Optimizing queries to hierarchically structured data

Apparatus for processing a query directed b data having a hierarchical structure with a plurality of data nodes, the apparatus comprising:

• a memory;
• and
• one or more processor devices coupled to the memory and configured to:
• identify one or more structural attributes describing the hierarchical structure of the data;
• partition the query into two or more query partitions using at least one of the one or more identified structural attributes;
• determine a parallel execution plan for the query by evaluating strategies comprising:
• a first strategy which splits the query into at least two of the query partitions;
• a second strategy which splits the hierarchical structure of the data;
• and a third strategy which splits both the query and the hierarchical structure of the data;
• select one of the evaluated strategies as the parallel execution to be executed;
• execute the selected parallel execution plan in parallel on different computer processes.

An article of manufacture for processing a query directed to data having a hierarchical structure with a plurality of data nodes, the article of manufacture comprising a computer readable storage medium for storing a computer readable program code which, when executed by a computer, causes the computer to:

• identify one or more structural attributes describing the hierarchical structure of the data;
• partition the query into two or more query partitions using at least one of the one or more identified structural attributes;
• determine a parallel execution plan for the query by evaluating strategies comprising:
• a first strategy which splits the query into at least two of the query partitions;
• a second strategy which splits the hierarchical structure of the data;
• and a third strategy which splits both the query and the hierarchical structure of the data;
• select one of the evaluated strategies as the parallel execution plan to be executed;
• and
• cause execution of the selected parallel execution plan in parallel on different computer processes.