Revert temporal primary keys and foreign keys

This feature set did not handle empty ranges correctly, and it's now
too late for PostgreSQL 17 to fix it.

The following commits are reverted:

    6db4598fcb8 Add stratnum GiST support function
    46a0cd4cefb Add temporal PRIMARY KEY and UNIQUE constraints
    86232a49a43 Fix comment on gist_stratnum_btree
    030e10ff1a3 Rename pg_constraint.conwithoutoverlaps to conperiod
    a88c800deb6 Use daterange and YMD in without_overlaps tests instead of tsrange.
    5577a71fb0c Use half-open interval notation in without_overlaps tests
    34768ee3616 Add temporal FOREIGN KEY contraints
    482e108cd38 Add test for REPLICA IDENTITY with a temporal key
    c3db1f30cba doc:  clarify PERIOD and WITHOUT OVERLAPS in CREATE TABLE
    144c2ce0cc7 Fix ON CONFLICT DO NOTHING/UPDATE for temporal indexes

Discussion: https://www.postgresql.org/message-id/[email protected]

4 files changed, 17 insertions, 173 deletions

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 5a6f65025b1..15f6255d865 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -2731,17 +2731,6 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>conperiod</structfield> <type>bool</type>
-      </para>
-      <para>
-       This constraint is defined with <literal>WITHOUT OVERLAPS</literal>
-       (for primary keys and unique constraints) or <literal>PERIOD</literal>
-       (for foreign keys).
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>conkey</structfield> <type>int2[]</type>
        (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attnum</structfield>)
       </para>
diff --git a/doc/src/sgml/gist.sgml b/doc/src/sgml/gist.sgml
index dcf9433fa78..39c7bf370d6 100644
--- a/doc/src/sgml/gist.sgml
+++ b/doc/src/sgml/gist.sgml
@@ -266,7 +266,7 @@ CREATE INDEX ON my_table USING GIST (my_inet_column inet_ops);
 
  <para>
    There are five methods that an index operator class for
-   <acronym>GiST</acronym> must provide, and seven that are optional.
+   <acronym>GiST</acronym> must provide, and six that are optional.
    Correctness of the index is ensured
    by proper implementation of the <function>same</function>, <function>consistent</function>
    and <function>union</function> methods, while efficiency (size and speed) of the
@@ -289,11 +289,6 @@ CREATE INDEX ON my_table USING GIST (my_inet_column inet_ops);
    user-specified parameters.
    The optional eleventh method <function>sortsupport</function> is used to
    speed up building a <acronym>GiST</acronym> index.
-   The optional twelfth method <function>stratnum</function> is used to
-   translate well-known <literal>RT*StrategyNumber</literal>s (from
-   <filename>src/include/access/stratnum.h</filename>) into strategy numbers
-   used by the operator class.  This lets the core code look up operators for
-   temporal constraint indexes.
  </para>
 
  <variablelist>
@@ -1168,76 +1163,6 @@ my_sortsupport(PG_FUNCTION_ARGS)
       </para>
      </listitem>
     </varlistentry>
-
-    <varlistentry>
-     <term><function>stratnum</function></term>
-     <listitem>
-      <para>
-       Given an <literal>RT*StrategyNumber</literal> value from
-       <filename>src/include/access/stratnum.h</filename>, returns a strategy
-       number used by this operator class for matching functionality.  The
-       function should return <literal>InvalidStrategy</literal> if the
-       operator class has no matching strategy.
-      </para>
-
-      <para>
-       This is used for temporal index constraints (i.e., <literal>PRIMARY
-       KEY</literal> and <literal>UNIQUE</literal>).  If the operator class
-       provides this function and it returns results for
-       <literal>RTEqualStrategyNumber</literal>, it can be used in the
-       non-<literal>WITHOUT OVERLAPS</literal> part(s) of an index constraint.
-       If it returns results for <literal>RTOverlapStrategyNumber</literal>,
-       the operator class can be used in the <literal>WITHOUT
-       OVERLAPS</literal> part of an index constraint.
-      </para>
-
-      <para>
-       The <acronym>SQL</acronym> declaration of the function must look like
-       this:
-
-<programlisting>
-CREATE OR REPLACE FUNCTION my_stratnum(integer)
-RETURNS integer
-AS 'MODULE_PATHNAME'
-LANGUAGE C STRICT;
-</programlisting>
-      </para>
-
-       <para>
-        The matching code in the C module could then follow this skeleton:
-
-<programlisting>
-PG_FUNCTION_INFO_V1(my_stratnum);
-
-Datum
-my_stratnum(PG_FUNCTION_ARGS)
-{
-    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(1);
-    StrategyNumber ret = InvalidStrategy;
-
-    switch (strategy)
-    {
-        case RTEqualStrategyNumber:
-            ret = BTEqualStrategyNumber;
-    }
-
-    PG_RETURN_UINT16(ret);
-}
-</programlisting>
-      </para>
-
-      <para>
-       One translation function is provided by
-       <productname>PostgreSQL</productname>:
-       <literal>gist_stratnum_identity</literal> is for operator classes that
-       already use the <literal>RT*StrategyNumber</literal> constants.  It
-       returns whatever is passed to it.  The <literal>btree_gist</literal>
-       extension defines a second translation function,
-       <literal>gist_stratnum_btree</literal>, for operator classes that use
-       the <literal>BT*StrategyNumber</literal> constants.
-      </para>
-     </listitem>
-    </varlistentry>
   </variablelist>
 
   <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index a5bf80fb27e..f19306e7760 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -77,10 +77,10 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXI
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
 { CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
-  UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, <replaceable class="parameter">column_name</replaceable> WITHOUT OVERLAPS ] ) <replaceable class="parameter">index_parameters</replaceable> |
-  PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, <replaceable class="parameter">column_name</replaceable> WITHOUT OVERLAPS ] ) <replaceable class="parameter">index_parameters</replaceable> |
+  UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> |
+  PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> |
   EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ] ( <replaceable class="parameter">exclude_element</replaceable> WITH <replaceable class="parameter">operator</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable class="parameter">predicate</replaceable> ) ] |
-  FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, PERIOD <replaceable class="parameter">column_name</replaceable> ] ) REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> [, ... ] [, PERIOD <replaceable class="parameter">column_name</replaceable> ] ) ]
+  FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> [, ... ] ) ]
     [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <replaceable
 class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -964,7 +964,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 
    <varlistentry id="sql-createtable-parms-unique">
     <term><literal>UNIQUE [ NULLS [ NOT ] DISTINCT ]</literal> (column constraint)</term>
-    <term><literal>UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, <replaceable class="parameter">column_name</replaceable> WITHOUT OVERLAPS ] )</literal>
+    <term><literal>UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable class="parameter">column_name</replaceable> [, ... ] )</literal>
     <optional> <literal>INCLUDE ( <replaceable class="parameter">column_name</replaceable> [, ...])</literal> </optional> (table constraint)</term>
 
     <listitem>
@@ -979,30 +979,6 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      If the <literal>WITHOUT OVERLAPS</literal> option is specified for the
-      last column, then that column is checked for overlaps instead of
-      equality.  In that case, the other columns of the constraint will allow
-      duplicates so long as the duplicates don't overlap in the
-      <literal>WITHOUT OVERLAPS</literal> column.  (This is sometimes called a
-      temporal key, if the column is a range of dates or timestamps, but
-      PostgreSQL allows ranges over any base type.)  In effect, such a
-      constraint is enforced with an <literal>EXCLUDE</literal> constraint
-      rather than a <literal>UNIQUE</literal> constraint.  So for example
-      <literal>UNIQUE (id, valid_at WITHOUT OVERLAPS)</literal> behaves like
-      <literal>EXCLUDE USING GIST (id WITH =, valid_at WITH
-      &amp;&amp;)</literal>.  The <literal>WITHOUT OVERLAPS</literal> column
-      must have a range or multirange type.  (Technically, any type is allowed
-      whose default GiST opclass includes an overlaps operator.  See the
-      <literal>stratnum</literal> support function under <xref
-      linkend="gist-extensibility"/> for details.)  The non-<literal>WITHOUT
-      OVERLAPS</literal> columns of the constraint can be any type that can be
-      compared for equality in a GiST index.  By default, only range types are
-      supported, but you can use other types by adding the <xref
-      linkend="btree-gist"/> extension (which is the expected way to use this
-      feature).
-     </para>
-
-     <para>
       For the purpose of a unique constraint, null values are not
       considered equal, unless <literal>NULLS NOT DISTINCT</literal> is
       specified.
@@ -1023,11 +999,9 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      Adding a unique constraint will automatically create a unique B-tree
-      index on the column or group of columns used in the constraint.  But if
-      the constraint includes a <literal>WITHOUT OVERLAPS</literal> clause, it
-      will use a GiST index.  The created index has the same name as the unique
-      constraint.
+      Adding a unique constraint will automatically create a unique btree
+      index on the column or group of columns used in the constraint.  The
+      created index has the same name as the unique constraint.
      </para>
 
      <para>
@@ -1045,7 +1019,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 
    <varlistentry id="sql-createtable-parms-primary-key">
     <term><literal>PRIMARY KEY</literal> (column constraint)</term>
-    <term><literal>PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, <replaceable class="parameter">column_name</replaceable> WITHOUT OVERLAPS ] )</literal>
+    <term><literal>PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] )</literal>
     <optional> <literal>INCLUDE ( <replaceable class="parameter">column_name</replaceable> [, ...])</literal> </optional> (table constraint)</term>
     <listitem>
      <para>
@@ -1078,11 +1052,10 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      As with a <literal>UNIQUE</literal> constraint, adding a
-      <literal>PRIMARY KEY</literal> constraint will automatically create a
-      unique B-tree index, or GiST if <literal>WITHOUT OVERLAPS</literal> was
-      specified, on the column or group of columns used in the constraint.
-      That index has the same name as the primary key constraint.
+      Adding a <literal>PRIMARY KEY</literal> constraint will automatically
+      create a unique btree index on the column or group of columns used in
+      the constraint.  That index has the same name as the primary key
+      constraint.
      </para>
 
      <para>
@@ -1151,8 +1124,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
    <varlistentry id="sql-createtable-parms-references">
     <term><literal>REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH <replaceable class="parameter">matchtype</replaceable> ] [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ]</literal> (column constraint)</term>
 
-   <term><literal>FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] [, PERIOD <replaceable class="parameter">column_name</replaceable> ] )
-    REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> [, ... ] [, PERIOD <replaceable class="parameter">column_name</replaceable> ] ) ]
+   <term><literal>FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] )
+    REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> [, ... ] ) ]
     [ MATCH <replaceable class="parameter">matchtype</replaceable> ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ]
     [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ]</literal>
@@ -1168,32 +1141,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       primary key of the <replaceable class="parameter">reftable</replaceable>
       is used.  Otherwise, the <replaceable class="parameter">refcolumn</replaceable>
       list must refer to the columns of a non-deferrable unique or primary key
-      constraint or be the columns of a non-partial unique index.
-     </para>
-
-     <para>
-      If the last column is marked with <literal>PERIOD</literal>, it is
-      treated in a special way.  While the non-<literal>PERIOD</literal>
-      columns are compared for equality (and there must be at least one of
-      them), the <literal>PERIOD</literal> column is not.  Instead, the
-      constraint is considered satisfied if the referenced table has matching
-      records (based on the non-<literal>PERIOD</literal> parts of the key)
-      whose combined <literal>PERIOD</literal> values completely cover the
-      referencing record's.  In other words, the reference must have a
-      referent for its entire duration.  This column must be a range or
-      multirange type.  In addition, the referenced table must have a primary
-      key or unique constraint declared with <literal>WITHOUT
-      OVERLAPS</literal>. Finally, if the foreign key has a PERIOD
-      <replaceable class="parameter">column_name</replaceable> specification
-      the corresponding <replaceable class="parameter">refcolumn</replaceable>,
-      if present, must also be marked <literal>PERIOD</literal>.  If the
-      <replaceable class="parameter">refcolumn</replaceable> clause is omitted,
-      and thus the reftable's primary key constraint chosen, the primary key
-      must have its final column marked <literal>WITHOUT OVERLAPS</literal>.
-     </para>
-
-     <para>
-      The user
+      constraint or be the columns of a non-partial unique index.  The user
       must have <literal>REFERENCES</literal> permission on the referenced
       table (either the whole table, or the specific referenced columns).  The
       addition of a foreign key constraint requires a
@@ -1267,10 +1215,6 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
           values of the referencing column(s) to the new values of the
           referenced columns, respectively.
          </para>
-
-         <para>
-          In a temporal foreign key, this option is not supported.
-         </para>
         </listitem>
        </varlistentry>
 
@@ -1282,10 +1226,6 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
           referencing columns, to null. A subset of columns can only be
           specified for <literal>ON DELETE</literal> actions.
          </para>
-
-         <para>
-          In a temporal foreign key, this option is not supported.
-         </para>
         </listitem>
        </varlistentry>
 
@@ -1299,10 +1239,6 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
           (There must be a row in the referenced table matching the default
           values, if they are not null, or the operation will fail.)
          </para>
-
-         <para>
-          In a temporal foreign key, this option is not supported.
-         </para>
         </listitem>
        </varlistentry>
       </variablelist>
diff --git a/doc/src/sgml/xindex.sgml b/doc/src/sgml/xindex.sgml
index 3a19dab15e0..22d8ad1aac4 100644
--- a/doc/src/sgml/xindex.sgml
+++ b/doc/src/sgml/xindex.sgml
@@ -508,7 +508,7 @@
    </table>
 
   <para>
-   GiST indexes have twelve support functions, seven of which are optional,
+   GiST indexes have eleven support functions, six of which are optional,
    as shown in <xref linkend="xindex-gist-support-table"/>.
    (For more information see <xref linkend="gist"/>.)
   </para>
@@ -590,12 +590,6 @@
         (optional)</entry>
        <entry>11</entry>
       </row>
-      <row>
-       <entry><function>stratnum</function></entry>
-       <entry>translate well-known strategy numbers to ones
-        used by the operator class (optional)</entry>
-       <entry>12</entry>
-      </row>
      </tbody>
     </tgroup>
    </table>