Method for identifying discreted deadlock conditions on the multiple database system

摘要

1. TECHNICAL FIELD OF THE INVENTION;The present invention relates to a distributed deadlock identification method in a multiple database system.;2. The technical problem to be solved by the invention;The present invention seeks to provide a distributed deadlock identification method that identifies all deadlocks that may occur while ensuring maximum system performance.;3. Summary of the Solution of the Invention;In the distributed deadlock identification method applied to a multi-database system, a first step of checking whether a timed out transaction exists and initializing an index value I of a local database and setting a read-only variable to true ; A second step of checking whether the number of the local databases is equal to or larger than the index value of the local database, initializing the access index value J of each local database, and initializing the number of accesses to the I-th local database; If the number of accesses of the I-th local database is greater than or equal to 'J', the number of accesses to the I-th local database is increased by a predetermined first number, 'J' is increased by a predetermined first number, and the number of accesses of the I-th database is increased. A third step of setting the flag to true; If the number of accesses of the I local database is not greater than 'J', check whether the flag of the 'I' local database is true, and if the flag is true, initialize 'J', specify a read-only variable, and set the flag to true. Otherwise, determining whether all accessed transactions are in read mode; A fifth step of extending a time for waiting for a response from a local database if all transactions accessed in the fourth step are in a read mode; And a sixth step of retracting the timed out transaction by checking a flag of the local database and the number of accesses to the local database if all the transactions accessed in the fourth step are not in the read mode.;4. Important uses of the invention;The present invention is used in multiple database systems.