CN208781225U - A blockchain spatiotemporal data query system and electronic equipment - Google Patents

Abstract

The present application relates to a blockchain spatiotemporal data query system and electronic equipment. It includes: a block chain module for storing block data, a data insertion module electrically connected with the block chain module; a time range search module electrically connected with the block chain module; through the time range The search module is a spatial range search module electrically connected to the blockchain module; wherein, the topology structure G of the directed acyclic graph in the blockchain module is set to two parts: node set V and edge set E. The query system structure of the present application can quickly return the results in the blockchain that meet the given requirements in an "online" manner.

Description

A blockchain spatiotemporal data query system and electronic equipment

technical field

The present application belongs to the technical field of Internet databases, and in particular relates to a blockchain spatiotemporal data query system and electronic equipment.

Background technique

Blockchain technology, also known as distributed ledger technology, is an Internet database technology and a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. Blockchain is a new decentralized infrastructure and distributed computing paradigm that has gradually emerged with the increasing popularity of digital cryptocurrencies such as Bitcoin. Because blockchain has the advantages of decentralization, time series data, collective maintenance, security and reliability, etc., it has been widely used in finance, medical care, education and other industries in recent years. Industry and academia are also exploring blockchain More application scenarios. The rise of blockchain technology has inspired a large number of new applications in various fields including spatiotemporal data management, for example, consider the supply chain scenario of tracking items during transportation. During transportation, it is required not only to continuously update spatiotemporal information, but also to support fast query of spatiotemporal data, such as listing all data located at l at time t, or all data located at l during the time period from t1 to t2. However, the current blockchain technology cannot efficiently respond to the query of spatiotemporal data, and the research on efficient query of spatiotemporal data has always attracted much attention in the database. application prospects.

The blockchain uses Merkle trees to hash transaction data in blocks, where each block contains a block header and a block body. The role of the block header is to link to the previous block to provide integrity for the blockchain, and the block body contains verification. data records during the creation of past blocks. When the data in the blockchain needs to be queried, the transaction data of the current block can be queried through the block body, and the previous block of the current block in the blockchain can be found through the block header. At present, to query data in a certain data mode in the blockchain, it is necessary to start from the newly added block on the blockchain, first query the transaction data in the block body, and then trace back to the previous block through the block header. Queries, and so on, traverse the transaction data of the entire blockchain.

To sum up, the shortcomings of the existing blockchain technology are: 1), does not support efficient management of spatiotemporal data, including efficient storage of spatiotemporal data and efficient query of spatiotemporal data; 2), the current block Chain-to-data query needs to start from the newly added block on the blockchain, and trace back to the previous block through its block header, block by block. In the worst case, it is necessary to facilitate the entire query Blockchain data, obviously, such query is very inefficient and time-consuming, and is not suitable for fast query; 3), the current blockchain data query response method is not suitable for the query of frequently changing spatiotemporal data; 4), for The spatial coordinate data also does not have some indexes to speed up the whole process; 5) In the blockchain system, indexing of multidimensional data such as spatiotemporal data often requires more than one complex index, which is not only very cumbersome but also expensive.

SUMMARY OF THE INVENTION

The present application provides a blockchain spatiotemporal data query system and electronic equipment, aiming to solve one of the above technical problems in the prior art at least to a certain extent.

In order to solve the above problems, the application provides the following technical solutions:

A blockchain spatiotemporal data query system, comprising:

Blockchain module: used to store block data;

Data insertion module: electrically connected to the blockchain module;

Time range search module: electrically connected to the blockchain module;

Spatial range search module: electrically connected to the blockchain module through the time range search module;

Wherein, the topology structure G of the directed acyclic graph in the blockchain module is set to two parts: node set V and edge set E.

Preferably, time meta information is set in the block header of each block in the block chain module;

The topology G has multiple source nodes s for each v∈V.

Preferably, the root node information in the block header is based on a tree-type index structure combining Merkle tree and kd tree; the root node is respectively connected with the root node of the right subtree and the root node of the left subtree.

In order to solve the above technical problem, an embodiment of the present application further provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein,

The memory storage is provided with the above-mentioned blockchain module, and the processor is provided with the above-mentioned data insertion module, time range search module and space range search module.

Compared with the prior art, the beneficial effects of the embodiments of the present application are: the blockchain spatiotemporal data query system and electronic device of the embodiments of the present application form a new tree-shaped index by combining the Merkle tree and the kd tree, so that it can be The space-time data in the blockchain system is stored in the ring graph structure. Based on this, the blocks that meet the time range are filtered in the directed acyclic graph, and the data that meets the space range is queried in the filtered blocks. Compared with the prior art, the advantages of the embodiments of the present application are:

1. This application, from the adjustment of the storage structure of the blockchain to the corresponding modules for querying the blockchain modules, is designed for spatiotemporal data, which can meet the application scenarios of the blockchain in spatiotemporal data management;

2. In this application, specific time meta information is added to the header of each block to record the time interval of the spatiotemporal data in the block. When querying, the block that meets the limit can be quickly found through a given time limit. The combined index of Merkle tree and kd tree can locate the corresponding data in the block, improving the problem that each query response in the prior art needs to traverse each block and read the data in each block, which is very inefficient ;

3. To improve the problem that it is difficult to establish a non-complex index structure for multi-dimensional data in the blockchain system, a tree index structure combining Merkle tree and kd tree is established for spatial data, and the key value obtained through the tree index can be quickly located. to the original data;

4. For the scenarios where spatiotemporal data is mostly used for frequent updates, the data structure in the blockchain module of the present application adopts a Directed Acyclic Graph (DAG) structure with faster verification time, and the verification time of this structure is better than that of the chain structure.

Description of drawings

1 is a schematic structural diagram of a blockchain spatiotemporal data query system according to an embodiment of the present application;

2 is a schematic structural diagram of a hardware device of a blockchain spatiotemporal data query system according to an embodiment of the application;

3 is a directed acyclic graph of an embodiment of the present application;

4 is a response example diagram for performing a spatiotemporal range query on a directed acyclic graph according to an embodiment of the present application;

5 is a flowchart of the blockchain spatiotemporal data query system according to an embodiment of the present application;

6 is a flowchart of a time range search in an embodiment of the present application;

FIG. 7 is a flowchart of a spatial range search provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

Please refer to FIG. 1 , which is a schematic diagram of a framework of a blockchain spatiotemporal data query system according to an embodiment of the present application. The blockchain spatiotemporal data query system of the present application includes: a blockchain module for storing block data, a data insertion module electrically connected to the blockchain module; a time range search module electrically connected to the blockchain module module; a spatial range search module electrically connected to the blockchain module through the time range search module; wherein, the topology structure G of the directed acyclic graph in the blockchain module is set to two parts: node set V and edge set E.

Preferably, time meta information is set in the block header of each block in the blockchain module to facilitate retrieval by the time range search module;

As shown in FIG. 3, topology G has multiple source nodes s for each v∈V (node v belonging to node set V). The source node s is the node with in-degree 0 in the directed acyclic graph. For each node v in topology G, they are verified by subsequent nodes, which in turn are verified by further subsequent nodes. By analogy, it can be seen that the block nodes newly added to the topology structure G have no subsequent nodes to verify them, so they are the source nodes to be verified. Using the source node s, the previously verified nodes can be traced back, and the topology structure G of the entire directed acyclic graph can be traversed conveniently.

Preferably, the root node information in the block header is based on a tree-type index structure combining Merkle tree and kd tree; the root node is respectively connected with the root node of the right subtree and the root node of the left subtree.

Specifically, the data insertion module: it is also used to insert the spatiotemporal data in the blockchain system into the tree index structure based on the combination of Merkle tree and kd tree during the update process of the blockchain block, and store it in the block At the same time, for each block in the blockchain module, time meta information is introduced into the block header; in the embodiment of this application, the structure of the spatiotemporal data in the blockchain adopts Merkle tree and kd tree based on Combined tree index structure. Among them, the Merkle tree is a tree structure for storing hash values, its leaves are the hash values of the data, and the non-leaf nodes are the hash values of the concatenated strings of their corresponding child nodes. The kd tree is a binary tree constructed for multi-dimensional Euclidean space division, which also represents a division of the k-dimensional space formed by the k-dimensional data set, that is, each node in the tree corresponds to a k-dimensional hyperrectangle. Combining the two, the data in the kd tree node is hashed according to the Merkle tree rules. Merkle Patricia-trie is used to store key-value pairs of spatiotemporal data, so that the key values obtained through the tree index structure can be quickly located to the original data. For the time meta information added in the header of each block, it is used to record the time interval of the spatiotemporal data in the block. When querying, the block that conforms to the time range can be quickly found through the given time range. According to the Merkle tree and kd The tree-type index structure combined with the tree can locate the corresponding data in the block.

Time range search module: It is also used in the process of spatio-temporal data query, given the time range and space range corresponding to the spatio-temporal data, using the time meta-information in the block header of each block in the blockchain module in the directed acyclic graph ( DAG) topology structure G(V, E) to search for blocks that meet the time range; in the embodiment of this application, in terms of blockchain technology, a directed acyclic graph (DAG) that requires a shorter verification time is selected, It can improve the efficiency of the blockchain, allowing parallel blocks to be produced in the network and requiring less time for verification. In the DAG network, each transaction is confirmed, and it needs to be linked to a relatively new transaction that already exists in the network for link confirmation, so that the width of the network is kept within a certain range, and new transactions can be confirmed faster. time.

To achieve fast temporal search on DAGs, the present application introduces temporal meta-information contained in each block header. Given a time range β, firstly, on the DAG topology G(V, E), a block that satisfies the conditions is searched according to β. As shown in Fig. 3, the topology G has multiple source nodes s for each v∈V (ie newly added nodes to be verified in the directed acyclic graph), the source node starts the query, and all subsequent queries are considered Retraces the nearest preceding node of the current point. The time range search for each DAG block is implemented with breadth-first algorithm (BFS). Specifically, the time range search method of the time range search module is: given a time range β=(start time, end time), use the current latest verification block returned by the GetRobustAccepted(G) function, thereby starting to run BFS; During the execution of BFS, if the time meta-information in the block header is within the given time range β, that is, Then put the block into the result set; when the search block is outside the time range β or the end time of the time meta information in the block header of all the next blocks is less than the start time of β, the operation of BFS is terminated.

Spatial range search module: It is also used to read the root node information of the tree index structure based on the combination of Merkle tree and kd tree in the block header of each block that meets the time range, and then access the entire Merkle tree and kd from top to bottom. The tree-type index structure combined with trees can search for key data within the spatial range, and then obtain the corresponding original spatiotemporal data through MerklePatricia-trie technology according to the key data; this application proposes an efficient blockchain query response method for spatiotemporal data, which enables It can support queries such as "all data in the l area in the s time period".

Further, the space range search method of the space range search module is: after the time range search module completes the search, the root node of the tree index structure based on the combination of Merkle tree and kd tree is obtained from the block header, starting from the root node. Continue down a simple path comparing the given spatial extent with the tree node; if the given spatial extent is larger than the tree node, the path goes to the right subtree of the tree, and if the given spatial extent is smaller than the tree node, the path Enter the left subtree of the tree until a hyperrectangle that conforms to the spatial range is accessed, and the data in the hyperrectangle is returned; for the returned data, because they are all hash values, it is necessary to find the Merkle Patricia-trie technology in the block header The root node of the key-value pair index; according to the key-value pair index based on the Merkle Patricia-trie technology, the hash value data is converted into the original spatiotemporal data, and the original spatiotemporal data is returned.

The experiment of this application establishes a dedicated test network on iota's tangle (based on directed acyclic graph), and uses the spatiotemporal data on Pokemon Go for testing. It can be found that in the test network, users use the method proposed in this application. , which can query the qualified spatiotemporal data "online", and its query response time is very fast. For the query method, the experiment adopts a variety of mainstream query methods: knn query, ball-point query, range query and bounded knn query.

FIG. 2 is a schematic structural diagram of a hardware device of a blockchain spatiotemporal data query system provided by an embodiment of the present application. As shown in Figure 7, the device includes one or more processors and memory. Taking a processor as an example, the device may further include: an input system and an output system.

The processor, the memory, the input system, and the output system can be connected by a bus or in other ways, and the connection by a bus is taken as an example in FIG. 2 .

As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules. The processor executes various functional applications and data processing of the electronic device by running the non-transitory software programs, instructions and modules stored in the memory, that is, the processing method of the above method embodiment is implemented.

The memory may include a stored program area and a stored data area, wherein the stored program area can store an operating system and an application program required by at least one function; the stored data area can store data and the like. Additionally, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory may optionally include memory located remotely from the processor, which may be connected to the processing system via a network. Examples of such networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

The input system can receive input numerical or character information and generate signal input. The output system may include a display device such as a display screen.

The one or more modules are stored in the memory, and when executed by the one or more processors, perform the following operations of any of the foregoing method embodiments:

Step a: Insert the spatiotemporal data in the blockchain system into a tree index structure based on the combination of Merkle tree and kd tree, and store it in the blockchain module; for each block in the blockchain module , introducing time meta-information in the block header;

Step b: Given the time range and space range corresponding to the spatiotemporal data, use the time meta-information in the block header of each block in the blockchain module to search the topology G of the directed acyclic graph to find the time that matches the time range of blocks;

Step c: Read the root node information of the tree-type index structure based on the combination of the Merkle tree and the kd tree in the block header that meets the time range, search for key data that meets the space range, and then according to the Descriptive key data gets the corresponding spatiotemporal data.

The above product can execute the method provided by the embodiments of the present application, and has functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, reference may be made to the method provided in this embodiment of the present application.

An embodiment of the present application provides a non-transitory (non-volatile) computer storage medium, where the computer storage medium stores computer-executable instructions, and the computer-executable instructions can perform the following operations:

Step a: Insert the spatiotemporal data in the blockchain system into a tree index structure based on the combination of Merkle tree and kd tree, and store it in the blockchain module; for each block in the blockchain module , introducing time meta-information in the block header;

Step b: Given the time range and space range corresponding to the spatiotemporal data, use the time meta-information in the block header of each block in the blockchain module to search the topology G of the directed acyclic graph to find the time that matches the time range of blocks;

Step c: Read the root node information of the tree-type index structure based on the combination of the Merkle tree and the kd tree in the block header that meets the time range, search for key data that meets the space range, and then according to the Descriptive key data gets the corresponding spatiotemporal data.

An embodiment of the present application provides a computer program product, the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, the computer program includes program instructions, and when the program instructions are executed by a computer , which causes the computer to do the following:

Step a: Insert the spatiotemporal data in the blockchain system into a tree index structure based on the combination of Merkle tree and kd tree, and store it in the blockchain module; for each block in the blockchain module , introducing time meta-information in the block header;

Step b: Given the time range and space range corresponding to the spatiotemporal data, use the time meta-information in the block header of each block in the blockchain module to search the topology G of the directed acyclic graph to find the time that matches the time range of blocks;

Step c: Read the root node information of the tree-type index structure based on the combination of the Merkle tree and the kd tree in the block header that meets the time range, search for key data that meets the space range, and then according to the Descriptive key data gets the corresponding spatiotemporal data.

Please refer to FIG. 5 , which is a flowchart of a blockchain spatiotemporal data query system according to an embodiment of the present application. The blockchain spatiotemporal data query system of the embodiment of the present application includes the following steps:

Step 100: During the block chain block update process, the spatiotemporal data in the block chain system is inserted into the tree index structure based on the combination of Merkle tree and kd tree, and stored in the block chain module; at the same time, for Each block in the blockchain module introduces time meta information in the block header;

In step 100, regarding the structure of spatiotemporal data in the blockchain, the present application adopts a tree index structure based on the combination of Merkle tree and kd tree. Among them, the Merkle tree is a tree structure for storing hash values, its leaves are the hash values of the data, and the non-leaf nodes are the hash values of the concatenated strings of their corresponding child nodes. The kd tree is a binary tree constructed for multi-dimensional Euclidean space division, which also represents a division of the k-dimensional space formed by the k-dimensional data set, that is, each node in the tree corresponds to a k-dimensional hyperrectangle. Combining the two, the data in the kd tree node is hashed according to the Merkle tree rules. Merkle Patricia-trie is used to store key-value pairs of spatiotemporal data, so that the key values obtained through the tree index structure can be quickly located to the original data. For the time meta information added in the header of each block, it is used to record the time interval of the spatiotemporal data in the block. When querying, the block that conforms to the time range can be quickly found through the given time range. According to the Merkle tree and kd The tree-type index structure combined with the tree can locate the corresponding data in the block.

Step 200: In the process of spatiotemporal data query, given the time range and space range corresponding to the spatiotemporal data, use the time meta-information in the block header of each block in the blockchain module in the topology structure of the directed acyclic graph (DAG). G(V, E) is searched for blocks that meet the time range; among them, the node set of topology structure G is V, and the edge set of topology structure G is E.

In step 200, in terms of blockchain technology, this application selects a directed acyclic graph (DAG) that requires a shorter verification time, which can improve the efficiency of the blockchain, enable parallel blocks to be generated in the network, and verify the required results. less time. In the DAG network, each transaction is confirmed, and it needs to be linked to a relatively new transaction that already exists in the network for link confirmation, so that the width of the network is kept within a certain range, and new transactions can be confirmed faster. time. The directed acyclic graph is shown in Figure 3.

To achieve fast temporal search on DAGs, the present application introduces temporal meta-information contained in each block header. Given a time range β, firstly, on the DAG topology G(V, E), a block that satisfies the conditions is searched according to β. As shown in FIG. 3 , the topology structure G has multiple source nodes s for each v∈V (that is, the source node s is a node to be verified newly added to the directed acyclic graph topology structure G), and the source node starts to query, All subsequent queries are considered to trace back to the nearest previous node of the current point. The time range search for each DAG block is implemented with breadth-first algorithm (BFS).

For details, please refer to FIG. 6 , which is a flowchart of a time range search in an embodiment of the present application. The steps for a time range search include:

Step 201: Given a time range β=(start time, end time), use the current latest verification block returned by the GetRobustAccepted(G) function, thereby starting to run BFS;

Step 202: During the execution of BFS, if the time meta-information in the block header is within a given time range β, that is, then put the block into the result set;

Step 203: When it is found that the block is outside the time range β or the end time of the time meta-information in the block headers of all the next blocks is less than the start time of β, the operation of BFS is terminated.

Step 300: For each block that meets the time range, read the root node information of the tree index structure based on the combination of Merkle tree and kd tree in the block header of each block, and then access the entire Merkle tree and The tree-type index structure combined with kd tree searches for the key data within the spatial range, and then obtains the corresponding original spatiotemporal data through MerklePatricia-trie technology according to the key data;

In step 300, the present application proposes an efficient blockchain query response method for spatiotemporal data, so that it can support queries such as "all data in the area l in the s time period".

The main process of the spatial range search is a tree traversal process. For details, please refer to FIG. 7 , which is a flowchart of the spatial range search in the embodiment of the present application. The steps of a spatial range search include:

Step 301: Obtain the root node of the tree index structure based on the combination of Merkle tree and kd tree from the block header of the block that matches the time range, and follow a simple path from the root node to connect the given space range to the tree. node for comparison;

Step 302: If the given space range is larger than the tree node, the path enters the right subtree of the tree; if the given space range is smaller than the tree node, the path enters the left subtree of the tree, until a supertree that meets the space range is accessed. rectangle, and return the data in the super rectangle;

Step 303: For the returned data, since it is a hash value, the root node of the key-value pair index based on the MerklePatricia-trie technology needs to be found in the block header;

Step 304: Convert the hash value data into original spatiotemporal data according to the key-value pair index based on the Merkle Patricia-trie technology, and return the original spatiotemporal data.

Note that the spatial range search process will process all blocks that meet the given time range once, and the returned data is the spatiotemporal data that meets the requirements of the spatiotemporal query. FIG. 4 is an example diagram of the response of performing a spatiotemporal range query on a directed acyclic graph. First, the blocks within the time range are obtained according to the given time range, and then, according to the given space range, the corresponding hyperrectangles are found in each block, and the data results in the hyperrectangles are returned.

The blockchain spatiotemporal data query system and electronic device of the embodiments of the present application form a new tree index by combining the Merkle tree and the kd tree to store the spatiotemporal data in the blockchain system on the directed acyclic graph structure. Based on this , filter the blocks that fit the time range in the directed acyclic graph, and query the data that fit the spatial range in the filtered blocks. Compared with the prior art, the advantages of the embodiments of the present application are:

1. This application, from the adjustment of the storage structure of the blockchain to the query of the data by the blockchain system, is designed for spatiotemporal data and can meet the application scenarios of the blockchain in spatiotemporal data management;

2. The spatiotemporal data query method of the present application is very efficient, and can quickly return results that meet the given requirements in an "online" manner. Moreover, the speed of block generation to verification in the present application is greatly improved. Efficient indexes are all lightweight, occupy a small space, and meet the requirements of space-time blockchain;

3. The query response process is simple and easy to implement, and can be applied to various mainstream spatiotemporal data queries such as knn and range queries;

4. In this application, specific time meta information is added to the header of each block to record the time interval of the spatiotemporal data in the block. When querying, the block that meets the limit can be quickly found through a given time limit. The combined index of Merkle tree and kd tree can locate the corresponding data in the block, improving the problem that each query response in the prior art needs to traverse each block and read the data in each block, which is very inefficient ;

5. To improve the problem that it is difficult to establish a non-complex index structure for multi-dimensional data in the blockchain system, establish a tree index combining Merkle tree and kd tree for spatial data, and use Merkle Patricia-trie for each spatiotemporal data. Key-value pair, which is convenient for quickly locating the key value obtained through the tree index to the original data;

6. For the scenarios where spatiotemporal data is mostly used for frequent updates, the blockchain of this application adopts a directed acyclic graph structure (DAG) with faster verification time, and the verification time of this structure is better than that of the chain structure.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined in this application may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. A block chain spatiotemporal data query system is characterized in that, comprising: Blockchain module: used to store block data; Data insertion module: electrically connected to the blockchain module; Time range search module: electrically connected to the blockchain module; Spatial range search module: electrically connected to the blockchain module through the time range search module; Wherein, the topology structure G of the directed acyclic graph in the blockchain module is set to two parts: node set V and edge set E. 2. The blockchain spatiotemporal data query system according to claim 1, wherein time meta information is set in each block header in the blockchain module; The topology G has multiple source nodes s for each v∈V. 3. The blockchain spatiotemporal data query system according to claim 2, wherein the root node information in the block header is based on a tree-type index structure combined with a Merkle tree and a kd tree; the root nodes are respectively Connect to the root node of the right subtree and the root node of the left subtree. 4. An electronic device comprising: at least one processor; and a memory communicatively coupled to the at least one processor; wherein, The memory storage is provided with the blockchain module according to any one of claims 1-3, and the processor is provided with the data insertion module, the time range search module and the space according to any one of claims 1-3 Scope search module.