WL#2126 - Multi_read_range.

Added the required structures and functions for
handing over multiple key ranges to the table handler.


include/my_base.h:
  WL#2126 - Multi_read_range.
  Moved key range flags from sql/opt_range.h to here.
  Added the multi-range structure.
sql/handler.cc:
  WL#2126 - Multi_read_range.
  Added the new table handler methods.
sql/handler.h:
  WL#2126 - Multi_read_range.
  Added a new table flag.
  Added a declaration for the handler buffer.
  Added new elements to class handler.
  Added new function declarations.
sql/mysqld.cc:
  WL#2126 - Multi_read_range.
  Added an option to set new system variable 'multi_range_count'.
sql/opt_range.cc:
  WL#2126 - Multi_read_range.
  Added initialization for the new class members.
  Added initialization for the extended get_next().
  Added de-initialization for the allocated buffers.
  Added a buffer allocation method.
  Added an inner loop to collect multiple ranges.
  Adapted range collection loops to the new initialization.
sql/opt_range.h:
  WL#2126 - Multi_read_range.
  Moved key range flags from here to include/my_base.h.
  Added new elements to class QUICK_RANGE_SELECT.
  Added a copy constructor.
sql/records.cc:
  WL#2126 - Multi_read_range.
  Added a call of the allocation method.
sql/set_var.cc:
  WL#2126 - Multi_read_range.
  Added the new system variable 'multi_range_count'.
sql/sql_class.h:
  WL#2126 - Multi_read_range.
  Added the new system variable 'multi_range_count'.

1 files changed, 26 insertions, 0 deletions

diff --git a/sql/handler.h b/sql/handler.h
index f0faeff9234..62638ee456b 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -76,6 +76,7 @@
 #define HA_FILE_BASED	       (1 << 26)
 #define HA_NO_VARCHAR	       (1 << 27)
 #define HA_CAN_BIT_FIELD       (1 << 28) /* supports bit fields */
+#define HA_NEED_READ_RANGE_BUFFER (1 << 29) /* for read_multi_range */
 
 
 /* bits in index_flags(index_number) for what you can do with index */
@@ -276,6 +277,21 @@ typedef struct st_ha_check_opt
 } HA_CHECK_OPT;
 
 
+/*
+  This is a buffer area that the handler can use to store rows.
+  'end_of_used_area' should be kept updated after calls to
+  read-functions so that other parts of the code can use the
+  remaining area (until next read calls is issued).
+*/
+
+typedef struct st_handler_buffer
+{
+  const byte *buffer;         /* Buffer one can start using */
+  const byte *buffer_end;     /* End of buffer */
+  byte *end_of_used_area;     /* End of area that was used by handler */
+} HANDLER_BUFFER;
+
+
 class handler :public Sql_alloc
 {
  protected:
@@ -310,6 +326,12 @@ public:
   time_t check_time;
   time_t update_time;
 
+  /* The following are for read_multi_range */
+  bool multi_range_sorted;
+  KEY_MULTI_RANGE *multi_range_curr;
+  KEY_MULTI_RANGE *multi_range_end;
+  HANDLER_BUFFER *multi_range_buffer;
+
   /* The following are for read_range() */
   key_range save_end_range, *end_range;
   KEY_PART_INFO *range_key_part;
@@ -421,6 +443,10 @@ public:
   virtual int index_next_same(byte *buf, const byte *key, uint keylen);
   virtual int index_read_last(byte * buf, const byte * key, uint key_len)
    { return (my_errno=HA_ERR_WRONG_COMMAND); }
+  virtual int read_multi_range_first(KEY_MULTI_RANGE **found_range_p,
+                                     KEY_MULTI_RANGE *ranges, uint range_count,
+                                     bool sorted, HANDLER_BUFFER *buffer);
+  virtual int read_multi_range_next(KEY_MULTI_RANGE **found_range_p);
   virtual int read_range_first(const key_range *start_key,
                                const key_range *end_key,
                                bool eq_range, bool sorted);