Re: How to reduce SE .dat & .idx file sizes?

In article <g2vFUGAQaLQ1EwaW@smooth1.demon.co.uk>, David Williams <djw@smooth1.demon.co.uk> wrote: >In article <353F881E.15476F01@fullcompass.com>, Alan W. Jurgensen ><alan@fullcompass.com> writes >> >>WHAT'S THIS "ALTER TABLE (same as an unload/load but more user-friendly)" >>suggestion in the FAQ???? >> > Ah, the old "magic" trick. > > > Go into isql > > Table -> Alter > > Add a column > > magic char(1) > > > then again go into Alter the Table and drop the column magic. > Warning: Alter Table may be dangerous to your application !! Our application used to use the Alter Table trick to compress large tables; the tables are so large that the operation takes as long as an hour. If an Alter Table operaiton is cancelled while it is in progress, due to operation cancellation or machine going down, the database is left in a corrupted state, and support people have to manually massage the system catalogues. The corruption is due to the way Informix implements Alter Table. Specifically, a new table is created, with some of its attributes going into the system catalogues, but not all. For example, the tabname field is left blank. If the Alter Table is aborted, this blank field in the systables system catalogue screws up processing for other Informix processes. We have gone to unload/drop table/create table/reload to avoid this mess.