Help about ALTER TABLE tablename drop VERCOLS

Hello, my friends. Informix 11.50.FC9W2GE, in linux_64 RedHat boxes (a cluster, with one HDR, and one SDS boxes). I am trying to find something more specific about drop VERCOLS, but nothing found in the manuals yet. If I start that command in one huge table (in OLTP system with unbuffered logging), does the engine start an implicit transaction? I wish I could avoid a LONGTX, in that case, and also try to avoid a table rebuild. Thanks a lot, anyway. Regards.