Re: Serious Assistance with PostgreSQL True Infinite Arbitrary Precision Maths.

I'm guessing from the silence, and my subjective opinion that this kind of need in a relational database - an innovation of the business world - is especially rare, that the probability that your particular combination of requirements exists is basically zero.  Especially as the one project you found, pgmp, no longer seems to be developed and in its current state doesn't meet your requirements.  In short, I'm doubting that you will find something that is both free of money and your effort.  On the positive side, it seems the harder part of all this, the math library, already exists.  And its is most likely possible to get a working API to that in PostgreSQL in a manner similar to the pgmp project.  So the needed effort is hopefully just in gluing the two worlds together.

As you are already using a C++ library the following section of the documentation [1] may help.  Figuring out how to write a wrapper-oriented extension over top of the C++ ttmath library seems doable.  Especially since you have the pgmp project to use as a jumping off point (I'm guessing there are some C++ wrapped extensions out there too - even if not for this specific library).  Licensing is something to consider though - and outside my willingness to advise upon.

1. https://www.postgresql.org/docs/current/xfunc-c.html#EXTEND-CPP

David J.