Addressed the feedback from the review of Monty on the cumulative patch for

mwl#21.

1 files changed, 60 insertions, 60 deletions

diff --git a/sql/opt_range.h b/sql/opt_range.h
index d894cfaf91d..32a88dd0193 100644
--- a/sql/opt_range.h
+++ b/sql/opt_range.h
@@ -328,6 +328,7 @@ public:
     selects output and/or can produce output suitable for merging.
   */
   virtual void add_info_string(String *str) {}
+
   /*
     Return 1 if any index used by this quick select
     uses field which is marked in passed bitmap.
@@ -406,9 +407,11 @@ protected:
                                 QUICK_RANGE_SELECT *pk_quick_select,
                                 READ_RECORD *read_record,
                                 bool intersection,
+                                key_map *filtered_scans,
                                 Unique **unique_ptr);
 
   friend class QUICK_SELECT_DESC;
+  friend class QUICK_INDEX_SORT_SELECT;
   friend class QUICK_INDEX_MERGE_SELECT;
   friend class QUICK_INDEX_INTERSECT_SELECT;
   friend class QUICK_ROR_INTERSECT_SELECT;
@@ -464,40 +467,44 @@ public:
 
 
 /*
-  QUICK_INDEX_MERGE_SELECT - index_merge access method quick select.
+  QUICK_INDEX_SORT_SELECT is the base class for the common functionality of:
+  - QUICK_INDEX_MERGE_SELECT, access based on multi-index merge/union 
+  - QUICK_INDEX_INTERSECT_SELECT, access based on  multi-index intersection 
+    
 
-    QUICK_INDEX_MERGE_SELECT uses
+    QUICK_INDEX_SORT_SELECT uses
      * QUICK_RANGE_SELECTs to get rows
-     * Unique class to remove duplicate rows
+     * Unique class
+       - to remove duplicate rows for QUICK_INDEX_MERGE_SELECT
+       - to intersect rows for QUICK_INDEX_INTERSECT_SELECT
 
   INDEX MERGE OPTIMIZER
-    Current implementation doesn't detect all cases where index_merge could
+    Current implementation doesn't detect all cases where index merge could
     be used, in particular:
-     * index_merge will never be used if range scan is possible (even if
-       range scan is more expensive)
 
-     * index_merge+'using index' is not supported (this the consequence of
+     * index merge+'using index' is not supported (this the consequence of
        the above restriction)
 
      * If WHERE part contains complex nested AND and OR conditions, some ways
-       to retrieve rows using index_merge will not be considered. The choice
+       to retrieve rows using index merge will not be considered. The choice
        of read plan may depend on the order of conjuncts/disjuncts in WHERE
        part of the query, see comments near imerge_list_or_list and
        SEL_IMERGE::or_sel_tree_with_checks functions for details.
 
-     * There is no "index_merge_ref" method (but index_merge on non-first
+     * There is no "index_merge_ref" method (but index merge on non-first
        table in join is possible with 'range checked for each record').
 
-    See comments around SEL_IMERGE class and test_quick_select for more
-    details.
 
   ROW RETRIEVAL ALGORITHM
 
-    index_merge uses Unique class for duplicates removal.  index_merge takes
-    advantage of Clustered Primary Key (CPK) if the table has one.
-    The index_merge algorithm consists of two phases:
+    index merge/intersection uses Unique class for duplicates removal. 
+    index merge/intersection takes advantage of Clustered Primary Key (CPK)
+    if the table has one.
+    The index merge/intersection algorithm consists of two phases:
+
+    Phase 1 
+    (implemented by a QUICK_INDEX_MERGE_SELECT::read_keys_and_merge call):
 
-    Phase 1 (implemented in QUICK_INDEX_MERGE_SELECT::prepare_unique):
     prepare()
     {
       activate 'index only';
@@ -511,32 +518,31 @@ public:
       deactivate 'index only';
     }
 
-    Phase 2 (implemented as sequence of QUICK_INDEX_MERGE_SELECT::get_next
-    calls):
+    Phase 2 
+    (implemented as sequence of QUICK_INDEX_MERGE_SELECT::get_next calls):
 
     fetch()
     {
-      retrieve all rows from row pointers stored in Unique;
+      retrieve all rows from row pointers stored in Unique
+      (merging/intersecting them);
       free Unique;
-      retrieve all rows for CPK scan;
+      if (! intersection) 
+        retrieve all rows for CPK scan;
     }
 */
 
-class QUICK_INDEX_MERGE_SELECT : public QUICK_SELECT_I
+class QUICK_INDEX_SORT_SELECT : public QUICK_SELECT_I
 {
+protected:
   Unique *unique;
 public:
-  QUICK_INDEX_MERGE_SELECT(THD *thd, TABLE *table);
-  ~QUICK_INDEX_MERGE_SELECT();
+  QUICK_INDEX_SORT_SELECT(THD *thd, TABLE *table);
+  ~QUICK_INDEX_SORT_SELECT();
 
   int  init();
   int  reset(void);
-  int  get_next();
   bool reverse_sorted() { return false; }
   bool unique_key_range() { return false; }
-  int get_type() { return QS_TYPE_INDEX_MERGE; }
-  void add_keys_and_lengths(String *key_names, String *used_lengths);
-  void add_info_string(String *str);
   bool is_keys_used(const MY_BITMAP *fields);
 #ifndef DBUG_OFF
   void dbug_dump(int indent, bool verbose);
@@ -544,60 +550,54 @@ public:
 
   bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
 
-  /* range quick selects this index_merge read consists of */
+  /* range quick selects this index merge/intersect consists of */
   List<QUICK_RANGE_SELECT> quick_selects;
 
   /* quick select that uses clustered primary key (NULL if none) */
   QUICK_RANGE_SELECT* pk_quick_select;
 
-  /* true if this select is currently doing a clustered PK scan */
-  bool  doing_pk_scan;
-
   MEM_ROOT alloc;
   THD *thd;
-  int read_keys_and_merge();
+  virtual int read_keys_and_merge()= 0;
 
   /* used to get rows collected in Unique */
   READ_RECORD read_record;
 };
 
-class QUICK_INDEX_INTERSECT_SELECT : public QUICK_SELECT_I
+
+
+class QUICK_INDEX_MERGE_SELECT : public QUICK_INDEX_SORT_SELECT
 {
-  Unique *unique;
+private:
+  /* true if this select is currently doing a clustered PK scan */
+  bool  doing_pk_scan;
+protected:
+  int read_keys_and_merge();
+
 public:
-  QUICK_INDEX_INTERSECT_SELECT(THD *thd, TABLE *table);
-  ~QUICK_INDEX_INTERSECT_SELECT();
+  QUICK_INDEX_MERGE_SELECT(THD *thd, TABLE *table)
+    :QUICK_INDEX_SORT_SELECT(thd, table) {}
 
-  int  init();
-  int  reset(void);
-  int  get_next();
-  bool reverse_sorted() { return false; }
-  bool unique_key_range() { return false; }
-  int get_type() { return QS_TYPE_INDEX_INTERSECT; }
+  int get_next();
+  int get_type() { return QS_TYPE_INDEX_MERGE; }
   void add_keys_and_lengths(String *key_names, String *used_lengths);
   void add_info_string(String *str);
-  bool is_keys_used(const MY_BITMAP *fields);
-#ifndef DBUG_OFF
-  void dbug_dump(int indent, bool verbose);
-#endif
-
-  bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
-
-  /* range quick selects this index_merge read consists of */
-  List<QUICK_RANGE_SELECT> quick_selects;
-
-  /* quick select that uses clustered primary key (NULL if none) */
-  QUICK_RANGE_SELECT* pk_quick_select;
-
-  /* true if this select is currently doing a clustered PK scan */
-  bool  doing_pk_scan;
+};
 
-  MEM_ROOT alloc;
-  THD *thd;
+class QUICK_INDEX_INTERSECT_SELECT : public QUICK_INDEX_SORT_SELECT
+{
+protected:
   int read_keys_and_merge();
 
-  /* used to get rows collected in Unique */
-  READ_RECORD read_record;
+public:
+  QUICK_INDEX_INTERSECT_SELECT(THD *thd, TABLE *table)
+    :QUICK_INDEX_SORT_SELECT(thd, table) {}
+
+  key_map filtered_scans;
+  int get_next();
+  int get_type() { return QS_TYPE_INDEX_INTERSECT; }
+  void add_keys_and_lengths(String *key_names, String *used_lengths);
+  void add_info_string(String *str);
 };