Commented by: @AlexPeshkoff

I don't understand why was it added as a feature request. Blob filters work in firebird for a long-long time. Just write your compress/decompress filter, define needed blob sub-type - and go.
What am I missing here?
Certainly, storing compressed BLOB data in system tables may be a feature request, but I doubt you've meant it. And anyway it is not clear from your request.

Commented by: m_Th (m_th)

Theoretically you're right. But in practice no one will do it, IMHO. Giving what documentation is available for doing such a thing, how many users knows where to search for, how many users have the required programming skills to do it (remember that the percent of the users which knows C/C++ is very small in Fb user base) in order to know to do it, to have VS or gcpp or, better, both - to know the Firebird's calling conventions and structures, to have the time to do / test / mantain a cross-platform version both for the filter and for the compressing engine, renders the probability to have such a feature towards to 0 (zero). And the worse of all things is the user's perception that the BLOB filters are something 'esotheric' and 'dark'. The harderst thing is to change the way of thinking of your user base. And now we need to expand this user base not to scary them. We need distinguishing features not to tell something like: "Ok, here are the sources, compile them as you wish, you have somewhere in the source tree the SQZ.cpp. you can fix also a BLOB filter if you want compression, but it's your bussiness how to code, test and deploy it". For you, instead, which are a skilled C++ developer and know the internals of Fb a wrapper arround SQZ.cpp engine is very easy to do. It will be reliable, cross-platform, and "auto registering" in all databases - a feature which users often ask (ie. to have embedded functions / global UDF aso.). That's why I proposed this. Unfortunatelly the outside world doesn't have your skills and their TCO (total cost of ownership) and TTM (time to market) doesn't permit them to deal with such things. We need to minimize these, if we can afford.

hth.