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MDEV-26996 Support descending indexes in the range optimizer

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- Code cleanup
- Disable "Using index for GROUP BY" over indexes with DESC keyparts
This commit is contained in:
Sergei Petrunia
2021-12-14 16:39:37 +03:00
committed by Sergei Golubchik
parent 3a82c256da
commit cbfe6a5e86
6 changed files with 82 additions and 47 deletions
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23
sql/opt_range.cc
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@@ -2809,12 +2809,11 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
trace_idx_details.add("usable", false).add("cause", "fulltext");
continue; // ToDo: ft-keys in non-ft ranges, if possible SerG
}
trace_idx_details.add("usable", true);
param.key[param.keys]=key_parts;
key_part_info= key_info->key_part;
uint cur_key_len= 0;
Json_writer_array trace_keypart(thd, "key_parts");
bool unusable_has_desc_keyparts= false;
for (uint part= 0 ; part < n_key_parts ;
part++, key_parts++, key_part_info++)
{
@@ -2829,18 +2828,9 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
(key_info->flags & HA_SPATIAL) ? Field::itMBR : Field::itRAW;
/* Only HA_PART_KEY_SEG is used */
key_parts->flag= (uint8) key_part_info->key_part_flag;
if (key_part_info->key_part_flag & HA_REVERSE_SORT)
unusable_has_desc_keyparts= true;
trace_keypart.add(key_parts->field->field_name);
}
trace_keypart.end();
trace_idx_details.add("usable", !unusable_has_desc_keyparts);
unusable_has_desc_keyparts= false;
if (unusable_has_desc_keyparts) // TODO MDEV-13756
{
key_parts= param.key[param.keys];
continue;
}
param.real_keynr[param.keys++]=idx;
if (cur_key_len > max_key_len)
max_key_len= cur_key_len;
@@ -13836,6 +13826,17 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree, double read_time)
cause= "not covering";
goto next_index;
}
{
for (uint i= 0; i < table->actual_n_key_parts(cur_index_info); i++)
{
if (cur_index_info->key_part[i].key_part_flag & HA_REVERSE_SORT)
{
cause="Reverse-ordered (not supported yet)";
goto next_index;
}
}
}
/*
This function is called on the precondition that the index is covering.