Re: What's the meaning of mysqli.rollback_on_cached_plink?

Hi, Kalle thanks for CCing, I'm indeed not on the docs list. On Di, 2018-04-24 at 18:24 +0200, Kalle Sommer Nielsen wrote: > 2018-04-24 18:05 GMT+02:00 Christoph M. Becker <cmbecker69@gmx.de>: > > > > Hi everybody! > > > > While updating the German translation, cool! > > I've stumbled upon > > mysqli.rollback_on_cached_plink, which is documented[1] as: > > > > > > > > Used for rollbacking connections put back into the persistent > > > connection pool. > > The migration guide[2] uses a slightly different wording: > > > > > > > > […] to rollback connections put back into the persistent > > > connection > > > pool. > > Frankly, I don't understand what that's supposed to mean (are these > > even > > proper English sentences?) > > > > The respective commit[3] message isn't more helpful, but from > > reading > > the actual commit, it seems that: > > > > If mysqli.rollback_on_cached_plink is enabled, and a persistent > > connection is closed, it is attempted to rollback any pending > > transactions, and if that succeeds, the persistent connection is > > actually closed, instead of putting it back into the persistent > > connection pool.  If mysqli.rollback_on_cached_plink is disabled, > > no > > attempt to rollback or close the connection is made, and it is put > > back > > into the persistent connection pool. > > > > Is that correct?  Any clarification is welcome! > > Yes that is correct. http://git.php.net/?p=php-src.git;a=blob;f=ext/mysqli/mysqli_api.c;h=2b cbe2846ebe495e00c398bfa5786e6f1741749b;hb=HEAD#l694 is the relevant code. So when the connection is "closed" (be it explicetily by using mysqli_close() or implicitly by scope/scrpt end) and you are using persitent connections the connection is put back in the pool of persistent connections available. If this setting is set also a rollback is initiated to rollback all transactions.  Interestingly mysqlnd also does a "change_user" call when taking connections out of the persistent connection pool which, among other things, will also does a rollback of outstanding transactions. In effect I believe the only effect is to decide /when/ the rollback happens - at "close" time or when taking the connection out of the pool for a new connections. johannes