database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Fixed several bugs for mwl #253.

Browse Source 
One of them is quite serious: the function table_cond_selectivity used
the TABLE_REF structure for ref/eq_ref access methods as if they had been
filled. In  fact these structure are filled after the best execution plan
has been chosen.

The other bugs happened due to:
- an erroneous attempt at get statistics on the result of materialization
  of a view
- incorrect handling of ranges with no left/right limits when calculating
  selectivity of range conditions on non-indexed columns
- lack of cleanup for some newly introduced fields
This commit is contained in:
Igor Babaev
2013-03-30 15:37:21 -07:00
parent e59e529635
commit 9055498634
6 changed files with 914 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
sql/sql_statistics.cc
View File

@ -3303,6 +3303,18 @@ double get_column_avg_frequency(Field * field)
{
double res;
TABLE *table= field->table;
/*
Statistics is shared by table instances and is accessed through
the table share. If table->s->field is not set for 'table', then
no column statistics is available for the table .
*/
if (!table->s->field)
{
res= table->stat_records();
return res;
}
Column_statistics *col_stats= table->s->field[field->field_index]->read_stats;
if (!col_stats)
@ -3323,8 +3335,8 @@ double get_column_range_cardinality(Field *field,
if (!col_stats)
res= table->stat_records();
else if (min_endp->length == max_endp->length &&
!memcmp(min_endp->key, max_endp->key, min_endp->length))
else if (min_endp && max_endp && min_endp->length == max_endp->length &&
!memcmp(min_endp->key, max_endp->key, min_endp->length))
{
double avg_frequency= col_stats->get_avg_frequency();
res= avg_frequency;
@ -3346,13 +3358,27 @@ double get_column_range_cardinality(Field *field,
{
if (col_stats->min_value && col_stats->max_value)
{
double sel;
store_key_image_to_rec(field, (uchar *) min_endp->key, min_endp->length);
double min_mp_pos= field->middle_point_pos(col_stats->min_value,
col_stats->max_value);
store_key_image_to_rec(field, (uchar *) max_endp->key, max_endp->length);
double max_mp_pos= field->middle_point_pos(col_stats->min_value,
col_stats->max_value);
double sel, min_mp_pos, max_mp_pos;
if (min_endp)
{
store_key_image_to_rec(field, (uchar *) min_endp->key,
min_endp->length);
min_mp_pos= field->middle_point_pos(col_stats->min_value,
col_stats->max_value);
}
else
min_mp_pos= 0.0;
if (max_endp)
{
store_key_image_to_rec(field, (uchar *) max_endp->key,
max_endp->length);
max_mp_pos= field->middle_point_pos(col_stats->min_value,
col_stats->max_value);
}
else
max_mp_pos= 1.0;
Histogram *hist= &col_stats->histogram;
if (hist->get_size() == 0)
sel= (max_mp_pos - min_mp_pos);