Fixed bug #54539.

Added a possibility not to factor out the condition pushed to
the access index out of the condition pushed to a joined table.
This is useful for the condition pushed to the index when a hashed
join buffer for BKA is employed. In this case the index condition
may be false for some, but for all records with the same key.
So the condition must be checked not only after index lookup,
but after fetching row data as well, and it makes sense not to 
factor out the condition from the condition checked after reading
row data,
The bug happened because the condition pushed to an index always
was factor out from the condition pushed to the accessed table. 

******
Fixed bug #54539.
Added a possibility not to factor out the condition pushed to
the access index out of the condition pushed to a joined table.
This is useful for the condition pushed to the index when a hashed
join buffer for BKA is employed. In this case the index condition
may be false for some, but for all records with the same key.
So the condition must be checked not only after index lookup,
but after fetching row data as well, and it makes sense not to 
factor out the condition from the condition checked after reading
row data,
The bug happened because the condition pushed to an index always
was factor out from the condition pushed to the accessed table. 

mysql-test/r/join_cache.result

@@ -4823,7 +4823,7 @@ explain select t2.f1, t2.f2, t2.f3 from t1,t2
 where t1.f1=t2.f1 and t2.f2 between t1.f1 and t2.f2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	3	Using index condition(BKA); Using join buffer
+1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	3	Using index condition(BKA); Using where; Using join buffer
 set join_cache_level=8;
 select t2.f1, t2.f2, t2.f3 from t1,t2
 where t1.f1=t2.f1 and t2.f2 between t1.f1 and t1.f2 and t2.f2 + 1 >= t1.f1 + 1;
@@ -4836,7 +4836,7 @@ explain select t2.f1, t2.f2, t2.f3 from t1,t2
 where t1.f1=t2.f1 and t2.f2 between t1.f1 and t2.f2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	3	Using index condition(BKA); Using join buffer
+1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	3	Using index condition(BKA); Using where; Using join buffer
 drop table t1,t2;
 set join_cache_level=default;
 #
@@ -5303,4 +5303,31 @@ NULL
 NULL
 set join_cache_level = default;
 DROP TABLE t1,t2;
+#
+# BUG#54359 "Extra rows with join_cache_level=7,8 and two joins
+# --and multi-column index"
+#
+CREATE TABLE t1 (
+pk int NOT NULL,
+a int DEFAULT NULL,
+b varchar(16) DEFAULT NULL,
+c varchar(16) DEFAULT NULL,
+INDEX idx (b,a))
+;
+INSERT INTO t1 VALUES (4,9,'k','k');
+INSERT INTO t1 VALUES (12,5,'k','k');
+set join_cache_level = 8;
+EXPLAIN
+SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
+WHERE s.pk AND s.a  >= t.pk AND  s.b  = t.c;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	s	ref	idx	idx	19	test.t.c	1	Using index condition(BKA); Using where; Using join buffer
+SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
+WHERE s.pk AND s.a  >= t.pk AND  s.b  = t.c;
+a
+9
+9
+set join_cache_level = default;
+DROP TABLE t1;
 set @@optimizer_switch=@save_optimizer_switch;

mysql-test/t/join_cache.test

@@ -2076,5 +2076,33 @@ SELECT t2.a FROM t1 LEFT JOIN t2 ON t2.b  = t1.b;
 set join_cache_level = default;
 DROP TABLE t1,t2;
 
+--echo #
+--echo # BUG#54359 "Extra rows with join_cache_level=7,8 and two joins
+--echo # --and multi-column index"
+--echo #
+
+CREATE TABLE t1 (
+  pk int NOT NULL,
+  a int DEFAULT NULL,
+  b varchar(16) DEFAULT NULL,
+  c varchar(16) DEFAULT NULL,
+  INDEX idx (b,a))
+;
+
+INSERT INTO t1 VALUES (4,9,'k','k');
+INSERT INTO t1 VALUES (12,5,'k','k');
+
+set join_cache_level = 8;
+
+EXPLAIN
+SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
+  WHERE s.pk AND s.a  >= t.pk AND  s.b  = t.c;
+
+SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
+  WHERE s.pk AND s.a  >= t.pk AND  s.b  = t.c;
+
+set join_cache_level = default;
+DROP TABLE t1;
+
 # this must be the last command in the file
 set @@optimizer_switch=@save_optimizer_switch;

sql/opt_index_cond_pushdown.cc

@@ -272,12 +272,14 @@ Item *make_cond_remainder(Item *cond, bool exclude_index)
                      in tab->select_cond
       keyno          Index for which extract and push the condition
       other_tbls_ok  TRUE <=> Fields of other non-const tables are allowed
+      factor_out     TRUE <=> Factor out the extracted condition
 
   DESCRIPTION
     Try to extract and push the index condition down to table handler
 */
 
-void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok)
+void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok,
+                     bool factor_out)
 {
   DBUG_ENTER("push_index_cond");
   Item *idx_cond;
@@ -350,7 +352,8 @@ void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok)
       if (idx_remainder_cond != idx_cond)
         tab->ref.disable_cache= TRUE;
 
-      Item *row_cond= make_cond_remainder(tab->select_cond, TRUE);
+      Item *row_cond= factor_out ?  make_cond_remainder(tab->select_cond, TRUE) :
+	                            tab->pre_idx_push_select_cond;
 
       DBUG_EXECUTE("where",
                    print_where(row_cond, "remainder cond", QT_ORDINARY););

sql/sql_select.cc

@@ -7422,6 +7422,8 @@ end_sj_materialize(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
       no_jbuf_after       don't use join buffering after table with this number
       icp_other_tables_ok OUT TRUE if condition pushdown supports
                           other tables presence
+      idx_cond_fact_out   OUT TRUE if condition pushed to the index is factored
+                          out of the condition pushed to the table
 
   DESCRIPTION
     The function finds out whether the table 'tab' can be joined using a join
@@ -7545,7 +7547,8 @@ static
 uint check_join_cache_usage(JOIN_TAB *tab,
                             JOIN *join, ulonglong options,
                             uint no_jbuf_after,
-                            bool *icp_other_tables_ok)
+                            bool *icp_other_tables_ok,
+                            bool *idx_cond_fact_out)
 {
   uint flags;
   COST_VECT cost;
@@ -7562,6 +7565,7 @@ uint check_join_cache_usage(JOIN_TAB *tab,
   uint i= tab - join->join_tab;
 
   *icp_other_tables_ok= TRUE;
+  *idx_cond_fact_out= TRUE;
   if (cache_level == 0 || i == join->const_tables)
     return 0;
 
@@ -7665,7 +7669,10 @@ uint check_join_cache_usage(JOIN_TAB *tab,
       if ((options & SELECT_DESCRIBE) ||
 	  ((tab->cache= new JOIN_CACHE_BNLH(join, tab, prev_cache)) &&
            !tab->cache->init()))
+      {
+        *icp_other_tables_ok= FALSE;        
         return (4-test(!prev_cache));
+      }
       goto no_join_cache;
     }
     if (cache_level > 4 && no_bka_cache)
@@ -7694,7 +7701,10 @@ uint check_join_cache_usage(JOIN_TAB *tab,
         if ((options & SELECT_DESCRIBE) ||
             ((tab->cache= new JOIN_CACHE_BKAH(join, tab, flags, prev_cache)) &&
             !tab->cache->init()))
+	{
+          *idx_cond_fact_out= FALSE;
           return (8-test(!prev_cache));
+        }
         goto no_join_cache;
       }
     }
@@ -7754,6 +7764,7 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
     JOIN_TAB *tab=join->join_tab+i;
     TABLE *table=tab->table;
     bool icp_other_tables_ok;
+    bool idx_cond_fact_out;
     tab->read_record.table= table;
     tab->read_record.file=table->file;
     tab->read_record.unlock_row= rr_unlock_row;
@@ -7800,7 +7811,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
       tab->read_first_record= tab->type == JT_SYSTEM ?
                                 join_read_system :join_read_const;
       if ((jcl= check_join_cache_usage(tab, join, options,
-                                       no_jbuf_after, &icp_other_tables_ok)))
+                                       no_jbuf_after, &icp_other_tables_ok,
+                                       &idx_cond_fact_out)))
       {
         tab->use_join_cache= TRUE;
         tab[-1].next_select=sub_select_cache;
@@ -7812,13 +7824,15 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
         table->file->extra(HA_EXTRA_KEYREAD);
       }
       else if (!jcl || jcl > 4)
-        push_index_cond(tab, tab->ref.key, icp_other_tables_ok);
+        push_index_cond(tab, tab->ref.key, 
+                       icp_other_tables_ok, idx_cond_fact_out);
         break;
     case JT_EQ_REF:
       tab->read_record.unlock_row= join_read_key_unlock_row;
       /* fall through */
       if ((jcl= check_join_cache_usage(tab, join, options,
-                                       no_jbuf_after, &icp_other_tables_ok)))
+                                       no_jbuf_after, &icp_other_tables_ok,
+                                       &idx_cond_fact_out)))
       {
         tab->use_join_cache= TRUE;
         tab[-1].next_select=sub_select_cache;
@@ -7830,7 +7844,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
 	table->file->extra(HA_EXTRA_KEYREAD);
       }
       else if (!jcl || jcl > 4) 
-        push_index_cond(tab, tab->ref.key, icp_other_tables_ok );
+        push_index_cond(tab, tab->ref.key,
+                        icp_other_tables_ok, idx_cond_fact_out);
       break;
     case JT_REF_OR_NULL:
     case JT_REF:
@@ -7842,7 +7857,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
       delete tab->quick;
       tab->quick=0;
       if ((jcl= check_join_cache_usage(tab, join, options,
-                                       no_jbuf_after, &icp_other_tables_ok)))
+                                       no_jbuf_after, &icp_other_tables_ok,
+                                       &idx_cond_fact_out)))
       {
         tab->use_join_cache= TRUE;
         tab[-1].next_select=sub_select_cache;
@@ -7851,7 +7867,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
 	  !table->no_keyread)
         table->enable_keyread();
       else if (!jcl || jcl > 4)
-        push_index_cond(tab, tab->ref.key, icp_other_tables_ok);
+        push_index_cond(tab, tab->ref.key, 
+                        icp_other_tables_ok, idx_cond_fact_out);
       break;
     case JT_ALL:
       /*
@@ -7861,7 +7878,7 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
           materialization nest.
       */
       if (check_join_cache_usage(tab, join, options, no_jbuf_after,
-                                 &icp_other_tables_ok))
+                                 &icp_other_tables_ok, &idx_cond_fact_out))
       {
         tab->use_join_cache= TRUE;
         tab[-1].next_select=sub_select_cache;
@@ -7938,7 +7955,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
 	}
         if (tab->select && tab->select->quick &&
             tab->select->quick->index != MAX_KEY && ! tab->table->key_read)
-          push_index_cond(tab, tab->select->quick->index, icp_other_tables_ok);
+          push_index_cond(tab, tab->select->quick->index, 
+                          icp_other_tables_ok, idx_cond_fact_out);
       }
       break;
     case JT_FT:

sql/sql_select.h

@@ -2449,7 +2449,8 @@ inline bool optimizer_flag(THD *thd, uint flag)
 void eliminate_tables(JOIN *join);
 
 /* Index Condition Pushdown entry point function */
-void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok);
+void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok,
+                     bool factor_out);
 
 /****************************************************************************
   Temporary table support for SQL Runtime