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Merge 10.3 into 10.4

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This commit is contained in:
Marko Mäkelä
2019-05-05 15:03:48 +03:00
parent b132b8895e e8dd18a474
commit d3dcec5d65
125 changed files with 1950 additions and 1736 deletions
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20
sql/table.cc
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@@ -7639,6 +7639,26 @@ bool TABLE::add_tmp_key(uint key, uint key_parts,
key_part_info++;
}
/*
For the case when there is a derived table that would give distinct rows,
the index statistics are passed to the join optimizer to tell that a ref
access to all the fields of the derived table will produce only one row.
*/
st_select_lex_unit* derived= pos_in_table_list ?
pos_in_table_list->derived: NULL;
if (derived)
{
st_select_lex* first= derived->first_select();
uint select_list_items= first->get_item_list()->elements;
if (key_parts == select_list_items)
{
if ((!first->is_part_of_union() && (first->options & SELECT_DISTINCT)) ||
derived->check_distinct_in_union())
keyinfo->rec_per_key[key_parts - 1]= 1;
}
}
set_if_bigger(s->max_key_length, keyinfo->key_length);
s->keys++;
return FALSE;