MDEV-15073: Generic UDAF parser code in server for windows functions

Added support for usual agreggate UDF (UDAF)
Added remove() call support for more efficient window function processing
Added example of aggregate UDF with efficient windows function support

10 files changed, 386 insertions, 0 deletions

diff --git a/mysql-test/main/udf.result b/mysql-test/main/udf.result
index 6af6b167511..13eb186135b 100644
--- a/mysql-test/main/udf.result
+++ b/mysql-test/main/udf.result
@@ -465,3 +465,108 @@ a	b
 Hello	HL
 DROP FUNCTION METAPHON;
 DROP TABLE t1;
+
+MDEV-15073: Generic UDAF parser code in server for windows functions
+
+CREATE AGGREGATE FUNCTION avgcost
+RETURNS REAL SONAME "UDF_EXAMPLE_LIB";
+CREATE AGGREGATE FUNCTION avg2
+RETURNS REAL SONAME "UDF_EXAMPLE_LIB";
+CREATE FUNCTION myfunc_double RETURNS REAL SONAME "UDF_EXAMPLE_LIB";
+create table t1(pk int primary key,
+a int,
+sum int,
+price float(24));
+insert into t1 values
+(1, 1, 100, 50.00),
+(2, 1, 100, 100.00),
+(3, 1, 100, 50.00),
+(4, 1, 100, 50.00),
+(5, 1, 100, 50.00),
+(6, 1, 100, NULL),
+(7, 1, NULL, NULL),
+(8, 2, 2,   2),
+(9, 2, 4,   4);
+select pk, a, sum, price, avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+from t1;
+pk	a	sum	price	avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+1	1	100	50	75.0000
+2	1	100	100	66.6667
+3	1	100	50	66.6667
+4	1	100	50	50.0000
+5	1	100	50	50.0000
+6	1	100	NULL	50.0000
+7	1	NULL	NULL	0.0000
+8	2	2	2	3.3333
+9	2	4	4	3.3333
+select pk, a, sum, price, avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+pk	a	sum	price	avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+1	1	100	50	50.0000
+2	1	100	100	75.0000
+3	1	100	50	75.0000
+4	1	100	50	50.0000
+5	1	100	50	50.0000
+6	1	100	NULL	50.0000
+7	1	NULL	NULL	0.0000
+8	2	2	2	2.0000
+9	2	4	4	3.3333
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+from t1;
+pk	a	sum	price	avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+1	1	100	50	0.7500
+2	1	100	100	0.6667
+3	1	100	50	0.6667
+4	1	100	50	0.5000
+5	1	100	50	0.5000
+6	1	100	NULL	0.5000
+7	1	NULL	NULL	0.0000
+8	2	2	2	1.0000
+9	2	4	4	1.0000
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+pk	a	sum	price	avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+1	1	100	50	0.5000
+2	1	100	100	0.7500
+3	1	100	50	0.7500
+4	1	100	50	0.5000
+5	1	100	50	0.5000
+6	1	100	NULL	0.5000
+7	1	NULL	NULL	0.0000
+8	2	2	2	1.0000
+9	2	4	4	1.0000
+select pk, a, sum, price, tttttttt(sprice,sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from ' at line 1
+select pk, a, sum, price, myfunc_double(sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from ' at line 1
+select pk, a, sum, price, round(sprice,sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from ' at line 1
+select pk, a, sum, price, myfunc_double(sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from ' at line 1
+set @save_sql_mode = @@sql_mode;
+set sql_mode="oracle";
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+pk	a	sum	price	avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+1	1	100	50	0.5000
+2	1	100	100	0.7500
+3	1	100	50	0.7500
+4	1	100	50	0.5000
+5	1	100	50	0.5000
+6	1	100	NULL	0.5000
+7	1	NULL	NULL	0.0000
+8	2	2	2	1.0000
+9	2	4	4	1.0000
+set sql_mode= @save_sql_mode;
+drop table t1;
+DROP FUNCTION avgcost;
+DROP FUNCTION avg2;
+DROP FUNCTION myfunc_double;
diff --git a/mysql-test/main/udf.test b/mysql-test/main/udf.test
index c3a25c6bcce..43d66dc68e2 100644
--- a/mysql-test/main/udf.test
+++ b/mysql-test/main/udf.test
@@ -528,3 +528,69 @@ DROP FUNCTION METAPHON;
 #INSERT INTO t1 (a) VALUES ('Hello');
 #SELECT * FROM t1;
 DROP TABLE t1;
+
+--echo
+--echo MDEV-15073: Generic UDAF parser code in server for windows functions
+--echo
+
+--replace_result $UDF_EXAMPLE_SO UDF_EXAMPLE_LIB
+eval CREATE AGGREGATE FUNCTION avgcost
+        RETURNS REAL SONAME "$UDF_EXAMPLE_SO";
+--replace_result $UDF_EXAMPLE_SO UDF_EXAMPLE_LIB
+eval CREATE AGGREGATE FUNCTION avg2
+        RETURNS REAL SONAME "$UDF_EXAMPLE_SO";
+--replace_result $UDF_EXAMPLE_SO UDF_EXAMPLE_LIB
+eval CREATE FUNCTION myfunc_double RETURNS REAL SONAME "$UDF_EXAMPLE_SO";
+
+create table t1(pk int primary key,
+                a int,
+                sum int,
+                price float(24));
+insert into t1 values
+  (1, 1, 100, 50.00),
+  (2, 1, 100, 100.00),
+  (3, 1, 100, 50.00),
+  (4, 1, 100, 50.00),
+  (5, 1, 100, 50.00),
+  (6, 1, 100, NULL),
+  (7, 1, NULL, NULL),
+  (8, 2, 2,   2),
+  (9, 2, 4,   4);
+
+--sorted_result
+select pk, a, sum, price, avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+from t1;
+--sorted_result
+select pk, a, sum, price, avgcost(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+
+--sorted_result
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+from t1;
+--sorted_result
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+--error ER_PARSE_ERROR
+select pk, a, sum, price, tttttttt(sprice,sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+--error ER_PARSE_ERROR
+select pk, a, sum, price, myfunc_double(sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+--error ER_PARSE_ERROR
+select pk, a, sum, price, round(sprice,sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+--error ER_PARSE_ERROR
+select pk, a, sum, price, myfunc_double(sum) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+
+set @save_sql_mode = @@sql_mode;
+set sql_mode="oracle";
+--sorted_result
+select pk, a, sum, price, avg2(sum, price) over (partition by a order by pk ROWS BETWEEN 1 PRECEDING AND 0 FOLLOWING)
+from t1;
+set sql_mode= @save_sql_mode;
+
+drop table t1;
+DROP FUNCTION avgcost;
+DROP FUNCTION avg2;
+DROP FUNCTION myfunc_double;
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 0e52b2988a3..b571289ca12 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -3235,6 +3235,25 @@ bool Item_udf_sum::add()
   DBUG_RETURN(0);
 }
 
+
+bool Item_udf_sum::supports_removal() const
+{
+  DBUG_ENTER("Item_udf_sum::supports_remove");
+  DBUG_PRINT("info", ("support: %d", udf.supports_removal()));
+  DBUG_RETURN(udf.supports_removal());
+}
+
+
+void Item_udf_sum::remove()
+{
+  my_bool tmp_null_value;
+  DBUG_ENTER("Item_udf_sum::remove");
+  udf.remove(&tmp_null_value);
+  null_value= tmp_null_value;
+  DBUG_VOID_RETURN;
+}
+
+
 void Item_udf_sum::cleanup()
 {
   /*
diff --git a/sql/item_sum.h b/sql/item_sum.h
index f58fa0b9688..01583d32f45 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -1563,6 +1563,8 @@ public:
 
   void clear();
   bool add();
+  bool supports_removal() const;
+  void remove();
   void reset_field() {};
   void update_field() {};
   void cleanup();
diff --git a/sql/sql_udf.cc b/sql/sql_udf.cc
index 9a036156de6..aee4869bd40 100644
--- a/sql/sql_udf.cc
+++ b/sql/sql_udf.cc
@@ -76,6 +76,8 @@ static const char *init_syms(udf_func *tmp, char *nm)
     (void)strmov(end, "_add");
     if (!((tmp->func_add= (Udf_func_add) dlsym(tmp->dlhandle, nm))))
       return nm;
+    (void)strmov(end, "_remove");
+    tmp->func_remove= (Udf_func_add) dlsym(tmp->dlhandle, nm);
   }
 
   (void) strmov(end,"_deinit");
@@ -565,6 +567,7 @@ int mysql_create_function(THD *thd,udf_func *udf)
   u_d->func_deinit= udf->func_deinit;
   u_d->func_clear= udf->func_clear;
   u_d->func_add= udf->func_add;
+  u_d->func_remove= udf->func_remove;
 
   /* create entry in mysql.func table */
 
diff --git a/sql/sql_udf.h b/sql/sql_udf.h
index 6e6fed2a81a..4fa75759269 100644
--- a/sql/sql_udf.h
+++ b/sql/sql_udf.h
@@ -47,6 +47,7 @@ typedef struct st_udf_func
   Udf_func_deinit func_deinit;
   Udf_func_clear func_clear;
   Udf_func_add func_add;
+  Udf_func_add func_remove;
   ulong usage_count;
 } udf_func;
 
@@ -131,6 +132,20 @@ class udf_handler :public Sql_alloc
     func(&initid, &f_args, &is_null, &error);
     *null_value= (my_bool) (is_null || error);
   }
+  bool supports_removal() const
+  { return MY_TEST(u_d->func_remove); }
+  void remove(my_bool *null_value)
+  {
+    DBUG_ASSERT(u_d->func_remove);
+    if (get_arguments())
+    {
+      *null_value=1;
+      return;
+    }
+    Udf_func_add func= u_d->func_remove;
+    func(&initid, &f_args, &is_null, &error);
+    *null_value= (my_bool) (is_null || error);
+  }
   String *val_str(String *str,String *save_str);
 };
 
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index b2f1131f594..1d9fde183cd 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -11350,6 +11350,21 @@ window_func:
           {
             ((Item_sum *) $1)->mark_as_window_func_sum_expr();
           }
+        |
+          function_call_generic
+          {
+            Item* item = (Item*)$1;
+            /* Only UDF aggregate here possible */
+            if ((item == NULL) ||
+                (item->type() != Item::SUM_FUNC_ITEM)
+                || (((Item_sum *)item)->sum_func() != Item_sum::UDF_SUM_FUNC))
+            {
+              thd->parse_error();
+              MYSQL_YYABORT;
+            }
+
+            ((Item_sum *) $1)->mark_as_window_func_sum_expr();
+          }
         ;
 
 simple_window_func:
diff --git a/sql/sql_yacc_ora.yy b/sql/sql_yacc_ora.yy
index e17e959d1e5..843309ad1a9 100644
--- a/sql/sql_yacc_ora.yy
+++ b/sql/sql_yacc_ora.yy
@@ -11384,6 +11384,21 @@ window_func:
           {
             ((Item_sum *) $1)->mark_as_window_func_sum_expr();
           }
+        |
+          function_call_generic
+          {
+            Item* item = (Item*)$1;
+            /* Only UDF aggregate here possible */
+            if ((item == NULL) ||
+                (item->type() != Item::SUM_FUNC_ITEM)
+                || (((Item_sum *)item)->sum_func() != Item_sum::UDF_SUM_FUNC))
+            {
+              thd->parse_error();
+              MYSQL_YYABORT;
+            }
+
+            ((Item_sum *) $1)->mark_as_window_func_sum_expr();
+          }
         ;
 
 simple_window_func:
diff --git a/sql/udf_example.c b/sql/udf_example.c
index 6db2b5e737a..bdc995b51fc 100644
--- a/sql/udf_example.c
+++ b/sql/udf_example.c
@@ -173,6 +173,13 @@ void avgcost_reset( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error
 void avgcost_clear( UDF_INIT* initid, char* is_null, char *error );
 void avgcost_add( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
 double avgcost( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
+my_bool avg2_init( UDF_INIT* initid, UDF_ARGS* args, char* message );
+void avg2_deinit( UDF_INIT* initid );
+void avg2_reset( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
+void avg2_clear( UDF_INIT* initid, char* is_null, char *error );
+void avg2_add( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
+void avg2_remove( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
+double avg2( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
 my_bool is_const_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
 char *is_const(UDF_INIT *initid, UDF_ARGS *args, char *result, unsigned long
                *length, char *is_null, char *error);
@@ -1049,6 +1056,138 @@ avgcost( UDF_INIT* initid, UDF_ARGS* args __attribute__((unused)),
   return data->totalprice/(double)data->totalquantity;
 }
 
+
+/*
+** Average 2 (number, sum)*/
+struct avg2_data
+{
+  ulonglong	count;
+  double	sum;
+};
+
+
+my_bool
+avg2_init( UDF_INIT* initid, UDF_ARGS* args, char* message )
+{
+  struct avg2_data*	data;
+
+  if (args->arg_count != 2)
+  {
+    strcpy(
+	   message,
+	   "wrong number of arguments: AVG2() requires two arguments"
+	   );
+    return 1;
+  }
+
+  if ((args->arg_type[0] != INT_RESULT) || (args->arg_type[1] != REAL_RESULT) )
+  {
+    strcpy(
+	   message,
+	   "wrong argument type: AVG2() requires an INT and a REAL"
+	   );
+    return 1;
+  }
+
+  /*
+  **	force arguments to double.
+  */
+  /*args->arg_type[0]	= REAL_RESULT;
+    args->arg_type[1]	= REAL_RESULT;*/
+
+  initid->maybe_null	= 0;		/* The result may be null */
+  initid->decimals	= 4;		/* We want 4 decimals in the result */
+  initid->max_length	= 20;		/* 6 digits + . + 10 decimals */
+
+  if (!(data = (struct avg2_data*) malloc(sizeof(struct avg2_data))))
+  {
+    strmov(message,"Couldn't allocate memory");
+    return 1;
+  }
+  data->count	= 0;
+  data->sum	= 0.0;
+
+  initid->ptr = (char*)data;
+
+  return 0;
+}
+
+void
+avg2_deinit( UDF_INIT* initid )
+{
+  free(initid->ptr);
+}
+
+
+/* This is only for MySQL 4.0 compability */
+void
+avg2_reset(UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* message)
+{
+  avgcost_clear(initid, is_null, message);
+  avgcost_add(initid, args, is_null, message);
+}
+
+/* This is needed to get things to work in MySQL 4.1.1 and above */
+
+void
+avg2_clear(UDF_INIT* initid, char* is_null __attribute__((unused)),
+              char* message __attribute__((unused)))
+{
+  struct avg2_data* data = (struct avg2_data*)initid->ptr;
+  data->sum=	0.0;
+  data->count=	0;
+}
+
+
+void
+avg2_add(UDF_INIT* initid, UDF_ARGS* args,
+            char* is_null __attribute__((unused)),
+            char* message __attribute__((unused)))
+{
+  if (args->args[0] && args->args[1])
+  {
+    struct avg2_data* data	= (struct avg2_data*)initid->ptr;
+    longlong quantity		= *((longlong*)args->args[0]);
+    double sum	                = *((double*)args->args[1]);
+
+    data->count	+= quantity;
+    data->sum	+= sum;
+  }
+}
+
+
+void
+avg2_remove(UDF_INIT* initid, UDF_ARGS* args,
+               char* is_null __attribute__((unused)),
+               char* message __attribute__((unused)))
+{
+  if (args->args[0] && args->args[1])
+  {
+    struct avg2_data* data	= (struct avg2_data*)initid->ptr;
+    longlong quantity		= *((longlong*)args->args[0]);
+    double sum	                = *((double*)args->args[1]);
+
+    data->count	-= quantity;
+    data->sum	-= sum;
+  }
+}
+
+
+double
+avg2( UDF_INIT* initid, UDF_ARGS* args __attribute__((unused)),
+         char* is_null, char* error __attribute__((unused)))
+{
+  struct avg2_data* data = (struct avg2_data*)initid->ptr;
+  if (!data->count)
+  {
+    *is_null = 1;
+    return 0.0;
+  }
+
+  *is_null = 0;
+  return data->sum/(double)data->count;
+}
+
 my_bool myfunc_argument_name_init(UDF_INIT *initid, UDF_ARGS *args,
 				  char *message);
 char *myfunc_argument_name(UDF_INIT *initid, UDF_ARGS *args, char *result,
diff --git a/sql/udf_example.def b/sql/udf_example.def
index 74230b638bf..903c2b74893 100644
--- a/sql/udf_example.def
+++ b/sql/udf_example.def
@@ -23,6 +23,13 @@ EXPORTS
   avgcost_add
   avgcost_clear
   avgcost
+  avg2_init
+  avg2_deinit
+  avg2_reset
+  avg2_add
+  avg2_remove
+  avg2_clear
+  avg2
   is_const
   is_const_init
   check_const_len