[wp-trac] [WordPress Trac] #64696: Real time collboration effectively disables persistent post caches while anyone edits a post

[WordPress Trac]

#64696: Real time collboration effectively disables persistent post caches while
anyone edits a post
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 Reporter:  peterwilsoncc      |       Owner:  (none)
     Type:  defect (bug)       |      Status:  new
 Priority:  normal             |   Milestone:  7.0
Component:  Posts, Post Types  |     Version:  trunk
 Severity:  normal             |  Resolution:
 Keywords:  has-patch          |     Focuses:  performance
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Comment (by westonruter):

 Replying to [comment:14 peterwilsoncc]:
 > Replying to [comment:12 westonruter]:
 > > ...even with back-off we definitely don't want syncing logic to have
 any impact on the frontend.
 >
 > As Dion indicates above, with the heartbeat API there is some amount of
 effect on the front end while editing. The same is true for revisions,
 autosaves and probably a few more things.

 True, but the problem just seems to be exponentially worse now since the
 cache invalidations can happen 4 times a second for every user syncing
 changes. In contrast, the most frequent heartbeat interval is once every
 15 seconds, but an autosave only happens once every 60. So while a user is
 typing continuously with realtime collaboration enabled, this can result
 in 240 invalidations of posts in the object cache per minute, whereas with
 autosave heartbeat it only happens once a minute. On a highly dynamic
 traffic'ed site without page caching, but having persistent object caching
 to deal with scaling issues, this can result in the object cache
 essentially being disabled and the database load being increased
 substantially.

 I don't necessarily like my workaround for this issue and I would like
 there to be a deeper solution to fix the issue of cached posts in the
 object cache being invalidated needlessly. But I'm also mindful that we're
 now in beta and this seems like a much bigger performance problem to solve
 for the general case which may be more appropriate for 7.1.

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Ticket URL: <https://core.trac.wordpress.org/ticket/64696#comment:15>
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