US 10,885,030 B2Granted

Database management system and computer system having first and second query execution parts which execute database operations in parallel

AssigneesHitachi, Ltd., The University of Tokyo

InventorsYuto Hayamizu, Kazuo Goda, Masaru Kitsuregawa, Nobuo Kawamura

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Abstract

A second query execution part is added to a database management system comprising a first query execution part configured to execute a query based on a query execution plan of a query to a database and to return a query execution result to the query issuance source and a buffer management part configured to read a data of a read request from the database to store the data into the buffer and to provide the data to an issuance source of the read request if data of a read request has not been stored in a buffer in the case where the read request of data is received and configured to read data of a read request from the buffer and to provide the data to a issuance source of the read request if data of a read request has been stored in the buffer.

Claims18

Dependent claims

A database management system for managing a database, comprising:

a query reception part configured to receive a query to the database from a query issuance source;
a query execution plan creation part configured to create a query execution plan that includes information indicating one or more database operations that are required for an execution of the received query and an execution procedure of the one or more database operations based on the received query;
a first query execution part configured to execute the query by executing database operations based on the created query execution plan and to return an execution result of the query to the query issuance source;
a second query execution part configured to execute the query by executing database operations based on the created query execution plan in parallel with the execution of the query by the first query execution part;
and
a buffer management part configured to read data of a read request from the database to store the data into the buffer and to provide the data of the read request to whichever one of the first and second query execution parts issued the read request if the data of the read request has not already been stored in the buffer,
the buffer management part being configured to, if the data has already been stored in the buffer based on a read request for the data from the second query execution part, in response to a read request for the data from the first query execution part, read the data of the read request from the buffer and provide the data to the first query execution part without reading the data from the database,
wherein, for the execution of the query, the second query execution part is configured to:
(a) create an execution instance for executing a database operation;
(b) send a read request of data required for an execution of a database operation corresponding to the execution instance to the buffer management part by executing the created execution instance;
(c) in the case where it is necessary to execute another database operation based on an execution result of the database operation corresponding to the execution instance that has been executed in (b), newly create one or more execution instances for executing the another database operation based on the execution result;
and
(d) execute (b) and (c) for each of the one or more execution instances that have been newly created, and
wherein the second query execution part is configured to execute at least two execution instances in parallel.

11 more elements

A computer system for managing a database, comprising:

a processor;
and
a buffer,
the processor being configured to:
receive a query to the database from a query issuance source;
create a query execution plan that includes information indicating one or more database operations that are required for an execution of the received query and an execution procedure of the one or more database operations based on the received query;
execute a first query execution procedure for executing the query by executing database operations based on the created query execution plan;
execute a second query execution procedure for executing the query by executing database operations based on the created query execution plan in parallel with the execution of the first query execution procedure;
read the required data from the database to store the data into the buffer and use the required data in the query execution procedure that requires the required data for the first and second query executions in the case where data required for any one of the first query execution and the second query execution has not already been stored in the buffer;
if the required data has already been stored in the buffer by being required in the second query execution procedure, if the query first execution procedure requires the required data, read the required data from the buffer and use the data in the first query execution procedure;
and
return a query execution result by the first query execution procedure of the first and second query executions to the query issuance source,
wherein, for the execution of the query, the second query execution procedure is configured to:
(a) create an execution instance for executing a database operation;
(b) send a read request of data required for an execution of a database operation corresponding to the execution instance to the buffer management part by executing the created execution instance;
(c) in the case where it is necessary to execute another database operation based on an execution result of the database operation corresponding to the execution instance that has been executed in (b), newly create one or more execution instances for executing the another database operation based on the execution result;
and
(d) execute (b) and (c) for each of the one or more execution instances that have been newly created, and
wherein the second query execution part is configured to execute at least two execution instances in parallel.

16 more elements

A database management method for managing a database, comprising:

receiving a query to the database from a query issuance source;
creating a query execution plan that includes information indicating one or more database operations that are required for an execution of the received query and an execution procedure of the one or more database operations based on the received query;
executing a first query execution procedure for executing the query by executing database operations based on the created query execution plan;
executing a second query execution procedure for executing the query by executing database operations based on the created query execution plan in parallel with the executing of the first query execution procedure;
reading the required data from the database to store the data into the buffer and use the required data in the query execution procedure that requires the required data for the first and second query executions in the case where data required for any one of the first query execution and the second query execution has not already been stored in the buffer;
when the required data has already been stored in the buffer by being required in the second query execution procedure, and when the first query execution procedure requires the required data, reading the required data from the buffer and using the data in the first query execution procedure;
and
returning a query execution result by the first query execution procedure of the first and second query executions to the query issuance source,
wherein, for the execution of the query, the second query execution procedure is configured to:
(a) create an execution instance for executing a database operation;
(b) send a read request of data required for an execution of a database operation corresponding to the execution instance to the buffer management part by executing the created execution instance;
(c) in the case where it is necessary to execute another database operation based on an execution result of the database operation corresponding to the execution instance that has been executed in (b), newly create one or more execution instances for executing the another database operation based on the execution result;
and
(d) execute (b) and (c) for each of the one or more execution instances that have been newly created, and
wherein the second query execution part is configured to execute at least two execution instances in parallel.

12 more elements

A non-transitory computer readable storage medium comprising a computer program having instructions for supporting a database management system, the instructions being performed by at least one processor to configure:

a query reception part configured to receive a query to the database from a query issuance source;
a query execution plan creation part configured to create a query execution plan that includes information indicating one or more database operations that are required for an execution of the received query and an execution procedure of the one or more database operations based on the received query;
a first query execution part configured to execute the query by executing database operations based on the created query execution plan and to return an execution result of the query to the query issuance source;
a second query execution part configured to execute the query by executing database operations based on the created query execution plan in parallel with the execution of the query by the first query execution part;
and
a buffer management part configured to read data of a read request from the database to store the data into the buffer and to provide the data of the read request to whichever one of the first and second query execution parts issued the read request if the data of the read request has not already been stored in the buffer,
the buffer management part being configured to, if the data has already been stored in the buffer based on a read request for the data from the second query execution part, in response to a read request for the data from the first query execution part, read the data of the read request from the buffer and provide the data to the first query execution part without reading the data from the database,
wherein, for the execution of the query, the second query execution part is configured to:
(a) create an execution instance for executing a database operation;
(b) send a read request of data required for an execution of a database operation corresponding to the execution instance to the buffer management part by executing the created execution instance;
(c) in the case where it is necessary to execute another database operation based on an execution result of the database operation corresponding to the execution instance that has been executed in (b), newly create one or more execution instances for executing the another database operation based on the execution result;
and
(d) execute (b) and (c) for each of the one or more execution instances that have been newly created, and
wherein the second query execution part is configured to execute at least two execution instances in parallel.

11 more elements

Dependencies are inferred from the claim text.