Methods, systems and articles of manufacture for selectively maintaining
query implementation information. A user is able to set a Predictive Query Threshold
which will be honored by a database system to determine for which queries information
will be collected. In one embodiment, the decision about whether to collect information
for a query is made before the query starts to run (i.e., before the plan is executed)
by comparing the Predictive Query Threshold to some cost factor (e.g. estimated
runtime). In another embodiment, each query may be monitored but the query implementation
information is only selectively logged. Specifically, the determination as to whether
query implementation information for a query should be logged is made after the
query implementation information is collected.