DS-MRR, key-ordered retrievals: commit for buildbot

sql/multi_range_read.h

@@ -37,6 +37,96 @@
 */
 
 
+/*
+  A simple memory buffer for reading and writing.
+
+  when writing, there is no user-visible "current" position, although
+  internally 'pos' points to just after the end of used area  (or at the 
+  start of it for reverse buffer).
+
+  When reading, there is current position pointing at start (for reverse
+  buffer, end) of the element that will be read next.
+   ^^ why end for reverse? it's more logical to point at start 
+
+  One can peek at what's behind that element by using advance_ptr function.
+
+  TODO: will the reverse buffer store {tuple; rowid} or {rowid; tuple} pairs?
+    (why does it matter??? Read and write in the same order and then it
+    shouldn't matter.)
+*/
+
+class SimpleBuffer
+{
+  uchar *start;
+  uchar *end;
+  uchar *read_pos;
+  uchar *write_pos;
+  
+  /*
+     1 <=> buffer grows/is filled/is read  from start to end
+    -1 <=> everthing is done from end to start instead.
+  */
+  int direction;
+public:
+  /* Write-mode functions */
+  void reset_for_writing();
+  void write(const uchar *data, size_t bytes);
+  bool have_space_for(size_t bytes);
+
+  uchar *used_area() { return (direction == 1)? read_pos : write_pos; }
+  size_t used_size();
+
+  /* Read-mode functions */
+  void reset_for_reading();
+
+  uchar *read(size_t bytes);
+  bool have_data(size_t bytes);
+  uchar *end_of_space();
+
+  /* Control functions */
+  void set_buffer_space(uchar *start_arg, uchar *end_arg, int direction_arg) 
+  {
+    start= start_arg;
+    end= end_arg;
+    direction= direction_arg;
+    reset_for_writing();
+  }
+
+  friend class PeekIterator;
+  class PeekIterator
+  {
+    // if direction==1 : pointer to what to return next
+    // if direction==-1: pointer to the end of what is to be returned next
+    uchar *pos;
+    SimpleBuffer *sb;
+  public:
+    void init(SimpleBuffer *sb_arg)
+    {
+      sb= sb_arg;
+      pos= sb->read_pos;
+    }
+    /* Return pointer to next chunk of nbytes bytes and avance over it */
+    uchar *get_next(size_t nbytes)
+    {
+      if (sb->direction == 1)
+      {
+        if (pos + nbytes > sb->write_pos)
+          return NULL;
+        uchar *res= pos;
+        pos += nbytes;
+        return res;
+      }
+      else
+      {
+        if (pos - nbytes <= sb->write_pos)
+          return NULL;
+        pos -= nbytes;
+        return pos;
+      }
+    }
+  };
+};
+
 /*
   DS-MRR implementation for one table. Create/use one object of this class for
   each ha_{myisam/innobase/etc} object. That object will be further referred to
@@ -73,6 +163,8 @@
        scanning.
 */
 
+
+
 class DsMrr_impl
 {
 public:
@@ -108,14 +200,27 @@ private:
   /* Secondary handler object.  It is used for scanning the index */
   handler *h2;
 
+  uchar *full_buf;
+  uchar *full_buf_end;
+
   /* Buffer to store rowids, or (rowid, range_id) pairs */
-  uchar *mrr_buf;
-  uchar *mrr_buf_cur;   /* Current position when reading/writing */
-  uchar *mrr_buf_last;  /* When reading: end of used buffer space */
-  uchar *mrr_buf_end;   /* End of the buffer */
+  SimpleBuffer rowid_buffer;
+  
+  uchar *identical_rowid_ptr;
+  
+  /* Identical keys */
+  bool in_identical_keys_range;
+  uchar *last_identical_key_ptr;
+  SimpleBuffer::PeekIterator identical_key_it;
 
-  uchar *mrr_buf_next_identical;
+  SimpleBuffer key_buffer;
+  
+  uint keyno;
+
+  /* Execution control */
+  bool do_sort_keys;
   bool use_key_pointers;
+  bool do_rowid_fetch;
 
   bool dsmrr_eof; /* TRUE <=> We have reached EOF when reading index tuples */
 
@@ -129,18 +234,33 @@ private:
   /** DS-MRR/CPK variables start */
 
   /* Length of lookup tuple being used, in bytes */
-  uint cpk_tuple_length;
+  uint key_tuple_length;
+  key_part_map key_tuple_map; 
+  /*
+    This is 
+      = key_tuple_length   if we copy keys to buffer
+      = sizeof(void*)      if we're using pointers to materialized keys.
+  */
+  uint key_size_in_keybuf;
+  
+  /* = key_size_in_keybuf [ + sizeof(range_assoc_info) ] */
+  uint key_buff_elem_size;
+  
+  /* = h->ref_length  [ + sizeof(range_assoc_info) ] */
+  uint rowid_buff_elem_size;
 
-  uint key_buf_element_size;
   /*
     TRUE <=> We're scanning on a full primary key (and not on prefix), and so 
     can get max. one match for each key 
   */
-  bool cpk_is_unique_scan;
+  bool index_ranges_unique;
   /* TRUE<=> we're in a middle of enumerating records from a range */ 
-  bool cpk_have_range;
-  /* Valid if cpk_have_range==TRUE: range_id of the range we're enumerating */
-  char *cpk_saved_range_info;
+  bool in_index_range;
+  uchar *cur_index_tuple;
+  /* if in_index_range==TRUE: range_id of the range we're enumerating */
+  char *cur_range_info;
+
+  char *first_identical_range_info;
 
   bool choose_mrr_impl(uint keyno, ha_rows rows, uint *flags, uint *bufsz, 
                        COST_VECT *cost);
@@ -150,6 +270,11 @@ private:
   static int key_tuple_cmp(void* arg, uchar* key1, uchar* key2);
   int dsmrr_fill_rowid_buffer();
   void dsmrr_fill_key_buffer();
-  int dsmrr_next_cpk(char **range_info);
+  int dsmrr_next_from_index(char **range_info);
+
+  void setup_buffer_sizes(key_range *sample_key);
+
+  static range_seq_t key_buf_seq_init(void *init_param, uint n_ranges, uint flags);
+  static uint key_buf_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range);
 };