force_not_null option support for file_fdw

diff --git a/contrib/file_fdw/data/text.csv b/contrib/file_fdw/data/text.csv
index ...bd4c327 .
*** a/contrib/file_fdw/data/text.csv
--- b/contrib/file_fdw/data/text.csv
***************
*** 0 ****
--- 1,4 ----
+ 123,123
+ abc,abc
+ NULL,NULL
+ ABC,ABC
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 224e74f..548dcd2 100644
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 23,30 ****
--- 23,32 ----
  #include "foreign/fdwapi.h"
  #include "foreign/foreign.h"
  #include "miscadmin.h"
+ #include "nodes/makefuncs.h"
  #include "optimizer/cost.h"
  #include "utils/rel.h"
+ #include "utils/syscache.h"
  
  PG_MODULE_MAGIC;
  
*************** static struct FileFdwOption valid_option
*** 57,72 ****
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
- 	/*
- 	 * force_not_null is not supported by file_fdw.  It would need a parser
- 	 * for list of columns, not to mention a way to check the column list
- 	 * against the table.
- 	 */
  
  	/* Sentinel */
  	{NULL, InvalidOid}
--- 59,70 ----
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
+ 	{"force_not_null", AttributeRelationId},	/* specified as boolean value */
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
  
  	/* Sentinel */
  	{NULL, InvalidOid}
*************** static void fileGetOptions(Oid foreignta
*** 112,117 ****
--- 110,116 ----
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
+ static List * get_force_not_null(Oid relid);
  
  
  /*
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 145,150 ****
--- 144,150 ----
  	List	   *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
  	Oid			catalog = PG_GETARG_OID(1);
  	char	   *filename = NULL;
+ 	char	   *force_not_null = NULL;
  	List	   *other_options = NIL;
  	ListCell   *cell;
  
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 198,204 ****
  							 buf.data)));
  		}
  
! 		/* Separate out filename, since ProcessCopyOptions won't allow it */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
--- 198,207 ----
  							 buf.data)));
  		}
  
! 		/*
! 		 * Separate out filename and force_not_null, since ProcessCopyOptions
! 		 * won't allow them.
! 		 */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 207,212 ****
--- 210,229 ----
  						 errmsg("conflicting or redundant options")));
  			filename = defGetString(def);
  		}
+ 		else if (strcmp(def->defname, "force_not_null") == 0)
+ 		{
+ 			if (force_not_null)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("conflicting or redundant options")));
+ 
+ 			force_not_null = defGetString(def);
+ 			if (strcmp(force_not_null, "true") != 0 &&
+ 				strcmp(force_not_null, "false") != 0)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("force_not_null must be true or false")));
+ 		}
  		else
  			other_options = lappend(other_options, def);
  	}
*************** is_valid_option(const char *option, Oid 
*** 245,254 ****
--- 262,355 ----
  }
  
  /*
+  * Retrieve per-column generic options from pg_attribute and construct a list
+  * of column names for "force_not_null".
+  */
+ static List *
+ get_force_not_null(Oid relid)
+ {
+ 	Relation	rel;
+ 	TupleDesc	tupleDesc;
+ 	AttrNumber	natts;
+ 	AttrNumber	attnum;
+ 	List	   *columns = NIL;
+ 
+ 	rel = heap_open(relid, AccessShareLock);
+ 	tupleDesc = RelationGetDescr(rel);
+ 	natts = tupleDesc->natts;
+ 
+ 	/* Retrieve FDW options from every user-defined attributes. */
+ 	for (attnum = 1; attnum < natts; attnum++)
+ 	{
+ 		HeapTuple	tuple;
+ 		Form_pg_attribute	attr;
+ 		Datum		datum;
+ 		bool		isnull;
+ 		List	   *options;
+ 		ListCell   *cell;
+ 
+ 
+ 		tuple = SearchSysCache2(ATTNUM,
+ 								RelationGetRelid(rel),
+ 								Int16GetDatum(attnum));
+ 		if (!HeapTupleIsValid(tuple))
+ 			elog(ERROR,
+ 				 "cache lookup failed for attribute %d of relation %u",
+ 				 attnum, RelationGetRelid(rel));
+ 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+ 
+ 		/* Skip dropped attributes. */
+ 		if (attr->attisdropped)
+ 		{
+ 			ReleaseSysCache(tuple);
+ 			continue;
+ 		}
+ 
+ 		datum = SysCacheGetAttr(ATTNUM,
+ 								tuple,
+ 								Anum_pg_attribute_attfdwoptions,
+ 								&isnull);
+ 		if (isnull)
+ 			datum = PointerGetDatum(NULL);
+ 		options = untransformRelOptions(datum);
+ 
+ 		/*
+ 		 * Find force_not_null option and append attname to the list if
+ 		 * the value was true.
+ 		 */
+ 		foreach (cell, options)
+ 		{
+ 			DefElem	   *def = (DefElem *) lfirst(cell);
+ 			const char *value = defGetString(def);
+ 
+ 			if (strcmp(def->defname, "force_not_null") == 0 &&
+ 				strcmp(value, "true") == 0)
+ 			{
+ 				columns = lappend(columns, makeString(NameStr(attr->attname)));
+ 				elog(DEBUG1, "%s: force_not_null", NameStr(attr->attname));
+ 			}
+ 
+ 		}
+ 
+ 		ReleaseSysCache(tuple);
+ 	}
+ 
+ 	heap_close(rel, AccessShareLock);
+ 
+ 	/* Return DefElem only when any column is set "force_not_null=true". */
+ 	if (columns != NIL)
+ 		return list_make1(makeDefElem("force_not_null", (Node *) columns));
+ 	else
+ 		return NIL;
+ }
+ 
+ /*
   * Fetch the options for a file_fdw foreign table.
   *
   * We have to separate out "filename" from the other options because
   * it must not appear in the options list passed to the core COPY code.
+  * And we must construct List of DefElem from pg_attribute.attfdwoptions for
+  * "force_not_null".
   */
  static void
  fileGetOptions(Oid foreigntableid,
*************** fileGetOptions(Oid foreigntableid,
*** 296,301 ****
--- 397,405 ----
  		prev = lc;
  	}
  
+ 	/* Retrieve force_not_null from pg_attribute and append it to the list. */
+ 	options = list_concat(options, get_force_not_null(foreigntableid));
+ 
  	/*
  	 * The validator should have checked that a filename was included in the
  	 * options, but check again, just in case.
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index 1405752..5d7347f 100644
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 78,83 ****
--- 78,97 ----
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
  
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
  SELECT * FROM agg_csv ORDER BY a;
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 6dd2653..cf2cba5 100644
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 93,98 ****
--- 93,128 ----
  	b	float4
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: filename, format, header, delimiter, quote, escape, null, encoding
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ERROR:  COPY force not null available only in CSV mode
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+  word1 | word2 
+ -------+-------
+  123   | 123
+  ABC   | ABC
+  NULL  | 
+  abc   | abc
+ (4 rows)
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
    a  |   b    
*************** SET ROLE file_fdw_superuser;
*** 216,222 ****
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 7 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
--- 246,252 ----
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 8 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
*************** drop cascades to user mapping for no_pri
*** 224,227 ****
--- 254,258 ----
  drop cascades to foreign table agg_text
  drop cascades to foreign table agg_csv
  drop cascades to foreign table agg_bad
+ drop cascades to foreign table text_csv
  DROP ROLE file_fdw_superuser, file_fdw_user, no_priv_user;
diff --git a/doc/src/sgml/file-fdw.sgml b/doc/src/sgml/file-fdw.sgml
index 8497d9a..5b35451 100644
*** a/doc/src/sgml/file-fdw.sgml
--- b/doc/src/sgml/file-fdw.sgml
***************
*** 111,124 ****
   </variablelist>
  
   <para>
!   <command>COPY</>'s <literal>OIDS</literal>, <literal>FORCE_QUOTE</literal>,
!   and <literal>FORCE_NOT_NULL</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table, not in the
!   options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>
  
--- 111,147 ----
   </variablelist>
  
   <para>
!   A column of a foreign table created using this wrapper can have the
!   following options:
!  </para>
! 
!  <variablelist>
! 
!   <varlistentry>
!    <term><literal>force_not_null</literal></term>
! 
!    <listitem>
!     <para>
!      Specifies whether values for the column shouldn't been matched against
!      the null string.  Acceptable values are <literal>true</> for no matching,
!      and <literal>false</> for matching (case sensitive).
!      <literal>true</> is same as specifying the column in <command>COPY</>'s
!      <literal>FORCE_NOT_NULL</literal> option.
!     </para>
!    </listitem>
!   </varlistentry>
! 
!  </variablelist>
! 
!  <para>
!   <command>COPY</>'s <literal>OIDS</literal> and
!   <literal>FORCE_QUOTE</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table or its columns, not
!   in the options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>
  

diff --git a/contrib/file_fdw/data/text.csv b/contrib/file_fdw/data/text.csv
index ...09827e7 .
*** a/contrib/file_fdw/data/text.csv
--- b/contrib/file_fdw/data/text.csv
***************
*** 0 ****
--- 1,4 ----
+ AAA,AAA
+ XYZ,XYZ
+ NULL,NULL
+ ABC,ABC
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 224e74f..548dcd2 100644
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 23,30 ****
--- 23,32 ----
  #include "foreign/fdwapi.h"
  #include "foreign/foreign.h"
  #include "miscadmin.h"
+ #include "nodes/makefuncs.h"
  #include "optimizer/cost.h"
  #include "utils/rel.h"
+ #include "utils/syscache.h"
  
  PG_MODULE_MAGIC;
  
*************** static struct FileFdwOption valid_option
*** 57,72 ****
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
- 	/*
- 	 * force_not_null is not supported by file_fdw.  It would need a parser
- 	 * for list of columns, not to mention a way to check the column list
- 	 * against the table.
- 	 */
  
  	/* Sentinel */
  	{NULL, InvalidOid}
--- 59,70 ----
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
+ 	{"force_not_null", AttributeRelationId},	/* specified as boolean value */
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
  
  	/* Sentinel */
  	{NULL, InvalidOid}
*************** static void fileGetOptions(Oid foreignta
*** 112,117 ****
--- 110,116 ----
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
+ static List * get_force_not_null(Oid relid);
  
  
  /*
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 145,150 ****
--- 144,150 ----
  	List	   *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
  	Oid			catalog = PG_GETARG_OID(1);
  	char	   *filename = NULL;
+ 	char	   *force_not_null = NULL;
  	List	   *other_options = NIL;
  	ListCell   *cell;
  
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 198,204 ****
  							 buf.data)));
  		}
  
! 		/* Separate out filename, since ProcessCopyOptions won't allow it */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
--- 198,207 ----
  							 buf.data)));
  		}
  
! 		/*
! 		 * Separate out filename and force_not_null, since ProcessCopyOptions
! 		 * won't allow them.
! 		 */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 207,212 ****
--- 210,229 ----
  						 errmsg("conflicting or redundant options")));
  			filename = defGetString(def);
  		}
+ 		else if (strcmp(def->defname, "force_not_null") == 0)
+ 		{
+ 			if (force_not_null)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("conflicting or redundant options")));
+ 
+ 			force_not_null = defGetString(def);
+ 			if (strcmp(force_not_null, "true") != 0 &&
+ 				strcmp(force_not_null, "false") != 0)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("force_not_null must be true or false")));
+ 		}
  		else
  			other_options = lappend(other_options, def);
  	}
*************** is_valid_option(const char *option, Oid 
*** 245,254 ****
--- 262,355 ----
  }
  
  /*
+  * Retrieve per-column generic options from pg_attribute and construct a list
+  * of column names for "force_not_null".
+  */
+ static List *
+ get_force_not_null(Oid relid)
+ {
+ 	Relation	rel;
+ 	TupleDesc	tupleDesc;
+ 	AttrNumber	natts;
+ 	AttrNumber	attnum;
+ 	List	   *columns = NIL;
+ 
+ 	rel = heap_open(relid, AccessShareLock);
+ 	tupleDesc = RelationGetDescr(rel);
+ 	natts = tupleDesc->natts;
+ 
+ 	/* Retrieve FDW options from every user-defined attributes. */
+ 	for (attnum = 1; attnum < natts; attnum++)
+ 	{
+ 		HeapTuple	tuple;
+ 		Form_pg_attribute	attr;
+ 		Datum		datum;
+ 		bool		isnull;
+ 		List	   *options;
+ 		ListCell   *cell;
+ 
+ 
+ 		tuple = SearchSysCache2(ATTNUM,
+ 								RelationGetRelid(rel),
+ 								Int16GetDatum(attnum));
+ 		if (!HeapTupleIsValid(tuple))
+ 			elog(ERROR,
+ 				 "cache lookup failed for attribute %d of relation %u",
+ 				 attnum, RelationGetRelid(rel));
+ 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+ 
+ 		/* Skip dropped attributes. */
+ 		if (attr->attisdropped)
+ 		{
+ 			ReleaseSysCache(tuple);
+ 			continue;
+ 		}
+ 
+ 		datum = SysCacheGetAttr(ATTNUM,
+ 								tuple,
+ 								Anum_pg_attribute_attfdwoptions,
+ 								&isnull);
+ 		if (isnull)
+ 			datum = PointerGetDatum(NULL);
+ 		options = untransformRelOptions(datum);
+ 
+ 		/*
+ 		 * Find force_not_null option and append attname to the list if
+ 		 * the value was true.
+ 		 */
+ 		foreach (cell, options)
+ 		{
+ 			DefElem	   *def = (DefElem *) lfirst(cell);
+ 			const char *value = defGetString(def);
+ 
+ 			if (strcmp(def->defname, "force_not_null") == 0 &&
+ 				strcmp(value, "true") == 0)
+ 			{
+ 				columns = lappend(columns, makeString(NameStr(attr->attname)));
+ 				elog(DEBUG1, "%s: force_not_null", NameStr(attr->attname));
+ 			}
+ 
+ 		}
+ 
+ 		ReleaseSysCache(tuple);
+ 	}
+ 
+ 	heap_close(rel, AccessShareLock);
+ 
+ 	/* Return DefElem only when any column is set "force_not_null=true". */
+ 	if (columns != NIL)
+ 		return list_make1(makeDefElem("force_not_null", (Node *) columns));
+ 	else
+ 		return NIL;
+ }
+ 
+ /*
   * Fetch the options for a file_fdw foreign table.
   *
   * We have to separate out "filename" from the other options because
   * it must not appear in the options list passed to the core COPY code.
+  * And we must construct List of DefElem from pg_attribute.attfdwoptions for
+  * "force_not_null".
   */
  static void
  fileGetOptions(Oid foreigntableid,
*************** fileGetOptions(Oid foreigntableid,
*** 296,301 ****
--- 397,405 ----
  		prev = lc;
  	}
  
+ 	/* Retrieve force_not_null from pg_attribute and append it to the list. */
+ 	options = list_concat(options, get_force_not_null(foreigntableid));
+ 
  	/*
  	 * The validator should have checked that a filename was included in the
  	 * options, but check again, just in case.
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index 1405752..5d7347f 100644
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 78,83 ****
--- 78,97 ----
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
  
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
  SELECT * FROM agg_csv ORDER BY a;
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 6dd2653..fb430f6 100644
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 93,98 ****
--- 93,128 ----
  	b	float4
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: filename, format, header, delimiter, quote, escape, null, encoding
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ERROR:  COPY force not null available only in CSV mode
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+  word1 | word2 
+ -------+-------
+  AAA   | AAA
+  ABC   | ABC
+  NULL  | 
+  XYZ   | XYZ
+ (4 rows)
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
    a  |   b    
*************** SET ROLE file_fdw_superuser;
*** 216,222 ****
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 7 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
--- 246,252 ----
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 8 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
*************** drop cascades to user mapping for no_pri
*** 224,227 ****
--- 254,258 ----
  drop cascades to foreign table agg_text
  drop cascades to foreign table agg_csv
  drop cascades to foreign table agg_bad
+ drop cascades to foreign table text_csv
  DROP ROLE file_fdw_superuser, file_fdw_user, no_priv_user;
diff --git a/doc/src/sgml/file-fdw.sgml b/doc/src/sgml/file-fdw.sgml
index 8497d9a..5b35451 100644
*** a/doc/src/sgml/file-fdw.sgml
--- b/doc/src/sgml/file-fdw.sgml
***************
*** 111,124 ****
   </variablelist>
  
   <para>
!   <command>COPY</>'s <literal>OIDS</literal>, <literal>FORCE_QUOTE</literal>,
!   and <literal>FORCE_NOT_NULL</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table, not in the
!   options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>
  
--- 111,147 ----
   </variablelist>
  
   <para>
!   A column of a foreign table created using this wrapper can have the
!   following options:
!  </para>
! 
!  <variablelist>
! 
!   <varlistentry>
!    <term><literal>force_not_null</literal></term>
! 
!    <listitem>
!     <para>
!      Specifies whether values for the column shouldn't been matched against
!      the null string.  Acceptable values are <literal>true</> for no matching,
!      and <literal>false</> for matching (case sensitive).
!      <literal>true</> is same as specifying the column in <command>COPY</>'s
!      <literal>FORCE_NOT_NULL</literal> option.
!     </para>
!    </listitem>
!   </varlistentry>
! 
!  </variablelist>
! 
!  <para>
!   <command>COPY</>'s <literal>OIDS</literal> and
!   <literal>FORCE_QUOTE</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table or its columns, not
!   in the options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>
  

diff --git a/contrib/file_fdw/data/text.csv b/contrib/file_fdw/data/text.csv
index ...09827e7 .
*** a/contrib/file_fdw/data/text.csv
--- b/contrib/file_fdw/data/text.csv
***************
*** 0 ****
--- 1,4 ----
+ AAA,AAA
+ XYZ,XYZ
+ NULL,NULL
+ ABC,ABC
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 224e74f..4174919 100644
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 23,30 ****
--- 23,32 ----
  #include "foreign/fdwapi.h"
  #include "foreign/foreign.h"
  #include "miscadmin.h"
+ #include "nodes/makefuncs.h"
  #include "optimizer/cost.h"
  #include "utils/rel.h"
+ #include "utils/syscache.h"
  
  PG_MODULE_MAGIC;
  
*************** static struct FileFdwOption valid_option
*** 57,73 ****
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
- 	/*
- 	 * force_not_null is not supported by file_fdw.  It would need a parser
- 	 * for list of columns, not to mention a way to check the column list
- 	 * against the table.
- 	 */
- 
  	/* Sentinel */
  	{NULL, InvalidOid}
  };
--- 59,70 ----
  	{"escape", ForeignTableRelationId},
  	{"null", ForeignTableRelationId},
  	{"encoding", ForeignTableRelationId},
+ 	{"force_not_null", AttributeRelationId},	/* specified as boolean value */
  
  	/*
  	 * force_quote is not supported by file_fdw because it's for COPY TO.
  	 */
  
  	/* Sentinel */
  	{NULL, InvalidOid}
  };
*************** static void fileGetOptions(Oid foreignta
*** 112,118 ****
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
! 
  
  /*
   * Foreign-data wrapper handler function: return a struct with pointers
--- 109,115 ----
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
! static List * get_force_not_null(Oid relid);
  
  /*
   * Foreign-data wrapper handler function: return a struct with pointers
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 145,150 ****
--- 142,148 ----
  	List	   *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
  	Oid			catalog = PG_GETARG_OID(1);
  	char	   *filename = NULL;
+ 	char	   *force_not_null = NULL;
  	List	   *other_options = NIL;
  	ListCell   *cell;
  
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 198,204 ****
  							 buf.data)));
  		}
  
! 		/* Separate out filename, since ProcessCopyOptions won't allow it */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
--- 196,205 ----
  							 buf.data)));
  		}
  
! 		/*
! 		 * Separate out filename and force_not_null, since ProcessCopyOptions
! 		 * won't allow them.
! 		 */
  		if (strcmp(def->defname, "filename") == 0)
  		{
  			if (filename)
*************** file_fdw_validator(PG_FUNCTION_ARGS)
*** 207,212 ****
--- 208,227 ----
  						 errmsg("conflicting or redundant options")));
  			filename = defGetString(def);
  		}
+ 		else if (strcmp(def->defname, "force_not_null") == 0)
+ 		{
+ 			if (force_not_null)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("conflicting or redundant options")));
+ 
+ 			force_not_null = defGetString(def);
+ 			if (strcmp(force_not_null, "true") != 0 &&
+ 				strcmp(force_not_null, "false") != 0)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_SYNTAX_ERROR),
+ 						 errmsg("force_not_null must be true or false")));
+ 		}
  		else
  			other_options = lappend(other_options, def);
  	}
*************** is_valid_option(const char *option, Oid 
*** 245,254 ****
--- 260,352 ----
  }
  
  /*
+  * Retrieve per-column generic options from pg_attribute and construct a list
+  * of column names for "force_not_null".
+  */
+ static List *
+ get_force_not_null(Oid relid)
+ {
+ 	Relation	rel;
+ 	TupleDesc	tupleDesc;
+ 	AttrNumber	natts;
+ 	AttrNumber	attnum;
+ 	List	   *columns = NIL;
+ 
+ 	rel = heap_open(relid, AccessShareLock);
+ 	tupleDesc = RelationGetDescr(rel);
+ 	natts = tupleDesc->natts;
+ 
+ 	/* Retrieve FDW options from every user-defined attributes. */
+ 	for (attnum = 1; attnum < natts; attnum++)
+ 	{
+ 		HeapTuple	tuple;
+ 		Form_pg_attribute	attr;
+ 		Datum		datum;
+ 		bool		isnull;
+ 		List	   *options;
+ 		ListCell   *cell;
+ 
+ 		tuple = SearchSysCache2(ATTNUM,
+ 								RelationGetRelid(rel),
+ 								Int16GetDatum(attnum));
+ 		if (!HeapTupleIsValid(tuple))
+ 			elog(ERROR,
+ 				 "cache lookup failed for attribute %d of relation %u",
+ 				 attnum, RelationGetRelid(rel));
+ 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+ 
+ 		/* Skip dropped attributes. */
+ 		if (attr->attisdropped)
+ 		{
+ 			ReleaseSysCache(tuple);
+ 			continue;
+ 		}
+ 
+ 		datum = SysCacheGetAttr(ATTNUM,
+ 								tuple,
+ 								Anum_pg_attribute_attfdwoptions,
+ 								&isnull);
+ 		if (isnull)
+ 			datum = PointerGetDatum(NULL);
+ 		options = untransformRelOptions(datum);
+ 
+ 		/*
+ 		 * Find force_not_null option and append attname to the list if
+ 		 * the value was true.
+ 		 */
+ 		foreach (cell, options)
+ 		{
+ 			DefElem	   *def = (DefElem *) lfirst(cell);
+ 			const char *value = defGetString(def);
+ 
+ 			if (strcmp(def->defname, "force_not_null") == 0 &&
+ 				strcmp(value, "true") == 0)
+ 			{
+ 				char *attname = pstrdup(NameStr(attr->attname));
+ 				columns = lappend(columns, makeString(attname));
+ 				elog(DEBUG1, "%s: force_not_null", attname);
+ 			}
+ 		}
+ 
+ 		ReleaseSysCache(tuple);
+ 	}
+ 
+ 	heap_close(rel, AccessShareLock);
+ 
+ 	/* Return DefElem only when any column is set "force_not_null=true". */
+ 	if (columns != NIL)
+ 		return list_make1(makeDefElem("force_not_null", (Node *) columns));
+ 	else
+ 		return NIL;
+ }
+ 
+ /*
   * Fetch the options for a file_fdw foreign table.
   *
   * We have to separate out "filename" from the other options because
   * it must not appear in the options list passed to the core COPY code.
+  * And we must construct List of DefElem from pg_attribute.attfdwoptions for
+  * "force_not_null".
   */
  static void
  fileGetOptions(Oid foreigntableid,
*************** fileGetOptions(Oid foreigntableid,
*** 296,301 ****
--- 394,402 ----
  		prev = lc;
  	}
  
+ 	/* Retrieve force_not_null from pg_attribute and append it to the list. */
+ 	options = list_concat(options, get_force_not_null(foreigntableid));
+ 
  	/*
  	 * The validator should have checked that a filename was included in the
  	 * options, but check again, just in case.
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index 1405752..5d7347f 100644
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 78,83 ****
--- 78,97 ----
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
  
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
  SELECT * FROM agg_csv ORDER BY a;
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 6dd2653..fb430f6 100644
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
*************** CREATE FOREIGN TABLE agg_bad (
*** 93,98 ****
--- 93,128 ----
  	b	float4
  ) SERVER file_server
  OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
+ -- per-column options tests
+ ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_not_null '*');           -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ ALTER SERVER file_server OPTIONS (ADD force_not_null '*');                      -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE USER MAPPING FOR public SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: 
+ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*');    -- ERROR
+ ERROR:  invalid option "force_not_null"
+ HINT:  Valid options in this context are: filename, format, header, delimiter, quote, escape, null, encoding
+ CREATE FOREIGN TABLE text_csv (
+     word1 text OPTIONS (force_not_null 'true'),
+     word2 text OPTIONS (force_not_null 'false')
+ ) SERVER file_server
+ OPTIONS (format 'text', filename '@abs_srcdir@/data/text.csv', null 'NULL');
+ SELECT * FROM text_csv ORDER BY word1;                      -- ERROR
+ ERROR:  COPY force not null available only in CSV mode
+ ALTER FOREIGN TABLE text_csv OPTIONS (SET format 'csv');
+ SELECT * FROM text_csv ORDER BY word1;
+  word1 | word2 
+ -------+-------
+  AAA   | AAA
+  ABC   | ABC
+  NULL  | 
+  XYZ   | XYZ
+ (4 rows)
+ 
  -- basic query tests
  SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
    a  |   b    
*************** SET ROLE file_fdw_superuser;
*** 216,222 ****
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 7 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
--- 246,252 ----
  -- cleanup
  RESET ROLE;
  DROP EXTENSION file_fdw CASCADE;
! NOTICE:  drop cascades to 8 other objects
  DETAIL:  drop cascades to server file_server
  drop cascades to user mapping for file_fdw_user
  drop cascades to user mapping for file_fdw_superuser
*************** drop cascades to user mapping for no_pri
*** 224,227 ****
--- 254,258 ----
  drop cascades to foreign table agg_text
  drop cascades to foreign table agg_csv
  drop cascades to foreign table agg_bad
+ drop cascades to foreign table text_csv
  DROP ROLE file_fdw_superuser, file_fdw_user, no_priv_user;
diff --git a/doc/src/sgml/file-fdw.sgml b/doc/src/sgml/file-fdw.sgml
index 8497d9a..5b35451 100644
*** a/doc/src/sgml/file-fdw.sgml
--- b/doc/src/sgml/file-fdw.sgml
***************
*** 111,124 ****
   </variablelist>
  
   <para>
!   <command>COPY</>'s <literal>OIDS</literal>, <literal>FORCE_QUOTE</literal>,
!   and <literal>FORCE_NOT_NULL</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table, not in the
!   options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>
  
--- 111,147 ----
   </variablelist>
  
   <para>
!   A column of a foreign table created using this wrapper can have the
!   following options:
!  </para>
! 
!  <variablelist>
! 
!   <varlistentry>
!    <term><literal>force_not_null</literal></term>
! 
!    <listitem>
!     <para>
!      Specifies whether values for the column shouldn't been matched against
!      the null string.  Acceptable values are <literal>true</> for no matching,
!      and <literal>false</> for matching (case sensitive).
!      <literal>true</> is same as specifying the column in <command>COPY</>'s
!      <literal>FORCE_NOT_NULL</literal> option.
!     </para>
!    </listitem>
!   </varlistentry>
! 
!  </variablelist>
! 
!  <para>
!   <command>COPY</>'s <literal>OIDS</literal> and
!   <literal>FORCE_QUOTE</literal> options are currently not supported by
    <literal>file_fdw</>.
   </para>
  
   <para>
!   These options can only be specified for a foreign table or its columns, not
!   in the options of the <literal>file_fdw</> foreign-data wrapper, nor in the
    options of a server or user mapping using the wrapper.
   </para>