Revert "Modified files for MERGE"

This reverts commit 354f13855e6381d288dfaa52bcd4f2cb0fd4a5eb.

8 files changed, 6 insertions, 73 deletions

diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 8729ccd5c5a..943adfef774 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -3917,11 +3917,9 @@ char *PQcmdTuples(PGresult *res);
        <structname>PGresult</structname>. This function can only be used following
        the execution of a <command>SELECT</command>, <command>CREATE TABLE AS</command>,
        <command>INSERT</command>, <command>UPDATE</command>, <command>DELETE</command>,
-       <command>MERGE</command>, <command>MOVE</command>, <command>FETCH</command>,
-       or <command>COPY</command> statement, or an <command>EXECUTE</command> of a
-       prepared query that contains an <command>INSERT</command>,
-       <command>UPDATE</command>, <command>DELETE</command>
-       or <command>MERGE</command> statement.
+       <command>MOVE</command>, <command>FETCH</command>, or <command>COPY</command> statement,
+       or an <command>EXECUTE</command> of a prepared query that contains an
+       <command>INSERT</command>, <command>UPDATE</command>, or <command>DELETE</command> statement.
        If the command that generated the <structname>PGresult</structname> was anything
        else, <function>PQcmdTuples</function> returns an empty string. The caller
        should not free the return value directly. It will be freed when
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 0e3e89af560..24613e3c754 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -423,31 +423,6 @@ COMMIT;
    </para>
 
    <para>
-    The <command>MERGE</command> allows the user to specify various combinations
-    of <command>INSERT</command>, <command>UPDATE</command> or
-    <command>DELETE</command> subcommands. A <command>MERGE</command> command
-    with both <command>INSERT</command> and <command>UPDATE</command>
-    subcommands looks similar to <command>INSERT</command> with an
-    <literal>ON CONFLICT DO UPDATE</literal> clause but does not guarantee
-    that either <command>INSERT</command> and <command>UPDATE</command> will occur.
-
-    If MERGE attempts an UPDATE or DELETE and the row is concurrently updated
-    but the join condition still passes for the current target and the current
-    source tuple, then MERGE will behave the same as the UPDATE or DELETE commands
-    and perform its action on the latest version of the row, using standard
-    EvalPlanQual. MERGE actions can be conditional, so conditions must be
-    re-evaluated on the latest row, starting from the first action.
-
-    On the other hand, if the row is concurrently updated or deleted so that
-    the join condition fails, then MERGE will execute a NOT MATCHED action, if it
-    exists and the AND WHEN qual evaluates to true.
-
-    If MERGE attempts an INSERT and a unique index is present and a duplicate
-    row is concurrently inserted then a uniqueness violation is raised. MERGE
-    does not attempt to avoid the ERROR by attempting an UPDATE.
-   </para>
-
-   <para>
     Because Read Committed mode starts each command with a new snapshot
     that includes all transactions committed up to that instant,
     subsequent commands in the same transaction will see the effects
@@ -925,8 +900,7 @@ ERROR:  could not serialize access due to read/write dependencies among transact
 
         <para>
          The commands <command>UPDATE</command>,
-         <command>DELETE</command>, <command>INSERT</command> and
-         <command>MERGE</command>
+         <command>DELETE</command>, and <command>INSERT</command>
          acquire this lock mode on the target table (in addition to
          <literal>ACCESS SHARE</literal> locks on any other referenced
          tables).  In general, this lock mode will be acquired by any
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 59f6112b07c..5b2aac618e3 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -1246,7 +1246,7 @@ EXECUTE format('SELECT count(*) FROM %I '
 </programlisting>
      Another restriction on parameter symbols is that they only work in
      <command>SELECT</command>, <command>INSERT</command>, <command>UPDATE</command>, and
-     <command>DELETE</command> and <command>MERGE</command> commands.  In other statement
+     <command>DELETE</command> commands.  In other statement
      types (generically called utility statements), you must insert
      values textually even if they are just data values.
     </para>
@@ -1529,7 +1529,6 @@ GET DIAGNOSTICS integer_var = ROW_COUNT;
           <listitem>
            <para>
             <command>UPDATE</command>, <command>INSERT</command>, and <command>DELETE</command>
-            and <command>MERGE</command>
             statements set <literal>FOUND</literal> true if at least one
             row is affected, false if no row is affected.
            </para>
diff --git a/doc/src/sgml/ref/allfiles.sgml b/doc/src/sgml/ref/allfiles.sgml
index 4e01e5641cf..22e68932115 100644
--- a/doc/src/sgml/ref/allfiles.sgml
+++ b/doc/src/sgml/ref/allfiles.sgml
@@ -159,7 +159,6 @@ Complete list of usable sgml source files in this directory.
 <!ENTITY load               SYSTEM "load.sgml">
 <!ENTITY lock               SYSTEM "lock.sgml">
 <!ENTITY move               SYSTEM "move.sgml">
-<!ENTITY merge              SYSTEM "merge.sgml">
 <!ENTITY notify             SYSTEM "notify.sgml">
 <!ENTITY prepare            SYSTEM "prepare.sgml">
 <!ENTITY prepareTransaction SYSTEM "prepare_transaction.sgml">
diff --git a/doc/src/sgml/ref/create_policy.sgml b/doc/src/sgml/ref/create_policy.sgml
index 32f39a48ba9..0e35b0ef43e 100644
--- a/doc/src/sgml/ref/create_policy.sgml
+++ b/doc/src/sgml/ref/create_policy.sgml
@@ -94,13 +94,6 @@ CREATE POLICY <replaceable class="parameter">name</replaceable> ON <replaceable
    exist, a <quote>default deny</quote> policy is assumed, so that no rows will
    be visible or updatable.
   </para>
-
-  <para>
-   No separate policy exists for <command>MERGE</command>. Instead policies
-   defined for <literal>SELECT</literal>, <literal>INSERT</literal>,
-   <literal>UPDATE</literal> and <literal>DELETE</literal> are applied
-   while executing MERGE, depending on the actions that are activated.
-  </para>
  </refsect1>
 
  <refsect1>
diff --git a/doc/src/sgml/ref/insert.sgml b/doc/src/sgml/ref/insert.sgml
index da294aaa46a..62e142fd8ef 100644
--- a/doc/src/sgml/ref/insert.sgml
+++ b/doc/src/sgml/ref/insert.sgml
@@ -579,13 +579,6 @@ INSERT <replaceable>oid</replaceable> <replaceable class="parameter">count</repl
    is a partition, an error will occur if one of the input rows violates
    the partition constraint.
   </para>
-
-  <para>
-   You may also wish to consider using <command>MERGE</command>, since that
-   allows mixed <command>INSERT</command>, <command>UPDATE</command> and
-   <command>DELETE</command> within a single statement.
-   See <xref linkend="sql-merge"/>.
-  </para>
  </refsect1>
 
  <refsect1>
@@ -756,9 +749,7 @@ INSERT INTO distributors (did, dname) VALUES (10, 'Conrad International')
    Also, the case in
    which a column name list is omitted, but not all the columns are
    filled from the <literal>VALUES</literal> clause or <replaceable>query</replaceable>,
-   is disallowed by the standard. If you prefer a more SQL Standard
-   conforming statement than <literal>ON CONFLICT</literal>, see
-   <xref linkend="sql-merge"/>.
+   is disallowed by the standard.
   </para>
 
   <para>
diff --git a/doc/src/sgml/reference.sgml b/doc/src/sgml/reference.sgml
index ef2270c4673..d27fb414f7c 100644
--- a/doc/src/sgml/reference.sgml
+++ b/doc/src/sgml/reference.sgml
@@ -186,7 +186,6 @@
    &listen;
    &load;
    &lock;
-   &merge;
    &move;
    &notify;
    &prepare;
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index cce58fbf1d0..c43dbc9786e 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -183,26 +183,6 @@
    </para>
 
    <para>
-    No separate triggers are defined for <command>MERGE</command>. Instead,
-    statement-level or row-level <command>UPDATE</command>,
-    <command>DELETE</command> and <command>INSERT</command> triggers are fired
-    depending on what actions are specified in the <command>MERGE</command> query
-    and what actions are activated.
-   </para>
-
-   <para>
-    While running a <command>MERGE</command> command, statement-level
-    <literal>BEFORE</literal> and <literal>AFTER</literal> triggers are fired for
-    events specified in the actions of the <command>MERGE</command> command,
-    irrespective of whether the action is finally activated or not. This is same as
-    an <command>UPDATE</command> statement that updates no rows, yet
-    statement-level triggers are fired. The row-level triggers are fired only
-    when a row is actually updated, inserted or deleted. So it's perfectly legal
-    that while statement-level triggers are fired for certain type of action, no
-    row-level triggers are fired for the same kind of action.
-   </para>
-
-   <para>
     Trigger functions invoked by per-statement triggers should always
     return <symbol>NULL</symbol>. Trigger functions invoked by per-row
     triggers can return a table row (a value of