Resource limits allow you to limit resource usage in different ways, including by I/O
cost, elapsed time, row count, tempdb space usage, and idle time.
Limiting I/O Cost
I/O cost is based on the number of logical and physical accesses (“reads”) used during query processing. To determine the most efficient processing plan before execution, the SAP ASE optimizer uses both logical and physical resources to compute an estimated I/O cost.
Limiting Elapsed Time
Elapsed time is the number of seconds required to execute a query batch or transaction, determined by such factors as query complexity, server load, and waiting for locks.
Limiting the Size of the Result Set
The row_count limit type limits the number of rows returned to the user. A limit violation occurs when the number of rows returned by a select statement exceeds the limit value.
Setting Limits for tempdb Space Usage
The tempdb_space resource limit restricts the number of pages a tempdb database can have during a single session. If a user exceeds the specified limit, the session can be terminated, or the batch or transaction aborted.
Limiting Idle Time
Idle time is the number of seconds that a connection remains inactive, waiting for user input. An inactive connection continues to use server resources, and may also hold resources (for example, locks) that can block other active processes running on the same server.