I have recently started having core dump files

I have recently started having core dump files in public_html folder. I've downloaded a couple of them and run "gdb -c" on them, and it tells me they were generated by wp-cron.php.

So I installed a cron view plugin to see what's set up. The only two things which happen as frequently as the core files are generated are the following...
Jul 4, 2013 @ 23:32 (1372980771) Every 5 Mins membership_communications_process
Jul 4, 2013 @ 23:37 (1372981068) Every 15 Mins membership_perform_cron_processes_quarterhourly

So it looks like it's pointing to the membership plugin. Are there any open issues on this?

Am I safe to verify my theory by deactivating the membership plugin? I have a site that is going live in 3 days and cannot risk losing all the membership setup!

Though I have seen core files 1 minute apart - which is obviously more often than the 5 minutes cron.

I am running WP3.5.2 with all plugins up to date.

Thanks,
Andy

  • andy_paterson

    Yes, there was one inactive communication that I had set up as a test once. I have deleted that now, but have seen another core file appearing.

    If I've understood correctly from reading up on WP cron jobs, WP runs cron stuff when users view pages, but I can disable that via a define and set it up in my cpanel. I could then possibly get that to email me on each cron job and in order to compare the times of core files and cron jobs.

  • andy_paterson

    I think I have (hopefully!) resolved this, and the membership plugin is out of the picture. I followed some instructions on disabling the wp cron job and setting it up in cpanel so that I could get some further stats. As I have a multisite setup I had to set a couple of cron jobs up. I set them for different interval times, and then after a while I could see that the core files time stamps matched a particular site (which doesn't have membership plugin). This site however did have a frequent job set up by the 'WordPress Backup to Dropbox' plugin. I hadn't realised that this plugin would have it's cron job listed in a different site - the settings page for it is in the network dashboard, so I hadn't looked in this other site. (I guess this other site was the first site, so is the main/default one.)

    So I've stopped the dropbox backup, (temporarily) changed my cron job to be every minute, and will hopefully have no core files in the morning!

  • andy_paterson

    Just for the benefit of others...
    Setting this plugin to stop backing up was not efficient. By the morning there were a load more core files. They started at 4.01am and then I could see in error_log the following:
    [06-Jul-2013 03:01:05 UTC] WordPress database error Table 'myusername_wp1.wp_sitecategories' doesn't exist for query SHOW CREATE TABLE wp_sitecategories made by do_action_ref_array, call_user_func_array, run_dropbox_backup, WP_Backup->execute, WP_Backup_Database_Core->execute, WP_Backup_Database->backup_database_tables
    [06-Jul-2013 03:01:05 UTC] WordPress database error Table 'myusername_wp1.wp_sitecategories' doesn't exist for query SELECT COUNT(*) FROM wp_sitecategories made by do_action_ref_array, call_user_func_array, run_dropbox_backup, WP_Backup->execute, WP_Backup_Database_Core->execute, WP_Backup_Database->backup_database_tables

    Given perhaps an hour time difference between systems (since I am in BST at the moment, compared with GMT) I decided that it wasn't a coincidence, and so I just deactivated the back up plugin. No core files since then, but we'll see!

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