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bug#28570: handler::index_read() is called with different find_flag when

ORDER BY is used

The range analysis module did not correctly signal to the 
handler that a range represents a ref (EQ_RANGE flag). This causes 
non-range queries like 
SELECT ... FROM ... WHERE keypart_1=const, ..., keypart_n=const 
ORDER BY ... FOR UPDATE
to wait for a lock unneccesarily if another running transaction uses
SELECT ... FOR UPDATE on the same table.

Fixed by setting EQ_RANGE for all range accesses that represent 
an equality predicate. 


mysql-test/r/innodb_mysql.result:
  bug#28570: Test Result
mysql-test/t/innodb_mysql.test:
  bug#28570: Test Case
sql/handler.cc:
  bug#28570: Updated comment
sql/opt_range.cc:
  bug#28570: Removed the criterion that key has to be unique (HA_NOSAME) in 
  order for the EQ_RANGE flag to be set. It is sufficient that the range 
  represent a ref access.
This commit is contained in:
unknown
2007-08-15 09:23:44 +02:00
parent 1f83b35181
commit 01f8130aa6
4 changed files with 50 additions and 3 deletions

View File

@ -6369,8 +6369,7 @@ QUICK_RANGE_SELECT *get_quick_select_for_ref(THD *thd, TABLE *table,
range->min_key=range->max_key=(char*) ref->key_buff;
range->min_length=range->max_length=ref->key_length;
range->flag= ((ref->key_length == key_info->key_length &&
(key_info->flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
HA_NOSAME) ? EQ_RANGE : 0);
(key_info->flags & HA_END_SPACE_KEY) == 0) ? EQ_RANGE : 0);
if (!(quick->key_parts=key_part=(KEY_PART *)
alloc_root(&quick->alloc,sizeof(KEY_PART)*ref->key_parts)))