Are you sure you put a dot?
50.000 or 50000?
Makes a big difference...
You can find the complete SQL syntax at the syntax guide. Go to
http://www.ibm.com/software/data/informix
library
Documentation on Informix Products.
Informix Dynamic Server (Your Version).
An example would be, if your table is not fragmented...
ALTER FRAGMENT ON events INIT IN dbspace;
where dbspace is the location where you want to put the table.
If your feeling is that it's a big table, you could fragment it over different dbspaces. 100000 rows is not so big though. Depends a bit on the size of the row.