fix the bug which leading to wrong answer of sql string_agg(orderby) …

…& agg(distinct)

src/backend/executor/nodeAgg.c

@@ -320,7 +320,7 @@ initialize_aggregates(AggState *aggstate,
 
 			/* CDB: Set enhanced sort options. */
 			{
-				int 		unique = peragg->aggref->aggdistinct &&
+				int 		unique = peraggstate->aggref->aggdistinct &&
 									 ( gp_enable_sort_distinct ? 1 : 0) ;
 				int 		sort_flags = gp_sort_flags; /* get the guc */
 				int         maxdistinct = gp_sort_max_distinct; /* get guc */

src/test/regress/expected/aggregate_with_sort_distinct.out

@@ -0,0 +1,35 @@
+drop schema if exists agg_sort_distinct_regress_schema cascade;
+NOTICE:  schema "agg_sort_distinct_regress_schema" does not exist, skipping
+create schema if not exists agg_sort_distinct_regress_schema;
+set search_path to agg_sort_distinct_regress_schema;
+create table test_multi_order_agg(a int, b int);
+NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'a' as the Greenplum Database data distribution key for this table.
+HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
+insert into test_multi_order_agg values (1, 1), (1, null), (null, 1);
+set gp_enable_sort_distinct to on;
+select string_agg(a::text, ','), string_agg(distinct b::text, ',') from test_multi_order_agg;
+ string_agg | string_agg 
+------------+------------
+ 1,1        | 1
+(1 row)
+
+select string_agg(a::text, ',' order by b), string_agg(distinct b::text, ',') from test_multi_order_agg;
+ string_agg | string_agg 
+------------+------------
+ 1,1        | 1
+(1 row)
+
+set gp_enable_sort_distinct to off;
+select string_agg(a::text, ','), string_agg(distinct b::text, ',') from test_multi_order_agg;
+ string_agg | string_agg 
+------------+------------
+ 1,1        | 1
+(1 row)
+
+select string_agg(a::text, ',' order by b), string_agg(distinct b::text, ',') from test_multi_order_agg;
+ string_agg | string_agg 
+------------+------------
+ 1,1        | 1
+(1 row)
+
+

src/test/regress/greenplum_schedule

@@ -182,6 +182,7 @@ test: bfv_catalog bfv_index bfv_olap bfv_aggregate bfv_partition bfv_partition_p
 # NOTE: gporca_faults uses gp_fault_injector - so do not add to a parallel group
 test: gporca_faults
 
+test: aggregate_with_sort_distinct
 test: aggregate_with_groupingsets
 
 test: nested_case_null sort bb_mpph

src/test/regress/sql/aggregate_with_sort_distinct.sql

@@ -0,0 +1,16 @@
+drop schema if exists agg_sort_distinct_regress_schema cascade;
+create schema if not exists agg_sort_distinct_regress_schema;
+
+set search_path to agg_sort_distinct_regress_schema;
+
+create table test_multi_order_agg(a int, b int);
+
+insert into test_multi_order_agg values (1, 1), (1, null), (null, 1);
+
+set gp_enable_sort_distinct to on;
+select string_agg(a::text, ','), string_agg(distinct b::text, ',') from test_multi_order_agg;
+select string_agg(a::text, ',' order by b), string_agg(distinct b::text, ',') from test_multi_order_agg;
+
+set gp_enable_sort_distinct to off;
+select string_agg(a::text, ','), string_agg(distinct b::text, ',') from test_multi_order_agg;
+select string_agg(a::text, ',' order by b), string_agg(distinct b::text, ',') from test_multi_order_agg;