While I don't actually know the solution to your search problem, I can explain why "old:" works. That uses a different search/indexing mechanism. My understanding is that it's not as efficient, but it's nice to have as a backup. That said, when you try and search without it, do you get any errors in the logs? If you run tracer, do you get any errors there?
I have to admit, in my experience of using a lot of different Pega instances here within Pega itself, quite often when I search for something, say FOO, I get nothing-matched, so I merely type old:FOO and then I get stuff. It's almost gotten to the point where I immediately type old:FOO without even bothering with the non-old attempt first. /Eric
Thanks for the details. From the tracer I was able to figure out that in line 1803, the check for whether to use distributed mode (Elastic Search) is coming as false because of which it is searching in the older Lucene index rather the Elastic Search index.
Please check the values of the following Data-Admin-System-Settings instances
Note that all of them should be true. If not, please change them to true and re-index work.
Thanks for all your help. Providing me with the complete path "indexing/distributed/search_enabled" made it easier to find the DSS entry. I saw that it was set to false - I set it to true and now it works.
In general you should not worry about setting these. If the upgrade guide was followed correctly, where all the indices were built from the search landing page, this setting would have been set to true by the platform itself. Looks like, it did not happen in this case. You can refer to the details in this PDN post (upgrade guide is referred at the very end) - https://pdn.pega.com/release-note/improved-full-text-search