Vincent Courson, Google Search Outreach, has written a blog post about Google’s search indexing problems of late, how it fixed them and lessons it has learned.

In the post, Google explained some of the recent indexing issues the company had over the past few months. This includes the indexing issue with new content from last Thursday, a similar issue from last May and Google de-indexing sites from back in April.

Google’s index is the place where Google stores the results you see in the search results pages. If there is an issue with the index, it can impact what Google serves to searchers. Google stores these URLs in data centers across the world and pushes updates to all those data centers over time.

Google lost part of its index. Google said that it lost part of its index in April because of a deployment issue. “So, as we pushed some planned changes to the Search index, on April 5th parts of the deployment system broke, on a Friday no-less!,” Courson wrote. “More specifically: as we were updating the index over some of our data centers, a small number of documents ended up being dropped from the index accidentally. Hence: we lost part of the index.”

Communication and documentation. Google said that the company communicated the issues over Twitter as quickly as it could. Google also documents these issues in Google Search Console on the data anomalies page and within the Google Search Console reports. In the Google Search Console reports, Google may add an indicator noting the issue and link that over to the data anomalies page.

Here is what that looks like:

Going forward: Google listed three decisions it has made for communicating about indexing issues:

Explore ways to more quickly share information within Search Console itself about widespread bugs, and have that information serve as the main point of reference for webmasters to check, in case they are suspecting outages. More promptly post to the Search Console data anomalies page, when relevant (if the disturbance is going to be seen over the long term in Search Console data). Continue tweeting as quickly as we can about such issues to quickly reassure webmasters we’re aware and that the issue is on our end.

Why we should care. No one wants Google to have indexing issues; not SEOs, not site owners, not advertisers, and not Google. But when things do go wrong, it is useful for the SEO community to know details and timing around the issues to be able to communicate to clients and stakeholders that Google has confirmed the problems and why reports may show less traffic on specific days.