diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 48631cc..eff2b0e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -14881,6 +14881,13 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
+        <literal><function>pg_size_pretty(<type>numeric</type>)</function></literal>
+        </entry>
+       <entry><type>text</type></entry>
+       <entry>Converts a size in bytes into a human-readable format with size units</entry>
+      </row>
+      <row>
+       <entry>
         <literal><function>pg_table_size(<type>regclass</type>)</function></literal>
         </entry>
        <entry><type>bigint</type></entry>
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 26a8c01..494ce27 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -24,6 +24,7 @@
 #include "storage/fd.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/numeric.h"
 #include "utils/rel.h"
 #include "utils/relmapper.h"
 #include "utils/syscache.h"
@@ -550,6 +551,93 @@ pg_size_pretty(PG_FUNCTION_ARGS)
 	PG_RETURN_TEXT_P(cstring_to_text(buf));
 }
 
+Datum
+pg_size_pretty_num(PG_FUNCTION_ARGS)
+{
+	Numeric		size = PG_GETARG_NUMERIC(0);
+	Numeric		limit, limit2;
+
+	char		*buf, *result;
+
+	limit = DatumGetNumeric(DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) (10 * 1024))));
+	limit2 = DatumGetNumeric(DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) (10 * 1024 * 2 - 1))));
+
+	if (DatumGetBool(DirectFunctionCall2(numeric_lt, NumericGetDatum(size), NumericGetDatum(limit))))
+	{
+		buf = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(size)));
+		result = strcat(buf, " bytes");
+	}
+	else
+	{
+		Numeric		arg2;
+
+		/* keep one extra bit for rounding */
+		/* size >>= 9 */
+		arg2 = DatumGetNumeric(DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) pow(2, 9))));
+		size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), NumericGetDatum(arg2)));
+
+		if (DatumGetBool(DirectFunctionCall2(numeric_lt, NumericGetDatum(size), NumericGetDatum(limit2))))
+		{
+			/* size = (size + 1) / 2 */
+			size = DatumGetNumeric(DirectFunctionCall2(numeric_add, NumericGetDatum(size), 
+													DirectFunctionCall1(int8_numeric, Int64GetDatum(1))));
+			size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), 
+													DirectFunctionCall1(int8_numeric, Int64GetDatum(2))));
+			buf = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(size)));
+			result = strcat(buf, " kB");
+		}
+		else
+		{
+			Numeric		arg3;
+
+			/* size >>= 10 */
+			arg3 = DatumGetNumeric(DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) pow(2, 10))));
+			size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), NumericGetDatum(arg3)));
+
+			if (DatumGetBool(DirectFunctionCall2(numeric_lt, NumericGetDatum(size), NumericGetDatum(limit2))))
+			{
+				/* size = (size + 1) / 2 */
+				size = DatumGetNumeric(DirectFunctionCall2(numeric_add, NumericGetDatum(size), 
+														DirectFunctionCall1(int8_numeric, Int64GetDatum(1))));
+				size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), 
+														DirectFunctionCall1(int8_numeric, Int64GetDatum(2))));
+				buf = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(size)));
+				result = strcat(buf, " MB");
+			}
+			else
+			{
+				/* size >>= 10 */
+				size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), NumericGetDatum(arg3)));
+
+				if (DatumGetBool(DirectFunctionCall2(numeric_lt, NumericGetDatum(size), NumericGetDatum(limit2))))
+				{
+					/* size = (size + 1) / 2 */
+					size = DatumGetNumeric(DirectFunctionCall2(numeric_add, NumericGetDatum(size), 
+															DirectFunctionCall1(int8_numeric, Int64GetDatum(1))));
+					size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), 
+															DirectFunctionCall1(int8_numeric, Int64GetDatum(2))));
+					buf = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(size)));
+					result = strcat(buf, " GB");
+				}
+				else
+				{
+					/* size = (size + 1) / 2 */
+					size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), NumericGetDatum(arg3)));
+					size = DatumGetNumeric(DirectFunctionCall2(numeric_add, NumericGetDatum(size), 
+															DirectFunctionCall1(int8_numeric, Int64GetDatum(1))));
+					size = DatumGetNumeric(DirectFunctionCall2(numeric_div_trunc, NumericGetDatum(size), 
+															DirectFunctionCall1(int8_numeric, Int64GetDatum(2))));
+
+					buf = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(size)));
+					result = strcat(buf, " TB");
+				}
+			}
+		}
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
+
 /*
  * Get the filenode of a relation
  *
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index b6ac195..0d8d486 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3364,6 +3364,7 @@ DESCR("disk space usage for the specified fork of a table or index");
 DATA(insert OID = 2286 ( pg_total_relation_size PGNSP PGUID 12 1 0 0 0 f f f t f v 1 0 20 "2205" _null_ _null_ _null_ _null_ pg_total_relation_size _null_ _null_ _null_ ));
 DESCR("total disk space usage for the specified table and associated indexes");
 DATA(insert OID = 2288 ( pg_size_pretty			PGNSP PGUID 12 1 0 0 0 f f f t f v 1 0 25 "20" _null_ _null_ _null_ _null_ pg_size_pretty _null_ _null_ _null_ ));
+DATA(insert OID = 3151 ( pg_size_pretty			PGNSP PGUID 12 1 0 0 0 f f f t f v 1 0 25 "1700" _null_ _null_ _null_ _null_ pg_size_pretty_num _null_ _null_ _null_ ));
 DESCR("convert a long int to a human readable text using size units");
 DATA(insert OID = 2997 ( pg_table_size			PGNSP PGUID 12 1 0 0 0 f f f t f v 1 0 20 "2205" _null_ _null_ _null_ _null_ pg_table_size _null_ _null_ _null_ ));
 DESCR("disk space usage for the specified table, including TOAST, free space and visibility map");
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 68179d5..3d07f29 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -453,6 +453,7 @@ extern Datum pg_database_size_name(PG_FUNCTION_ARGS);
 extern Datum pg_relation_size(PG_FUNCTION_ARGS);
 extern Datum pg_total_relation_size(PG_FUNCTION_ARGS);
 extern Datum pg_size_pretty(PG_FUNCTION_ARGS);
+extern Datum pg_size_pretty_num(PG_FUNCTION_ARGS);
 extern Datum pg_table_size(PG_FUNCTION_ARGS);
 extern Datum pg_indexes_size(PG_FUNCTION_ARGS);
 extern Datum pg_relation_filenode(PG_FUNCTION_ARGS);