a config.h #define, and the runtime value can be controlled via SET.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.31 2000/02/27 21:07:03 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.32 2000/03/17 05:29:03 tgl Exp $
Postgres documentation
-->
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>MAX_EXPR_DEPTH</term>
+ <listitem>
+ <para>
+ Sets the maximum expression nesting depth that the parser will
+ accept. The default value is high enough for any normal query,
+ but you can raise it if you need to. (But if you raise it too high,
+ you run the risk of backend crashes due to stack overflow.)
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="parameter">integer</replaceable></term>
+ <term>ON</term>
+ <listitem>
+ <para>
+ Maximum depth.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</para>
</refsect2>
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/variable.c,v 1.31 2000/02/27 21:10:41 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/variable.c,v 1.32 2000/03/17 05:29:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "miscadmin.h"
#include "optimizer/cost.h"
#include "optimizer/paths.h"
+#include "parser/parse_expr.h"
#include "utils/builtins.h"
#include "utils/tqual.h"
#include "utils/trace.h"
static bool show_ksqo(void);
static bool reset_ksqo(void);
static bool parse_ksqo(char *);
+static bool reset_max_expr_depth(void);
+static bool show_max_expr_depth(void);
+static bool parse_max_expr_depth(char *);
static bool show_XactIsoLevel(void);
static bool reset_XactIsoLevel(void);
static bool parse_XactIsoLevel(char *);
return TRUE;
}
+/*
+ * MAX_EXPR_DEPTH
+ */
+static bool
+parse_max_expr_depth(char *value)
+{
+ int newval;
+
+ if (value == NULL)
+ {
+ reset_max_expr_depth();
+ return TRUE;
+ }
+
+ newval = pg_atoi(value, sizeof(int), '\0');
+
+ if (newval < 10) /* somewhat arbitrary limit */
+ elog(ERROR, "Bad value for MAX_EXPR_DEPTH (%s)", value);
+
+ max_expr_depth = newval;
+
+ return TRUE;
+}
+
+static bool
+show_max_expr_depth()
+{
+ elog(NOTICE, "MAX_EXPR_DEPTH is %d", max_expr_depth);
+ return TRUE;
+}
+
+static bool
+reset_max_expr_depth(void)
+{
+ max_expr_depth = DEFAULT_MAX_EXPR_DEPTH;
+ return TRUE;
+}
+
/* SET TRANSACTION */
static bool
{
"ksqo", parse_ksqo, show_ksqo, reset_ksqo
},
+ {
+ "max_expr_depth", parse_max_expr_depth,
+ show_max_expr_depth, reset_max_expr_depth
+ },
{
"XactIsoLevel", parse_XactIsoLevel, show_XactIsoLevel, reset_XactIsoLevel
},
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.73 2000/03/14 23:06:32 thomas Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.74 2000/03/17 05:29:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "utils/builtins.h"
#include "utils/syscache.h"
+
+int max_expr_depth = DEFAULT_MAX_EXPR_DEPTH;
+
+static int expr_depth_counter = 0;
+
static Node *parser_typecast_constant(Value *expr, TypeName *typename);
static Node *parser_typecast_expression(ParseState *pstate,
Node *expr, TypeName *typename);
static Node *transformIndirection(ParseState *pstate, Node *basenode,
List *indirection);
+
+/*
+ * Initialize for parsing a new query.
+ *
+ * We reset the expression depth counter here, in case it was left nonzero
+ * due to elog()'ing out of the last parsing operation.
+ */
+void
+parse_expr_init(void)
+{
+ expr_depth_counter = 0;
+}
+
+
/*
* transformExpr -
* analyze and transform expressions. Type checking and type casting is
if (expr == NULL)
return NULL;
+ /*
+ * Guard against an overly complex expression leading to coredump
+ * due to stack overflow here, or in later recursive routines that
+ * traverse expression trees. Note that this is very unlikely to
+ * happen except with pathological queries; but we don't want someone
+ * to be able to crash the backend quite that easily...
+ */
+ if (++expr_depth_counter > max_expr_depth)
+ elog(ERROR, "Expression too complex: nesting depth exceeds max_expr_depth = %d",
+ max_expr_depth);
+
switch (nodeTag(expr))
{
case T_Attr:
break;
}
+ expr_depth_counter--;
+
return result;
}
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.43 2000/01/26 05:56:43 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.44 2000/03/17 05:29:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parser.h"
+#include "parser/parse_expr.h"
#if defined(FLEX_SCANNER)
extern void DeleteBuffer(void);
parsetree = NIL; /* in case parser forgets to set it */
parser_init(typev, nargs);
+ parse_expr_init();
+
yyresult = yyparse();
#if defined(FLEX_SCANNER)
*
* Copyright 2000 by PostgreSQL Global Development Group
*
- * $Header: /cvsroot/pgsql/src/bin/psql/tab-complete.c,v 1.15 2000/03/05 13:30:19 petere Exp $
+ * $Header: /cvsroot/pgsql/src/bin/psql/tab-complete.c,v 1.16 2000/03/17 05:29:06 tgl Exp $
*/
/*-----------
"client_encoding",
"server_encoding",
"KSQO",
+ "max_expr_depth",
"XactIsoLevel",
"PG_Options",
NULL
-
-
-/* the purpose of this file is to reduce the use of #ifdef's through
- * the code base by those porting the software, and to facilitate the
- * eventual use of autoconf to build the server
+/*
+ * PostgreSQL configuration-settings file.
+ *
+ * config.h.in is processed by configure to produce config.h.
+ *
+ * If you want to modify any of the tweakable settings in the first part
+ * of this file, you can do it in config.h.in before running configure,
+ * or in config.h afterwards. Of course, if you edit config.h, then your
+ * changes will be overwritten the next time you run configure.
+ *
+ * $Id: config.h.in,v 1.110 2000/03/17 05:29:06 tgl Exp $
*/
#ifndef CONFIG_H
/*
* Default runtime limit on number of backend server processes per postmaster;
* this is just the default setting for the postmaster's -N switch.
- * (Actual value is set by configure script.)
+ * (Actual value is now set by configure script.)
*/
#undef DEF_MAXBACKENDS
/*
* DEF_PGPORT is the TCP port number on which the Postmaster listens by
* default. This can be overriden by command options, environment variables,
- * and the postconfig hook. (set by configure script)
+ * and the postconfig hook. (now set by configure script)
*/
#undef DEF_PGPORT
-/*
- * If you do not plan to use Host based authentication,
- * comment out the following line (set by build script)
- */
-#undef HBA
-
/*
* As soon as the backend blocks on a lock, it waits this number of seconds
* before checking for a deadlock.
*/
#define DEADLOCK_CHECK_TIMER 1
-/*
- * This flag enables the use of indexes in plans generated for function
- * executions which normally are always executed with sequential scans.
- */
-#define INDEXSCAN_PATCH
-
/*
* Maximum number of columns in an index and maximum number of arguments
* to a function. They must be the same value.
*/
/* #define UNSAFE_FLOATS */
-/*
- * There is a bug in the function executor. The backend crashes while trying to
- * execute an sql function containing an utility command (create, notify, ...).
- * The bug is part in the planner, which returns a number of plans different
- * than the number of commands if there are utility commands in the query, and
- * in part in the function executor which assumes that all commands are normal
- * query commands and causes a SIGSEGV trying to execute commands without plan.
- */
-#define FUNC_UTIL_PATCH
-
/*
* Define this to make libpgtcl's "pg_result -assign" command process C-style
* backslash sequences in returned tuple data and convert Postgres array
#define FASTBUILD /* access/nbtree/nbtsort.c */
/*
- * TBL_FREE_CMD_MEMORY: free memory allocated for an user query inside
+ * TBL_FREE_CMD_MEMORY: free memory allocated for a user query inside
* transaction block after this query is done.
*/
#define TBL_FREE_CMD_MEMORY
*/
#define MAXPGPATH 1024
+/*
+ * DEFAULT_MAX_EXPR_DEPTH: default value of max_expr_depth SET variable.
+ */
+#define DEFAULT_MAX_EXPR_DEPTH 10000
+
+/*
+ * Leftover cruft for enabling long-since-verified patches.
+ * You don't want to touch these.
+ */
+#define INDEXSCAN_PATCH
+#define FUNC_UTIL_PATCH
+
+
/*
*------------------------------------------------------------------------
- * The following is set using configure.
+ * Everything past here is set by the configure script.
*------------------------------------------------------------------------
*/
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: parse_expr.h,v 1.17 2000/02/26 21:11:09 tgl Exp $
+ * $Id: parse_expr.h,v 1.18 2000/03/17 05:29:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#define EXPR_COLUMN_FIRST 1
#define EXPR_RELATION_FIRST 2
+extern int max_expr_depth;
+
extern Node *transformExpr(ParseState *pstate, Node *expr, int precedence);
extern Oid exprType(Node *expr);
extern int32 exprTypmod(Node *expr);
extern bool exprIsLengthCoercion(Node *expr, int32 *coercedTypmod);
+extern void parse_expr_init(void);
#endif /* PARSE_EXPR_H */
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