Hi, Nikita! On Dec 28, Nikita Malyavin wrote: > Hi, Sergei! > > In short, I am on the side of standard conformance.
Our TRUNCATE is not exactly a standard TRUNCATE. it's defined as DROP+REPLACE. But generally I agree, standard conformance. > Next two statements are generally out of scope of this bug, but: I > like to see extra2 reading in separate function, and i believe that > `TABLE_SHARE::init_from_binary_frm_image` needs more decomposiiton. May be... not sure... > Further: > > > I don't quite like that a small and simple function dd_frm_type(), > > which used to just read few first bytes of the frm file, gets more > > and more complex, growing into a complete frm-open method. > > > > So, perhaps, I'd consider changing TRUNCATE to open the table > > properly without all that just-read-few-bytes shortcuts. > > Wasn't the there some performance issue as the reason to introduce > such read-few-bytes thing? If it's not the case, then I'm okay with > that, but feels like TRUNCATE code written in manner to make IO as > fast as possible there. I don't know if there was... but now it's certainly used in some cases to avoid full table open. Mainly in ha_table_exists(), which is used in many places in the server. And there we don't care whether a table is versioned or not. TRUNCATE uses it too, but it's not a performance critical statement, so I think it's ok to do a full table open. > > Or, may be, simply document that TRUNCATE works on versioning tables > > just as DROP+CREATE does. There is no logical reason why it > > shouldn't - if one can do SHOW CREATE TABLE and CREATE OR REPLACE, > > then TRUNCATE won't add any new functionality on top of that. That's > > the easiest and most logical "fix" to this bug. Agree? > > Consider we'll have VTMD someday at last. Then the TRUNCATE behavior > will differ for different `vers_alter_history` modes. It is better to > extend the command (or create new one) to make something related to > versioning: either truncate only actual data, or only history (we > already have delete history for this one), or both. Okay, then just do a full table open. I'd try to remove HTON_CAN_RECREATE flag completely and implement recreate logic inside handler::delete_all_rows() Regards, Sergei Chief Architect MariaDB and secur...@mariadb.org _______________________________________________ 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
