MySQL group by kills the query performance - mysql

Question

I have MySQL query currently selecting and joining 13 tables and finally grouping ~60k rows. The query without grouping takes ~0ms but with grouping the query time increases to ~1.7sec. The field, which is used for grouping is primary field and is indexed. Where could be the issue?
I know group by without aggregate is considered invalid query and bad practise but I need distinct base table rows and can not use DISTINCT syntax.
The query itself looks like this:
SELECT `table_a`.*
FROM `table_a`
LEFT JOIN `table_b`
ON `table_b`.`invoice` = `table_a`.`id`
LEFT JOIN `table_c` AS `r1`
ON `r1`.`invoice_1` = `table_a`.`id`
LEFT JOIN `table_c` AS `r2`
ON `r2`.`invoice_2` = `table_a`.`id`
LEFT JOIN `table_a` AS `i1`
ON `i1`.`id` = `r1`.`invoice_2`
LEFT JOIN `table_a` AS `i2`
ON `i2`.`id` = `r2`.`invoice_1`
JOIN `table_d` AS `_u0`
ON `_u0`.`id` = 1
LEFT JOIN `table_e` AS `_ug0`
ON `_ug0`.`user` = `_u0`.`id`
JOIN `table_f` AS `_p0`
ON ( `_p0`.`enabled` = 1
AND ( ( `_p0`.`role` < 2
AND `_p0`.`who` IS NULL )
OR ( `_p0`.`role` = 2
AND ( `_p0`.`who` = '0'
OR `_p0`.`who` = `_u0`.`id` ) )
OR ( `_p0`.`role` = 3
AND ( `_p0`.`who` = '0'
OR `_p0`.`who` = `_ug0`.`group` ) ) ) )
AND ( `_p0`.`action` = '*'
OR `_p0`.`action` = 'read' )
AND ( `_p0`.`related_table` = '*'
OR `_p0`.`related_table` = 'table_name' )
JOIN `table_a` AS `_e0`
ON ( ( `_p0`.`related_id` = 0
OR `_p0`.`related_id` = `_e0`.`id`
OR `_p0`.`related_user` = `_e0`.`user`
OR `_p0`.`related_group` = `_e0`.`group` )
OR ( `_p0`.`role` = 0
AND `_e0`.`user` = `_u0`.`id` )
OR ( `_p0`.`role` = 1
AND `_e0`.`group` = `_ug0`.`group` ) )
AND `_e0`.`id` = `table_a`.`id`
JOIN `table_d` AS `_u1`
ON `_u1`.`id` = 1
LEFT JOIN `table_e` AS `_ug1`
ON `_ug1`.`user` = `_u1`.`id`
JOIN `table_f` AS `_p1`
ON ( `_p1`.`enabled` = 1
AND ( ( `_p1`.`role` < 2
AND `_p1`.`who` IS NULL )
OR ( `_p1`.`role` = 2
AND ( `_p1`.`who` = '0'
OR `_p1`.`who` = `_u1`.`id` ) )
OR ( `_p1`.`role` = 3
AND ( `_p1`.`who` = '0'
OR `_p1`.`who` = `_ug1`.`group` ) ) ) )
AND ( `_p1`.`action` = '*'
OR `_p1`.`action` = 'read' )
AND ( `_p1`.`related_table` = '*'
OR `_p1`.`related_table` = 'table_name' )
JOIN `table_g` AS `_e1`
ON ( ( `_p1`.`related_id` = 0
OR `_p1`.`related_id` = `_e1`.`id`
OR `_p1`.`related_user` = `_e1`.`user`
OR `_p1`.`related_group` = `_e1`.`group` )
OR ( `_p1`.`role` = 0
AND `_e1`.`user` = `_u1`.`id` )
OR ( `_p1`.`role` = 1
AND `_e1`.`group` = `_ug1`.`group` ) )
AND `_e1`.`id` = `table_a`.`company`
WHERE `table_a`.`date_deleted` IS NULL
AND `table_a`.`company` = 4
AND `table_a`.`type` = 1
AND `table_a`.`date_composed` >= '2016-05-04 14:43:55'
GROUP BY `table_a`.`id`

Answer 1

The ORs kill performance.
This composite index may help: INDEX(company, type, date_deleted, date_composed).
LEFT JOIN table_b ON table_b.invoice = table_a.id seems to do absolutely nothing other than slow down the processing. No fields of table_b are used or SELECTed. Since it is a LEFT join, it does not limit the output. Etc. Get rid if it, or justify it.
Ditto for other joins.
What happens with JOIN and GROUP BY: First, all the joins are performed; this explodes the number of rows in the intermediate 'table'. Then the GROUP BY implodes the set of rows.
One technique for avoiding this explode-implode sluggishness is to do
SELECT ...,
( SELECT ... ) AS ...,
...
instead of a JOIN or LEFT JOIN. However, that works only if there is zero or one row in the subquery. Usually this is beneficial when an aggregate (such as SUM) can be moved into the subquery.
For further discussion, please include SHOW CREATE TABLE.