As far as I know I haven't used Ajax anywhere in my code. Yet, while debugging, I have breakpoints being hit with 'admin-ajax.php' at the root of the call stack. This second hit of my breakpoint occurs between 10 and 30 seconds after the original. The weird thing is, as of yet there is no HTML output, so no scripts are present in the browser.
Any ideas why or where this is happening and why my php scripts are being called twice?
This is probably the new Heartbeat API. It is running in intervals from 15 to 60 seconds and offers a simple way to communicate with WordPress per AJAX in the background.
You can disable it in JavaScript with wp.heartbeat.stop(); and in PHP with remove_action( 'admin_init', 'wp_auth_check_load' ); (might not be enough on some pages).
Plenty of related snippets out there seems to no longer apply because code was considerably refactored.
This seems to be closest I got to stopping it without exploding things (as of 3.8):
add_action(
'admin_print_footer_scripts',
function () {
?>
<script type="text/javascript">
jQuery(document).ready(function ($) {
$(window)
.off('blur.wp-heartbeat-focus')
.off('focus.wp-heartbeat-focus')
.trigger('unload.wp-heartbeat');
});
</script><?php
}
);
Placing this in functions.php turns off Hearteat API
add_action( 'init', 'my_deregister_heartbeat', 1 );
function my_deregister_heartbeat() {
global $pagenow;
if ( 'post.php' != $pagenow && 'post-new.php' != $pagenow )
wp_deregister_script('heartbeat');
}
I've not tested it myself but you can check out more here: http://wordpress.org/support/topic/admin-ajaxphp-being-called-from-admin-pages-causing-db-connection-issues
To disable the heartbeat check you can use this code:
add_action( 'init', 'my_deregister_heartbeat', 1 );
function my_deregister_heartbeat() {
global $pagenow;
if ( 'post.php' != $pagenow && 'post-new.php' != $pagenow )
wp_deregister_script('heartbeat');
}
source: @azaozz/core.trac
