[wp-trac] [WordPress Trac] #24958: Large number of revisions cause memory exhaustion

[WordPress Trac]

#24958: Large number of revisions cause memory exhaustion
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 Reporter:  jshreve       |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  3.6.1
Component:  Revisions     |     Version:
 Severity:  normal        |  Resolution:
 Keywords:                |
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Changes (by nacin):

 * milestone:  Awaiting Review => 3.6.1


Comment:

 wp_update_post() triggers save_post which calls wp_save_post_revision()
 which calls wp_get_post_revisions() to get the last revision.

 We should set up wp_get_post_revisions() to be able to request the last
 non-autosave in a single query, rather than potentially loading all
 revisions into memory. I almost did this in 3.6 for wp_get_post_autosave()
 because it used to do a direct WP_Query for an autosave, and now it calls
 wp_get_post_revisions(), which can be painful.

 This should fix the issue of wp_update_post(). It won't fix the revisions
 screen, which *does* have some failover if it takes too long (or too much
 memory) to process all of the diffs, but it does still try to load all
 revisions at once. We should place a limit on that actual query, say 200,
 to force it to occur in chunks. Our JS will handle it automatically.

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Ticket URL: <http://core.trac.wordpress.org/ticket/24958#comment:4>
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