Bug #76280 [Com]: Performance degrades permantly when overwriting PHP files, until apache restart

Edit report at https://bugs.php.net/bug.php?id=76280&edit=1 ID: 76280 Comment by: teo8976 at gmail dot com Reported by: teo8976 at gmail dot com Summary: Performance degrades permantly when overwriting PHP files, until apache restart Status: Feedback Type: Bug Package: opcache Operating System: debian PHP Version: 5.6.36 Block user comment: N Private report: N New Comment: > Please check whether the deployment > of new files triggered an opcache restart How can I check that? > Generally any slowdown should only be temporary though It isn't. When this happens, the slowdown is permanent until I restart apache. In the screenshot I attached (where I unintentionally cut off the part that showed the times), it went on for several hours. It was also surprisingly "stable", everything being consistently X% slower (of course it is possible that the slowdown was affecting a specific piece of code being called by all scripts) > In any case, PHP 5 is no longer supported http://php.net/supported-versions.php says "security support until 31 december" this year. Something that can cause a website to go down permanently because of a performance degradation with no good reason, I would call a security issue. Previous Comments: ------------------------------------------------------------------------ [2018-04-27 19:44:35] nikic@php.net Please check whether the deployment of new files triggered an opcache restart (because the opcache SHM memory limit was reached). Generally any slowdown should only be temporary though. In any case, PHP 5 is no longer supported and PHP 7 has quite a lot of changes to improve performance, including in opcache. Additionally, the second-level file cache can be used to reduce the performance impact of opcache restarts. ------------------------------------------------------------------------ [2018-04-27 19:18:44] teo8976 at gmail dot com Here's some example performance data (oh come on, I can't attach a screenshot??) https://ibb.co/h3J6bx This is avarage execution time (measured on the server side) of all requests, but graphs for any given single url would show exactly the same pattern. ------------------------------------------------------------------------ [2018-04-27 19:09:56] teo8976 at gmail dot com Description: ------------ I have a website (well, it's not mine actually) that gets about 1k requests per minute. Sometimes I upload updated PHP files. Obviously this means I'm overwriting files at the very same time they are being executed. I expect that to cause errors (experienced by the users) during the short period of time while files are being overwritten (usually a few seconds). However, what I wouldn't expect and happens VERY often is that: after that, general performance degrades, meaning that the execution of EVERY SINGLE script in every single request is significantly slower. Sometimes it's just a few dozens % increase in execution time, sometimes it explodes to the point that the whole websites goes down. Restarting apache returns performance to normal every time, whether there had been a total collapse or just a degradation in performance. Expected result: ---------------- When you overwrite PHP files in a website that is being visited by thousands of people, you'd expect a small percentage of them to experience random errors, if a file is being overwritten just when it's being executing. However, as soon as all the requests that were being handled are done, everything should go back to working normally, and there shoul be no need to restart Apache Actual result: -------------- See description. Seriously, this is fucking pathetic. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=76280&edit=1