*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
***************
*** 14461,14466 **** postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
--- 14461,14475 ----
         <entry><type>record</type></entry>
         <entry>Return information about a file</entry>
        </row>
+       <row>
+        <entry>
+         <literal><function>pg_execute_from_file(<parameter>filename</> <type>text</>
+ [, <parameter>variable</parameter> <type>text</type>, <parameter>value</parameter> <type>text</type>
+ [, ...] ]) )</function></literal>
+        </entry>
+        <entry><type>void</type></entry>
+        <entry>Executes the <acronym>SQL</> commands contained in a file, replacing given placeholders.</entry>
+       </row>
       </tbody>
      </tgroup>
     </table>
***************
*** 14499,14504 **** SELECT (pg_stat_file('filename')).modification;
--- 14508,14527 ----
  </programlisting>
     </para>
  
+    <indexterm>
+     <primary>pg_execute_from_file</primary>
+    </indexterm>
+    <para>
+     <function>pg_execute_from_file</> makes the server
+     execute <acronym>SQL</> commands to be found in a file. This function is
+     reserved to superusers.
+    </para>
+    <para>
+     The script might contain placeholders that will be replaced by the
+     values given in the <literal>VARIADIC</literal> arguments, which must be
+     a pair of variable names and values.
+    </para>
+ 
     <para>
      The functions shown in <xref linkend="functions-advisory-locks"> manage
      advisory locks.  For details about proper use of these functions, see
***************
*** 14521,14526 **** SELECT (pg_stat_file('filename')).modification;
--- 14544,14550 ----
         <entry><type>void</type></entry>
         <entry>Obtain exclusive advisory lock</entry>
        </row>
+ 
        <row>
         <entry>
          <literal><function>pg_advisory_lock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
*** a/src/backend/utils/adt/genfile.c
--- b/src/backend/utils/adt/genfile.c
***************
*** 7,12 ****
--- 7,13 ----
   * Copyright (c) 2004-2010, PostgreSQL Global Development Group
   *
   * Author: Andreas Pflug <pgadmin@pse-consulting.de>
+  *         Dimitri Fontaine <dimitri@2ndQuadrant.fr>
   *
   * IDENTIFICATION
   *	  src/backend/utils/adt/genfile.c
***************
*** 21,31 ****
--- 22,34 ----
  #include <dirent.h>
  
  #include "catalog/pg_type.h"
+ #include "executor/spi.h"
  #include "funcapi.h"
  #include "mb/pg_wchar.h"
  #include "miscadmin.h"
  #include "postmaster/syslogger.h"
  #include "storage/fd.h"
+ #include "utils/array.h"
  #include "utils/builtins.h"
  #include "utils/memutils.h"
  #include "utils/timestamp.h"
***************
*** 264,266 **** pg_ls_dir(PG_FUNCTION_ARGS)
--- 267,441 ----
  
  	SRF_RETURN_DONE(funcctx);
  }
+ 
+ /*
+  * Support functions for pg_execute_from_file and its variant,
+  * pg_execute_from_file_with_placeholders.
+  */
+ static char *
+ read_query_string_from_file(const char *filename)
+ {
+ 	FILE       *file;
+ 	int64       fsize = -1, nbytes;
+ 	struct stat fst;
+ 	char       *query_string = NULL;
+ 
+ 	/*
+ 	 * Only superuser can call pg_execute_from_file, and CREATE EXTENSION
+ 	 * uses that too. Don't double check the PATH. Also note that
+ 	 * extension's install files are not in $PGDATA but `pg_config
+ 	 * --sharedir`.
+ 	 */
+ 	if (stat(filename, &fst) < 0)
+ 		ereport(ERROR,
+ 				(errcode_for_file_access(),
+ 				 errmsg("could not stat file \"%s\": %m", filename)));
+ 
+ 	fsize = Int64GetDatum((int64) fst.st_size);
+ 
+ 	if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
+ 		ereport(ERROR,
+ 				(errcode_for_file_access(),
+ 				 errmsg("could not open file \"%s\" for reading: %m",
+ 						filename)));
+ 
+ 	if (ferror(file))
+ 		ereport(ERROR,
+ 				(errcode_for_file_access(),
+ 				 errmsg("could not read file \"%s\": %m", filename)));
+ 
+ 	query_string = (char *)palloc0((fsize+1)*sizeof(char));
+ 	nbytes = fread(query_string, 1, (size_t) fsize, file);
+ 	pg_verifymbstr(query_string, nbytes, false);
+ 	FreeFile(file);
+ 
+ 	return query_string;
+ }
+ 
+ /*
+  * Given an array of repeated {variable, value}, replaces the placeholders
+  * by their values in the given query_string, by calling replace_text over
+  * each pair of arguments.
+  */
+ static char *
+ replace_placeholders_in_query_string(const char *query_string,
+ 									 ArrayType *placeholders)
+ {
+ 	text       *src = cstring_to_text(query_string);
+ 	Datum	   *replacements;
+ 	int			nrep;
+ 	int			i;
+ 	char       *ret;
+ 
+ 	Assert(ARR_ELEMTYPE(placeholders) == TEXTOID);
+ 
+ 	deconstruct_array(placeholders, TEXTOID, -1, false, 'i',
+ 					  &replacements, NULL, &nrep);
+ 
+ 	if (nrep % 2 != 0)
+ 		ereport(ERROR,
+ 				(errmsg("Expected pairs of variable names and values"),
+ 				 errdetail("Please give an even number of replacement parameters")));
+ 
+ 	for (i = 0; i < nrep; i+=2)
+ 	{
+ 		Datum	    rep;
+ 
+ 		elog(DEBUG1,
+ 			 "pg_execute_from_file replaces '%s' with '%s'",
+ 			 text_to_cstring(DatumGetTextP(replacements[i])),
+ 			 text_to_cstring(DatumGetTextP(replacements[i+1])));
+ 
+ 		rep = DirectFunctionCall3(replace_text,
+ 								  PointerGetDatum(src),
+ 								  replacements[i], replacements[i+1]);
+ 		src = DatumGetTextP(rep);
+ 	}
+ 	ret = text_to_cstring(src);
+ 	elog(DEBUG2, "pg_execute_from_file: %s", ret);
+ 
+ 	return ret;
+ }
+ 
+ /*
+  * The bulk of the execute from file functions, just call SPI to do the real
+  * work
+  */
+ static void
+ pg_execute_from_query_string(const char *filename, const char *query_string)
+ {
+ 	/*
+ 	 * We abuse some internal knowledge from spi.h here. As we don't know
+ 	 * which queries are going to get executed, we don't know what to expect
+ 	 * as an OK return code from SPI_execute().  We assume that
+ 	 * SPI_OK_CONNECT, SPI_OK_FINISH and SPI_OK_FETCH are quite improbable,
+ 	 * though, and the errors are negatives.  So a valid return code is
+ 	 * considered to be SPI_OK_UTILITY or anything from there.
+ 	 */
+ 	if (SPI_connect() != SPI_OK_CONNECT)
+ 		elog(ERROR, "SPI_connect failed");
+ 
+ 	if (SPI_execute(query_string, false, 0) < SPI_OK_UTILITY)
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_DATA_EXCEPTION),
+ 				 errmsg("File '%s' could not be executed", filename)));
+ 
+ 	if (SPI_finish() != SPI_OK_FINISH)
+ 		elog(ERROR, "SPI_finish failed");
+ }
+ 
+ /*
+  * Read a file then execute the SQL commands it contains.
+  */
+ Datum
+ pg_execute_from_file(PG_FUNCTION_ARGS)
+ {
+ 	text	   *filename_t = PG_GETARG_TEXT_P(0);
+ 	char       *filename   = text_to_cstring(filename_t);
+ 
+ 	if (!superuser())
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ 				 (errmsg("must be superuser to execute file"))));
+ 
+ 	pg_execute_from_query_string(
+ 		filename,
+ 		read_query_string_from_file(filename));
+ 
+ 	PG_RETURN_VOID();
+ }
+ 
+ /*
+  * Variant accepting a VARIADIC text parameter containing placeholder
+  * variables and values, one after the other (so the variadic array length
+  * must be even).
+  *
+  * The main use case of the replacement facility is for setting the
+  * extension's schema, using @pg_extschema@ variable and a user given
+  * schema.
+  *
+  * This could be implemented in a single function together with the previous
+  * pg_execute_from_file, if only it was possible to fill in the
+  * proargdefaults pg_proc column from the backend code.
+  */
+ Datum
+ pg_execute_from_file_with_placeholders(PG_FUNCTION_ARGS)
+ {
+ 	text	   *filename_t   = PG_GETARG_TEXT_P(0);
+ 	ArrayType  *placeholders = PG_GETARG_ARRAYTYPE_P(1);
+ 	char       *filename     = text_to_cstring(filename_t);
+ 	char       *query_string = NULL;
+ 
+ 	if (!superuser())
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ 				 (errmsg("must be superuser to execute file"))));
+ 
+ 	pg_execute_from_query_string(
+ 		filename,
+ 		replace_placeholders_in_query_string(
+ 			read_query_string_from_file(filename),
+ 			placeholders));
+ 
+ 	PG_RETURN_VOID();
+ }
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
***************
*** 3399,3412 **** DESCR("reload configuration files");
  DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 f f f t f v 0 0 16 "" _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
  DESCR("rotate log file");
  
! DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ pg_stat_file _null_ _null_ _null_ ));
  DESCR("return file information");
! DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
  DESCR("read text from a file");
! DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
  DESCR("list all files in a directory");
! DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
  DESCR("sleep for the specified time in seconds");
  
  DATA(insert OID = 2971 (  text				PGNSP PGUID 12 1 0 0 f f f t f i 1 0 25 "16" _null_ _null_ _null_ _null_ booltext _null_ _null_ _null_ ));
  DESCR("convert boolean to text");
--- 3399,3416 ----
  DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 f f f t f v 0 0 16 "" _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
  DESCR("rotate log file");
  
! DATA(insert OID = 2623 ( pg_stat_file			PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ pg_stat_file _null_ _null_ _null_ ));
  DESCR("return file information");
! DATA(insert OID = 2624 ( pg_read_file			PGNSP PGUID 12 1 0 0 f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
  DESCR("read text from a file");
! DATA(insert OID = 2625 ( pg_ls_dir				PGNSP PGUID 12 1 1000 0 f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
  DESCR("list all files in a directory");
! DATA(insert OID = 2626 ( pg_sleep				PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
  DESCR("sleep for the specified time in seconds");
+ DATA(insert OID = 3627 ( pg_execute_from_file	PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "25" _null_ _null_ _null_ _null_ pg_execute_from_file _null_ _null_ _null_ ));
+ DESCR("execute queries read from a file");
+ DATA(insert OID = 3928 ( pg_execute_from_file	PGNSP PGUID 12 1 0 25 f f f t f v 2 0 2278 "25 25" "{25,25}" "{i,v}" _null_ _null_ pg_execute_from_file_with_placeholders _null_ _null_ _null_ ));
+ DESCR("execute queries read from a file");
  
  DATA(insert OID = 2971 (  text				PGNSP PGUID 12 1 0 0 f f f t f i 1 0 25 "16" _null_ _null_ _null_ _null_ booltext _null_ _null_ _null_ ));
  DESCR("convert boolean to text");
*** a/src/include/utils/builtins.h
--- b/src/include/utils/builtins.h
***************
*** 443,448 **** extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
--- 443,450 ----
  extern Datum pg_stat_file(PG_FUNCTION_ARGS);
  extern Datum pg_read_file(PG_FUNCTION_ARGS);
  extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
+ extern Datum pg_execute_from_file(PG_FUNCTION_ARGS);
+ extern Datum pg_execute_from_file_with_placeholders (PG_FUNCTION_ARGS);
  
  /* misc.c */
  extern Datum current_database(PG_FUNCTION_ARGS);