Method of optimizing data processing, information processing apparatus and program

An information processing apparatus, comprising:

• at least a processor;
• and
• a memory in circuit communication with the processor,
• wherein the processor is configured to execute program instructions stored in the memory to implement:
• a query analysis part that analyzes queries to be processed and determines whether or not a first operation is included in the queries to be processed;
• a query optimization part that performs a query optimization process;
• and
• a query execution part that executes the queries to be processed after optimization by the query optimization part, wherein
• the first operation comprises joining a first table and a second table, each having a common key, to generate a merged table, and projects a value of one or more project target column(s) of records in the merged table,
• the query optimization process comprises determining whether content of the first operation satisfies a first condition and a second condition, if the query analysis part determines that the queries to be processed include the first operation, and replacing the first operation in the queries to be processed with a second operation, if the content of the first operation satisfies the first condition and the second condition,
• the first condition is that each value of the common key in the second table is unique,
• the second condition is that all of the project target columns are included in the first table, and
• the second operation comprises;
• identifying a value(s) of the common key of record(s) in the second table, as a target value(s);
• and
• projecting value(s) of the project target column(s) of a record(s) having the target value(s) in the common key column of the first table.

A non-transitory computer-readable medium storing a A program causing a computer performing optimizing data processing including a first operation, the first operation including joining a first table and a second table, each having a common key, to generate a merged table, and projecting a value of one or more project target column(s) of records in the merged table, to execute:

• determining, by the computer, whether content of the first operation satisfies a first condition and a second condition;
• and
• replacing, by the computer, the first operation with a second operation, if the content of the first operation satisfies the first condition and the second condition, wherein,
• the first condition is that each value of the common key in the second table is unique,
• the second condition is that all of the project target columns are included in the first table,
• the second operation comprises;
• identifying a value(s) of the common key of record(s) in the second table, as a target value(s);
• and
• projecting value(s) of the project target column(s) of a record(s) having the target value(s) in the common key column of the first table.