Spotlight on DB2 6.10 - User Guide

Statement Activity

Value

Elapsed Time (microsec)

The elapsed execution time for a statement. Time is shown in microseconds.

Rows Deleted Internally

The number of rows deleted from the database due to internal activity caused by a statement. The activity can occur when the statement activates triggers on the table being referenced. It can also occur due to a cascading delete that enforces an ON CASCADE DELETE referential constraint. If the number of internal deletes is high, check to see whether the triggers and constraints defined for the table are necessary.

Rows Fetched

The number of successful fetches performed on cursors for a statement.

Rows Inserted Internally

The number of rows inserted in a database due to internal activity caused by a statement. The activity occurs when the statement activates triggers on the table being referenced. If the number of internal inserts is high, check to see whether the triggers defined for the table are necessary. 

Rows Read

The number of rows read from the table referenced by a statement. These are rows that are read to return query results and not rows returned to the application. A high number could mean that a table would benefit from additional indexes.

Rows Updated Internally

The number of rows updated in the database due to internal activity caused by a statement. The activity can occur when the statement activates triggers on the table being referenced. It can also occur due to a SET NULL row update that enforces an ON DELETE SET NULL referential constraint. If the number of internal updates is high, check to see whether the triggers and constraints defined for the table are necessary.

Rows Written

The number of rows changed (inserted, deleted, or updated) in the table referenced by a statement. The number includes rows for temporary tables generated by the database manager in order to execute the statement.

Sort Overflows

The number of sort overflows for a statement. These are sorts that ran out of sort heap and might have required disk space for temporary storage. The I/O required in writing to disk imposes additional overhead.

Sort Time (msec)

The amount of time spent on sorts for a statement. The time is shown in milliseconds. It includes sort time for temporary tables created by the database manager in order to execute the statement. A long sort time could mean that a statement would benefit from tuning or that an index is needed to reduce the need to sort data.

Statement Sorts

The number of sorts performed on the data retrieved by a statement. It includes sorts of temporary tables generated by the database manager in order to execute the statement. A high number of sorts could mean that an index is in order. Indexes can reduce the need to sort data.

System CPU Time (microsec)

The system CPU time used by a statement. The time is shown in microseconds. A long system CPU time could mean that a statement would benefit from tuning.

User CPU Time (microsec)

The user CPU time used by a statement. The time is shown in microseconds. A long user CPU time could mean that a statement would benefit from tuning.