file_fdw: Fix for generated columns

Since file_fdw uses COPY internally, but COPY doesn't allow listing
generated columns in its column list, we need to make sure that we
don't add generated columns to the column lists internally generated
by file_fdw.

Reported-by: Erik Rijkers <[email protected]>

3 files changed, 21 insertions, 0 deletions

diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 391cd0d778..85534a3a76 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -922,6 +922,10 @@ check_selective_binary_conversion(RelOptInfo *baserel,
 			/* Skip dropped attributes (probably shouldn't see any here). */
 			if (attr->attisdropped)
 				continue;
+			/* Skip generated columns (COPY won't accept them in the column
+			 * list) */
+			if (attr->attgenerated)
+				continue;
 			*columns = lappend(*columns, makeString(pstrdup(attname)));
 		}
 	}
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index a5e79a4549..45b728eeb3 100644
--- a/contrib/file_fdw/input/file_fdw.source
+++ b/contrib/file_fdw/input/file_fdw.source
@@ -189,6 +189,12 @@ SELECT tableoid::regclass, * FROM p1;
 SELECT tableoid::regclass, * FROM p2;
 DROP TABLE pt;
 
+-- generated column tests
+CREATE FOREIGN TABLE gft1 (a int, b text, c text GENERATED ALWAYS AS ('foo') STORED) SERVER file_server
+OPTIONS (format 'csv', filename '@abs_srcdir@/data/list1.csv', delimiter ',');
+SELECT a, c FROM gft1;
+DROP FOREIGN TABLE gft1;
+
 -- privilege tests
 SET ROLE regress_file_fdw_superuser;
 SELECT * FROM agg_text ORDER BY a;
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 853c9f9b28..52b4d5f1df 100644
--- a/contrib/file_fdw/output/file_fdw.source
+++ b/contrib/file_fdw/output/file_fdw.source
@@ -375,6 +375,17 @@ SELECT tableoid::regclass, * FROM p2;
 (3 rows)
 
 DROP TABLE pt;
+-- generated column tests
+CREATE FOREIGN TABLE gft1 (a int, b text, c text GENERATED ALWAYS AS ('foo') STORED) SERVER file_server
+OPTIONS (format 'csv', filename '@abs_srcdir@/data/list1.csv', delimiter ',');
+SELECT a, c FROM gft1;
+ a |   c    
+---+--------
+ 1 | _null_
+ 1 | _null_
+(2 rows)
+
+DROP FOREIGN TABLE gft1;
 -- privilege tests
 SET ROLE regress_file_fdw_superuser;
 SELECT * FROM agg_text ORDER BY a;