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Bug #31890 Partitions: ORDER BY DESC in InnoDB not working.

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It's not InnoDB specific bug.
Error is in QUEUE code, about the way we handle queue->max_at_top.
It's either '0' or '-2' and we do '^' operation to get the proper
direction. Though queue->compare() function can return '-2' as
a result of comparison sometimes. So we'll get
queue->compare() ^ queue->max_at_top == 0 (when max_at_top is -2)
and _downheap() function code will go wrong way here:
...
    if (next_index < elements &&
        (queue->compare(queue->first_cmp_arg,
                        queue->root[next_index]+offset_to_key,
                        queue->root[next_index+1]+offset_to_key) ^
         queue->max_at_top) > 0)
      next_index++;
...

Fixed by changing max_at_top to be either 1 or -1, doing
'* max_at_top' to get proper direction.


include/queues.h:
  Bug #31890 Partitions: ORDER BY DESC in InnoDB not working
  
  max_at_top policy changed
mysql-test/r/partition.result:
  Bug #31890 Partitions: ORDER BY DESC in InnoDB not working
  
  test result
mysql-test/t/partition.test:
  Bug #31890 Partitions: ORDER BY DESC in InnoDB not working
  
  test case
mysys/queues.c:
  Bug #31890 Partitions: ORDER BY DESC in InnoDB not working.
  
  queue->max_at_top policy changed - now it can either be '1' or '-1'.
  We multiply comparison result on max_at_top to get the proper
  direction.
This commit is contained in:
unknown
2007-11-14 22:20:31 +04:00
parent d68b313dbc
commit c33c92d0f2
4 changed files with 80 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
mysys/queues.c
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@ -61,7 +61,7 @@ int init_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
queue->first_cmp_arg=first_cmp_arg;
queue->max_elements=max_elements;
queue->offset_to_key=offset_to_key;
queue->max_at_top= max_at_top ? (-1 ^ 1) : 0;
queue_set_max_at_top(queue, max_at_top);
DBUG_RETURN(0);
}
@ -137,7 +137,7 @@ int reinit_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
queue->compare=compare;
queue->first_cmp_arg=first_cmp_arg;
queue->offset_to_key=offset_to_key;
queue->max_at_top= max_at_top ? (-1 ^ 1) : 0;
queue_set_max_at_top(queue, max_at_top);
resize_queue(queue, max_elements);
DBUG_RETURN(0);
}
@ -208,16 +208,14 @@ void delete_queue(QUEUE *queue)
void queue_insert(register QUEUE *queue, uchar *element)
{
reg2 uint idx, next;
int cmp;
DBUG_ASSERT(queue->elements < queue->max_elements);
queue->root[0]= element;
idx= ++queue->elements;
/* max_at_top swaps the comparison if we want to order by desc */
while ((cmp= queue->compare(queue->first_cmp_arg,
element + queue->offset_to_key,
queue->root[(next= idx >> 1)] +
queue->offset_to_key)) &&
(cmp ^ queue->max_at_top) < 0)
while ((queue->compare(queue->first_cmp_arg,
element + queue->offset_to_key,
queue->root[(next= idx >> 1)] +
queue->offset_to_key) * queue->max_at_top) < 0)
{
queue->root[idx]= queue->root[next];
idx= next;
@ -287,19 +285,17 @@ void _downheap(register QUEUE *queue, uint idx)
while (idx <= half_queue)
{
int cmp;
next_index=idx+idx;
if (next_index < elements &&
(queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
queue->root[next_index+1]+offset_to_key) ^
queue->root[next_index+1]+offset_to_key) *
queue->max_at_top) > 0)
next_index++;
if (first &&
(((cmp=queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
element+offset_to_key)) == 0) ||
((cmp ^ queue->max_at_top) > 0)))
(((queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
element+offset_to_key) * queue->max_at_top) >= 0)))
{
queue->root[idx]= element;
return;
@ -314,7 +310,7 @@ void _downheap(register QUEUE *queue, uint idx)
{
if ((queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
element+offset_to_key) ^
element+offset_to_key) *
queue->max_at_top) < 0)
break;
queue->root[idx]=queue->root[next_index];
@ -334,7 +330,6 @@ void _downheap(register QUEUE *queue, uint idx)
{
uchar *element;
uint elements,half_queue,next_index,offset_to_key;
int cmp;
offset_to_key=queue->offset_to_key;
element=queue->root[idx];
@ -346,13 +341,12 @@ void _downheap(register QUEUE *queue, uint idx)
if (next_index < elements &&
(queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
queue->root[next_index+1]+offset_to_key) ^
queue->root[next_index+1]+offset_to_key) *
queue->max_at_top) > 0)
next_index++;
if ((cmp=queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
element+offset_to_key)) == 0 ||
(cmp ^ queue->max_at_top) > 0)
if ((queue->compare(queue->first_cmp_arg,
queue->root[next_index]+offset_to_key,
element+offset_to_key) * queue->max_at_top) >= 0)
break;
queue->root[idx]=queue->root[next_index];
idx=next_index;