If you cannot diagnose the problem using these hints, the following information will be needed by Sybase Technical Support to determine the source of the problem:
The table and index schema—create table, alter table...partition, and create index statements are most helpful. Provide output from sp_help if the actual create and alter commands are not available.
The output of the query run with commands:
dbcc traceon (3604,302, 310)
set showplan on
set noexec on
The statistics io output for the query.