[wp-hackers] ALTERNATE_WP_CRON... Is it worth it?

[Otto]

The ALTERNATE_WP_CRON mechanism works like this:

- User visits the site.
- Cron determines that it needs to run and ALTERNATE_WP_CRON is enabled.
- User gets a redirect to the same page that they're seeing right now,
but with an added doing_wp_cron=... parameter added to the URL.
- User goes to the new address and gets the page. Completely
transparent redirect.
- Meanwhile, the original process that sent the redirect goes off and
does the wp-cron stuff instead, in the background.

So, user won't notice a thing. The redirect is smart, and only happens
when there's actual jobs to be run. It doesn't redirect 1-in-20 or
something like that, or on-the-hour.. it only redirects when there's a
job that needs to get done. No jobs = no redirects.

There is an extremely thin chance that the doing_wp_cron could show up
in the link for a search engine bot, however, WordPress includes the
canonical link in the meta data by default to prevent that additional
query variable from being an issue in search results. No SEO impact.

-Otto


On Tue, Oct 9, 2012 at 1:14 PM, Micky Hulse <mickyhulse.lists at gmail.com> wrote:
> Hey all,
>
> In order to fix this cron error:
>
> <http://core.trac.wordpress.org/ticket/11831>
>
> ...the IS guy at my work opted to enable ALTERNATE_WP_CRON (I was
> kinda hoping he would have tweaked the server vs. patch with the
> alternate cron setting).
>
> The above ticket and the below post seemed to give us the most
> information about the alternate cron:
>
> <http://wordpress.org/support/topic/scheduled-posts-still-not-working-in-282#post-1175405>
>
> I have my concerns about using the alternate cron... Specifically,
> paragraph got me worried:
>
> "This alternate method uses a redirection approach, which makes the
> users browser get a redirect when the cron needs to run, so that they
> come back to the site immediately while cron continues to run in the
> connection they just dropped. This method is a bit iffy sometimes,
> which is why it's not the default."
>
> I guess my question is this: On a medium traffic site (let's say ~1.5
> million page views a month) could the alternate cron redirection cause
> problems for the front end user? What about SEO?
>
> I just don't like the thought of redirects happening for users for the
> sake of a cron that may or may not need to run. Am I being irrational?
>
> I'm wondering if I should just disable ALTERNATE_WP_CRON and turn off
> WP_DEBUG (i.e. out of site, out of mind).
>
> Thanks!
> Micky
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