[wp-trac] [WordPress Trac] #36455: Call opcache_reset() after plug-in, theme or core update

[WordPress Trac]

#36455: Call opcache_reset() after plug-in, theme or core update
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 Reporter:  nigro.simone             |       Owner:
     Type:  enhancement              |      Status:  new
 Priority:  normal                   |   Milestone:  5.0
Component:  Upgrade/Install          |     Version:
 Severity:  normal                   |  Resolution:
 Keywords:  has-patch needs-testing  |     Focuses:
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Comment (by jadonn):

 Some more research may be worthwhile before integrating this into core
 WordPress. Under certain PHP configurations, calling opcache_reset will
 reset the opcache for all users on a given server, or, at the very least,
 all websites that a given user owns. For example, if a server using PHP-
 FPM uses a common PHP-FPM master process, despite having separate pools of
 workers for each worker, calling opcache_reset will reset the opcache for
 all users on the server using the common PHP-FPM master process. I believe
 this same behavior occurs when using mod_php (running PHP as a Dynamic
 Shared Object in Apache) even when using mod_ruid2 or other security
 modules in Apache, but it has been a little while since I last worked with
 a server running mod_php/DSO for PHP handling.

 Clearing the opcache for all websites on a server or all websites owned by
 a single user would likely have a pretty significant impact on performance
 in terms of traffic that could be served and on website resource usage,
 outside of the security concerns, while the cache is being rebuilt.

 There are some real security concerns around opcache and from incorrectly
 configuring opcache due to how opcache memory is shared, but those may be
 better addressed elsewhere.

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Ticket URL: <https://core.trac.wordpress.org/ticket/36455#comment:39>
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