Allow the index name to be omitted in CREATE INDEX, causing the system to

choose an index name the same as it would do for an unnamed index constraint.
(My recent changes to the index naming logic have helped to ensure that this
will be a reasonable choice.)  Per a suggestion from Peter.

A necessary side-effect is to promote CONCURRENTLY to type_func_name_keyword
status, ie, it can't be a table/column/index name anymore unless quoted.
This is not all bad, since we have heard more than once of people typing
CREATE INDEX CONCURRENTLY ON foo (...) and getting a normal index build of
an index named "concurrently", which was not what they wanted.  Now this
syntax will result in a concurrent build of an index with system-chosen
name; which they can rename afterwards if they want something else.

doc/src/sgml/keywords.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/keywords.sgml,v 2.27 2009/11/05 23:24:22 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/keywords.sgml,v 2.28 2009/12/23 17:41:43 tgl Exp $ -->
 
 <appendix id="sql-keywords-appendix">
  <title><acronym>SQL</acronym> Key Words</title>
@@ -921,7 +921,7 @@
    </row>
    <row>
     <entry><token>CONCURRENTLY</token></entry>
-    <entry>non-reserved</entry>
+    <entry>reserved (can be function or type)</entry>
     <entry></entry>
     <entry></entry>
     <entry></entry>

doc/src/sgml/ref/create_index.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.71 2009/03/24 20:17:08 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.72 2009/12/23 17:41:43 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</replaceable> ON <replaceable class="parameter">table</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace</replaceable> ]
@@ -33,8 +33,8 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
   <title>Description</title>
 
   <para>
-   <command>CREATE INDEX</command> constructs an index named <replaceable
+   <command>CREATE INDEX</command> constructs an index
-   class="parameter">name</replaceable> on the specified table.
+   on the specified column(s) of the specified table.
    Indexes are primarily used to enhance database performance (though
    inappropriate use can result in slower performance).
   </para>
@@ -132,7 +132,9 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
        <para>
         The name of the index to be created.  No schema name can be included
         here; the index is always created in the same schema as its parent
-        table.
+        table.  If the name is omitted, <productname>PostgreSQL</> chooses a
+        suitable name based on the parent table's name and the indexed column
+        name(s).
        </para>
       </listitem>
      </varlistentry>
@@ -514,8 +516,10 @@ CREATE UNIQUE INDEX title_idx ON films (title);
    To create an index on the expression <literal>lower(title)</>,
    allowing efficient case-insensitive searches:
 <programlisting>
-CREATE INDEX lower_title_idx ON films ((lower(title)));
+CREATE INDEX ON films ((lower(title)));
 </programlisting>
+   (In this example we have chosen to omit the index name, so the system
+   will choose a name, typically <literal>films_lower_idx</>.)
   </para>
 
   <para>

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.698 2009/12/23 02:35:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.699 2009/12/23 17:41:43 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -253,7 +253,8 @@ static TypeName *TableFuncTypeName(List *columns);
 
 %type <str>		copy_file_name
 				database_name access_method_clause access_method attr_name
-				index_name name cursor_name file_name cluster_index_specification
+				name cursor_name file_name
+				index_name opt_index_name cluster_index_specification
 
 %type <list>	func_name handler_name qual_Op qual_all_Op subquery_Op
 				opt_class opt_inline_handler opt_validator validator_clause
@@ -325,7 +326,7 @@ static TypeName *TableFuncTypeName(List *columns);
 %type <node>	overlay_placing substr_from substr_for
 
 %type <boolean> opt_instead
-%type <boolean> index_opt_unique opt_verbose opt_full
+%type <boolean> opt_unique opt_concurrently opt_verbose opt_full
 %type <boolean> opt_freeze opt_default opt_recheck
 %type <defelt>	opt_binary opt_oids copy_delimiter
 
@@ -4822,36 +4823,17 @@ defacl_privilege_target:
  *
  *		QUERY: CREATE INDEX
  *
- * Note: we can't factor CONCURRENTLY into a separate production without
- * making it a reserved word.
- *
  * Note: we cannot put TABLESPACE clause after WHERE clause unless we are
  * willing to make TABLESPACE a fully reserved word.
  *****************************************************************************/
 
-IndexStmt:	CREATE index_opt_unique INDEX index_name
+IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
-			ON qualified_name access_method_clause '(' index_params ')'
-			opt_reloptions OptTableSpace where_clause
-				{
-					IndexStmt *n = makeNode(IndexStmt);
-					n->unique = $2;
-					n->concurrent = false;
-					n->idxname = $4;
-					n->relation = $6;
-					n->accessMethod = $7;
-					n->indexParams = $9;
-					n->options = $11;
-					n->tableSpace = $12;
-					n->whereClause = $13;
-					$$ = (Node *)n;
-				}
-			| CREATE index_opt_unique INDEX CONCURRENTLY index_name
 			ON qualified_name access_method_clause '(' index_params ')'
 			opt_reloptions OptTableSpace where_clause
 				{
 					IndexStmt *n = makeNode(IndexStmt);
 					n->unique = $2;
-					n->concurrent = true;
+					n->concurrent = $4;
 					n->idxname = $5;
 					n->relation = $7;
 					n->accessMethod = $8;
@@ -4863,11 +4845,21 @@ IndexStmt:	CREATE index_opt_unique INDEX index_name
 				}
 		;
 
-index_opt_unique:
+opt_unique:
 			UNIQUE									{ $$ = TRUE; }
 			| /*EMPTY*/								{ $$ = FALSE; }
 		;
 
+opt_concurrently:
+			CONCURRENTLY							{ $$ = TRUE; }
+			| /*EMPTY*/								{ $$ = FALSE; }
+		;
+
+opt_index_name:
+			index_name								{ $$ = $1; }
+			| /*EMPTY*/								{ $$ = NULL; }
+		;
+
 access_method_clause:
 			USING access_method						{ $$ = $2; }
 			| /*EMPTY*/								{ $$ = DEFAULT_INDEX_TYPE; }
@@ -10696,7 +10688,6 @@ unreserved_keyword:
 			| COMMENTS
 			| COMMIT
 			| COMMITTED
-			| CONCURRENTLY
 			| CONFIGURATION
 			| CONNECTION
 			| CONSTRAINTS
@@ -10988,6 +10979,7 @@ type_func_name_keyword:
 			  AUTHORIZATION
 			| BETWEEN
 			| BINARY
+			| CONCURRENTLY
 			| CROSS
 			| CURRENT_SCHEMA
 			| FREEZE

src/include/parser/kwlist.h

@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/include/parser/kwlist.h,v 1.7 2009/12/07 05:22:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/include/parser/kwlist.h,v 1.8 2009/12/23 17:41:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -83,7 +83,7 @@ PG_KEYWORD("comment", COMMENT, UNRESERVED_KEYWORD)
 PG_KEYWORD("comments", COMMENTS, UNRESERVED_KEYWORD)
 PG_KEYWORD("commit", COMMIT, UNRESERVED_KEYWORD)
 PG_KEYWORD("committed", COMMITTED, UNRESERVED_KEYWORD)
-PG_KEYWORD("concurrently", CONCURRENTLY, UNRESERVED_KEYWORD)
+PG_KEYWORD("concurrently", CONCURRENTLY, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("configuration", CONFIGURATION, UNRESERVED_KEYWORD)
 PG_KEYWORD("connection", CONNECTION, UNRESERVED_KEYWORD)
 PG_KEYWORD("constraint", CONSTRAINT, RESERVED_KEYWORD)

src/test/regress/expected/create_index.out

@@ -689,7 +689,8 @@ DETAIL:  Key (f2)=(b) is duplicated.
 -- test that expression indexes and partial indexes work concurrently
 CREATE INDEX CONCURRENTLY concur_index4 on concur_heap(f2) WHERE f1='a';
 CREATE INDEX CONCURRENTLY concur_index5 on concur_heap(f2) WHERE f1='x';
-CREATE INDEX CONCURRENTLY concur_index6 on concur_heap((f2||f1));
+-- here we also check that you can default the index name
+CREATE INDEX CONCURRENTLY on concur_heap((f2||f1));
 -- You can't do a concurrent index build in a transaction
 BEGIN;
 CREATE INDEX CONCURRENTLY concur_index7 ON concur_heap(f1);
@@ -711,10 +712,10 @@ Table "public.concur_heap"
 Indexes:
     "concur_index2" UNIQUE, btree (f1)
     "concur_index3" UNIQUE, btree (f2) INVALID
+    "concur_heap_expr_idx" btree ((f2 || f1))
     "concur_index1" btree (f2, f1)
     "concur_index4" btree (f2) WHERE f1 = 'a'::text
     "concur_index5" btree (f2) WHERE f1 = 'x'::text
-    "concur_index6" btree ((f2 || f1))
     "std_index" btree (f2)
 
 DROP TABLE concur_heap;

src/test/regress/sql/create_index.sql

@@ -300,7 +300,8 @@ CREATE UNIQUE INDEX CONCURRENTLY concur_index3 ON concur_heap(f2);
 -- test that expression indexes and partial indexes work concurrently
 CREATE INDEX CONCURRENTLY concur_index4 on concur_heap(f2) WHERE f1='a';
 CREATE INDEX CONCURRENTLY concur_index5 on concur_heap(f2) WHERE f1='x';
-CREATE INDEX CONCURRENTLY concur_index6 on concur_heap((f2||f1));
+-- here we also check that you can default the index name
+CREATE INDEX CONCURRENTLY on concur_heap((f2||f1));
 
 -- You can't do a concurrent index build in a transaction
 BEGIN;