Query execution and optimization with autonomic error recovery from network failures in a parallel computer system with multiple networks

摘要

A database query execution monitor determines if a network error or low performance condition exists and then where possible modifies the query. The query execution monitor then determines an alternate query execution plan to continue execution of the query. The query optimizer can re-optimize the query to use a different network or node. Thus, the query execution monitor allows autonomic error recovery for network failures using an alternate query execution. The alternate query execution could also be determined at the initial optimization time and then this alternate plan used to execute a query in the case of a particular network failure.

主权项

1. A computer apparatus comprising:
a plurality of nodes each having a memory and at least one processor; a database residing in the memory; a plurality of independent networks connecting the plurality of nodes; a network monitor that periodically monitors the plurality of independent networks to determine network loading and maintains a network file that contains information about network utilization for the plurality of independent networks; a query optimizer and a query to the database residing in the memory, wherein the query optimizer optimizes the query by generating an execution plan that includes using a network of the plurality of independent networks to execute the query; a query execution monitor residing in the memory and executed by the at least one processor, the query execution monitor detects a network failure on the network during execution of the query and in response to the network failure invokes the query optimizer to re-optimize the query by generating an alternate execution plan for the query to use a different independent network to execute the query, where the selection of the different independent network by the query optimizer is based on the information in the network file; wherein the network file is used by the query execution monitor and wherein the network file contains network file information comprising: network ID, a timestamp; current utilization, future utilization, availability, latency, and retransmits.