Post-review fixes for the patch that added the code allowing to use

hash join over equi-join conditions without supporting indexes.

sql/opt_index_cond_pushdown.cc

@@ -26,7 +26,7 @@
     FALSE  No
 */
 
-bool uses_index_fields_only(Item *item, TABLE *tbl, uint keyno, 
+bool uses_index_fields_only(Item *item, TABLE *tbl, uint keyno,
                             bool other_tbls_ok)
 {
   if (item->const_item())
@@ -279,15 +279,12 @@ Item *make_cond_remainder(Item *cond, bool exclude_index)
       tab            A join tab that has tab->table->file and its condition
                      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,
-                     bool factor_out)
+void push_index_cond(JOIN_TAB *tab, uint keyno)
 {
   DBUG_ENTER("push_index_cond");
   Item *idx_cond;
@@ -320,7 +317,7 @@ void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok,
                  print_where(tab->select_cond, "full cond", QT_ORDINARY););
 
     idx_cond= make_cond_for_index(tab->select_cond, tab->table, keyno,
-                                  other_tbls_ok);
+                                  tab->icp_other_tables_ok);
 
     DBUG_EXECUTE("where",
                  print_where(idx_cond, "idx cond", QT_ORDINARY););
@@ -339,10 +336,8 @@ void push_index_cond(JOIN_TAB *tab, uint keyno, bool other_tbls_ok,
           /*
             if cache is used then the value is TRUE only 
             for BKA[_UNIQUE] cache (see check_join_cache_usage func).
-            In this case other_tbls_ok is an equivalent of
-            cache->is_key_access().
           */
-          other_tbls_ok &&
+          tab->icp_other_tables_ok &&
           (idx_cond->used_tables() &
            ~(tab->table->map | tab->join->const_table_map)))
         tab->cache_idx_cond= idx_cond;
@@ -360,8 +355,9 @@ 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= factor_out ?  make_cond_remainder(tab->select_cond, TRUE) :
-	                            tab->pre_idx_push_select_cond;
+      Item *row_cond= tab->idx_cond_fact_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/opt_subselect.cc

@@ -1329,19 +1329,18 @@ bool find_eq_ref_candidate(TABLE *table, table_map sj_inner_tables)
 
   if (keyuse)
   {
-    while (1) /* For each key */
+    do
     {
-      if (keyuse->is_for_hash_join())
-      {
-        keyuse++;
-        if (keyuse->table != table)
-          return FALSE;
-        continue;
-      }
       uint key= keyuse->key;
-      KEY *keyinfo= table->key_info + key;
+      KEY *keyinfo;
       key_part_map bound_parts= 0;
-      if (keyinfo->flags & HA_NOSAME)
+      bool is_excluded_key= keyuse->is_for_hash_join(); 
+      if (!is_excluded_key)
+      {
+        keyinfo= table->key_info + key;
+        is_excluded_key= !test(keyinfo->flags & HA_NOSAME);
+      }
+      if (!is_excluded_key)
       {
         do  /* For all equalities on all key parts */
         {
@@ -1356,20 +1355,15 @@ bool find_eq_ref_candidate(TABLE *table, table_map sj_inner_tables)
 
         if (bound_parts == PREV_BITS(uint, keyinfo->key_parts))
           return TRUE;
-        if (keyuse->table != table)
-          return FALSE;
       }
       else
       {
         do
         {
           keyuse++;
-          if (keyuse->table != table)
-            return FALSE;
-        }
-        while (keyuse->key == key);
+        } while (keyuse->key == key && keyuse->table == table);
       }
-    }
+    } while (keyuse->table == table);
   }
   return FALSE;
 }

sql/sql_select.h

@@ -251,7 +251,15 @@ typedef struct st_join_table {
   */ 
   ha_rows       limit; 
   TABLE_REF	ref;
+  /* TRUE <=> condition pushdown supports other tables presence */
+  bool          icp_other_tables_ok;
+  /* 
+    TRUE <=> condition pushed to the index has to be factored out of
+    the condition pushed to the table
+  */
+  bool          idx_cond_fact_out;
   bool          use_join_cache;
+  uint          used_join_cache_level;
   ulong         join_buffer_size_limit;
   JOIN_CACHE	*cache;
   /*
@@ -1247,8 +1255,7 @@ 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,
-                     bool factor_out);
+void push_index_cond(JOIN_TAB *tab, uint keyno);
 
 /****************************************************************************
   Temporary table support for SQL Runtime