Commit ef27ec42 authored by sasha@mysql.sashanet.com's avatar sasha@mysql.sashanet.com
Browse files

option to free_root() to not my_free() the blocks 

fixed bug/updated count_distinct2 test
changed reset in count distinct to avoid calls to my_free()
parent b2977103

include/my_sys.h

+5 −1
Original line number Diff line number Diff line
@@ -108,6 +108,10 @@ extern int NEAR my_errno; /* Last error in mysys */ 


	/* root_alloc flags */

#define MY_KEEP_PREALLOC	1

#define MY_MARK_BLOCKS_FREE     2 /* do not my_free() blocks,

				     just move used into free list

				     and mark all blocks as fully free

				  */

  

	/* defines when allocating data */

include/my_tree.h

+3 −0
Original line number Diff line number Diff line
@@ -62,6 +62,9 @@ void init_tree(TREE *tree,uint default_alloc_size, int element_size, 
	       qsort_cmp2 compare, my_bool with_delete,

	       void (*free_element)(void*));

void delete_tree(TREE*);

void reset_tree(TREE*);

  /* similar to delete tree, except we do not my_free() blocks in mem_root

   */

#define is_tree_inited(tree) ((tree)->root != 0)



	/* Functions on leafs */

mysql-test/r/count_distinct2.result

+4 −0
Original line number Diff line number Diff line
@@ -70,3 +70,7 @@ count(distinct s,t) 
5

count(distinct n1)	count(distinct n2)

2	3

count(distinct n2)	n1

1	NULL

1	1

3	2

mysql-test/t/count_distinct2.test

+3 −0
Original line number Diff line number Diff line
@@ -40,3 +40,6 @@ select distinct s,t from t1; 
select count(distinct s,t) from t1;



select count(distinct n1), count(distinct n2) from t1;



select count(distinct n2), n1 from t1 group by n1;

drop table t1;

mysys/my_alloc.c

+40 −1
Original line number Diff line number Diff line
@@ -100,7 +100,41 @@ gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size) 
#endif

}



	/* deallocate everything used by alloc_root */

static inline void mark_blocks_free(MEM_ROOT* root)

{

  reg1 USED_MEM *next,*last = 0;



  /* iterate through (partially) free blocks, mark them fully free */

  for(next = root->free; next; next = next->next )

    {

      last = next;

      next->left = next->size - ALIGN_SIZE(sizeof(USED_MEM));

    }

  /* if free block list was not empty, point the next of the

     last free block to the beginning of the used list  */

  next = root->used; /* a little optimization to avoid dereferencing root

		      twice - we will shortly start iterating through used

		      list */

  if(last)

    last->next = next;

  else /* if free list is empty, just point it to the current used*/

    root->free = next;



  /* now go through the current used list, and mark each block

     as fully free. Note that because of our optimization, we do not

     need to initialize next here - see above

  */

  for(;next; next = next->next)

      next->left = next->size - ALIGN_SIZE(sizeof(USED_MEM));



  /* Now everything is set - we just need to indicate that nothing is used

     anymore

  */

  root->used = 0;

}



	/* deallocate everything used by alloc_root or just move

	 used blocks to free list if called with MY_USED_TO_FREE */



void free_root(MEM_ROOT *root, myf MyFlags)

{
@@ -109,6 +143,11 @@ void free_root(MEM_ROOT *root, myf MyFlags) 


  if (!root)

    DBUG_VOID_RETURN; /* purecov: inspected */

  if(MyFlags & MY_MARK_BLOCKS_FREE)

    {

      mark_blocks_free(root);

      DBUG_VOID_RETURN;

    }

  if (!(MyFlags & MY_KEEP_PREALLOC))

    root->pre_alloc=0;