[integer]:-1 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: UPDATE: id[integer]:-1 somedata[integer]:-1 somenum[integer]:0 zaphod1[integer]:null zaphod2[integer]:null
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table public.replication_example: DELETE: id[integer]:0
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table public.replication_example: DELETE: id[integer]:1
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table public.replication_example: DELETE: id[integer]:2
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table public.replication_example: DELETE: id[integer]:3
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table public.replication_example: DELETE: id[integer]:4
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table public.replication_example: DELETE: id[integer]:5
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COMMIT
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(28 rows)
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CREATE TABLE tr_unique(id2 serial unique NOT NULL, data int);
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INSERT INTO tr_unique(data) VALUES(10);
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ALTER TABLE tr_unique RENAME TO tr_pkey;

‎contrib/test_decoding/sql/ddl.sql‎

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@@ -93,6 +93,22 @@ COMMIT;
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/* display results */
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SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
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96+
-- MERGE support
97+
BEGIN;
98+
MERGE INTO replication_example t
99+
USING (SELECT i as id, i as data, i as num FROM generate_series(-20, 5) i) s
100+
ON t.id = s.id
101+
WHEN MATCHED AND t.id < 0 THEN
102+
UPDATE SET somenum = somenum + 1
103+
WHEN MATCHED AND t.id >= 0 THEN
104+
DELETE
105+
WHEN NOT MATCHED THEN
106+
INSERT VALUES (s.*);
107+
COMMIT;
108+
109+
/* display results */
110+
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
111+
96112
CREATE TABLE tr_unique(id2 serial unique NOT NULL, data int);
97113
INSERT INTO tr_unique(data) VALUES(10);
98114
ALTER TABLE tr_unique RENAME TO tr_pkey;

‎doc/src/sgml/libpq.sgml‎

Lines changed: 5 additions & 3 deletions
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@@ -3917,9 +3917,11 @@ char *PQcmdTuples(PGresult *res);
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<structname>PGresult</structname>. This function can only be used following
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the execution of a <command>SELECT</command>, <command>CREATE TABLE AS</command>,
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<command>INSERT</command>, <command>UPDATE</command>, <command>DELETE</command>,
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<command>MOVE</command>, <command>FETCH</command>, or <command>COPY</command> statement,
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or an <command>EXECUTE</command> of a prepared query that contains an
3922-
<command>INSERT</command>, <command>UPDATE</command>, or <command>DELETE</command> statement.
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<command>MERGE</command>, <command>MOVE</command>, <command>FETCH</command>,
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or <command>COPY</command> statement, or an <command>EXECUTE</command> of a
3922+
prepared query that contains an <command>INSERT</command>,
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<command>UPDATE</command>, <command>DELETE</command>
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or <command>MERGE</command> statement.
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If the command that generated the <structname>PGresult</structname> was anything
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else, <function>PQcmdTuples</function> returns an empty string. The caller
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should not free the return value directly. It will be freed when

‎doc/src/sgml/mvcc.sgml‎

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@@ -422,6 +422,31 @@ COMMIT;
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<literal>11</literal>, which no longer matches the criteria.
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</para>
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<para>
426+
The <command>MERGE</command> allows the user to specify various combinations
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of <command>INSERT</command>, <command>UPDATE</command> or
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<command>DELETE</command> subcommands. A <command>MERGE</command> command
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with both <command>INSERT</command> and <command>UPDATE</command>
430+
subcommands looks similar to <command>INSERT</command> with an
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<literal>ON CONFLICT DO UPDATE</literal> clause but does not guarantee
432+
that either <command>INSERT</command> and <command>UPDATE</command> will occur.
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434+
If MERGE attempts an UPDATE or DELETE and the row is concurrently updated
435+
but the join condition still passes for the current target and the current
436+
source tuple, then MERGE will behave the same as the UPDATE or DELETE commands
437+
and perform its action on the latest version of the row, using standard
438+
EvalPlanQual. MERGE actions can be conditional, so conditions must be
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re-evaluated on the latest row, starting from the first action.
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441+
On the other hand, if the row is concurrently updated or deleted so that
442+
the join condition fails, then MERGE will execute a NOT MATCHED action, if it
443+
exists and the AND WHEN qual evaluates to true.
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If MERGE attempts an INSERT and a unique index is present and a duplicate
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row is concurrently inserted then a uniqueness violation is raised. MERGE
447+
does not attempt to avoid the ERROR by attempting an UPDATE.
448+
</para>
449+
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<para>
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Because Read Committed mode starts each command with a new snapshot
427452
that includes all transactions committed up to that instant,
@@ -900,7 +925,8 @@ ERROR: could not serialize access due to read/write dependencies among transact
900925

901926
<para>
902927
The commands <command>UPDATE</command>,
903-
<command>DELETE</command>, and <command>INSERT</command>
928+
<command>DELETE</command>, <command>INSERT</command> and
929+
<command>MERGE</command>
904930
acquire this lock mode on the target table (in addition to
905931
<literal>ACCESS SHARE</literal> locks on any other referenced
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tables). In general, this lock mode will be acquired by any

‎doc/src/sgml/plpgsql.sgml‎

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@@ -1246,7 +1246,7 @@ EXECUTE format('SELECT count(*) FROM %I '
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</programlisting>
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Another restriction on parameter symbols is that they only work in
12481248
<command>SELECT</command>, <command>INSERT</command>, <command>UPDATE</command>, and
1249-
<command>DELETE</command> commands. In other statement
1249+
<command>DELETE</command> and <command>MERGE</command> commands. In other statement
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types (generically called utility statements), you must insert
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values textually even if they are just data values.
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</para>
@@ -1529,6 +1529,7 @@ GET DIAGNOSTICS integer_var = ROW_COUNT;
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<listitem>
15301530
<para>
15311531
<command>UPDATE</command>, <command>INSERT</command>, and <command>DELETE</command>
1532+
and <command>MERGE</command>
15321533
statements set <literal>FOUND</literal> true if at least one
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row is affected, false if no row is affected.
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</para>

‎doc/src/sgml/ref/allfiles.sgml‎

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@@ -159,6 +159,7 @@ Complete list of usable sgml source files in this directory.
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<!ENTITY load SYSTEM "load.sgml">
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<!ENTITY lock SYSTEM "lock.sgml">
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<!ENTITY move SYSTEM "move.sgml">
162+
<!ENTITY merge SYSTEM "merge.sgml">
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<!ENTITY notify SYSTEM "notify.sgml">
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<!ENTITY prepare SYSTEM "prepare.sgml">
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<!ENTITY prepareTransaction SYSTEM "prepare_transaction.sgml">

‎doc/src/sgml/ref/create_policy.sgml‎

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@@ -94,6 +94,13 @@ CREATE POLICY <replaceable class="parameter">name</replaceable> ON <replaceable
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exist, a <quote>default deny</quote> policy is assumed, so that no rows will
9595
be visible or updatable.
9696
</para>
97+
98+
<para>
99+
No separate policy exists for <command>MERGE</command>. Instead policies
100+
defined for <literal>SELECT</literal>, <literal>INSERT</literal>,
101+
<literal>UPDATE</literal> and <literal>DELETE</literal> are applied
102+
while executing MERGE, depending on the actions that are activated.
103+
</para>
97104
</refsect1>
98105

99106
<refsect1>

‎doc/src/sgml/ref/insert.sgml‎

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@@ -579,6 +579,13 @@ INSERT <replaceable>oid</replaceable> <replaceable class="parameter">count</repl
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is a partition, an error will occur if one of the input rows violates
580580
the partition constraint.
581581
</para>
582+
583+
<para>
584+
You may also wish to consider using <command>MERGE</command>, since that
585+
allows mixed <command>INSERT</command>, <command>UPDATE</command> and
586+
<command>DELETE</command> within a single statement.
587+
See <xref linkend="sql-merge"/>.
588+
</para>
582589
</refsect1>
583590

584591
<refsect1>
@@ -749,7 +756,9 @@ INSERT INTO distributors (did, dname) VALUES (10, 'Conrad International')
749756
Also, the case in
750757
which a column name list is omitted, but not all the columns are
751758
filled from the <literal>VALUES</literal> clause or <replaceable>query</replaceable>,
752-
is disallowed by the standard.
759+
is disallowed by the standard. If you prefer a more SQL Standard
760+
conforming statement than <literal>ON CONFLICT</literal>, see
761+
<xref linkend="sql-merge"/>.
753762
</para>
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<para>

‎doc/src/sgml/reference.sgml‎

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@@ -186,6 +186,7 @@
186186
&listen;
187187
&load;
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&lock;
189+
&merge;
189190
&move;
190191
&notify;
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&prepare;

‎doc/src/sgml/trigger.sgml‎

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@@ -182,6 +182,26 @@
182182
will be fired.
183183
</para>
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185+
<para>
186+
No separate triggers are defined for <command>MERGE</command>. Instead,
187+
statement-level or row-level <command>UPDATE</command>,
188+
<command>DELETE</command> and <command>INSERT</command> triggers are fired
189+
depending on what actions are specified in the <command>MERGE</command> query
190+
and what actions are activated.
191+
</para>
192+
193+
<para>
194+
While running a <command>MERGE</command> command, statement-level
195+
<literal>BEFORE</literal> and <literal>AFTER</literal> triggers are fired for
196+
events specified in the actions of the <command>MERGE</command> command,
197+
irrespective of whether the action is finally activated or not. This is same as
198+
an <command>UPDATE</command> statement that updates no rows, yet
199+
statement-level triggers are fired. The row-level triggers are fired only
200+
when a row is actually updated, inserted or deleted. So it's perfectly legal
201+
that while statement-level triggers are fired for certain type of action, no
202+
row-level triggers are fired for the same kind of action.
203+
</para>
204+
185205
<para>
186206
Trigger functions invoked by per-statement triggers should always
187207
return <symbol>NULL</symbol>. Trigger functions invoked by per-row

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