Partitioning ownership of a database among different database servers to control access to the database

Abstract

A database or some portion thereof is partitioned into ownership groups. Each ownership group is assigned one or more database servers as owners of the ownership group. The database servers that are assigned as owners of an ownership group are treated as the owners of all data items that belong to the ownership group. That is, they are allowed to directly access the data items within the ownership group, while other database servers are not allowed to directly access those data items. Accordingly, at least a portion of the database is partitioned into a plurality of ownership groups. Each ownership group is assigned an owner set. Only processes that are executing on database servers that are members of the owner set of an ownership group are allowed to directly access data within the ownership group.

Description

RELATED APPLICATION [0001] This application is a continuation of and claims priority to U.S. patent application Ser. No. 10 / 787,965, filed Feb. 25, 2004, entitled “Partitioning Ownership of a Database Among Different Database Servers to Control Access to the Database,” naming as inventor Gianfranco Putzolu, which claims domestic priority as a continuation application of prior U.S. patent application Ser. No. 09 / 896,373, filed Jun. 28, 2001, issued on Mar. 23, 2004 as U.S. Pat. No. 6,711,571, entitled “Partitioning Ownership of a Database Among Different Database Servers to Control Access to the Database,” naming as inventor Gianfranco Putzolu, which claims domestic priority as a continuation application of prior U.S. patent application Ser. No. 09 / 222,577, filed Dec. 28, 1998, issued on Nov. 20, 2001 as U.S. Pat. No. 6,321,238, entitled “Hybrid Shared Nothing / Shared Disk Database System,” naming as inventor Gianfranco Putzolu, the contents of which are hereby incorporated by referen...

AI Technical Summary

Problems solved by technology

In addition, there are scalability limits to shared everything architectures.

However, shared disk systems are more susceptible to unbalanced workload conditions.

For example, if a node has a process that is working on a work granule that requires large amounts of dynamic memory, the memory that belongs to the node may not be large enough to simultaneously store all required data.

Consequently, the process may have to swap data into and out of its node's local memory even though large amounts of memory remain available and unused in other nodes.

Shared disk systems provide compartmentalization of software failures resulting in memory corruption.

However, shared nothing systems are the most susceptible to unbalanced workload conditions.

Shared nothing systems provide compartmentalization of software failures resulting in memory and / or disk corruption.

Hence, the ownership techniques are simpler and more reliable than the shared disk lock management techniques, because they do not have high performance requirements.

Typically, however, these two types of architectures are mutually exclusive.

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