Just to catch you all up, on Monday afternoon we saw some insane changes to the search results rankings. Google confirmed later it was a bug and things were back to normal. Google then explained the bug stemmed from the indexing system. But what does that mean?
Here is Google's response on Twitter with what happened "On Monday we detected an issue with our indexing systems that affected Google search results. Once the issue was identified, it was promptly fixed by our Site Reliability Engineers and by now it has been mitigated."
On Monday we detected an issue with our indexing systems that affected Google search results. Once the issue was identified, it was promptly fixed by our Site Reliability Engineers and by now it has been mitigated.
— Google Webmasters (@googlewmc) August 11, 2020
Thank you for your patience!
What does that mean? Well, I assumed it means everything is connected. Something broke with the indexing system and it caused a ripple effect with the search results you saw on Monday night.
Gary Illyes from Google shared more details on Twitter on how things are connected:
The indexing system, Caffeine, does multiple things:
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
1. ingests fetchlogs,
2. renders and converts fetched data,
3. extracts links, meta and structured data,
4. extracts and computes some signals,
5. schedules new crawls,
6. and builds the index that is pushed to serving.
Don't oversimplify search for it's not simple at all: thousands of interconnected systems working together to provide users high quality and relevant results. Throw a grain of sand in the machinery and we have an outage like yesterday.
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
Okay, got it. But tell me more Gary...
Something was wrong with the index he said, it had to be rebuilt and it is rebuilt fast:
We still had the index (the index db), but something was wrong with it, because of how it was built by Caffeine. That's why we said it was an indexing issue, which manifested as a ranking issue externally.
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
Also, we can rebuild the whole serving index (db) within hours, yes.
The indexing system issue caused really different results to rank. Now, I saw new content ranking fine, so it was some sort of other indexing issue. It was not that Google couldn't index new content. It maybe lost signals or something within its index causing ranking issues?
Gary added that the index database was not damaged but the results from where it was served was incorrect. Why? Something went wrong with Caffeine, let me take you back to 2009 when Google launched Caffeine. It was Google's new infrastructure for its index, it was a faster way to get stuff into the index. Well, I guess Google is still using it 10+ years later. In any event, something went wrong with it:
「ということは、ルート①で、インデックスDBは、損傷が無かったという事ですね。」
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
the index db from where the results are served was incorrect, because of how caffeine built it. That's why the ranking was affected
It was not "strange data" but rather a "strange index" he said:
"strange index" would be more correct i think
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
Gary said this diagram that illustrates how data got into the system was why things did not work. Whatever Google did caused bad data to come in and then out to the search results searchers see. Here is what was illustrated:
that's pretty good!
— Gary 鯨理／경리 Illyes (@methode) August 11, 2020
Does this clarify anything for you all? In short, it looks like something went wrong when Google was building the index that caused weird search results to be produced to searchers. But I know it is way more complex than that.
Forum discussion at Twitter.
Gary commented on this:
Just to clarify, this is still a gross oversimplification, and it's just an illustration of how one thing can affect something else. Butterflies, anyone?
— Gary 鯨理／경리 Illyes (@methode) August 12, 2020
Also, thanks to all those who pointed out that we were wrong and this was, in fact, a ranking issue. 🙄 https://t.co/e8PsqZfs9P
