Patent Description:
Currently, data backup is a general method for improving availability of a distributed database system. To ensure database consistency, data backup needs to be consistent backup. A consensus algorithm needs to be used in consistent backup. Common consensus algorithms include a Paxos algorithm, a Raft algorithm, and the like. Further, in the distributed database system, to improve a speed and a throughput of data replication in a consistent backup process, when data backup is performed, data is usually divided into more than one data blocks for replication.

In a process of performing replication backup on a data block by using a consensus algorithm, in order to implement automatic fault recovery and fault tolerance, nodes participating in the consensus algorithm need to know status information of data blocks of each other. Therefore, the nodes need to send heartbeat information to each other to notify the status information of the data blocks in the nodes.

As shown in <FIG>, in the prior art, a leader data block leader sends heartbeat information to a follower data block corresponding to the leader data block. When there is a leader data block in a node, the node combines heartbeat information of all data blocks in the node, and sends combined heartbeat information to other nodes in which all data blocks that are located in same data block groups as the data blocks in the node are located. Nodes having a same data block type are nodes in which data blocks storing same data are located.

However, in a system, a node sends heartbeat information to all other nodes that include a same data block. In addition to a leader data block leader, the node further includes a data block that is not a leader. Therefore, the node sends a large quantity of useless heartbeat information after heartbeat information is combined. As shown in <FIG>, a data block <NUM> in a node <NUM> is a leader, and a data block <NUM> is not a leader. Because both the node <NUM> and a node <NUM> include the data block <NUM>, the node <NUM> sends heartbeat information to the node <NUM>. However, because the data block <NUM> in the node <NUM> is not a leader, the heartbeat information is useless heartbeat information. Useless heartbeat information results in an increase in a quantity of heartbeat information. Consequently, system performance is affected.

<CIT> relates to fault tolerant multi-stage data replication with relaxed coherency guarantees.

A first aspect of the implementations of the present disclosure provides a heartbeat information sending method, the method is performed by a heartbeat sending node, and the method includes: determining a heartbeat receiving node in which a follower data block corresponding to a current leader data block in the heartbeat sending node is located, where a data block group in which the current leader data block is located includes the follower data block; and sending heartbeat information of the heartbeat sending node to the heartbeat receiving node, where the heartbeat information of the heartbeat sending node carries a data block group identifier used to identify the data block group, and the data block group identifier is used to indicate that the leader data block in the data block group is located in the heartbeat sending node.

In the prior art, heartbeat information sent by a heartbeat sending node carries a node identifier of the heartbeat sending node, and a heartbeat receiving node has a node identifier of a node in which a leader data block corresponding to a follower data block in the heartbeat receiving node is located. When the heartbeat receiving node receives the heartbeat information, if the node identifier carried in the heartbeat information is the same as the node identifier corresponding to the follower data block, the follower data block receives the heartbeat information and responds to the heartbeat information. If a leader data block in a data block group in which the follower data block is located changes, that is, a data block that is located in the data block group and that is in another heartbeat sending node becomes the leader data block of the data block group, but the node identifier corresponding to the follower data block in the heartbeat receiving node does not change, when the another heartbeat sending node sends heartbeat information to the heartbeat receiving node, because a node identifier that is of the another heartbeat sending node and that is carried in the heartbeat information is different from the node identifier corresponding to the follower data block, the follower data block ignores the heartbeat information. Consequently, the follower data block is in isolation from the another heartbeat sending node.

In this implementation of this application, data block group identifiers used to identify data block groups in which the at least two leader data blocks are respectively located are carried in heartbeat information of a heartbeat sending node, so that after receiving the heartbeat information carrying the data block group identifiers, a heartbeat receiving node updates, to an identifier used to identify the heartbeat sending node, a node identifier corresponding to a follower data block, so as to prevent the follower data block from being in isolation from the heartbeat sending node.

With reference to the first aspect, in a first possible implementation of the first aspect, the sending heartbeat information of the heartbeat sending node to the heartbeat receiving node includes: sending the heartbeat information of the heartbeat sending node to the heartbeat receiving node when the heartbeat receiving node is a node that does not respond to an election request of the current leader data block. In this implementation of the present disclosure, the heartbeat information is sent to the heartbeat receiving node when the heartbeat receiving node is the node that does not respond to the election request of the current leader data block, so that a quantity of heartbeat information is reduced.

A second aspect of the implementations of the present disclosure provides a heartbeat information sending apparatus, including:.

With reference to the second aspect, in a first possible implementation of the second aspect, the sending unit is configured to:
send the heartbeat information of the heartbeat sending node to the heartbeat receiving node when the heartbeat receiving node is a node that does not respond to an election request of the current leader data block.

The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist.

Referring to <FIG> is a schematic diagram of a distributed database system that is applicable to an implementation of the present disclosure. The distributed database system includes multiple nodes. Each node includes at least one data block. In the Background, it is mentioned that data is divided into more than one data blocks for replication. For example, data in a node <NUM> is divided into a data block <NUM> and a data block <NUM>. The data block <NUM> is replicated, and the data block <NUM> is replicated. The distributed database system may have multiple data block groups. Each data block group has a unique data block group identifier and a unique leader data block leader. Leader data blocks of different data block groups may be located in a same node in the distributed database system, or may be located in different nodes in the distributed database system.

A consensus algorithm needs to be used in consistent backup. A Raft algorithm is used as an example. In the Raft algorithm, a unique leader data block in a data block group is elected, and another data block in the data block group is a follower data block. The leader data block is responsible for managing a log. All operations of adding a log and changing a status of a log are completed by using the leader data block. In the distributed database system, nodes participating in a consensus algorithm need to know status information of data blocks of each other. Therefore, a leader data block needs to send heartbeat information to a follower data block to notify status information of a node in which the leader data block is located.

The following describes in detail a heartbeat information sending method provided in an implementation of the present disclosure.

Referring to <FIG> is a flowchart of a heartbeat information sending method according to an implementation of the present disclosure. This implementation has not been claimed as such. The remaining description should be construed accordingly. The method includes the following content.

Step <NUM>: Determine heartbeat receiving nodes in which at least two follower data blocks corresponding to at least two leader data blocks in the heartbeat sending node are located.

In a distributed database system, a heartbeat sending node maintains a set leaderraftnode of at least two leader data blocks and a set <MAT> of heartbeat receiving nodes, where nodel indicates a set of nodes in which follower data blocks of a leader data block l are located. That is, if there are at least two leader data blocks in the heartbeat sending node, the set Sheartbeatnode of the heartbeat receiving nodes includes an union set of nodes in which follower data blocks of leader data blocks in the at least two leader data blocks in the heartbeat sending node are located.

In step <NUM>, the heartbeat sending node may determine the heartbeat receiving nodes by querying nodes included in a set Sheartbeatnode. That is, the heartbeat sending node determines the nodes included in the set Sheartbeatnode as the heartbeat receiving nodes.

Step <NUM>: When the heartbeat receiving nodes are a same node, send heartbeat information of the heartbeat sending node to the heartbeat receiving node, where the heartbeat information of the heartbeat sending node is heartbeat information obtained after respective heartbeat information of the at least two leader data blocks are combined.

In the distributed database system, when the heartbeat receiving nodes are the same node, that is, when the at least two follower data blocks are located in the same node, the heartbeat sending node combines the respective heartbeat information of the at least two leader data blocks to obtain combined heartbeat information, and sends the combined heartbeat information to a heartbeat information node, to reduce a quantity of heartbeat information.

It should be noted that, in addition to the leader data block, the heartbeat sending node may further include a follower data block that is located in another data block group. In the distributed database system, a status of a data block in the heartbeat sending node changes for a reason such as a node failure. One possible case is that the leader data block in the heartbeat sending node becomes a follower data block. Another possible case is that the follower data block in the heartbeat sending node becomes a leader data block. After the status of the data block in the heartbeat sending node changes, the heartbeat sending node updates the set Sheartbeatnode of the nodes. Update steps are as follows:.

In the prior art, after heartbeat information is combined, a follower data block in a node may be isolated by a leader data block. For example, as shown in graph a in <FIG>, both a data block <NUM> and a data block <NUM> in a node <NUM> are leader data blocks, and a node <NUM> includes a data block <NUM> and a data block <NUM>. After combining heartbeat information of the data block <NUM> and heartbeat information of the leader data block <NUM>, the node <NUM> needs to send only one piece of heartbeat information to the node <NUM>. The heartbeat information carries a node identifier of the node <NUM>. A node identifier corresponding to the data block <NUM> in the node <NUM> is the node identifier of the node <NUM>. If the node <NUM> receives the heartbeat information sent by the node <NUM>, a follower data block <NUM> receives the heartbeat information and responds to the heartbeat information.

As shown in graph b in <FIG>, after a data block <NUM> in a node <NUM> changes from a leader data block to a follower data block, and a data block <NUM> in a node <NUM> becomes a leader data block of a data block group in which the data block <NUM> is located, if the node <NUM> continues to send heartbeat information to a node <NUM>, because a node identifier corresponding to a data block <NUM> in the node <NUM> is still a node identifier of the node <NUM>, when the node <NUM> receives the heartbeat information sent by the node <NUM>, the data block <NUM> in the node <NUM> continues to regard the node <NUM> as a node in which the leader data block is located. However, when the node <NUM> receives heartbeat information sent by the node <NUM> (where the heartbeat information carries a node identifier of the node <NUM>), because the node identifier of the node <NUM> is different from the node identifier corresponding to the data block <NUM> in the node <NUM>, the data block <NUM> in the node <NUM> ignores the heartbeat information sent by the node <NUM>. Consequently, the data block <NUM> in the node <NUM> is in isolation from the leader data block in the node <NUM>.

To resolve the foregoing technical problem, an implementation of the present disclosure provides a heartbeat information sending method according to the claimed invention. As shown in <FIG>, the method includes following content.

Step <NUM>: Determine a heartbeat receiving node in which a follower data block corresponding to a current leader data block in the heartbeat sending node is located, where a data block group in which the current leader data block is located includes the follower data block.

In a distributed database system, for each data block participating in a Raft algorithm, a group node set noderafinode is maintained. noderaftnode includes nodes in which all data blocks that have a same data block group identifier in the system are located. A format of each element in noderaftnode is a tuple (raftgroupID, nodeID), where raftgroupID is a data block group identifier, and nodeID is a node identifier of a node in which a data block is located.

If a data block is elected to be a current leader data block, when a heartbeat receiving node is being determined, a corresponding noderaftnode may be queried according to a data block group identifier of a data block group in which the current leader data block is located, and a node in noderaftnode is determined as a heartbeat receiving node in which a follower data block corresponding to the current leader data block is located.

Step <NUM>: Send heartbeat information of the heartbeat sending node to the heartbeat receiving node, where the heartbeat information of the heartbeat sending node carries a data block group identifier used to identify the data block group, and the data block group identifier is used to indicate that the leader data block in the data block group is located in the heartbeat sending node.

For each node in noderaftnode, the heartbeat sending node maintains a leadermsgr set. A format of an element in the leadermsgr set is a tuple (raftgroupID, leaderID), where raftgroupID is a data block group identifier, and leaderID is a node identifier of a node in which a leader data block is located. When the heartbeat sending node sends heartbeat information to a node in noderaftnode, a data block leader identifier in leadermsgr is added to the heartbeat information.

Referring to <FIG>, after a heartbeat sending node sends, to a heartbeat receiving node, heartbeat information that carries a data block group identifier, the heartbeat receiving node performs the following steps. This implementation has not been claimed as such. The remaining description should be construed accordingly.

Step <NUM>: Receive heartbeat information from a heartbeat sending node, where the heartbeat information of the heartbeat sending node carries a data block group identifier used to identify a data block group.

Step <NUM>: Determine a follower data block that is located in the data block group and that is in the heartbeat receiving node.

Each data block participating in a Raft algorithm has a unique data block group identifier of a data block group in which the data block is located. Therefore, the heartbeat receiving node determines, according to the data block group identifier carried in the heartbeat information, the follower data block that is located in the data block group. A data block group identifier of the follower data block is the same as the data block group identifier carried in the heartbeat information.

Step <NUM>: Update, to an identifier used to identify the heartbeat sending node, a node identifier corresponding to the follower data block, where the node identifier is used to identify a node in which a leader data block in the data block group is located.

In step <NUM>, if the node identifier corresponding to the follower data is different from the identifier of the heartbeat sending node, the heartbeat receiving node updates, to the identifier of the heartbeat sending node, the node identifier corresponding to the follower data. Then, when the heartbeat receiving node receives the heartbeat information sent by the heartbeat sending node, because an updated node identifier corresponding to the follower data is the same as a node identifier carried in the heartbeat information, the follower data block can receive the heartbeat information and respond to the heartbeat information. Otherwise, the follower data block in the heartbeat receiving node is in isolation from the leader data block.

For example, still referring to graph b in <FIG>, after the data block <NUM> in the node <NUM> changes from a leader data block to a follower data block, and the data block <NUM> in the node <NUM> becomes a leader data block of a data block group in which the data block <NUM> is located, a node identifier corresponding to the data block <NUM> in the node <NUM> is a node identifier of the node <NUM>. The node <NUM> adds, to heartbeat information sent to the node <NUM>, a data block group identifier used to identify the data block group in which the data block <NUM> is located. After receiving the heartbeat information sent by the node <NUM>, the node <NUM> determines that a follower data block that is located in the data block group and that is in the node <NUM> is the data block <NUM>, and updates, to a node identifier of the node <NUM>, the node identifier corresponding to the data block <NUM>.

If the node <NUM> continues to send heartbeat information to the node <NUM>, because the node identifier corresponding to the data block <NUM> in the node <NUM> is updated to the node identifier of the node <NUM>, when the node <NUM> receives the heartbeat information sent by the node <NUM>, the data block <NUM> in the node <NUM> ignores the heartbeat information sent by the node <NUM>. However, when the node <NUM> receives the heartbeat information sent by the node <NUM>, the data block <NUM> in the node <NUM> receives the heartbeat information sent by the node <NUM>, and responds to the heartbeat information sent by the node <NUM>, so that after a status of the data block <NUM> in the node <NUM> changes, the data block <NUM> in the node <NUM> is not in isolation from the node <NUM>.

Optionally, the heartbeat information of the heartbeat sending node is sent to the heartbeat receiving node when the heartbeat receiving node is a node that does not respond to an election request of the current leader data block.

Leader data block election in a Raft algorithm is first described.

In the Raft algorithm, any data block is in one of three states at any moment: a leader data block (leader), a follower data block (follower), or a candidate data block (candidate). In the Raft algorithm, a time period is divided into continuous terms, and leader data block election is performed when each term starts. When election is performed, a node in which a candidate data block is located starts a new timer, sends a RequestVote RPC request (an election request) to nodes in which all other data blocks that are located in a same data block group as the candidate data block are located, and waits for responses of the nodes. If before the timer times out, the node in which the candidate data block is located receives approval votes returned by a majority of nodes in a system, the data block candidate data block becomes a leader data block.

After leader data block election ends, it is assumed that the candidate data block becomes a current leader data block. If a heartbeat sending node in which the current leader data block is located receives no approval vote of a heartbeat receiving node in an election process, the heartbeat sending node sends, to the heartbeat receiving node, heartbeat information that carries a data block group identifier. If the heartbeat sending node receives, in the election process, an approval vote returned by a heartbeat receiving node, the heartbeat sending node may not send, to the heartbeat receiving node, heartbeat information that carries a data block group identifier.

Based on a same disclosure conception, an implementation of the present disclosure further provides a heartbeat information sending apparatus. This implementation has not been claimed as such. The remaining description should be construed accordingly. As shown in <FIG>, the heartbeat information sending apparatus includes:.

Optionally, the heartbeat information of the heartbeat sending node carries data block group identifiers used to identify data block groups in which the at least two leader data blocks are respectively located, and the data block group identifiers are respectively used to indicate that the leader data blocks of the data block groups are located in the heartbeat sending node.

Various change manners and specific instances in the heartbeat information sending method in the implementation shown in <FIG> are also applicable to the heartbeat information sending apparatus in this implementation. According to the detailed description of the heartbeat information sending method, persons skilled in the art may clearly understand an implementation method of the heartbeat information sending apparatus in this implementation. Therefore, for conciseness of the specification, details are not repeatedly described herein.

Based on a same disclosure conception, an implementation of the present disclosure further provides a heartbeat sending node. This implementation has not been claimed as such. The remaining description should be construed accordingly. As shown in <FIG>, the heartbeat sending node includes a processor <NUM>, a transmitter <NUM>, and a communications bus <NUM>. The processor <NUM> and the transmitter <NUM> communicate with each other by using the communications bus <NUM>.

The processor <NUM> is configured to determine heartbeat receiving nodes in which at least two follower data blocks corresponding to at least two leader data blocks in the heartbeat sending node are located.

The transmitter <NUM> is configured to: when the heartbeat receiving nodes are a same node, send heartbeat information of the heartbeat sending node to the heartbeat receiving node. The heartbeat information of the heartbeat sending node is heartbeat information obtained after respective heartbeat information of the at least two leader data blocks are combined.

Further, in <FIG>, the communications bus <NUM> may include any quantity of interconnect buses and bridges. The communications bus <NUM> connects various circuits including one or more processors represented by the processor <NUM> and a memory represented by a memory <NUM>. The communications bus <NUM> may further connect various other circuits such as a peripheral device, a voltage stabilizer, and a power management circuit. These are known in the art and are not further described in this specification. A bus interface <NUM> provides an interface between the communications bus <NUM> and the transmitter <NUM>. The transmitter <NUM> may be a transceiver for providing a unit configured to communicate with various other apparatuses on a transmission medium.

The processor <NUM> is responsible for managing the communications bus <NUM> and general processing. The memory <NUM> may be configured to store data used when the processor <NUM> performs an operation.

Based on a same disclosure conception, an implementation of the present disclosure further provides a heartbeat information sending apparatus according to the claimed invention. As shown in <FIG>, the heartbeat information sending apparatus includes:.

Optionally, the sending unit <NUM> is configured to:
send the heartbeat information of the heartbeat sending node to the heartbeat receiving node when the heartbeat receiving node is a node that does not respond to an election request of the current leader data block.

The processor <NUM> is configured to determine a heartbeat receiving node in which a follower data block corresponding to a current leader data block in the heartbeat sending node is located. A data block group in which the current leader data block is located includes the follower data block.

The transmitter <NUM> is configured to send heartbeat information of the heartbeat sending node to the heartbeat receiving node. The heartbeat information of the heartbeat sending node carries a data block group identifier used to identify the data block group, and the data block group identifier is used to indicate that the leader data block in the data block group is located in the heartbeat sending node.

Optionally, the transmitter <NUM> is configured to:
send the heartbeat information of the heartbeat sending node to the heartbeat receiving node when the heartbeat receiving node is a node that does not respond to an election request of the current leader data block.

Based on a same disclosure conception, an implementation of the present disclosure further provides a heartbeat information processing apparatus. This implementation has not been claimed as such. The remaining description should be construed accordingly. As shown in <FIG>, the heartbeat information processing apparatus includes:.

Various change manners and specific instances in the heartbeat information processing method in the implementation shown in <FIG> are also applicable to the heartbeat information processing apparatus in this implementation. According to the detailed description of the heartbeat information processing method, persons skilled in the art may clearly understand an implementation method of the heartbeat information processing apparatus in this implementation. Therefore, for conciseness of the specification, details are not repeatedly described herein.

Based on a same disclosure conception, an implementation of the present disclosure further provides a heartbeat receiving node. As shown in <FIG>, the heartbeat receiving node includes a processor <NUM>, a receiver <NUM>, and a communications bus <NUM>. The processor <NUM> and the receiver <NUM> communicate with each other by using the communications bus <NUM>. This implementation has not been claimed as such. The remaining description should be construed accordingly.

The receiver <NUM> is configured to receive heartbeat information from a heartbeat sending node. The heartbeat information of the heartbeat sending node carries a data block group identifier used to identify a data block group.

The processor <NUM> is configured to: determine a follower data block that is located in the data block group and that is in the heartbeat receiving node; and update, to an identifier used to identify the heartbeat sending node, a node identifier corresponding to the follower data block. The node identifier is used to identify a node in which a leader data block in the data block group is located.

Further, in <FIG>, the communications bus <NUM> may include any quantity of interconnect buses and bridges. The communications bus <NUM> connects various circuits including one or more processors represented by the processor <NUM> and a memory represented by a memory <NUM>. The communications bus <NUM> may further connect various other circuits such as a peripheral device, a voltage stabilizer, and a power management circuit. These are known in the art and are not further described in this specification. A bus interface <NUM> provides an interface between the communications bus <NUM> and the receiver <NUM>. The receiver <NUM> may be a transceiver for providing a unit configured to communicate with various other apparatuses on a transmission medium.

The processor <NUM> is responsible for managing the communications bus <NUM> and general processing. The memory <NUM> may be configured to store data used when the processor <NUM> performs an operation. Various change manners and specific instances in the heartbeat information processing method in the implementation shown in <FIG> are also applicable to the heartbeat information processing apparatus in this implementation. According to the detailed description of the heartbeat information processing method, persons skilled in the art may clearly understand an implementation method of the heartbeat information processing apparatus in this implementation. Therefore, for conciseness of the specification, details are not repeatedly described herein.

Persons skilled in the art should understand that the implementations of the present disclosure may be provided as a method, a system, or a computer program product. Therefore, the present disclosure may use a form of hardware only implementations, software only implementations, or implementations with a combination of software and hardware. Moreover, the present disclosure may use a form of a computer program product that is implemented on one or more computer-usable storage media (including but not limited to a disk memory, an optical memory, and the like) that include computer-usable program code.

The present disclosure is described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to the implementations of the present disclosure. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device to generate a machine, so that the instructions executed by a computer or a processor of any other programmable data processing device generate an apparatus for implementing a function specified in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

The instruction apparatus implements a function specified in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

Therefore, the instructions executed on the computer or the another programmable device provide steps for implementing a function specified in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

Claim 1:
A heartbeat information sending method, wherein the method is performed by a heartbeat sending node, and the method comprises:
determining (<NUM>) a heartbeat receiving node in which a follower data block corresponding to a current leader data block in the heartbeat sending node is located; and
sending (<NUM>) heartbeat information of the heartbeat sending node to the heartbeat receiving node, wherein the heartbeat information of the heartbeat sending node carries a data block group identifier used to identify a data block group, wherein the data block group comprises the current leader data block and the follower data block, and wherein the data block group identifier is used to indicate that the leader data block in the data block group is located in the heartbeat sending node.