I recently migrated to 2.4.1 from 2.4.0 because of this bug. So negative on this one.
In the meantime i discovered why MariaDB has index problems. Its not because of the second order parameter, but because of the second order parameter which is the same field in a different table but with ASC order. The ASC is the thing but of course the second parameter shouldnt be there at all. I suspect its because of the "join fetch". Just for the record, of course i dont use @OrderBy on the relation. If i do it on the 1:n relation in question, i get this: ORDER BY t0.oid DESC, t24.distribution_oid ASC, t24.distribution_oid ASC LIMIT ?, ? Perhaps i try to downgrade a bit more because i am quite sure that this problem is new somehow.... i did another upgrade from an older version to 2.4.0 a few weeks ago. regards marc 2016-09-10 9:48 GMT+02:00 Mark Struberg <strub...@yahoo.de.invalid>: > Hi Marc! > > Can you please try with 2.4.0? > Is the generated query the same or without the column? > > LieGrue, > strub > > > > > On Saturday, 10 September 2016, 2:14, Marc Logemann < > marc.logem...@gmail.com> wrote: > > > > > > > >Hi, > > > >i suspect i found a bug which has bad consequences on MariaDB not using an > >index anymore. Lets take this JPAQL: > > > >select d from Distribution d join fetch d.distributionContainerList where > >d.client = ?1 and d.deleted = ?2 order by d.oid desc > > > >My Distribution entity is quite big when it comes to 1:n relations and > >stuff. So i wont get into the details here, but this JPAQL will result in > >the following SQL (compressed because too big otherwise): > > > >SELECT t0.oid, t0.jpaversion, t0.created, t0.createdby, ... > > FROM distribution t0 LEFT OUTER JOIN dist_altfrom t1 ON t0.altfrom_oid > >= t1.oid > > LEFT OUTER JOIN clients t3 ON t0.client_oid = t3.oid LEFT OUTER > >JOIN > > cmrcarrier t17 ON t0.cmrcarrier_oid = t17.oid LEFT OUTER JOIN > >countries > > t20 ON t0.empf_country = t20.isocode2 LEFT OUTER JOIN users t21 ON > > t0.user_oid = t21.oid INNER JOIN dist_container t24 ON t0.oid = > > t24.distribution_oid LEFT OUTER JOIN countries t2 ON t1.country = > > t2.isocode2 LEFT OUTER JOIN address t4 ON t3.address_oid = t4.oid > >LEFT > > OUTER JOIN bankaccount t6 ON t3.bankaccount_oid = t6.oid LEFT > OUTER > > JOIN communication t7 ON t3.communication_oid = t7.oid LEFT OUTER > >JOIN > > persons t8 ON t3.cperson_oid = t8.oid LEFT OUTER JOIN bankaccount > >t10 > > ON t3.nnbankaccount_oid = t10.oid LEFT OUTER JOIN workplaces t11 > ON > > t3.workplaceoid = t11.oid LEFT OUTER JOIN address t18 ON > > t17.address_oid = t18.oid LEFT OUTER JOIN communication t19 ON > > t17.communication_oid = t19.oid LEFT OUTER JOIN persons t22 ON > > t21.person_oid = t22.oid LEFT OUTER JOIN workplaces t23 ON > > t21.workplaceoid = t23.oid LEFT OUTER JOIN distribution t25 ON > > t24.old_distribution_oid = t25.oid LEFT OUTER JOIN countries t5 ON > > t4.country_id = t5.isocode2 LEFT OUTER JOIN communication t9 ON > > t8.communication_oid = t9.oid LEFT OUTER JOIN balance t12 ON > > t11.balance = t12.oid LEFT OUTER JOIN balance t13 ON t11.balance2 > = > > t13.oid LEFT OUTER JOIN clients t14 ON t11.client_oid = t14.oid > >LEFT > > OUTER JOIN printer t15 ON t11.labelprinter = t15.oid LEFT OUTER > >JOIN > > printer t16 ON t11.laserprinter = t16.oid > > WHERE (t0.client_oid = ? AND t0.deleted = ?) > > ORDER BY t0.oid DESC, t24.distribution_oid ASC LIMIT ?, ? > > > > > >Just look at the order by clause in the SQL. It correctly used t0.oid > >because JPAQL said so. But why on earth is there another order clause with > >the field "t24.distribution_oid" ?? This is a back reference for a 1:n > >relation from Table "dist_container" back to "distribution". > > > >The real problem is: as soon as there is another sorting parameter from a > >joined table, MariaDB doesnt use my ForeignKey Index anymore and does a > >FULL-Scan on the t24 table, which is pretty heavy on a multi million > >records table. When i leave out that ugly t24.distribution_oid ordering > >field, everything is fast and ok. > > > >Can anyone explain to me how this ordering field gets into the picture? > > > >thanks > >marc > > > > > > >
