We have some result on incremental update for MVs. We generate triggers in C to do the incremental maintenance. We posted the code to github about 1 year ago, but unfortunately i posted a not-right version of ctrigger.h header. The mistake was exposed to me when a person could not compile the generated triggers and reported to me. And now i re-posted with the right ctrigger.h file.
You can find the codes of the generator here: https://github.com/ntqvinh/PgMvIncrementalUpdate/commits/master. You can find how did we do here: https://link.springer.com/article/10.1134/S0361768816050066. The paper is about generating of codes in pl/pgsql. Anyway i see it is useful for reading the codes. I don't know if i can share the paper or not so that i don't publish anywhere else. The text about how to generate triggers in C was published with open-access but unfortunately, it is in Vietnamese.
