[wp-hackers] Alternative or reactivation for get_blog_info()

Andrew Nacin wp at andrewnacin.com
Thu Jul 25 06:37:52 UTC 2013

On Wed, Jul 24, 2013 at 5:18 AM, Malte Witt <m.witt at ia-sh.de> wrote:

> I stumbled upon this a few days ago, too.
> In my opinion get_blog_list() is perfectly fine. The Codex and the source
> is just saying: "For performance reasons this function is not recommended."
> That's true for installations with thousands of blogs. But I think most
> multisite installations out there in the real world have 3 to 100 sites and
> they have a perfect valid usecase for get_blog_list().
> If there is a no other reason why the function is deprecated (and I can't
> see any) I would say just reactivate it and place a big warning sign in the
> Codex, that this function shouldn't be used in super-large multisite
> installations.
> In short: +1 for reactivation of get_blog_list().

It's really just a poorly written function. No caching, no LIMIT (but does
"limiting" with an array_slice()), hits every site's posts table, etc. This
is one of the more dangerous functions performance-wise in core (probably
the most dangerous) because of how nasty it can be. If you have thousands
of sites, you'll run out of memory. If you have hundreds of sites, it could
take a long while to run. Even if you only have a few dozen sites, if you
have large post tables, this could take a few seconds to calculate. If it
actually did a proper LIMIT for both $start and $num, it'd be a lot better
off, but it's still pretty lame.

I've always had in my head a more robust WP_Site_Query, to be modeled after
WP_User_Query, WP_Comment_Query, and WP_Query. Fully functional arguments,
proper limiting, only touching the blogs table (post count is superflous —
query it yourself only if or when you need it), having numerous filters and
built-in caching (WP_Comment_Query does this well, IIRC), declining to do
anything when wp_is_large_network(), etc. Even though we've yet to get
around to making such a replacement, I have no regrets for us marking
get_blog_list() deprecated. What a terrible function.


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