The scheduling model for a distributed information system is proposed to get the effective way of a query processing. The scheduling model uses internal queries to support a parallel computing, dynamic load balancing and data integrity. The data integrity insured by the two different locking strategies: the page locking or the row locking. We create the simulation model based by the University ITMO distributed system to solve two problems: 1. Estimate the expediency of using the page locking or the row locking. 2. Estimate the influence of the page size at the distributed information system productivity when the system using the page or the row locking. The evaluation of the productivity is the quantity of queries that the distributed information system lost. The simulation model was launched with the different query intensity, the different mean sizes of requested data ("big" and "small" queries) and the different pages (data blocks) sizes. The obtained results can be used by database administrators for choose locking strategy with optimal page size for their own distributed information system.
