mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-04-29 03:35:34 +02:00
Code Issues Projects Releases Packages Wiki Activity

count(distinct) cleanup

Browse source 
mysql-test/t/count_distinct2.test:
  make default NULL in tree->MyISAM test to make sure restore_record()
  does not give a bad surprise
sql/item_sum.cc:
  cleanup according to Monty's suggestions
sql/item_sum.h:
  cleanup according to Monty's suggestions
This commit is contained in:
unknown 2001-05-29 18:53:37 -06:00
commit 7a8520640a
3 changed files with 13 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

10
sql/item_sum.cc
View file

@ -839,7 +839,8 @@ int dump_leaf(byte* key, uint32 count __attribute__((unused)),
{
char* buf = item->table->record[0];
int error;
memset(buf, 0xff, item->rec_offset); // make up for cheating in the tree
// the first item->rec_offset bytes are taken care of with
// restore_record(table,2) in setup()
memcpy(buf + item->rec_offset, key, item->tree.size_of_element);
if ((error = item->table->file->write_row(buf)))
{
@ -888,12 +889,17 @@ bool Item_sum_count_distinct::setup(THD *thd)
table->file->extra(HA_EXTRA_NO_ROWS); // Don't update rows
table->no_rows=1;
if(table->db_type == DB_TYPE_HEAP) // no blobs, otherwise it would be
// MyISAM
{
qsort_cmp2 compare_key;
void* cmp_arg;
int key_len;
// to make things easier for dump_leaf if we ever have to dump to
// MyISAM
restore_record(table,2);
if(table->fields == 1) // if we have only one field, which is
// the most common use of count(distinct), it is much faster
@ -941,7 +947,7 @@ bool Item_sum_count_distinct::setup(THD *thd)
// but this has to be handled - otherwise someone can crash
// the server with a DoS attack
max_elements_in_tree = (key_len) ? max_heap_table_size/key_len :
max_heap_table_size;
1;
}
return 0;