Total estimated I/O cost message

Total estimated I/O cost for statement N (at line N): X.

Adaptive Server prints this message only if a System Administrator has configured Adaptive Server to enable resource limits. Adaptive Server prints this line once for each query in a batch. The message displays the optimizer’s estimate of the total cost of logical and physical I/O. If the query runs in parallel, the cost per thread is printed. System Administrators can use this value when setting compile-time resource limits.

See “Total actual I/O cost value” on page 780 for information on how cost is computed

If you are using dbcc traceon(310), this value is the sum of the values in the FINAL PLAN output for the query.

The following example demonstrates showplan output for an Adaptive Server configured to allow resource limits:

select au_lname, au_fname
from authors 
where city = "Oakland"

    STEP 1
        The type of query is SELECT.

        FROM TABLE
        Nested iteration.
        Table Scan.
        Forward scan.
        Positioning at start of table.
        Using I/O Size 16 Kbytes for data pages.
        With LRU Buffer Replacement Strategy for data pages.

Total estimated I/O cost for statement 1 (at line 1): 1160.

For more information on creating resource limits, see in the System Administration Guide.