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

[WordPress Trac]

#24958: Large number of revisions cause memory exhaustion
------------------------------------+------------------------------
 Reporter:  jshreve                 |       Owner:  adamsilverstein
     Type:  defect (bug)            |      Status:  assigned
 Priority:  low                     |   Milestone:  Future Release
Component:  Revisions               |     Version:  3.6
 Severity:  normal                  |  Resolution:
 Keywords:  has-patch dev-feedback  |     Focuses:
------------------------------------+------------------------------

Comment (by pembo13):

 I'm still seeing this issue, WordPress version 4.9.4  Same error:

 {{{
 PHP Fatal error:  Allowed memory size of 268435456 bytes exhausted (tried
 to allocate 81920 bytes)
 }}}

 Checking the revisions:

 {{{
 SELECT COUNT(*) FROM `wp_posts` WHERE post_parent = '1978' AND post_type =
 'revision'
 }}}

 Yields 537.

 Looking at `$revisions = wp_get_post_revisions( $post_ID );` it seems like
 it's loading the entire post, but only information to generate the list
 are needed (ID,  post_author, post_date, post_title). Can we just reduce
 the fields that are being loaded?

 The database really doesn't mind 500+ rows, the issue is the PHP code
 trying to load all 500 posts in their entirety.

 ----

 Stack Trace:
 {{{
 Fatal error:  Allowed memory size of 268435456 bytes exhausted (tried to
 allocate 81920 bytes) in /var/www/wordpress/example.com/wp-includes/wp-
 db.php on line 1889, referer: https://example.com/wp-
 admin/edit.php?post_type=page
 Stack trace:, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    1. {main}() /var/www/wordpress/example.com/wp-admin/post.php:0,
 referer: https://example.com/wp-admin/edit.php?post_type=page
    2. include() /var/www/wordpress/example.com/wp-admin/post.php:174,
 referer: https://example.com/wp-admin/edit.php?post_type=page
    3. wp_get_post_revisions() /var/www/wordpress/example.com/wp-admin
 /edit-form-advanced.php:231, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    4. get_children() /var/www/wordpress/example.com/wp-
 includes/revision.php:453, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    5. get_posts() /var/www/wordpress/example.com/wp-includes/post.php:445,
 referer: https://example.com/wp-admin/edit.php?post_type=page
    6. WP_Query->query() /var/www/wordpress/example.com/wp-
 includes/post.php:1704, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    7. WP_Query->get_posts() /var/www/wordpress/example.com/wp-includes
 /class-wp-query.php:3230, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    8. wpdb->get_results() /var/www/wordpress/example.com/wp-includes
 /class-wp-query.php:2831, referer: https://example.com/wp-
 admin/edit.php?post_type=page
    9. wpdb->query() /var/www/wordpress/example.com/wp-includes/wp-
 db.php:2488, referer: https://example.com/wp-admin/edit.php?post_type=page
   10. mysqli_fetch_object() /var/www/wordpress/example.com/wp-includes/wp-
 db.php:1889, referer: https://example.com/wp-admin/edit.php?post_type=page

 }}}

--
Ticket URL: <https://core.trac.wordpress.org/ticket/24958#comment:18>
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