What happens to data after Index partition limit is reached?

I was reading index partitioning and after reading through the docs, found out that, the index partitioning has limits with respect to number of partitions. What exactly happens after partition limit is reached?

For example considering the below index example, I’m trying to partition is based on day and airline as most of my queries are based on day. Example how many travelled from a source to destination in a day…and so on…

As keep running the application for days for sure I will hit the partition limit which I set while creating the index., after hitting the limit will indexes stop performing or will the recents days partition override the old days partition?

What is the maximum partition number allowed?

CREATE INDEX idx_pe11 ON travel-sample(day, sourceairport, destinationairport, airline)
PARTITION BY HASH(day, airline) WITH {“num_partition”:16};

Thanks in advance!

AS you specified num_partition during DDL. You should give reasonable number. It based on HASH of given keys. Then map hash code to one of the partition (partition will have multiple hash codes some thing hashcode % num_partition). It will never exceed during DML.