SQLite only knows nested loop joins and the bloom filter can just tell us "no need to do a join, there is definitely no matching entry".

If it has a false positive all the time (the worst case) then the performance is the same as before the bloom filter optimization was implemented (besides the small bloom filter overhead).

As the bloom filter size in SQLite directly depends on the table size I estimated a false positive rate of 63.2% due to this bug, while it could have been just 11.75%.

It actually would have performed faster, but the false positive rate drastically increased.

90%?