DATABASE SYSTEM
According to one embodiment, there is provided a database system in which a database server and a storage are connected via a communication line. The storage includes a data area, a transaction information storage area, a journal log storage area, and a first circuit. The database server includes a second circuit. The second circuit writes transaction information into the transaction information storage area determined from a combination of the subject database server and a unit of division of processing executing transaction processing.
1 . A database system in which a database server executing processing based on a data control request and a storage are connected via a communication line, wherein
the storage includes
a data area that stores a database,
a transaction information storage area that stores transaction information including a start log or an end log for transaction processing,
a journal log storage area that stores a journal log including writing state of the data to the storage based on the data control request, and
a first circuit that manages lock state and the writing state of target data in the storage, and records the journal log in the journal log storage area, and
the database server includes a second circuit that, upon receipt of the data control request, determines the transaction information storage area from a combination of the subject database server and a unit of division of processing executing the transaction processing, and writes the transaction information into the determined transaction information storage area.
2 . The database system according to claim 1 , wherein, at the start of the transaction processing, the second circuit overwrites the start log into the transaction information storage area, and at the end of the transaction process, the second circuit overwrites the end log into the transaction information storage area.
3 . The database system according to claim 1 , wherein the start log includes a process type indicative of the start of the transaction processing and storage position of target data in the transaction processing.
4 . The database system according to claim 1 , wherein the end log includes a process type indicative of the end of the transaction processing.
5 . The database system according to claim 1 , wherein a unit of division of processing by the database server is a thread or a process.
6 . The database system according to claim 1 , further comprising a database client that is connected to the database server via a network and transmits the data control request to the database.
7 . The database system according to claim 1 , wherein, when the target data is unlocked, the first circuit of the storage erases the journal log corresponding to the target data.
8 . A database system in which a storage and a connection circuit are wired under a predetermined standard on a circuit board, the storage including node circuits configured to have non-volatile memory and a node controller controlling the non-volatile memory and to be connected together in a grid pattern, and the connection circuit being connectable to an external device, wherein
the connection circuit has a database server function, the database server function including a circuit that determines position of target data in transaction processing and performs an operation related to the target data based on a data control request, and records transaction information in a transaction information storage area, the transaction information including a start log or an end log for the transaction processing,
the non-volatile memory includes
a data area that stores a database, and
a journal log storage area that stores a journal log for use in a restoration process of the database system,
the node controller performs a writing process temporarily writing data to be written into the database and a commitment process confirming the temporarily written writing data, based on an instruction from the database server function, and records procedures of the processes in the journal log,
part of the non-volatile memory in the storage has the transaction information storage area that stores the transaction information, and
the circuit determines, upon reception of the data control request, the transaction information storage area from a combination of the subject database server and a unit of division of processing executing the transaction processing, and writes the transaction information into the determined transaction information storage area.
9 . The database system according to claim 8 , wherein, at the start of the transaction processing, the circuit overwrites the start log into the transaction information storage area, and at the end of the transaction process, the circuit overwrites the end log into the transaction information storage area.
10 . The database system according to claim 8 , wherein the start log includes a process type indicative of the start of the transaction processing and storage position of target data in the transaction processing.
11 . The database system according to claim 8 , wherein the end log includes a process type indicative of the end of the transaction processing.
12 . The database system according to claim 8 , wherein a unit of division of processing by the database server is a thread or a process.
13 . The database system according to claim 8 , wherein, when determining that the target data was not normally stored in the storage at the time of the previous power-off, the node controller uses the transaction information and the temporarily written writing data to maintain consistency of the data constituting the database.
14 . The database system according to claim 13 , wherein the circuit reads, when the transaction information is a start log, the journal log for the target data associated with the transaction processing in the start log from the storage, and executes, when there exists any of the target data in committed state in the read journal log, a rollforward process using the journal log on the target data related to the transaction processing.
15 . The database system according to claim 14 , wherein, when there exists no target data in committed state in the read journal log but there exists the target data in completely written state in the read journal log, the circuit deletes or invalidates the temporarily written writing data to execute the rollback process.
16 . The database system according to claim 14 , wherein, when there exists no target data in committed state and there exists no target data in completely written state in the read journal log, the circuit executes no process on the target data.
17 . The database system according to claim 8 , wherein the node controller receives a packet from one of the other node circuits or the connection circuit, and when the packet is addressed to the node circuit to the node controller belongs, performs an operation on the database based on contents of the packet, and when the packet is not addressed to the node circuit to the node controller belongs, transfers the packet to the other adjacent node circuit.
18 . The database system according to claim 8 , wherein the connection circuit further includes a database client function that accepts a data control request from a user.
19 . The database system according to claim 8 , wherein the external device is a database client that accepts a data control request from a user, the database client being connected to the connection circuit via a network.
20 . A database system including a database server and a storage storing a database, wherein
the storage includes
a first log storage area that stores a first log indicative of start or end of transaction processing, and
a second log area that stores writing state of data, and
the database server writes the first log into the first log storage area determined by a unit of division of processing for which a data control request is accepted.