Explicit unnecessary cast should be eliminated (#1984)

* Explicit unnecessary cast should be eliminated

This commit can eliminate unnecessary explicit cast in where condition
and tune the query to choose index in those conditions

Task: BABEL-4176
Signed-off-by: Zhibai Song <[email protected]>

contrib/babelfishpg_tsql/src/hooks.c

@@ -17,6 +17,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_trigger_d.h"
 #include "catalog/pg_type.h"
+#include "catalog/pg_operator.h"
 #include "commands/copy.h"
 #include "commands/explain.h"
 #include "commands/tablecmds.h"
@@ -38,6 +39,7 @@
 #include "parser/parse_utilcmd.h"
 #include "parser/parse_target.h"
 #include "parser/parse_type.h"
+#include "parser/parse_oper.h"
 #include "parser/parser.h"
 #include "parser/scanner.h"
 #include "parser/scansup.h"
@@ -115,6 +117,7 @@ static void modify_RangeTblFunction_tupdesc(char *funcname, Node *expr, TupleDes
 static void sort_nulls_first(SortGroupClause * sortcl, bool reverse);
 static int getDefaultPosition(const List *default_positions, const ListCell *def_idx, int argPosition);
 static List* replace_pltsql_function_defaults(HeapTuple func_tuple, List *defaults, List *fargs);
+static Node* optimize_explicit_cast(ParseState *pstate, Node *node);
 
 static ResTarget* make_restarget_from_colname(char * colName);
 static void transform_pivot_clause(ParseState *pstate, SelectStmt *stmt);
@@ -220,6 +223,7 @@ static bbfCustomProcessUtility_hook_type prev_bbfCustomProcessUtility_hook = NUL
 static bbfSelectIntoUtility_hook_type prev_bbfSelectIntoUtility_hook = NULL;
 static bbfSelectIntoAddIdentity_hook_type prev_bbfSelectIntoAddIdentity_hook = NULL;
 static sortby_nulls_hook_type prev_sortby_nulls_hook = NULL;
+static optimize_explicit_cast_hook_type prev_optimize_explicit_cast_hook = NULL;
 static table_variable_satisfies_visibility_hook_type prev_table_variable_satisfies_visibility = NULL;
 static table_variable_satisfies_update_hook_type prev_table_variable_satisfies_update = NULL;
 static table_variable_satisfies_vacuum_hook_type prev_table_variable_satisfies_vacuum = NULL;
@@ -394,6 +398,9 @@ InstallExtendedHooks(void)
 
 	pre_transform_pivot_clause_hook = transform_pivot_clause_hook;
 	transform_pivot_clause_hook = transform_pivot_clause;
+
+	prev_optimize_explicit_cast_hook = optimize_explicit_cast_hook;
+	optimize_explicit_cast_hook = optimize_explicit_cast;
 }
 
 void
@@ -457,6 +464,7 @@ UninstallExtendedHooks(void)
 	set_local_schema_for_func_hook = prev_set_local_schema_for_func_hook;
 	bbf_get_sysadmin_oid_hook = prev_bbf_get_sysadmin_oid_hook;
 	transform_pivot_clause_hook = pre_transform_pivot_clause_hook;
+	optimize_explicit_cast_hook = prev_optimize_explicit_cast_hook;
 }
 
 /*****************************************
@@ -4317,6 +4325,9 @@ transform_pivot_clause(ParseState *pstate, SelectStmt *stmt)
 	PLtsql_execstate 	*tsql_outmost_estat;
 	int				nestlevel;
 
+	if (sql_dialect != SQL_DIALECT_TSQL)
+		return;
+
 	new_src_sql_targetist = NULL;
 	new_pivot_aliaslist = NULL;
 	src_sql_groupbylist = NULL;
@@ -4453,3 +4464,58 @@ transform_pivot_clause(ParseState *pstate, SelectStmt *stmt)
 	tsql_outmost_estat->pivot_number++;	
 	MemoryContextSwitchTo(oldContext);
 }
+
+static Node* optimize_explicit_cast(ParseState *pstate, Node *node)
+{
+	if (sql_dialect != SQL_DIALECT_TSQL)
+		return node;
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, FuncExpr))
+	{
+		FuncExpr   *f = (FuncExpr *) node;
+		if (f->funcformat == COERCE_EXPLICIT_CAST){
+			Node* arg = (Node*)linitial(f->args);
+			if (nodeTag(arg) == T_Var && 
+			   ((Var*) arg)->vartype == INT4OID && 
+			   f->funcresulttype == INT8OID)
+				return optimize_explicit_cast(pstate, linitial(f->args));
+		}
+	}
+	else if (IsA(node, BoolExpr))
+	{
+		BoolExpr *r = (BoolExpr *) node;
+		ListCell *l;
+		foreach (l , r->args)
+		{
+			optimize_explicit_cast(pstate, (Node*)lfirst(l));
+		}
+	}
+	else if (IsA(node, OpExpr))
+	{
+		OpExpr *opExpr = (OpExpr*) node;
+		Form_pg_operator form;
+		HeapTuple	tuple;
+		Node* node = optimize_explicit_cast(pstate, linitial(opExpr->args));
+		Node* result = NULL;
+		if (node != linitial(opExpr->args))
+		{
+			char	   *opname;
+
+			tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(opExpr->opno));
+			if (!HeapTupleIsValid(tuple))
+				return node; // no need to error out in here, stop transform and quite, keep the original node
+			form = (Form_pg_operator) GETSTRUCT(tuple);
+
+			opname = NameStr(form->oprname);
+			if (strcmp(opname, "=") == 0)
+			{
+				result =(Node*)make_op(pstate, list_make1(makeString(opname)), node, lsecond(opExpr->args), pstate->p_last_srf, -1);
+			}
+			ReleaseSysCache(tuple);
+			if (result)
+				return result;
+		}
+	}
+	return node;
+}

test/JDBC/expected/cast_eliminate-vu-cleanup.out

@@ -0,0 +1,5 @@
+drop table cast_eliminate
+GO
+
+drop table cast_eliminate2
+GO

test/JDBC/expected/cast_eliminate-vu-prepare.out

@@ -0,0 +1,6 @@
+CREATE TABLE cast_eliminate( [ROID] [int] NOT NULL PRIMARY KEY );
+GO
+
+CREATE TABLE cast_eliminate2( [ROID] [bigint] NOT NULL PRIMARY KEY );
+GO
+

test/JDBC/expected/cast_eliminate-vu-verify.out

@@ -0,0 +1,82 @@
+set babelfish_showplan_all on
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = 1)
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = 1)
+Index Only Scan using cast_eliminate_pkey on cast_eliminate  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = 1)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS int) = 1)
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS int) = 1)
+Index Only Scan using cast_eliminate_pkey on cast_eliminate  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = 1)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (ROID = cast(1 as bigint))
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate  WHERE (ROID = cast(1 as bigint))
+Index Only Scan using cast_eliminate_pkey on cast_eliminate  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = '1'::bigint)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+Index Only Scan using cast_eliminate_pkey on cast_eliminate  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = '1'::bigint)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS BIGINT) = 1)
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS BIGINT) = 1)
+Index Only Scan using cast_eliminate2_pkey on cast_eliminate2  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = 1)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS int) = 1)
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS int) = 1)
+Seq Scan on cast_eliminate2  (cost=0.00..43.90 rows=11 width=4)
+  Filter: ((roid)::integer = 1)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (ROID = cast(1 as bigint))
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (ROID = cast(1 as bigint))
+Index Only Scan using cast_eliminate2_pkey on cast_eliminate2  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = '1'::bigint)
+~~END~~
+
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+GO
+~~START~~
+text
+Query Text: SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+Index Only Scan using cast_eliminate_pkey on cast_eliminate  (cost=0.15..8.17 rows=1 width=4)
+  Index Cond: (roid = '1'::bigint)
+~~END~~
+

test/JDBC/input/cast_eliminate-vu-cleanup.sql

@@ -0,0 +1,5 @@
+drop table cast_eliminate
+GO
+
+drop table cast_eliminate2
+GO

test/JDBC/input/cast_eliminate-vu-prepare.sql

@@ -0,0 +1,6 @@
+CREATE TABLE cast_eliminate( [ROID] [int] NOT NULL PRIMARY KEY );
+GO
+
+CREATE TABLE cast_eliminate2( [ROID] [bigint] NOT NULL PRIMARY KEY );
+GO
+

test/JDBC/input/cast_eliminate-vu-verify.sql

@@ -0,0 +1,26 @@
+set babelfish_showplan_all on
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = 1)
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS int) = 1)
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (ROID = cast(1 as bigint))
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS BIGINT) = 1)
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (CAST(ROID AS int) = 1)
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate2  WHERE (ROID = cast(1 as bigint))
+GO
+
+SELECT 1 AS [C1] FROM cast_eliminate  WHERE (CAST(ROID AS BIGINT) = cast( 1 as bigint ))
+GO

test/JDBC/parallel_query_jdbc_schedule

@@ -54,6 +54,7 @@ ignore#!#BABEL-4261
 ignore#!#babel_collection
 ignore#!#binary-index-vu-verify
 ignore#!#pgr_select_into
+ignore#!#cast_eliminate-vu-verify
 
 # Other or mixed issues
 ignore#!#545_1

test/JDBC/upgrade/13_4/schedule

@@ -216,4 +216,5 @@ timefromparts
 triggers_with_transaction
 BABEL-4046
 getdate
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/13_5/schedule

@@ -269,4 +269,5 @@ timefromparts
 triggers_with_transaction
 BABEL-4046
 getdate
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/13_6/schedule

@@ -325,4 +325,4 @@ BABEL-4046
 getdate
 BABEL-4410
 GRANT_SCHEMA
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10

test/JDBC/upgrade/13_7/schedule

@@ -317,4 +317,5 @@ timefromparts
 triggers_with_transaction
 BABEL-4046
 getdate
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/13_8/schedule

@@ -317,4 +317,5 @@ timefromparts
 triggers_with_transaction
 BABEL-4046
 getdate
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/13_9/schedule

@@ -322,3 +322,4 @@ getdate
 BABEL-4410
 GRANT_SCHEMA
 AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/14_10/schedule

@@ -413,3 +413,4 @@ BABEL-4384
 GRANT_SCHEMA
 default_params
 BABEL-3326
+cast_eliminate

test/JDBC/upgrade/14_3/schedule

@@ -340,3 +340,4 @@ BABEL-2619
 BABEL-4410
 GRANT_SCHEMA
 AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/14_5/schedule

@@ -355,3 +355,4 @@ BABEL-2619
 BABEL-4410
 GRANT_SCHEMA
 AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/14_6/schedule

@@ -388,4 +388,5 @@ BABEL_4330
 BABEL-2619
 BABEL-4410
 GRANT_SCHEMA
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/14_7/schedule

@@ -408,4 +408,5 @@ BABEL-4046
 getdate
 BABEL_4330
 BABEL-2619
-AUTO_ANALYZE-before-15-5-or-14-10
+AUTO_ANALYZE-before-15-5-or-14-10
+cast_eliminate

test/JDBC/upgrade/14_8/schedule

@@ -407,4 +407,5 @@ getdate
 BABEL_4330
 BABEL-2619
 AUTO_ANALYZE-before-15-5-or-14-10
-default_params
+default_params
+cast_eliminate

test/JDBC/upgrade/14_9/schedule

@@ -409,4 +409,5 @@ BABEL_4330
 BABEL-2619
 BABEL-4410
 AUTO_ANALYZE-before-15-5-or-14-10
-default_params
+default_params
+cast_eliminate

test/JDBC/upgrade/15_1/schedule

@@ -386,4 +386,5 @@ BABEL-4046
 getdate
 BABEL_4330
 AUTO_ANALYZE-before-15-5-or-14-10
-default_params
+default_params
+cast_eliminate

test/JDBC/upgrade/15_2/schedule

@@ -418,3 +418,4 @@ BABEL-4410
 GRANT_SCHEMA
 AUTO_ANALYZE-before-15-5-or-14-10
 default_params
+cast_eliminate

test/JDBC/upgrade/15_3/schedule

@@ -438,4 +438,5 @@ BABEL-4046
 getdate
 BABEL_4330
 AUTO_ANALYZE-before-15-5-or-14-10
-default_params
+default_params
+cast_eliminate

test/JDBC/upgrade/15_4/schedule

@@ -451,4 +451,5 @@ BABEL_4330
 BABEL-4410
 GRANT_SCHEMA
 AUTO_ANALYZE-before-15-5-or-14-10
-default_params
+default_params
+cast_eliminate