v2-0002-Remove-SPI-in-favor-of-import_attribute_statistic.patch

From c0be3905e22eafcfa09ed1f9644008897b210416 Mon Sep 17 00:00:00 2001
From: Corey Huinker <corey.huinker@gmail.com>
Date: Thu, 18 Jun 2026 16:28:10 -0400
Subject: [PATCH v2 2/7] Remove SPI in favor of import_attribute_statistics.

This patch removes the SPI calls in postgres_fdw.c that were related to
attribute statistics. Instead, the functions import_attribute_statistics()
and clear_attribute_statistics() have been created for this purpose.

Like the preceding patch, the goal is to remove SPI from the workflow
and isolate all code redundancy in attribute_stats.c, where it can be
handled at a later time.

Some additional checks were added to the regression tests to ensure that
values are properly conveyed from a loopback-foreign table to the local
table.
---
 src/include/statistics/attribute_stats.h      |  36 +++
 src/backend/statistics/attribute_stats.c      | 192 +++++++++++++
 .../postgres_fdw/expected/postgres_fdw.out    |  41 +++
 contrib/postgres_fdw/postgres_fdw.c           | 258 +++---------------
 contrib/postgres_fdw/sql/postgres_fdw.sql     |  32 +++
 5 files changed, 339 insertions(+), 220 deletions(-)
 create mode 100644 src/include/statistics/attribute_stats.h

diff --git a/src/include/statistics/attribute_stats.h b/src/include/statistics/attribute_stats.h
new file mode 100644
index 00000000000..4ebde0c7c3b
--- /dev/null
+++ b/src/include/statistics/attribute_stats.h
@@ -0,0 +1,36 @@
+/*-------------------------------------------------------------------------
+ *
+ * attribute_stats.h
+ *    Functions for the internal manipulation of attribute statistics.
+ *
+ * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/statistics/attribute_stats.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef ATTRIBUTE_STATS_H
+
+#include "access/genam.h"
+
+
+bool delete_attribute_statistics(Relation rel, AttrNumber attnum, bool inherited);
+
+bool import_attribute_statistics(Relation rel, const char *attname,
+								 AttrNumber attnum, bool inherited,
+								 const char *null_frac, const char *avg_width,
+								 const char *n_distinct,
+								 const char *most_common_vals,
+								 const char *most_common_freqs,
+								 const char *histogram_bounds,
+								 const char *correlation,
+								 const char *most_common_elems,
+								 const char *most_common_elem_freqs,
+								 const char *elem_count_histogram,
+								 const char *range_length_histogram,
+								 const char *range_empty_frac,
+								 const char *range_bounds_histogram);
+
+#define ATTRIBUTE_STATS_H
+#endif
diff --git a/src/backend/statistics/attribute_stats.c b/src/backend/statistics/attribute_stats.c
index 1cc4d657231..f67d62c0104 100644
--- a/src/backend/statistics/attribute_stats.c
+++ b/src/backend/statistics/attribute_stats.c
@@ -22,10 +22,12 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_operator.h"
 #include "nodes/makefuncs.h"
+#include "statistics/attribute_stats.h"
 #include "statistics/statistics.h"
 #include "statistics/stat_utils.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
+#include "utils/float.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
@@ -688,3 +690,193 @@ pg_restore_attribute_stats(PG_FUNCTION_ARGS)
 
 	PG_RETURN_BOOL(result);
 }
+
+/*
+ * Convenience routine for setting optional text arguments
+ */
+static void
+set_text_arg(NullableDatum *arg, const char *s)
+{
+	if (s)
+	{
+		arg->value = CStringGetTextDatum(s);
+		arg->isnull = false;
+	}
+	else
+	{
+		arg->value = (Datum) 0;
+		arg->isnull = true;
+	}
+}
+
+/*
+ * Convenience routine for setting optional float arguments
+ */
+static void
+set_float_arg(NullableDatum *arg, const char *s)
+{
+	arg->value = (Datum) 0;
+	arg->isnull = true;
+
+	if (s)
+	{
+		ErrorSaveContext escontext = {T_ErrorSaveContext};
+
+		float4		val;
+
+		val = float4in_internal((char *) s, NULL, "float", s, (Node *) &escontext);
+
+		if (escontext.error_occurred)
+		{
+			escontext.error_data->elevel = WARNING;
+			ThrowErrorData(escontext.error_data);
+			FreeErrorData(escontext.error_data);
+		}
+		else
+		{
+			arg->value = Float4GetDatum(val);
+			arg->isnull = false;
+		}
+	}
+}
+
+/*
+ * Convenience routine for setting optional int32 arguments
+ */
+static void
+set_int32_arg(NullableDatum *arg, const char *s)
+{
+	arg->value = (Datum) 0;
+	arg->isnull = true;
+
+	if (s)
+	{
+		ErrorSaveContext escontext = {T_ErrorSaveContext};
+
+		int32		val;
+
+		val = pg_strtoint32_safe(s, (Node *) &escontext);
+
+		if (escontext.error_occurred)
+		{
+			escontext.error_data->elevel = WARNING;
+			ThrowErrorData(escontext.error_data);
+			FreeErrorData(escontext.error_data);
+		}
+		else
+		{
+			arg->value = Int32GetDatum(val);
+			arg->isnull = false;
+		}
+	}
+}
+
+/*
+ * Convenience routine for setting optional float[] arguments
+ */
+static void
+set_floatarr_arg(NullableDatum *arg, const char *s)
+{
+	arg->value = (Datum) 0;
+	arg->isnull = true;
+
+	if (s)
+	{
+		ErrorSaveContext escontext = {T_ErrorSaveContext};
+
+		FmgrInfo	flinfo;
+		Datum		val;
+
+		fmgr_info(F_ARRAY_IN, &flinfo);
+
+		if (!InputFunctionCallSafe(&flinfo, (char *) s, FLOAT4OID, -1,
+								   (Node *) &escontext, &val))
+		{
+			escontext.error_data->elevel = WARNING;
+			ThrowErrorData(escontext.error_data);
+			FreeErrorData(escontext.error_data);
+		}
+		else
+		{
+			arg->value = val;
+			arg->isnull = false;
+		}
+	}
+}
+
+/*
+ * Delete attribute statistics.
+ */
+bool
+delete_attribute_statistics(Relation rel, AttrNumber attnum, bool inherited)
+{
+	return delete_pg_statistic(RelationGetRelid(rel), attnum, inherited);
+}
+
+/*
+ * Import attribute statistics from regular string inputs for all statitical
+ * values.
+ *
+ * To convey a "null"/not-set value for attnum, use InvalidAttrNumber.
+ */
+bool
+import_attribute_statistics(Relation rel, const char *attname,
+							AttrNumber attnum, bool inherited,
+							const char *null_frac, const char *avg_width,
+							const char *n_distinct,
+							const char *most_common_vals,
+							const char *most_common_freqs,
+							const char *histogram_bounds,
+							const char *correlation,
+							const char *most_common_elems,
+							const char *most_common_elem_freqs,
+							const char *elem_count_histogram,
+							const char *range_length_histogram,
+							const char *range_empty_frac,
+							const char *range_bounds_histogram)
+{
+	LOCAL_FCINFO(newfcinfo, NUM_ATTRIBUTE_STATS_ARGS);
+
+	InitFunctionCallInfoData(*newfcinfo, NULL, NUM_ATTRIBUTE_STATS_ARGS, InvalidOid, NULL, NULL);
+
+	/*
+	 * Convert all string inputs to their required datatypes. NULL values are
+	 * left as the default.
+	 */
+	newfcinfo->args[ATTRELSCHEMA_ARG].value = CStringGetTextDatum(get_namespace_name(RelationGetNamespace(rel)));
+	newfcinfo->args[ATTRELSCHEMA_ARG].isnull = false;
+	newfcinfo->args[ATTRELNAME_ARG].value = CStringGetTextDatum(RelationGetRelationName(rel));
+	newfcinfo->args[ATTRELNAME_ARG].isnull = false;
+
+	set_text_arg(&newfcinfo->args[ATTNAME_ARG], attname);
+
+	if (attnum != InvalidAttrNumber)
+	{
+		newfcinfo->args[ATTNUM_ARG].value = Int16GetDatum(attnum);
+		newfcinfo->args[ATTNUM_ARG].isnull = false;
+	}
+	else
+	{
+		newfcinfo->args[ATTNUM_ARG].value = (Datum) 0;
+		newfcinfo->args[ATTNUM_ARG].isnull = true;
+	}
+
+	newfcinfo->args[INHERITED_ARG].value = BoolGetDatum(inherited);
+	newfcinfo->args[INHERITED_ARG].isnull = false;
+
+	set_float_arg(&newfcinfo->args[NULL_FRAC_ARG], null_frac);
+	set_int32_arg(&newfcinfo->args[AVG_WIDTH_ARG], avg_width);
+	set_float_arg(&newfcinfo->args[N_DISTINCT_ARG], n_distinct);
+	set_text_arg(&newfcinfo->args[MOST_COMMON_VALS_ARG], most_common_vals);
+	set_floatarr_arg(&newfcinfo->args[MOST_COMMON_FREQS_ARG], most_common_freqs);
+	set_text_arg(&newfcinfo->args[HISTOGRAM_BOUNDS_ARG], histogram_bounds);
+	set_float_arg(&newfcinfo->args[CORRELATION_ARG], correlation);
+	set_text_arg(&newfcinfo->args[MOST_COMMON_ELEMS_ARG], most_common_elems);
+	set_floatarr_arg(&newfcinfo->args[MOST_COMMON_ELEM_FREQS_ARG], most_common_elem_freqs);
+	set_floatarr_arg(&newfcinfo->args[ELEM_COUNT_HISTOGRAM_ARG], elem_count_histogram);
+	set_text_arg(&newfcinfo->args[RANGE_LENGTH_HISTOGRAM_ARG], range_length_histogram);
+	set_float_arg(&newfcinfo->args[RANGE_EMPTY_FRAC_ARG], range_empty_frac);
+	set_text_arg(&newfcinfo->args[RANGE_BOUNDS_HISTOGRAM_ARG], range_bounds_histogram);
+
+	return attribute_statistics_update(newfcinfo);
+}
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index e90289e4ab1..e931fa64e0d 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -12927,6 +12927,47 @@ ANALYZE dtest_table;
 ANALYZE VERBOSE dtest_ftable;             -- should work
 INFO:  importing statistics for foreign table "public.dtest_ftable"
 INFO:  finished importing statistics for foreign table "public.dtest_ftable"
+-- dtest_ftables stats should now exactly match dtest_table
+-- compare the rowcounts, should get 0 rows back
+SELECT COUNT(*) FROM pg_stats
+WHERE schemaname = 'public' AND tablename = 'dtest_table'
+EXCEPT
+SELECT COUNT(*) FROM pg_stats
+WHERE schemaname = 'public' AND tablename = 'dtest_ftable';
+ count 
+-------
+(0 rows)
+
+-- compare values, should match
+SELECT relpages, reltuples
+FROM pg_class
+WHERE oid = 'public.dtest_table'::regclass
+EXCEPT
+SELECT relpages, reltuples
+FROM pg_class
+WHERE oid = 'public.dtest_ftable'::regclass;
+ relpages | reltuples 
+----------+-----------
+(0 rows)
+
+-- test only a few stats columns common to integer types
+SELECT attname, inherited, null_frac, avg_width, n_distinct,
+  most_common_vals::text as mcv, most_common_freqs,
+  histogram_bounds::text as hb, correlation
+FROM pg_stats
+WHERE schemaname = 'public'
+AND tablename = 'dtest_table'
+EXCEPT
+SELECT attname, inherited, null_frac, avg_width, n_distinct,
+  most_common_vals::text as mcv, most_common_freqs,
+  histogram_bounds::text as hb, correlation
+FROM pg_stats
+WHERE schemaname = 'public'
+AND tablename = 'dtest_ftable';
+ attname | inherited | null_frac | avg_width | n_distinct | mcv | most_common_freqs | hb | correlation 
+---------+-----------+-----------+-----------+------------+-----+-------------------+----+-------------
+(0 rows)
+
 -- cleanup
 DROP FOREIGN TABLE simport_ftable;
 DROP FOREIGN TABLE simport_fview;
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 673d56117b8..8aa589d5a56 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -24,7 +24,6 @@
 #include "commands/vacuum.h"
 #include "executor/execAsync.h"
 #include "executor/instrument.h"
-#include "executor/spi.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -43,6 +42,7 @@
 #include "parser/parsetree.h"
 #include "postgres_fdw.h"
 #include "statistics/statistics.h"
+#include "statistics/attribute_stats.h"
 #include "statistics/relation_stats.h"
 #include "storage/latch.h"
 #include "utils/builtins.h"
@@ -368,109 +368,6 @@ enum AttStatsColumns
 	ATTSTATS_NUM_FIELDS,
 };
 
-/* Attribute stats import query */
-static const char *attimport_sql =
-"SELECT pg_catalog.pg_restore_attribute_stats(\n"
-"\t'version', $1,\n"
-"\t'schemaname', $2,\n"
-"\t'relname', $3,\n"
-"\t'attnum', $4,\n"
-"\t'inherited', false::boolean,\n"
-"\t'null_frac', $5::real,\n"
-"\t'avg_width', $6::integer,\n"
-"\t'n_distinct', $7::real,\n"
-"\t'most_common_vals', $8,\n"
-"\t'most_common_freqs', $9::real[],\n"
-"\t'histogram_bounds', $10,\n"
-"\t'correlation', $11::real,\n"
-"\t'most_common_elems', $12,\n"
-"\t'most_common_elem_freqs', $13::real[],\n"
-"\t'elem_count_histogram', $14::real[],\n"
-"\t'range_length_histogram', $15,\n"
-"\t'range_empty_frac', $16::real,\n"
-"\t'range_bounds_histogram', $17)";
-
-/* Argument order in attribute stats import query */
-enum AttImportSqlArgs
-{
-	ATTIMPORT_SQL_VERSION = 0,
-	ATTIMPORT_SQL_SCHEMANAME,
-	ATTIMPORT_SQL_RELNAME,
-	ATTIMPORT_SQL_ATTNUM,
-	ATTIMPORT_SQL_NULL_FRAC,
-	ATTIMPORT_SQL_AVG_WIDTH,
-	ATTIMPORT_SQL_N_DISTINCT,
-	ATTIMPORT_SQL_MOST_COMMON_VALS,
-	ATTIMPORT_SQL_MOST_COMMON_FREQS,
-	ATTIMPORT_SQL_HISTOGRAM_BOUNDS,
-	ATTIMPORT_SQL_CORRELATION,
-	ATTIMPORT_SQL_MOST_COMMON_ELEMS,
-	ATTIMPORT_SQL_MOST_COMMON_ELEM_FREQS,
-	ATTIMPORT_SQL_ELEM_COUNT_HISTOGRAM,
-	ATTIMPORT_SQL_RANGE_LENGTH_HISTOGRAM,
-	ATTIMPORT_SQL_RANGE_EMPTY_FRAC,
-	ATTIMPORT_SQL_RANGE_BOUNDS_HISTOGRAM,
-	ATTIMPORT_SQL_NUM_FIELDS
-};
-
-/* Argument types in attribute stats import query */
-static const Oid attimport_argtypes[ATTIMPORT_SQL_NUM_FIELDS] =
-{
-	INT4OID, TEXTOID, TEXTOID, INT2OID,
-	TEXTOID, TEXTOID, TEXTOID, TEXTOID,
-	TEXTOID, TEXTOID, TEXTOID, TEXTOID,
-	TEXTOID, TEXTOID, TEXTOID, TEXTOID,
-	TEXTOID,
-};
-
-/*
- * The mapping of attribute stats query columns to the positional arguments in
- * the prepared pg_restore_attribute_stats() statement.
- */
-typedef struct
-{
-	enum AttStatsColumns res_field;
-	enum AttImportSqlArgs arg_num;
-} AttrResultArgMap;
-
-#define NUM_MAPPED_ATTIMPORT_ARGS 13
-
-static const AttrResultArgMap attr_result_arg_map[NUM_MAPPED_ATTIMPORT_ARGS] =
-{
-	{ATTSTATS_NULL_FRAC, ATTIMPORT_SQL_NULL_FRAC},
-	{ATTSTATS_AVG_WIDTH, ATTIMPORT_SQL_AVG_WIDTH},
-	{ATTSTATS_N_DISTINCT, ATTIMPORT_SQL_N_DISTINCT},
-	{ATTSTATS_MOST_COMMON_VALS, ATTIMPORT_SQL_MOST_COMMON_VALS},
-	{ATTSTATS_MOST_COMMON_FREQS, ATTIMPORT_SQL_MOST_COMMON_FREQS},
-	{ATTSTATS_HISTOGRAM_BOUNDS, ATTIMPORT_SQL_HISTOGRAM_BOUNDS},
-	{ATTSTATS_CORRELATION, ATTIMPORT_SQL_CORRELATION},
-	{ATTSTATS_MOST_COMMON_ELEMS, ATTIMPORT_SQL_MOST_COMMON_ELEMS},
-	{ATTSTATS_MOST_COMMON_ELEM_FREQS, ATTIMPORT_SQL_MOST_COMMON_ELEM_FREQS},
-	{ATTSTATS_ELEM_COUNT_HISTOGRAM, ATTIMPORT_SQL_ELEM_COUNT_HISTOGRAM},
-	{ATTSTATS_RANGE_LENGTH_HISTOGRAM, ATTIMPORT_SQL_RANGE_LENGTH_HISTOGRAM},
-	{ATTSTATS_RANGE_EMPTY_FRAC, ATTIMPORT_SQL_RANGE_EMPTY_FRAC},
-	{ATTSTATS_RANGE_BOUNDS_HISTOGRAM, ATTIMPORT_SQL_RANGE_BOUNDS_HISTOGRAM},
-};
-
-/* Attribute stats clear query */
-static const char *attclear_sql =
-"SELECT pg_catalog.pg_clear_attribute_stats($1, $2, $3, false)";
-
-/* Argument order in attribute stats clear query */
-enum AttClearSqlArgs
-{
-	ATTCLEAR_SQL_SCHEMANAME = 0,
-	ATTCLEAR_SQL_RELNAME,
-	ATTCLEAR_SQL_ATTNAME,
-	ATTCLEAR_SQL_NUM_FIELDS
-};
-
-/* Argument types in attribute stats clear query */
-static const Oid attclear_argtypes[ATTCLEAR_SQL_NUM_FIELDS] =
-{
-	TEXTOID, TEXTOID, TEXTOID,
-};
-
 /*
  * SQL functions
  */
@@ -688,15 +585,12 @@ static bool match_attrmap(PGresult *res,
 						  const char *remote_relname,
 						  int attrcnt,
 						  RemoteAttributeMapping *remattrmap);
-static bool import_fetched_statistics(Relation rel,
+static bool import_fetched_statistics(Relation relation,
 									  const char *schemaname,
 									  const char *relname,
 									  int attrcnt,
 									  const RemoteAttributeMapping *remattrmap,
 									  RemoteStatsResults *remstats);
-static void map_field_to_arg(PGresult *res, int row, int field,
-							 int arg, Datum *values, char *nulls);
-static bool import_spi_query_ok(void);
 static void produce_tuple_asynchronously(AsyncRequest *areq, bool fetch);
 static void fetch_more_data_begin(AsyncRequest *areq);
 static void complete_pending_request(AsyncRequest *areq);
@@ -6099,6 +5993,19 @@ match_attrmap(PGresult *res,
 	return true;
 }
 
+
+/*
+ * Conenience routine to fetch
+ */
+static char *
+get_opt_value(PGresult *res, int row, int col)
+{
+	if (PQgetisnull(res, row, col))
+		return NULL;
+
+	return PQgetvalue(res, row, col);
+}
+
 /*
  * Import fetched statistics into the local statistics tables.
  */
@@ -6110,28 +6017,11 @@ import_fetched_statistics(Relation relation,
 						  const RemoteAttributeMapping *remattrmap,
 						  RemoteStatsResults *remstats)
 {
-	SPIPlanPtr	attimport_plan = NULL;
-	SPIPlanPtr	attclear_plan = NULL;
-	Datum		values[ATTIMPORT_SQL_NUM_FIELDS];
-	char		nulls[ATTIMPORT_SQL_NUM_FIELDS];
-	int			spirc;
 	bool		ok = false;
 
 	char	   *relpages = NULL;
 	char	   *reltuples = NULL;
 
-	/* Assign all the invariant parameters common to relation/attribute stats */
-	values[ATTIMPORT_SQL_VERSION] = Int32GetDatum(remstats->server_version_num);
-	nulls[ATTIMPORT_SQL_VERSION] = ' ';
-
-	values[ATTIMPORT_SQL_SCHEMANAME] = CStringGetTextDatum(schemaname);
-	nulls[ATTIMPORT_SQL_SCHEMANAME] = ' ';
-
-	values[ATTIMPORT_SQL_RELNAME] = CStringGetTextDatum(relname);
-	nulls[ATTIMPORT_SQL_RELNAME] = ' ';
-
-	SPI_connect();
-
 	/*
 	 * We import attribute statistics first, if any, because those are more
 	 * prone to errors.  This avoids making a modification of pg_class that
@@ -6139,26 +6029,16 @@ import_fetched_statistics(Relation relation,
 	 */
 	if (remstats->att != NULL)
 	{
-		Assert(PQnfields(remstats->att) == ATTSTATS_NUM_FIELDS);
-		Assert(PQntuples(remstats->att) >= 1);
+		PGresult   *res = remstats->att;
 
-		attimport_plan = SPI_prepare(attimport_sql, ATTIMPORT_SQL_NUM_FIELDS,
-									 (Oid *) attimport_argtypes);
-		if (attimport_plan == NULL)
-			elog(ERROR, "failed to prepare attimport_sql query");
-
-		attclear_plan = SPI_prepare(attclear_sql, ATTCLEAR_SQL_NUM_FIELDS,
-									(Oid *) attclear_argtypes);
-		if (attclear_plan == NULL)
-			elog(ERROR, "failed to prepare attclear_sql query");
-
-		nulls[ATTIMPORT_SQL_ATTNUM] = ' ';
+		Assert(PQnfields(res) == ATTSTATS_NUM_FIELDS);
+		Assert(PQntuples(res) >= 1);
 
 		for (int mapidx = 0; mapidx < attrcnt; mapidx++)
 		{
 			int			row = remattrmap[mapidx].res_index;
-			Datum	   *values2 = values + 1;
-			char	   *nulls2 = nulls + 1;
+			AttrNumber	attnum = remattrmap[mapidx].local_attnum;
+			const char *attname = remattrmap[mapidx].local_attname;
 
 			/* All mappings should have been assigned a result set row. */
 			Assert(row >= 0);
@@ -6168,42 +6048,28 @@ import_fetched_statistics(Relation relation,
 			 */
 			CHECK_FOR_INTERRUPTS();
 
-			/*
-			 * First, clear existing attribute stats.
-			 *
-			 * We can re-use the values/nulls because the number of parameters
-			 * is less and the first two params are the same as the second and
-			 * third ones in attimport_sql.
-			 */
-			values2[ATTCLEAR_SQL_ATTNAME] =
-				CStringGetTextDatum(remattrmap[mapidx].local_attname);
+			delete_attribute_statistics(relation, attnum, false);
 
-			spirc = SPI_execute_plan(attclear_plan, values2, nulls2, false, 1);
-			if (spirc != SPI_OK_SELECT)
-				elog(ERROR, "failed to execute attclear_sql query for column \"%s\" of foreign table \"%s.%s\"",
-					 remattrmap[mapidx].local_attname, schemaname, relname);
-
-			values[ATTIMPORT_SQL_ATTNUM] =
-				Int16GetDatum(remattrmap[mapidx].local_attnum);
-
-			/* Loop through all mappable columns to set remaining arguments */
-			for (int i = 0; i < NUM_MAPPED_ATTIMPORT_ARGS; i++)
-				map_field_to_arg(remstats->att, row,
-								 attr_result_arg_map[i].res_field,
-								 attr_result_arg_map[i].arg_num,
-								 values, nulls);
-
-			spirc = SPI_execute_plan(attimport_plan, values, nulls, false, 1);
-			if (spirc != SPI_OK_SELECT)
-				elog(ERROR, "failed to execute attimport_sql query for column \"%s\" of foreign table \"%s.%s\"",
-					 remattrmap[mapidx].local_attname, schemaname, relname);
-
-			if (!import_spi_query_ok())
+			if (!import_attribute_statistics(relation, attname,
+											 InvalidAttrNumber,
+											 false,
+											 get_opt_value(res, row, ATTSTATS_NULL_FRAC),
+											 get_opt_value(res, row, ATTSTATS_AVG_WIDTH),
+											 get_opt_value(res, row, ATTSTATS_N_DISTINCT),
+											 get_opt_value(res, row, ATTSTATS_MOST_COMMON_VALS),
+											 get_opt_value(res, row, ATTSTATS_MOST_COMMON_FREQS),
+											 get_opt_value(res, row, ATTSTATS_HISTOGRAM_BOUNDS),
+											 get_opt_value(res, row, ATTSTATS_CORRELATION),
+											 get_opt_value(res, row, ATTSTATS_MOST_COMMON_ELEMS),
+											 get_opt_value(res, row, ATTSTATS_MOST_COMMON_ELEM_FREQS),
+											 get_opt_value(res, row, ATTSTATS_ELEM_COUNT_HISTOGRAM),
+											 get_opt_value(res, row, ATTSTATS_RANGE_LENGTH_HISTOGRAM),
+											 get_opt_value(res, row, ATTSTATS_RANGE_EMPTY_FRAC),
+											 get_opt_value(res, row, ATTSTATS_RANGE_BOUNDS_HISTOGRAM)))
 			{
 				ereport(WARNING,
 						errmsg("could not import statistics for foreign table \"%s.%s\" --- attribute statistics import failed for column \"%s\" of this foreign table",
-							   schemaname, relname,
-							   remattrmap[mapidx].local_attname));
+							   schemaname, relname, attname));
 				goto import_cleanup;
 			}
 		}
@@ -6232,57 +6098,9 @@ import_fetched_statistics(Relation relation,
 	ok = true;
 
 import_cleanup:
-	if (attimport_plan)
-		SPI_freeplan(attimport_plan);
-	if (attclear_plan)
-		SPI_freeplan(attclear_plan);
-	SPI_finish();
 	return ok;
 }
 
-/*
- * Move a string value from a result set to a Text value of a Datum array.
- */
-static void
-map_field_to_arg(PGresult *res, int row, int field,
-				 int arg, Datum *values, char *nulls)
-{
-	if (PQgetisnull(res, row, field))
-	{
-		values[arg] = (Datum) 0;
-		nulls[arg] = 'n';
-	}
-	else
-	{
-		const char *s = PQgetvalue(res, row, field);
-
-		values[arg] = CStringGetTextDatum(s);
-		nulls[arg] = ' ';
-	}
-}
-
-/*
- * Check the 1x1 result set of a pg_restore_*_stats() command for success.
- */
-static bool
-import_spi_query_ok(void)
-{
-	TupleDesc	tupdesc;
-	Datum		dat;
-	bool		isnull;
-
-	Assert(SPI_tuptable != NULL);
-	Assert(SPI_processed == 1);
-
-	tupdesc = SPI_tuptable->tupdesc;
-	Assert(tupdesc->natts == 1);
-	Assert(TupleDescAttr(tupdesc, 0)->atttypid == BOOLOID);
-	dat = SPI_getbinval(SPI_tuptable->vals[0], tupdesc, 1, &isnull);
-	Assert(!isnull);
-
-	return DatumGetBool(dat);
-}
-
 /*
  * Import a foreign schema
  */
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index dfc58beb0d2..627177123b3 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -4584,6 +4584,38 @@ ANALYZE dtest_table;
 
 ANALYZE VERBOSE dtest_ftable;             -- should work
 
+-- dtest_ftables stats should now exactly match dtest_table
+-- compare the rowcounts, should get 0 rows back
+SELECT COUNT(*) FROM pg_stats
+WHERE schemaname = 'public' AND tablename = 'dtest_table'
+EXCEPT
+SELECT COUNT(*) FROM pg_stats
+WHERE schemaname = 'public' AND tablename = 'dtest_ftable';
+
+-- compare values, should match
+SELECT relpages, reltuples
+FROM pg_class
+WHERE oid = 'public.dtest_table'::regclass
+EXCEPT
+SELECT relpages, reltuples
+FROM pg_class
+WHERE oid = 'public.dtest_ftable'::regclass;
+
+-- test only a few stats columns common to integer types
+SELECT attname, inherited, null_frac, avg_width, n_distinct,
+  most_common_vals::text as mcv, most_common_freqs,
+  histogram_bounds::text as hb, correlation
+FROM pg_stats
+WHERE schemaname = 'public'
+AND tablename = 'dtest_table'
+EXCEPT
+SELECT attname, inherited, null_frac, avg_width, n_distinct,
+  most_common_vals::text as mcv, most_common_freqs,
+  histogram_bounds::text as hb, correlation
+FROM pg_stats
+WHERE schemaname = 'public'
+AND tablename = 'dtest_ftable';
+
 -- cleanup
 DROP FOREIGN TABLE simport_ftable;
 DROP FOREIGN TABLE simport_fview;
-- 
2.54.0