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Merge timka@10.100.64.80:/home/timka/mysql/src/4.1-bug-21787

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into  dl145s.mysql.com:/data/tkatchaounov/5.0-bug-21787
This commit is contained in:
timour/tkatchaounov@dl145s.mysql.com
2006-09-01 14:29:27 +02:00
parent 30ef47a93c 02e194cea2
commit 462c22c1ae
3 changed files with 38 additions and 7 deletions
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21
sql/sql_select.cc
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@ -8939,11 +8939,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
keyinfo->key_length+= key_part_info->length;
}
}
else
{
set_if_smaller(table->s->max_rows, rows_limit);
param->end_write_records= rows_limit;
}
if (distinct && field_count != param->hidden_field_count)
{
@ -8958,8 +8953,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
null_pack_length-=hidden_null_pack_length;
keyinfo->key_parts= ((field_count-param->hidden_field_count)+
test(null_pack_length));
set_if_smaller(table->s->max_rows, rows_limit);
param->end_write_records= rows_limit;
table->distinct= 1;
table->s->keys= 1;
if (blob_count)
@ -9011,6 +9004,20 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
0 : FIELDFLAG_BINARY;
}
}
/*
Push the LIMIT clause to the temporary table creation, so that we
materialize only up to 'rows_limit' records instead of all result records.
This optimization is not applicable when there is GROUP BY or there is
no GROUP BY, but there are aggregate functions, because both must be
computed for all result rows.
*/
if (!group && !thd->lex->current_select->with_sum_func)
{
set_if_smaller(table->s->max_rows, rows_limit);
param->end_write_records= rows_limit;
}
if (thd->is_fatal_error) // If end of memory
goto err; /* purecov: inspected */
table->s->db_record_offset= 1;