Revert support for ALTER TABLE ... MERGE/SPLIT PARTITION(S) commands

This commit reverts 1adf16b, 87c21bb, and subsequent fixes and
improvements including df64c81, c99ef18, 9dfcac8, 885742b,
842c9b2, fcf80c5, 96c7381, f4fc7cb, 60ae37a, 259c96f,
449cdcd, 3ca43db, 2a679ae, 3a82c68, fbd4321, d53a428,
c086896, 4e5d6c4, 04158e7.

The reason for reverting is security issues related to repeatable name lookups
(CVE-2014-0062).  Even though 04158e7 solved part of the problem, there
are still remaining issues, which aren't feasible to even carefully analyze
before the RC deadline.

Reported-by: Noah Misch, Robert Haas
Discussion: https://postgr.es/m/20240808171351.a9.nmisch%40google.com
Backpatch-through: 17

Author: akorotkov

doc/src/sgml/ddl.sgml

@@ -4355,44 +4355,6 @@ ALTER INDEX measurement_city_id_logdate_key
 ...
 </programlisting>
     </para>
-
-    <para>
-     There is also an option for merging multiple table partitions into
-     a single partition using the
-     <link linkend="sql-altertable-merge-partitions"><command>ALTER TABLE ... MERGE PARTITIONS</command></link>.
-     This feature simplifies the management of partitioned tables by allowing
-     users to combine partitions that are no longer needed as
-     separate entities.  It's important to note that this operation is not
-     supported for hash-partitioned tables and acquires an
-     <literal>ACCESS EXCLUSIVE</literal> lock, which could impact high-load
-     systems due to the lock's restrictive nature.  For example, we can
-     merge three monthly partitions into one quarter partition:
-<programlisting>
-ALTER TABLE measurement
-    MERGE PARTITIONS (measurement_y2006m01,
-                      measurement_y2006m02,
-                      measurement_y2006m03) INTO measurement_y2006q1;
-</programlisting>
-    </para>
-
-    <para>
-     Similarly to merging multiple table partitions, there is an option for
-     splitting a single partition into multiple using the
-     <link linkend="sql-altertable-split-partition"><command>ALTER TABLE ... SPLIT PARTITION</command></link>.
-     This feature could come in handy when one partition grows too big
-     and needs to be split into multiple.  It's important to note that
-     this operation is not supported for hash-partitioned tables and acquires
-     an <literal>ACCESS EXCLUSIVE</literal> lock, which could impact high-load
-     systems due to the lock's restrictive nature.  For example, we can split
-     the quarter partition back to monthly partitions:
-<programlisting>
-ALTER TABLE measurement SPLIT PARTITION measurement_y2006q1 INTO
-   (PARTITION measurement_y2006m01 FOR VALUES FROM ('2006-01-01') TO ('2006-02-01'),
-    PARTITION measurement_y2006m02 FOR VALUES FROM ('2006-02-01') TO ('2006-03-01'),
-    PARTITION measurement_y2006m03 FOR VALUES FROM ('2006-03-01') TO ('2006-04-01'));
-</programlisting>
-    </para>
-
    </sect3>
 
    <sect3 id="ddl-partitioning-declarative-limitations">

doc/src/sgml/ref/alter_table.sgml

@@ -37,13 +37,6 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ATTACH PARTITION <replaceable class="parameter">partition_name</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT }
 ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     DETACH PARTITION <replaceable class="parameter">partition_name</replaceable> [ CONCURRENTLY | FINALIZE ]
-ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
-    SPLIT PARTITION <replaceable class="parameter">partition_name</replaceable> INTO
-        (PARTITION <replaceable class="parameter">partition_name1</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT },
-         PARTITION <replaceable class="parameter">partition_name2</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT } [, ...])
-ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
-    MERGE PARTITIONS (<replaceable class="parameter">partition_name1</replaceable>, <replaceable class="parameter">partition_name2</replaceable> [, ...])
-        INTO <replaceable class="parameter">partition_name</replaceable>
 
 <phrase>where <replaceable class="parameter">action</replaceable> is one of:</phrase>
 
@@ -1124,140 +1117,14 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
-   <varlistentry id="sql-altertable-split-partition">
-    <term><literal>SPLIT PARTITION <replaceable class="parameter">partition_name</replaceable> INTO (PARTITION <replaceable class="parameter">partition_name1</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT }, PARTITION <replaceable class="parameter">partition_name2</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT } [, ...])</literal></term>
-
-    <listitem>
-     <para>
-      This form splits a single partition of the target table. Hash-partitioning
-      is not supported. Bounds of new partitions should not overlap with new and
-      existing partitions (except <replaceable class="parameter">partition_name</replaceable>).
-      If the split partition is a DEFAULT partition, one of the new partitions must be DEFAULT.
-      In case one of the new partitions or one of existing partitions is DEFAULT,
-      new partitions <replaceable class="parameter">partition_name1</replaceable>,
-      <replaceable class="parameter">partition_name2</replaceable>, ... can have spaces
-      between partitions bounds.  If the partitioned table does not have a DEFAULT
-      partition, the DEFAULT partition can be defined as one of the new partitions.
-     </para>
-     <para>
-      In case new partitions do not contain a DEFAULT partition and the partitioned table
-      does not have a DEFAULT partition, the following must be true: sum bounds of
-      new partitions <replaceable class="parameter">partition_name1</replaceable>,
-      <replaceable class="parameter">partition_name2</replaceable>, ... should be
-      equal to bound of split partition <replaceable class="parameter">partition_name</replaceable>.
-      One of the new partitions <replaceable class="parameter">partition_name1</replaceable>,
-      <replaceable class="parameter">partition_name2</replaceable>, ... can have
-      the same name as split partition <replaceable class="parameter">partition_name</replaceable>
-      (this is suitable in case of splitting a DEFAULT partition: we split it, but after
-      splitting we have a partition with the same name).
-      Only simple, non-partitioned partition can be split.
-     </para>
-     <para>
-      The new partitions will be created the same as tables created with the
-      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_nameN</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY EXCLUDING STATISTICS)</literal>.
-      The indexes and identity are created later, after moving the data
-      into the new partitions.
-      Extended statistics aren't copied from the parent table, for consistency with
-      <command>CREATE TABLE PARTITION OF</command>.
-
-      New partitions will have the same table access method as the parent.
-      If the parent table is persistent then new partitions are created
-      persistent.  If the parent table is temporary then new partitions
-      are also created temporary.  New partitions will also be created in
-      the same tablespace as the parent.
-     </para>
-     <note>
-      <para>
-       This command acquires an <literal>ACCESS EXCLUSIVE</literal> lock.
-       This is a significant limitation, which limits the usage of this
-       command with large partitioned tables under a high load.
-      </para>
-     </note>
-    </listitem>
-   </varlistentry>
-
-   <varlistentry id="sql-altertable-merge-partitions">
-    <term><literal>MERGE PARTITIONS (<replaceable class="parameter">partition_name1</replaceable>, <replaceable class="parameter">partition_name2</replaceable> [, ...]) INTO <replaceable class="parameter">partition_name</replaceable></literal></term>
-
-    <listitem>
-     <para>
-      This form merges several partitions into the one partition of the target table.
-      Hash-partitioning is not supported.  If DEFAULT partition is not in the
-      list of partitions <replaceable class="parameter">partition_name1</replaceable>,
-      <replaceable class="parameter">partition_name2</replaceable> [, ...]:
-      <itemizedlist>
-       <listitem>
-        <para>
-         For range-partitioned tables it is necessary that the ranges
-         of the partitions <replaceable class="parameter">partition_name1</replaceable>,
-         <replaceable class="parameter">partition_name2</replaceable> [, ...] can
-         be merged into one range without spaces and overlaps (otherwise an error
-         will be generated).  The combined range will be the range for the partition
-         <replaceable class="parameter">partition_name</replaceable>.
-        </para>
-       </listitem>
-       <listitem>
-        <para>
-         For list-partitioned tables the value lists of all partitions
-         <replaceable class="parameter">partition_name1</replaceable>,
-         <replaceable class="parameter">partition_name2</replaceable> [, ...] are
-         combined and form the list of values of partition
-         <replaceable class="parameter">partition_name</replaceable>.
-        </para>
-       </listitem>
-      </itemizedlist>
-      If DEFAULT partition is in the list of partitions <replaceable class="parameter">partition_name1</replaceable>,
-      <replaceable class="parameter">partition_name2</replaceable> [, ...]:
-      <itemizedlist>
-       <listitem>
-        <para>
-         The partition <replaceable class="parameter">partition_name</replaceable>
-         will be the DEFAULT partition.
-        </para>
-       </listitem>
-       <listitem>
-        <para>
-         For range- and list-partitioned tables the ranges and lists of values
-         of the merged partitions can be any.
-        </para>
-       </listitem>
-      </itemizedlist>
-      The new partition <replaceable class="parameter">partition_name</replaceable>
-      can have the same name as one of the merged partitions.  Only simple,
-      non-partitioned partitions can be merged.
-     </para>
-     <para>
-      The new partition will be created the same as a table created with the
-      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_name</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY EXCLUDING STATISTICS)</literal>.
-      The indexes and identity are created later, after moving the data
-      into the new partition.
-      Extended statistics aren't copied from the parent table, for consistency with
-      <command>CREATE TABLE PARTITION OF</command>.
-      The new partition will have the same table access method as the parent.
-      If the parent table is persistent then the new partition is created
-      persistent.  If the parent table is temporary then the new partition
-      is also created temporary.  The new partition will also be created in
-      the same tablespace as the parent.
-     </para>
-     <note>
-      <para>
-       This command acquires an <literal>ACCESS EXCLUSIVE</literal> lock.
-       This is a significant limitation, which limits the usage of this
-       command with large partitioned tables under a high load.
-      </para>
-     </note>
-    </listitem>
-   </varlistentry>
-
   </variablelist>
   </para>
 
   <para>
    All the forms of ALTER TABLE that act on a single table, except
    <literal>RENAME</literal>, <literal>SET SCHEMA</literal>,
-   <literal>ATTACH PARTITION</literal>, <literal>DETACH PARTITION</literal>,
-   <literal>SPLIT PARTITION</literal>, and <literal>MERGE PARTITIONS</literal>
-   can be combined into
+   <literal>ATTACH PARTITION</literal>, and
+   <literal>DETACH PARTITION</literal> can be combined into
    a list of multiple alterations to be applied together.  For example, it
    is possible to add several columns and/or alter the type of several
    columns in a single command.  This is particularly useful with large
@@ -1500,8 +1367,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       <term><replaceable class="parameter">partition_name</replaceable></term>
       <listitem>
        <para>
-        The name of the table to attach as a new partition or to detach from this table,
-        or the name of split partition, or the name of the new merged partition.
+        The name of the table to attach as a new partition or to detach from this table.
        </para>
       </listitem>
      </varlistentry>
@@ -1917,31 +1783,6 @@ ALTER TABLE measurement
     DETACH PARTITION measurement_y2015m12;
 </programlisting></para>
 
-  <para>
-   To split a single partition of the range-partitioned table:
-<programlisting>
-ALTER TABLE sales_range SPLIT PARTITION sales_feb_mar_apr2023 INTO
-   (PARTITION sales_feb2023 FOR VALUES FROM ('2023-02-01') TO ('2023-03-01'),
-    PARTITION sales_mar2023 FOR VALUES FROM ('2023-03-01') TO ('2023-04-01'),
-    PARTITION sales_apr2023 FOR VALUES FROM ('2023-04-01') TO ('2023-05-01'));
-</programlisting></para>
-
-  <para>
-   To split a single partition of the list-partitioned table:
-<programlisting>
-ALTER TABLE sales_list SPLIT PARTITION sales_all INTO
-   (PARTITION sales_west FOR VALUES IN ('Lisbon', 'New York', 'Madrid'),
-    PARTITION sales_east FOR VALUES IN ('Bejing', 'Delhi', 'Vladivostok'),
-    PARTITION sales_central FOR VALUES IN ('Warsaw', 'Berlin', 'Kyiv'));
-</programlisting></para>
-
-  <para>
-   To merge several partitions into one partition of the target table:
-<programlisting>
-ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_east, sales_central)
-    INTO sales_all;
-</programlisting></para>
-
  </refsect1>
 
  <refsect1>