MDEV-30256 Wrong result (missing rows) upon join with empty table

The problem was an assignment in test_quick_select() that flagged empty
tables with "Impossible where". This test was however wrong as it
didn't work correctly for left join.

Removed the test, but added checking of empty tables in DELETE and UPDATE
to get similar EXPLAIN as before.

The new tests is a bit more strict (better) than before as it catches all
cases of empty tables in single table DELETE/UPDATE.

mysql-test/main/analyze_stmt.result

@@ -258,7 +258,7 @@ drop table t1;
 create table t1 (i int);
 analyze delete from t1 returning *;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	0	0.00	100.00	100.00	
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 drop table t1;
 #
 # MDEV-6396: ANALYZE INSERT/REPLACE is accepted, but does not produce a plan

mysql-test/main/derived_cond_pushdown.result

@@ -21096,7 +21096,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 Warnings:
-Note	1003	/* select#1 */ select NULL AS `f`,NULL AS `f` from `test`.`t1` `a` straight_join `test`.`t1` `b` join `test`.`v2` where 0
+Note	1003	/* select#1 */ select NULL AS `f`,`v2`.`f` AS `f` from `test`.`t1` `a` straight_join `test`.`t1` `b` join `test`.`v2` where 0
 DROP VIEW v1,v2;
 DROP TABLE t1;
 #

mysql-test/main/explain_non_select.result

@@ -145,7 +145,7 @@ DROP TABLE t1;
 create table t1 (i int);
 explain partitions update t1 set i = 3;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	0	
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 create table t2 (a int, b int) partition by hash(a) partitions 5;
 insert into t2 values (0,0),(1,1),(2,2),(3,3),(4,4);
 explain partitions update t2 set b=3 where a in (3,4);

mysql-test/main/filesort_debug.result

@@ -63,6 +63,7 @@ c27 TEXT,
 c28 TEXT,
 primary key (pk)
 );
+insert into t1 (pk) values (1),(2),(3);
 CALL mtr.add_suppression("Out of sort memory");
 DELETE IGNORE FROM t1 ORDER BY c26,c7,c23,c4,c25,c5,c20,
 c19,c21,c8,c1,c27,c28,c3,c9,c22,c24,c6,c2,pk LIMIT 2;

mysql-test/main/filesort_debug.test

@@ -86,6 +86,8 @@ CREATE TABLE t1 (
   primary key (pk)
 );
 
+insert into t1 (pk) values (1),(2),(3);
+
 CALL mtr.add_suppression("Out of sort memory");
 
 --error ER_OUT_OF_SORTMEMORY

mysql-test/main/join.result

@@ -3435,4 +3435,24 @@ SELECT COUNT(*) FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.
 COUNT(*)
 2
 DROP TABLE t1, t2, t3;
-# End of 10.5 tests
+#
+# MDEV-30256 Wrong result (missing rows) upon join with empty table
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+CREATE TABLE t3 (c INT PRIMARY KEY);
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON (t2.b >= t3.c) ON (t1.a < t2.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	0	Using index; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (incremental, BNL join)
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON (t2.b >= t3.c) ON (t1.a < t2.b);
+a	b	c
+1	NULL	NULL
+2	NULL	NULL
+DROP TABLE t1,t2,t3;
+#
+# End of 11.0 tests
+#

mysql-test/main/join.test

@@ -1838,4 +1838,19 @@ SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
 SELECT COUNT(*) FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
 DROP TABLE t1, t2, t3;
 
---echo # End of 10.5 tests
+--echo #
+--echo # MDEV-30256 Wrong result (missing rows) upon join with empty table
+--echo #
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+CREATE TABLE t3 (c INT PRIMARY KEY);
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON (t2.b >= t3.c) ON (t1.a < t2.b);
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON (t2.b >= t3.c) ON (t1.a < t2.b);
+DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # End of 11.0 tests
+--echo #

mysql-test/main/myisam_explain_non_select_all.result

@@ -2978,8 +2978,7 @@ JOIN t1 AS a12 ON a12.c1 = a11.c1
 ) d1
 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	0	100.00	
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 DROP TABLE t1, t2, t3;
 #73
 CREATE TABLE t1 (id INT);
@@ -3106,7 +3105,7 @@ CALL p10();
 DROP PROCEDURE p10;
 CALL p9();
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	0	
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 DROP PROCEDURE p9;
 CALL p8();
 DROP PROCEDURE p8;

mysql-test/main/ps.result

@@ -5552,13 +5552,11 @@ CREATE TABLE t2 (c2 INT) ENGINE=MyISAM;
 CREATE TABLE t3 (c3 INT) ENGINE=MyISAM;
 EXPLAIN EXTENDED UPDATE t3 SET c3 = ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11 STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12 ON a12.c1 = a11.c1 ) d1 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	0	100.00	
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 PREPARE stmt FROM "EXPLAIN EXTENDED UPDATE t3 SET c3 = ( SELECT COUNT(d1.c1) FROM ( SELECT a11.c1 FROM t1 AS a11 STRAIGHT_JOIN t2 AS a21 ON a21.c2 = a11.c1 JOIN t1 AS a12 ON a12.c1 = a11.c1 ) d1 )";
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	0	100.00	
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 DEALLOCATE PREPARE stmt;
 DROP TABLE t1, t2, t3;
 #

mysql-test/suite/binlog/r/binlog_unsafe.result

@@ -2338,11 +2338,7 @@ Warnings:
 Note	1592	Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement is unsafe because it uses a LIMIT clause. This is unsafe because the set of rows included cannot be predicted
 Note	1592	Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. REPLACE... SELECT is unsafe because the order in which rows are retrieved by the SELECT determines which (if any) rows are replaced. This order cannot be predicted and may differ on master and the slave
 UPDATE t1 SET a=1 LIMIT 1;
-Warnings:
-Note	1592	Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement is unsafe because it uses a LIMIT clause. This is unsafe because the set of rows included cannot be predicted
 DELETE FROM t1 LIMIT 1;
-Warnings:
-Note	1592	Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement is unsafe because it uses a LIMIT clause. This is unsafe because the set of rows included cannot be predicted
 CREATE PROCEDURE p1()
 BEGIN
 INSERT INTO t1 SELECT * FROM t1 LIMIT 1;

sql/opt_range.cc

@@ -2716,8 +2716,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
   SEL_ARG **backup_keys= 0;
   ha_rows table_records= head->stat_records();
   handler *file= head->file;
-  /* We trust that if stat_records() is 0 the table is really empty! */
-  bool impossible_range= table_records == 0;
+  bool impossible_range= 0;
   DBUG_ENTER("SQL_SELECT::test_quick_select");
   DBUG_PRINT("enter",("keys_to_use: %lu  prev_tables: %lu  const_tables: %lu",
 		      (ulong) keys_to_use.to_ulonglong(), (ulong) prev_tables,

sql/sql_delete.cc

@@ -526,7 +526,9 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   select=make_select(table, 0, 0, conds, (SORT_INFO*) 0, 0, &error);
   if (unlikely(error))
     DBUG_RETURN(TRUE);
-  if ((select && select->check_quick(thd, safe_update, limit)) || !limit)
+  if (unlikely((select && select->check_quick(thd, safe_update, limit)) ||
+               table->stat_records() == 0 ||
+               !limit))
   {
     query_plan.set_impossible_where();
     if (thd->lex->describe || thd->lex->analyze_stmt)

sql/sql_update.cc

@@ -581,8 +581,10 @@ int mysql_update(THD *thd,
   set_statistics_for_table(thd, table);
 
   select= make_select(table, 0, 0, conds, (SORT_INFO*) 0, 0, &error);
-  if (unlikely(error || !limit || thd->is_error() ||
-               (select && select->check_quick(thd, safe_update, limit))))
+  if (unlikely(error || thd->is_error() || !limit ||
+               (select && select->check_quick(thd, safe_update, limit)) ||
+               table->stat_records() == 0))
+
   {
     query_plan.set_impossible_where();
     if (thd->lex->describe || thd->lex->analyze_stmt)

storage/spider/mysql-test/spider/bg/r/spider_fixes.result

@@ -481,7 +481,6 @@ DELETE FROM t1;
 Warnings:
 Error	12702	Remote table 'auto_test_remote.ter1_1' is not found
 Error	12702	Remote table 'auto_test_remote.ter1_1' is not found
-Error	1146	Table 'auto_test_remote.ter1_1' doesn't exist
 TRUNCATE t1;
 Warnings:
 Error	1146	Table 'auto_test_remote.ter1_1' doesn't exist

storage/spider/mysql-test/spider/r/spider_fixes.result

@@ -481,7 +481,6 @@ DELETE FROM t1;
 Warnings:
 Error	12702	Remote table 'auto_test_remote.ter1_1' is not found
 Error	12702	Remote table 'auto_test_remote.ter1_1' is not found
-Error	1146	Table 'auto_test_remote.ter1_1' doesn't exist
 TRUNCATE t1;
 Warnings:
 Error	1146	Table 'auto_test_remote.ter1_1' doesn't exist