Long loads or queries may cause issues.
Monitor paging to determine if thrashing is a problem.
Reset your buffer sizes as needed.
You can also limit the amount of thrashing during a query execution that involves hash algorithms. Adjusting the HASH_THRASHING_PERCENT database option controls the percentage of hard disk I/Os allowed before the statement is rolled back and an error is returned.
The default value of HASH_THRASHING_PERCENT is 10%. Increasing the value permits more paging to disk before a rollback, and decreasing the value permits less paging before a rollback.
Queries involving hash algorithms that executed in earlier versions of SAP Sybase IQ may now be rolled back when the default HASH_THRASHING_PERCENT limit is reached, and you may see either of these messages:
To identify possible problems with a query, generate a query plan by running the query with the temporary database options QUERY_PLAN = 'ON' and QUERY _DETAIL = 'ON', then examine the estimates in the query plan. The option QUERY_PLAN_AFTER_RUN = 'ON' provides additional information, as the query plan is printed after the query has finished running. The generated query plan is in the message log file.