revert: Transform OR clauses to ANY expression

This commit reverts 72bd38c due to implementation and design issues.

Reported-by: Tom Lane
Discussion: https://postgr.es/m/3604469.1712628736%40sss.pgh.pa.us

Author: akorotkov

doc/src/sgml/config.sgml

@@ -6304,63 +6304,6 @@ SELECT * FROM parent WHERE key = 2400;
       </listitem>
      </varlistentry>
 
-     <varlistentry id="guc-or-to-any-transform-limit" xreflabel="or_to_any_transform_limit">
-      <term><varname>or_to_any_transform_limit</varname> (<type>boolean</type>)
-       <indexterm>
-        <primary><varname>or_to_any_transform_limit</varname> configuration parameter</primary>
-       </indexterm>
-      </term>
-      <listitem>
-       <para>
-        Sets the minimum length of arguments in an <literal>OR</literal>
-        expression exceeding which planner will try to lookup and group
-        multiple similar <literal>OR</literal> expressions to
-        <literal>ANY</literal> (<xref linkend="functions-comparisons-any-some"/>)
-        expressions.  The grouping technique of this transformation is based
-        on the equivalence of variable sides.  One side of such an expression
-        must be a constant clause, and the other must contain a variable
-        clause.  The default value is <literal>5</literal>.  The value of
-        <literal>-1</literal> completely disables the transformation.
-       </para>
-       <para>
-        The advantage of this <literal>OR-to-ANY</literal> transformation is
-        faster query planning and execution.  In certain cases, this
-        transformation also leads to more effective plans containing
-        a single index scan instead of multiple bitmap scans.  However, it
-        may also cause a planning regression when distinct
-        <literal>OR</literal> arguments are better to match to distinct indexes.
-        This may happen when they have different matching partial indexes or
-        have different distributions of other columns used in the query.
-        Generally, more groupable <literal>OR</literal> arguments mean that
-        transformation will be more likely to win than to lose.
-       </para>
-       <para>
-        For example, this query has its set of five <literal>OR</literal>
-        expressions transformed to <literal>ANY</literal> with the default
-        value of <varname>or_to_any_transform_limit</varname>.  But not with
-        the increased value.
-<programlisting>
-# EXPLAIN SELECT * FROM tbl WHERE key = 1 OR key = 2 OR key = 3 OR key = 4 OR key = 5;
-                     QUERY PLAN
------------------------------------------------------
- Seq Scan on tbl  (cost=0.00..51.44 rows=64 width=4)
-   Filter: (key = ANY ('{1,2,3,4,5}'::integer[]))
-(2 rows)
-
-# SET or_to_any_transform_limit = 6;
-SET
-
-# EXPLAIN SELECT * FROM tbl WHERE key = 1 OR key = 2 OR key = 3 OR key = 4 OR key = 5;
-                                QUERY PLAN
----------------------------------------------------------------------------
- Seq Scan on tbl  (cost=0.00..67.38 rows=63 width=4)
-   Filter: ((key = 1) OR (key = 2) OR (key = 3) OR (key = 4) OR (key = 5))
-(2 rows)
-</programlisting>
-       </para>
-      </listitem>
-     </varlistentry>
-
      <varlistentry id="guc-plan-cache-mode" xreflabel="plan_cache_mode">
       <term><varname>plan_cache_mode</varname> (<type>enum</type>)
       <indexterm>

src/backend/nodes/queryjumblefuncs.c

@@ -141,33 +141,6 @@ JumbleQuery(Query *query)
 	return jstate;
 }
 
-JumbleState *
-JumbleExpr(Expr *expr, uint64 *exprId)
-{
-	JumbleState *jstate = NULL;
-
-	Assert(exprId != NULL);
-
-	jstate = (JumbleState *) palloc(sizeof(JumbleState));
-
-	/* Set up workspace for query jumbling */
-	jstate->jumble = (unsigned char *) palloc(JUMBLE_SIZE);
-	jstate->jumble_len = 0;
-	jstate->clocations_buf_size = 32;
-	jstate->clocations = (LocationLen *)
-		palloc(jstate->clocations_buf_size * sizeof(LocationLen));
-	jstate->clocations_count = 0;
-	jstate->highest_extern_param_id = 0;
-
-	/* Compute query ID */
-	_jumbleNode(jstate, (Node *) expr);
-	*exprId = DatumGetUInt64(hash_any_extended(jstate->jumble,
-											   jstate->jumble_len,
-											   0));
-
-	return jstate;
-}
-
 /*
  * Enables query identifier computation.
  *