Hi, I'm working on a v13 site which has around 10k content nodes. It has a news search facility on the front-end which uses Examine and separately its Content Delivery API also powers a third-party app. We're finding that both the news search (which relies on the 'out of the box' External examine index) and the Content Delivery API keep failing to yield any results after 'a few days'. Logging into the CMS and rebuilding the indexes fixes it, but that's not a viable long-term solution. I wondered if anyone knows what might be causing the indexes to be dropped and/or if there's a way they can be automatically set to rebuild, periodically? The site is hosted on the client's own Windows VM — it's a decent spec AFAIK but it is used to host several sites. Could it be a memory issue? (Although I thought indexes were written to disk so that might not be too relevant?) Any pointers gratefully received!

Have you checked the logs to see if it shows anything around the time when it stops working? To answer your question, there is an IIndexRebuilder you can inject to rebuild the indexes - you can see Umbraco use it within their own startup here: https://github.com/umbraco/Umbraco-CMS/blob/b0b2b597403bb381c23ff47f2b1ffc8aeaab1dc0/src/Umbraco.Infrastructure/Examine/RebuildOnStartupHandler.cs#L82