fragmentation

I have a table, ds_archive, I just run alter fragment on table ds_archive add partition pt7 (archive_dt >=datetime(2008-01-01 00:00:00) year to second) AND (archive_dt < datetime(2009-01-01 00:00:00) year to second ) in dbdw1 before rmd; and added the fragment pt7(see below). It took more than half hour and locked the whole table to do that.( not tolerable for online maintenance) Fact: The remainder fragment has no data. Observation: Looks IDS does not take the knowledge about the fragmentation criteria, otherwise the Alter statement should be finished fast. Thanks, Frank create table "informix".ds_archive ( dataset_name varchar(255,44) not null , archive_site char(10) not null , path_name varchar(250,50), archive_dt datetime year to second ) with crcols fragment by expression partition pt1 (archive_dt < datetime(2006-01-01 00:00:00) year to second ) in dbdw00 , partition pt5 ((archive_dt >= datetime(2006-01-01 00:00:00) year to second ) AND (archive_dt < datetime(2007-01-01 00:00:00) year to second ) ) in dbdw01 , partition pt6 ((archive_dt >= datetime(2007-01-01 00:00:00) year to second ) AND (archive_dt < datetime(2008-01-01 00:00:00) year to second ) ) in dbdw01 , partition pt7 ((archive_dt >= datetime(2008-01-01 00:00:00) year to second ) AND (archive_dt < datetime(2009-01-01 00:00:00) year to second ) ) in dbdw01 , partition rmd remainder in dbdw01 extent size 4096 next size 4096 lock mode row; create index "informix".ds_arch_idx on "informix".ds_archive (archive_dt) using btree ; create unique index "informix".ds_arch_uidx on "informix".ds_archive (dataset_name,archive_site,archive_dt) using btree ; alter table "informix".ds_archive add constraint primary key (dataset_name,archive_site,archive_dt) constraint "informix" .ds_arch_pk ; -- Yunyao "Frank" Qu Computer Sciences Corporation(CSC) NOAA/CLASS, (301)817-4696