I have few thousands posts and need to list all of them in the admin. When I used WP_Query to get them all at once I got a memory error. Then I split it into several query calls and it worked just fine with 256 MB limit. Here is the code:
$limit = 200;
$offset = 0;
while (TRUE) {
$posts = new WP_Query(array(
'posts_per_page' => $limit,
'offset' => $offset,
'post_type' => $post_type,
'orderby' => 'title',
'order' => 'ASC',
'post_status' => array('publish', 'private', 'draft', 'inherit'),
));
if (!$posts->have_posts()) break;
while($posts->have_posts())
{
$posts->the_post();
# do some echoing with the $post
}
$offset += $limit;
} /*(TRUE)*/
So this works just fine on development server. But when moved to production, it throws memory error Allowed memory size of 268435456 bytes exhausted (tried to allocate 64 bytes) ...
I tried lowering the $limit
but it doesn’t help (on dev it actually works just fine with $limit = 500
.
What else can I do to force it to release memory?
2 Answers
The posts are still held in memory under WordPress’ cache mechanism (even though you replace $posts
on every loop) – delete each one after operating on it:
# do some echoing with the $post
# wipe post from memory
wp_cache_delete( $post->ID, 'posts' );
wp_cache_delete( $post->ID, 'post_meta' );
Pro tip: save some needless queries with no_found_rows => true
in your query args.
And if you’re not using categories/tags in your loop, save even more queries (& memory) with update_post_term_cache => false
in your query args.