Refactor CREATE/ALTER DATABASE syntax so options need not be keywords.

Most of the existing option names are keywords anyway, but we can get rid
of LC_COLLATE and LC_CTYPE as keywords known to the lexer/grammar.  This
immediately reduces the size of the grammar tables by about 8KB, and will
save more when we add additional CREATE/ALTER DATABASE options in future.

A side effect of the implementation is that the CONNECTION LIMIT option
can now also be spelled CONNECTION_LIMIT.  We choose not to document this,
however.

Vik Fearing, based on a suggestion by me; reviewed by Pavel Stehule

Author: tglsfdc

src/backend/commands/dbcommands.c

@@ -39,6 +39,7 @@
 #include "catalog/pg_tablespace.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
+#include "commands/defrem.h"
 #include "commands/seclabel.h"
 #include "commands/tablespace.h"
 #include "mb/pg_wchar.h"
@@ -188,7 +189,7 @@ createdb(const CreatedbStmt *stmt)
 						 errmsg("conflicting or redundant options")));
 			dctype = defel;
 		}
-		else if (strcmp(defel->defname, "connectionlimit") == 0)
+		else if (strcmp(defel->defname, "connection_limit") == 0)
 		{
 			if (dconnlimit)
 				ereport(ERROR,
@@ -204,21 +205,22 @@ createdb(const CreatedbStmt *stmt)
 					 errhint("Consider using tablespaces instead.")));
 		}
 		else
-			elog(ERROR, "option \"%s\" not recognized",
-				 defel->defname);
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("option \"%s\" not recognized", defel->defname)));
 	}
 
 	if (downer && downer->arg)
-		dbowner = strVal(downer->arg);
+		dbowner = defGetString(downer);
 	if (dtemplate && dtemplate->arg)
-		dbtemplate = strVal(dtemplate->arg);
+		dbtemplate = defGetString(dtemplate);
 	if (dencoding && dencoding->arg)
 	{
 		const char *encoding_name;
 
 		if (IsA(dencoding->arg, Integer))
 		{
-			encoding = intVal(dencoding->arg);
+			encoding = defGetInt32(dencoding);
 			encoding_name = pg_encoding_to_char(encoding);
 			if (strcmp(encoding_name, "") == 0 ||
 				pg_valid_server_encoding(encoding_name) < 0)
@@ -227,28 +229,25 @@ createdb(const CreatedbStmt *stmt)
 						 errmsg("%d is not a valid encoding code",
 								encoding)));
 		}
-		else if (IsA(dencoding->arg, String))
+		else
 		{
-			encoding_name = strVal(dencoding->arg);
+			encoding_name = defGetString(dencoding);
 			encoding = pg_valid_server_encoding(encoding_name);
 			if (encoding < 0)
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_OBJECT),
 						 errmsg("%s is not a valid encoding name",
 								encoding_name)));
 		}
-		else
-			elog(ERROR, "unrecognized node type: %d",
-				 nodeTag(dencoding->arg));
 	}
 	if (dcollate && dcollate->arg)
-		dbcollate = strVal(dcollate->arg);
+		dbcollate = defGetString(dcollate);
 	if (dctype && dctype->arg)
-		dbctype = strVal(dctype->arg);
+		dbctype = defGetString(dctype);
 
 	if (dconnlimit && dconnlimit->arg)
 	{
-		dbconnlimit = intVal(dconnlimit->arg);
+		dbconnlimit = defGetInt32(dconnlimit);
 		if (dbconnlimit < -1)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -379,7 +378,7 @@ createdb(const CreatedbStmt *stmt)
 		char	   *tablespacename;
 		AclResult	aclresult;
 
-		tablespacename = strVal(dtablespacename->arg);
+		tablespacename = defGetString(dtablespacename);
 		dst_deftablespace = get_tablespace_oid(tablespacename, false);
 		/* check permissions */
 		aclresult = pg_tablespace_aclcheck(dst_deftablespace, GetUserId(),
@@ -1341,7 +1340,7 @@ AlterDatabase(AlterDatabaseStmt *stmt, bool isTopLevel)
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "connectionlimit") == 0)
+		if (strcmp(defel->defname, "connection_limit") == 0)
 		{
 			if (dconnlimit)
 				ereport(ERROR,
@@ -1358,23 +1357,32 @@ AlterDatabase(AlterDatabaseStmt *stmt, bool isTopLevel)
 			dtablespace = defel;
 		}
 		else
-			elog(ERROR, "option \"%s\" not recognized",
-				 defel->defname);
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("option \"%s\" not recognized", defel->defname)));
 	}
 
 	if (dtablespace)
 	{
-		/* currently, can't be specified along with any other options */
-		Assert(!dconnlimit);
+		/*
+		 * While the SET TABLESPACE syntax doesn't allow any other options,
+		 * somebody could write "WITH TABLESPACE ...".  Forbid any other
+		 * options from being specified in that case.
+		 */
+		if (list_length(stmt->options) != 1)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			   errmsg("option \"%s\" cannot be specified with other options",
+					  dtablespace->defname)));
 		/* this case isn't allowed within a transaction block */
 		PreventTransactionChain(isTopLevel, "ALTER DATABASE SET TABLESPACE");
-		movedb(stmt->dbname, strVal(dtablespace->arg));
+		movedb(stmt->dbname, defGetString(dtablespace));
 		return InvalidOid;
 	}
 
-	if (dconnlimit)
+	if (dconnlimit && dconnlimit->arg)
 	{
-		connlimit = intVal(dconnlimit->arg);
+		connlimit = defGetInt32(dconnlimit);
 		if (connlimit < -1)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),

src/backend/parser/gram.y

@@ -264,10 +264,10 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 %type <dbehavior>	opt_drop_behavior
 
-%type <list>	createdb_opt_list alterdb_opt_list copy_opt_list
+%type <list>	createdb_opt_list createdb_opt_items copy_opt_list
 				transaction_mode_list
 				create_extension_opt_list alter_extension_opt_list
-%type <defelt>	createdb_opt_item alterdb_opt_item copy_opt_item
+%type <defelt>	createdb_opt_item copy_opt_item
 				transaction_mode_item
 				create_extension_opt_item alter_extension_opt_item
 
@@ -462,6 +462,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <list>	var_list
 %type <str>		ColId ColLabel var_name type_function_name param_name
 %type <str>		NonReservedWord NonReservedWord_or_Sconst
+%type <str>		createdb_opt_name
 %type <node>	var_value zone_value
 
 %type <keyword> unreserved_keyword type_func_name_keyword
@@ -564,7 +565,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 	KEY
 
-	LABEL LANGUAGE LARGE_P LAST_P LATERAL_P LC_COLLATE_P LC_CTYPE_P
+	LABEL LANGUAGE LARGE_P LAST_P LATERAL_P
 	LEADING LEAKPROOF LEAST LEFT LEVEL LIKE LIMIT LISTEN LOAD LOCAL
 	LOCALTIME LOCALTIMESTAMP LOCATION LOCK_P
 
@@ -8320,77 +8321,51 @@ CreatedbStmt:
 		;
 
 createdb_opt_list:
-			createdb_opt_list createdb_opt_item		{ $$ = lappend($1, $2); }
+			createdb_opt_items						{ $$ = $1; }
 			| /* EMPTY */							{ $$ = NIL; }
 		;
 
+createdb_opt_items:
+			createdb_opt_item						{ $$ = list_make1($1); }
+			| createdb_opt_items createdb_opt_item	{ $$ = lappend($1, $2); }
+		;
+
 createdb_opt_item:
-			TABLESPACE opt_equal name
-				{
-					$$ = makeDefElem("tablespace", (Node *)makeString($3));
-				}
-			| TABLESPACE opt_equal DEFAULT
-				{
-					$$ = makeDefElem("tablespace", NULL);
-				}
-			| LOCATION opt_equal Sconst
-				{
-					$$ = makeDefElem("location", (Node *)makeString($3));
-				}
-			| LOCATION opt_equal DEFAULT
-				{
-					$$ = makeDefElem("location", NULL);
-				}
-			| TEMPLATE opt_equal name
-				{
-					$$ = makeDefElem("template", (Node *)makeString($3));
-				}
-			| TEMPLATE opt_equal DEFAULT
-				{
-					$$ = makeDefElem("template", NULL);
-				}
-			| ENCODING opt_equal Sconst
-				{
-					$$ = makeDefElem("encoding", (Node *)makeString($3));
-				}
-			| ENCODING opt_equal Iconst
-				{
-					$$ = makeDefElem("encoding", (Node *)makeInteger($3));
-				}
-			| ENCODING opt_equal DEFAULT
-				{
-					$$ = makeDefElem("encoding", NULL);
-				}
-			| LC_COLLATE_P opt_equal Sconst
-				{
-					$$ = makeDefElem("lc_collate", (Node *)makeString($3));
-				}
-			| LC_COLLATE_P opt_equal DEFAULT
-				{
-					$$ = makeDefElem("lc_collate", NULL);
-				}
-			| LC_CTYPE_P opt_equal Sconst
+			createdb_opt_name opt_equal SignedIconst
 				{
-					$$ = makeDefElem("lc_ctype", (Node *)makeString($3));
+					$$ = makeDefElem($1, (Node *)makeInteger($3));
 				}
-			| LC_CTYPE_P opt_equal DEFAULT
+			| createdb_opt_name opt_equal opt_boolean_or_string
 				{
-					$$ = makeDefElem("lc_ctype", NULL);
+					$$ = makeDefElem($1, (Node *)makeString($3));
 				}
-			| CONNECTION LIMIT opt_equal SignedIconst
+			| createdb_opt_name opt_equal DEFAULT
 				{
-					$$ = makeDefElem("connectionlimit", (Node *)makeInteger($4));
-				}
-			| OWNER opt_equal name
-				{
-					$$ = makeDefElem("owner", (Node *)makeString($3));
-				}
-			| OWNER opt_equal DEFAULT
-				{
-					$$ = makeDefElem("owner", NULL);
+					$$ = makeDefElem($1, NULL);
 				}
 		;
 
+/*
+ * Ideally we'd use ColId here, but that causes shift/reduce conflicts against
+ * the ALTER DATABASE SET/RESET syntaxes.  Instead call out specific keywords
+ * we need, and allow IDENT so that database option names don't have to be
+ * parser keywords unless they are already keywords for other reasons.
+ *
+ * XXX this coding technique is fragile since if someone makes a formerly
+ * non-keyword option name into a keyword and forgets to add it here, the
+ * option will silently break.  Best defense is to provide a regression test
+ * exercising every such option, at least at the syntax level.
+ */
+createdb_opt_name:
+			IDENT							{ $$ = $1; }
+			| CONNECTION LIMIT				{ $$ = pstrdup("connection_limit"); }
+			| ENCODING						{ $$ = pstrdup($1); }
+			| LOCATION						{ $$ = pstrdup($1); }
+			| OWNER							{ $$ = pstrdup($1); }
+			| TABLESPACE					{ $$ = pstrdup($1); }
+			| TEMPLATE						{ $$ = pstrdup($1); }
+		;
+
 /*
  *	Though the equals sign doesn't match other WITH options, pg_dump uses
  *	equals for backward compatibility, and it doesn't seem worth removing it.
@@ -8407,13 +8382,20 @@ opt_equal:	'='										{}
  *****************************************************************************/
 
 AlterDatabaseStmt:
-			ALTER DATABASE database_name opt_with alterdb_opt_list
+			ALTER DATABASE database_name WITH createdb_opt_list
 				 {
 					AlterDatabaseStmt *n = makeNode(AlterDatabaseStmt);
 					n->dbname = $3;
 					n->options = $5;
 					$$ = (Node *)n;
 				 }
+			| ALTER DATABASE database_name createdb_opt_list
+				 {
+					AlterDatabaseStmt *n = makeNode(AlterDatabaseStmt);
+					n->dbname = $3;
+					n->options = $4;
+					$$ = (Node *)n;
+				 }
 			| ALTER DATABASE database_name SET TABLESPACE name
 				 {
 					AlterDatabaseStmt *n = makeNode(AlterDatabaseStmt);
@@ -8435,19 +8417,6 @@ AlterDatabaseSetStmt:
 		;
 
 
-alterdb_opt_list:
-			alterdb_opt_list alterdb_opt_item		{ $$ = lappend($1, $2); }
-			| /* EMPTY */							{ $$ = NIL; }
-		;
-
-alterdb_opt_item:
-			CONNECTION LIMIT opt_equal SignedIconst
-				{
-					$$ = makeDefElem("connectionlimit", (Node *)makeInteger($4));
-				}
-		;
-
-
 /*****************************************************************************
  *
  *		DROP DATABASE [ IF EXISTS ]
@@ -12958,8 +12927,6 @@ unreserved_keyword:
 			| LANGUAGE
 			| LARGE_P
 			| LAST_P
-			| LC_COLLATE_P
-			| LC_CTYPE_P
 			| LEAKPROOF
 			| LEVEL
 			| LISTEN

src/include/parser/kwlist.h

@@ -215,8 +215,6 @@ PG_KEYWORD("language", LANGUAGE, UNRESERVED_KEYWORD)
 PG_KEYWORD("large", LARGE_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("last", LAST_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("lateral", LATERAL_P, RESERVED_KEYWORD)
-PG_KEYWORD("lc_collate", LC_COLLATE_P, UNRESERVED_KEYWORD)
-PG_KEYWORD("lc_ctype", LC_CTYPE_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("leading", LEADING, RESERVED_KEYWORD)
 PG_KEYWORD("leakproof", LEAKPROOF, UNRESERVED_KEYWORD)
 PG_KEYWORD("least", LEAST, COL_NAME_KEYWORD)