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Bug#16394084: LOOSE INDEX SCAN WITH QUOTED INT PREDICATE

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RETURNS RANDOM DATA
                 
MySQL 5.5 specific version of bugfix.
      
When Loose Index Scan Range access is used, MySQL execution needs
to copy non-aggregated fields. end_send() checked if this was
necessary by checking if join_tab->select->quick had type
QS_TYPE_GROUP_MIN_MAX.
      
In this bug, however, MySQL created a sort index to sort the rows
read from this range access method. create_sort_index() deletes
join_tab->select->quick which makes it impossible to inquire
the join_tab if LIS has been used.
      
The fix for MySQL 5.5 is to introduce a variable in JOIN_TAB
that stores whether or not LIS has been used. There is no need
for this variable in later MySQL versions because the relevant
code has been refactored.
This commit is contained in:
Jorgen Loland
2013-03-20 11:20:12 +01:00
parent 57129a3a4b
commit 015c320a75
2 changed files with 44 additions and 5 deletions
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15
sql/sql_select.cc
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@ -2713,6 +2713,8 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
s->const_keys.init();
s->checked_keys.init();
s->needed_reg.init();
s->filesort_used_loose_index_scan= false;
s->filesort_used_loose_index_scan_agg_distinct= false;
table_vector[i]=s->table=table=tables->table;
table->pos_in_table_list= tables;
error= table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
@ -6163,6 +6165,8 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
join_tab->read_first_record= join_init_read_record;
join_tab->join= this;
join_tab->ref.key_parts= 0;
join_tab->filesort_used_loose_index_scan= false;
join_tab->filesort_used_loose_index_scan_agg_distinct= false;
bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
temp_table->status=0;
temp_table->null_row=0;
@ -14240,6 +14244,17 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
tablesort_result_cache= table->sort.io_cache;
table->sort.io_cache= NULL;
if (select->quick &&
select->quick->get_type() == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX)
{
tab->filesort_used_loose_index_scan= true;
QUICK_GROUP_MIN_MAX_SELECT *minmax_quick=
static_cast<QUICK_GROUP_MIN_MAX_SELECT*>(select->quick);
if (minmax_quick->is_agg_distinct())
tab->filesort_used_loose_index_scan_agg_distinct= true;
}
/*
If a quick object was created outside of create_sort_index()
that might be reused, then do not call select->cleanup() since