[wp-trac] [WordPress Trac] #11399: clean_post_cache() generates enormous amounts of queries on sites with lots of pages, revisions or attachments

[WordPress Trac]

#11399: clean_post_cache() generates enormous amounts of queries on sites with lots
of pages, revisions or attachments
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 Reporter:  Denis-de-Bernardy                    |       Owner:
     Type:  defect (bug)                         |      Status:  new
 Priority:  normal                               |   Milestone:  Future
Component:  Optimization                         |  Release
 Severity:  normal                               |     Version:  2.9
 Keywords:  dev-feedback has-patch needs-        |  Resolution:
  feedback                                       |
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Changes (by simonwheatley):

 * keywords:  needs-patch dev-feedback has-patch needs-feedback => dev-
     feedback has-patch needs-feedback


Comment:

 Part of the problem is that the query to get the post children, which are
 then iterated over, includes revisions. Given that revisions shouldn't (?)
 change, perhaps the query could be adjusted to not clear the caches of
 children which are revisions. Something like the next diff.

 In my client's particularly deeply nested hierarchy of this reduced the
 number of times `clean_post_cache` was called from approximately 4,500
 calls to 500 calls with `WP_POST_REVISIONS` set to 10 (so it could have
 been even worse).

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Ticket URL: <http://core.trac.wordpress.org/ticket/11399#comment:10>
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