Linked-in delinked! What on earth happened to it?

This morning  a strange sight greeted me when I tried to get on to Linked-in –  a HTTP 500 error!! Never have I encountered such a thing with any major online service that is delivered from a worldwide CDN (Content Delivery Network).

A couple of servers down here and there and minor disruptions in service (slow load-time due to rerouting) is understandable, but a 500 error? As far as I know, this occurs only if there’s something severely wrong with the application’s code causing Apache to hiccup and die while trying to deliver it.

And for Linked-in to be knocked out on this scale, the same code-base must have propagated to all their servers across the world.

Linked-in down

If you ask me it’s outright callousness on part of their dev team to let something like this happen. Even if I were to consider that someone’s been playing naughty with ’em, I can’t imagine on what scale the hacking would have happened to make their whole network behave the same way!!

P.S. By the time I got over with writing this post (11:20am UTC+7), they’re still in the same state. Someone probably needs to stick a finger in their eyes and point it out… they can at least afford to put up a graceful “Maintenance mode” page, till they rectify this.

Feedburner: When you face a – Your Ping resulted in an Error “Ping is throttled. Please try again in a minute or so.”

Content TheftYesterday I came upon a couple of splogs ripping off my feeds and publishing the content as their own – lock, stock and barrel (if I may), including the ugly SHA1 hash that I was using as a digital fingerprint to detect content theft.

Digital fingerprints (a unique combination of random characters) happen to be a very good way of nabbing content rippers. 99.99% chances are that these people use automated programs (bots) that scrape content off third-party blogs  (primarily from feeds) and post as their own, which are then used in conjunction with various monetization programs (e.g. AdSense) to generate revenue for the splogger. The scraper bots make verbatim copies of your content and are unable to distinguish between actual content and the fingerprint – hence that too gets published in the splog. Catching such rip-offs can be as simple as doing a Google search for your fingerprint.

Problem lies with that fact that an ugly string of random characters is appended to each of your feed item, which gets displayed to your valid subscribers too. It short, it “destroys” the presentation, creating a nasty impression about your blog. Sploggers on the other hand aren’t bothered by this as all they care about is posting content and making money from it.

While the fingerprint helps you detect content theft, there isn’t much that you can do about it except for going through a lengthy process of serving a notice to the splogger and then informing the web-host (citing the DMCA) in case of non-action. Hence, I decided to get rid of the fingerprint and append a custom copyright message to my feed footers instead – with links back to my post and blog. At least this way it earns me some form of attribution – without making the feed look ugly.  Incidentally, the most suitable plugin I found for this job is Better Feed.

What’s all this got to do with FeedBurner?

Coming to that in a moment. That was a rant that I absolutely HAD TO get out of my system.

Once I was done with my new feed footer,  I tried using the FeedBurner Ping service to update my feed.  That’s when this error message got shoved into my face…

Your Ping resulted in an Error “Ping is throttled. Please try again in a minute or so.”

Googling for it didn’t fetch me any solution – just pages upon pages of complaints to the same effect. Most likely, it’s a problem that’s taken roots in recent times. Whatever, the cause was, it kept me at bay for hours! It simply wouldn’t let me see my updated feed (my blog feed is set to auto-redirect to FeedBurner).

The Solution

Feedburner "Resync now" buttonUse the Resync Now button that’s situated towards lower part of the Troubleshootize page of FeedBurner. When all else fails, hit the big red button 😀

The resync button…

  • Clears our cached version and refreshes its content from your Original Feed
  • Creates podcast enclosures for items that did not previously have them and contain links to podcast content
  • Reports any feed formatting problems encountered during the resync

… Voila! My updated feed appeared rightaway. So, if you’re facing a similar error message, my recommendation is to try the Resync button. It works.

Update: Finally came up with some information on the ping is throttled error message. Indeed, it is an issue that cropped up recently – but, at least now we have an explanation.

Table ‘wordpress.wp_post2cat’ doesn’t exist – Error while upgrading to WordPress 2.3

Just today I performed an upgrade to the brand new WordPress 2.3.

Problem #1

The upgrade went without a hitch but the moment I refreshed my site I got this long error message that went like…

WordPress database error: [Table 'wordpress.wp_post2cat' doesn't exist]
SELECT p2c.category_id AS cat_id, COUNT(p2c.rel_id) AS numposts, UNIX_TIMESTAMP(max(p.post_date_gmt)) + '0' AS last_post_date, UNIX_TIMESTAMP(max(p.post_date_gmt)) AS last_post_date_gmt FROM wp_post2cat p2c INNER JOIN wp_posts p ON WHERE (p.post_status='publish' OR p.post_status='static') AND p.post_date_gmt<='2007-09-27 11:44:24' GROUP BY p2c.category_id ORDER BY numposts DESC...

The same error kept appearing on the top of every single page. Now be aware that this new version of WordPress has a radically different table organisation. In all probability that was the cause of this error.

My first task was to disable every single plug-in I had installed. I was hoping that the error would go away immediately. It did not. After a bit of investigation I figured that even though the WP-Cache plug-in was disabled, it kept delivering the cached pages nevertheless. Deactivating it from the Plugins Panel didn’t help much. What I had to do was to go to Options > WP-Cache and disable it there. Only then did the caching stop.

The next step involved reactivating the plug-ins one-by-one and refreshing the site every time to see which plug-in was causing the error. I know it’s a painstaking task – but there’s no easy way out. Of course, you can make some well-aimed guesses, as the most likely culprit(s) are the plug-in(s) dealing with post categories, keywords, tags etc. Likewise, it didn’t take me long to catch the darned plug-in red-handed. Turned out to be Jerome’s Keywords (v2.0 beta 3). I use the Jerome’s Keywords Related Posts plug-in to display reading suggestions after each post. This plug-in in turn is dependent on Jerome’s Keywords.

As of now, I don’t think there’s any solution to this – except for deactivating the plug-in. I’ve posted a comment at the author’s site and waiting for some sort of a response.

Problem #2

As soon as I tackled the first one, a new one crept up silently and threw me off-balance again. This time the error message appeared when I tried to create a new post and save it. The screen went totally blank except for a lonely error message…

WordPress database error: [Table 'wordpress.wp_categories' doesn't exist]
SELECT c.cat_ID AS ID, MAX(p.post_modified) AS last_mod FROM `wp_categories` c, `wp_post2cat` pc, `wp_posts` p WHERE pc.category_id = c.cat_ID AND p.ID = pc.post_id AND p.post_status = 'publish' AND p.post_type='post' GROUP BY c.cat_id...

This one wasn’t hard to diagnose as half of my plug-ins were already deactivated. I simply started rolling back the activations one-by-one and had the trouble-maker in a minute or two. This time it was Google XML Sitemaps Generator (v3.0b8). Visiting the authors site took me to a post at the support forum at Seems like this version of the plug-in has some sort of a conflict with Popularity Contest. The solution is quite simple here. Simply download the new v3.0b10 of this plug-in and update it. The error message disappears right-away.

So here are two very common problems you’re going to face while upgrading to WordPress v2.3. This post is intended to help those who’re facing the same problem and groping in the dark as I was a couple of hours back.

All the best.