Re: `COM_RESET_CONNECTION` support in `mysqlnd`

> Personally, given that both of these versions are EOL, this feels > acceptable, but I'm curious what others think. Notably, if we were to > implement configuration for this we'd likely need to introduce yet > another INI variable; I have an impression that PHP maintainers are > somewhat skeptical of adding new INI settings. I think it's ok to drop support of EOL versions. But I also think it's possible to support both new and ancient mysql even without any runtime options (ini setting, PDO constant et al). First try to send COM_RESET_CONNECTION and if server return error, try COM_CHANGE_USER. Result of this check may be cached for improved performance, but not strictly necessary. This at least won't break anyone. But if you are feel strongly about completely dropping COM_CHANGE_USER, then some deprecation period should exist. Users should see at least E_DEPRECATED errors in their logs before day X. I know about changelog page and NEWS file, but among all the PHP programmers I know, no one reads them. > Secondly, I'm curious what people think about implementing this in > both PDO *and* mysqlnd. In PDO, we can replace the liveness > check > with this command, which would act as both a liveness check and a > reset for no additional round-trip cost. It's ok to replace liveness check with reset, but I think you choose wrong place for implementation. You changed the pdo_mysql_check_liveness function and now it not just "liveness check", which leads to a discrepancy with its name and also liveness functions from other PDO drivers. I'd rather implement in on PDO level. Something like: ```c // pdo_dbh.c:420 /* is the connection still alive ? */ - if (pdbh->methods->check_liveness && FAILURE == (pdbh->methods->check_liveness)(pdbh)) { + if (!(pdbh->methods->reset && (pdbh->methods->reset)(pdbh)) && pdbh->methods->check_liveness && FAILURE == (pdbh->methods->check_liveness)(pdbh)) { /* nope... need to kill it */ pdbh->refcount--; zend_list_close(le); pdbh = NULL; } ``` See also the sluggish discussion about PDO: https://externals.io/message/129740