how much logical log for a BIG alter table?

Hello fellow Informix users, We are having some problems with converting the database for some of our costomers. Because of a datamodel change we have to do an alter table on a large transaction table. On some sites it happened, that the single alter table statement hit a long transaction. Although we could work around it by unloading the table and deleting the contents before the alter table, we'd like to prevent this type of error, since we are using an own made installation tool and the people who are doing the actual conversion, shouldn't be forced into this 'manual trickery'. So we'd like to add an instruction to our upgrade documentation stating something like 'for the conversion of table 'xyz' a logical log size of xx MB per yy K records is required'. Here are my two questions: 1. How can I find out, what exactly is logged per record in the alter table statement and how much space is requiured. 2. Does it make any difference in logical log requirements if I - add 15 fields in one alter table - add 1 field in 15 consecutive alter tables Most of our costomers are running Online 5.0 in ANSI mode. Thanks for your help! Herman. --------------------------------------------------------------------------- Herman Nienhuis Siemens Nixdorf Informationsystems Tel. : ++31 3473 65275 Software Center AP Fax : ++31 3473 65212 Mijlweg 7 Email: hnienhuis.via@sni.de 4131 PJ Vianen, The Netherlands ---------------------------------------------------------------------------