We've also had MDEV-19082 <https://jira.mariadb.org/browse/MDEV-19082> -- change application-time period tables to use HA_EXTRA_REMEMBER_POS.
On Fri, 6 Dec 2019 at 18:33, Nikita Malyavin <nikitamalya...@gmail.com> wrote: > Hi Sergei! > > I traced out the problem I faced with refs comparison -- It's in key_copy > implementation, which uses field->get_key_image, which in turn copied data > to the buffer passed, but from `field->ptr`. The latter is important -- it > means, current key_copy implementation always copies data from > table->record[0]. > > I have already came across it while implementing FKs, and have fixed the > implementation in the separate commit (see key_copy: use from_record > argument to copy the data from). That fixes 'innodb' test combination. > > I think now everything you wanted so far is in the branch, so am waiting > now for your comments on the new code! > > Kind regards, > Nikita Malyavin > > On Thu, 5 Dec 2019 at 02:36, Sergei Golubchik <s...@mariadb.org> wrote: > >> Hi, Nikita! >> >> On Dec 05, Nikita Malyavin wrote: >> > Heh, unfortunately comparing refs will not work in conjunction with >> KEYREAD: >> > >> > for innodb ref can be a primary key, if it has it, so index is not >> > clustered. The index we're evaluating can be different from a primary >> key. >> > >> > In that case some values can be left unfetched with KEYREAD. >> > >> > All that is because if innodb has primary key, it just does key_copy >> >> In InnoDB every secondary key automatically has primary key at the >> end, because after finding the key value in a secondary index, >> InnoDB needs to fetch the corresponding row, so it has to know the PK >> value for that secondary key. >> >> Generalizing, every secondary key has to have the "ref" for the >> corresponding row. In InnoDB it's PK, in MyISAM it's the row offset, in >> MEMORY it's pointer. But either way, in any engine, any secondary key >> knows the ref for the corresponding row. >> >> Regards, >> Sergei >> VP of MariaDB Server Engineering >> and secur...@mariadb.org > > -- Yours truly, Nikita Malyavin
_______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
