Re: How to change column type NCHAR back to CHAR

Richard Spitz wrote: > > Hi Informixers, > > due to the abysmal performance of MATCHES queries against NCHAR columns > (this is a "bug called feature" that Informix has finally acknowledged > and is working on) I have to change back quite a few of these columns > back to CHAR. This is on Informix IDS 7.30UC6, DB_LOCALE (and CLIENT_LOCALE) > is de_de.8859-1. > > From the description of the "IN PLACE ALTER TABLE" in the Performance > Guide, this change is not in the list of modifications that can be done > in place. So I assume that the tables will have to be completely rebuilt, > freeing the space originally used by them and starting at a different > location on disk. Will extent information for that table be automatically > carried over, or do I have to tweak manually there? I want to avoid frag- > mentation of these tables over several extents across the disk. > What happens with indices that are defined on these columns? Will they > be changed or rebuilt automatically, or do I have to do rebuild them > manually? The values of EXTENT SIZE and NEXT SIZE will carry over. However the actual extents will depend on what contiguous space is available. Run oncheck -pT to see both the table's extent report and the ALTERversions to see if the ALTER was indeed not done in-place. Art S. Kagel