If you have used Sitecore SXA search components, you are actually using sxacontent_txm field in Solr. It’s a computed field and out of box functionality of SXA that go through all data sources of a page and add all content to the field for search purpose. Pretty handy for setting up your site search quickly.
Above was exactly what I did, however after a certain point, I realised that the site search stopped working and after checking Solr indexes, I found that sxacontent_txm field disappeared.
After some Googling and reading, came across following statements in Sitecore Commerce 9.0 Update 2 and 3’s release notes:
As you can see, this explains why the field is gone and SXA search not working is expected actually. Which matches our case because this happened after Sitecore Commerce was installed on top of our Sitecore instance.
Submitted a ticket to Sitecore in the hope that they probably have a patch already(Sometime they do, just trying my luck XD)
So the reason they do this is due to since it go through all the related items, in Commerce context, there could be too large number of catalogue items the crawler goes through which causes performance issues(Not familiar with Commerce yet, so don’t take this part 100%, just take it as rough idea).
And for now, patch or solution is only on the roadmap, however without any timeline yet. The configuration may be enabled if Commerce has less than 100 items or another way is to not use the sxacontent field but apply custom implementations.