WO2020010763A1

WO2020010763A1 - Blockchain spatio-temporal data querying method and system, and electronic apparatus

Info

Publication number: WO2020010763A1
Application number: PCT/CN2018/114374
Authority: WO
Inventors: 曲强
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2018-07-12
Filing date: 2018-11-07
Publication date: 2020-01-16
Also published as: CN108595720B; CN108595720A

Abstract

The present application relates to a blockchain spatio-temporal data querying method and system, and an electronic apparatus. The method comprises: Step a: inserting spatio-temporal data of a blockchain system into a tree index structure which is based on a combination of a Merkle tree and a k-d tree, and storing the same in a blockchain module; and for each block in the blockchain module, introducing time meta-information into a block header; Step b: configuring a time range and a space range corresponding to the spatio-temporal data, and using the time meta-information in the block header of each block in the blockchain module to search a topology G of a directed acyclic graph for a block matching the time range; and Step c: reading root node information of the tree index structure based on the combination of the Merkle tree and the k-d tree in the block header of the blocks matching the time range, searching for key data matching the space range, and acquiring corresponding spatio-temporal data according to the key data. The present application is highly efficient, and can rapidly provide, in an "online" manner, a result matching a specific requirement.

Description

Method, system and electronic equipment for querying space-time data of blockchain

Technical field

The present application belongs to the technical field of Internet databases, and particularly relates to a method and system for querying space-time data of a blockchain and an electronic device.

Background technique

Blockchain technology, also known as distributed ledger technology, is an Internet database technology. It is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanisms, and encryption algorithms. Blockchain is a new type of decentralized infrastructure and distributed computing paradigm that gradually rises with the increasing popularity of digital cryptocurrencies such as Bitcoin. Because blockchain has the advantages of decentralization, time series data, collective maintenance, security and credibility, in recent years, it has been widely used in finance, medical, education and other industries. Industry and academia are also exploring blockchain More application scenarios. With the rise of blockchain technology, a large number of new applications have been generated in various fields, including spatio-temporal data management. For example, consider the supply chain scenario of tracking items during transportation. During transportation, it is required not only to continuously update the spatiotemporal information, but also to support fast query of spatiotemporal data, such as listing all the data at time t at t, or all data at time l from t1 to t2. However, the current blockchain technology cannot efficiently respond to the query of spatio-temporal data, and the research on efficient query of spatio-temporal data has been attracting attention in the database. If efficient spatio-temporal data query can be performed on the blockchain, it will have a wide range of Application prospects.

The blockchain uses the Merkle tree to hash transaction data in the block. Each block contains a block header and a block body. The function of the block header is to link to the previous block to provide integrity for the blockchain. The block body contains verification. Data records during block creation. When you need to query the data in the blockchain, you can query the transaction data of the current block through the block body, and you can find the previous block of the current block in the blockchain through the block header. At present, the query of data in a data mode in the blockchain needs 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.

In summary, the disadvantages of the existing blockchain technology are: 1), does not support efficient management of spatio-temporal data, including efficient storage of spatio-temporal data and efficient query of spatio-temporal data; 2), the current block Querying data by the chain needs to start from the newly added block on the blockchain and trace back to the previous block through its block header. Such a query is performed on a block-by-block basis. In the worst case, it is necessary to facilitate the data of the entire blockchain after the query. Obviously, such a query is very inefficient and time-consuming, and is not suitable for quick querying. 3). The blockchain data query response method is not suitable for frequently changing spatio-temporal data queries; 4), there is no index for spatial coordinate data to speed up the entire process; 5), multi-dimensional data is established in the blockchain system for spatio-temporal data Indexes often require more than one complex index, which is cumbersome and expensive.

Summary of the invention

This application provides a method, system, and electronic device for querying space-time data of a blockchain, which aims to solve at least one of the above-mentioned technical problems in the prior art.

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

A method for querying space-time data of a blockchain includes the following steps:

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

Step b: Given the time range and space range corresponding to the time-space 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 for the time Range of blocks

Step c: Read the root node information based on the tree-type index structure of the Merkle tree and the kd tree in the block header of the time range, and search for key data that conforms to the spatial range. Said key data to obtain corresponding spatiotemporal data;

The node set of the topology G is V, and the edge set of the topology G is E.

The technical solution adopted in the embodiment of the present application further includes: In the step b, the search uses the time meta-information in the header of each block in the blockchain module to find a match in the topology G of the directed acyclic graph. The blocks in the time range are specifically: searching for the blocks of the directed acyclic graph according to the time range is implemented with a width-first algorithm, and the topology G has multiple source nodes s for each v ∈ V. The source node s starts to query, and all subsequent queries are considered to trace back to the nearest previous node at the current point.

The technical solution adopted in the embodiment of the present application further includes: In the step b, the search uses the time meta-information in the header of each block in the blockchain module to find a match in the topology G of the directed acyclic graph. The time range blocks specifically include:

Step b1: Given the time range β, use the current latest verification block returned by the GetRobustAccepted function to start running the width-first algorithm;

Step b2: In the running process of the width-first algorithm, if the time meta-information in the block header is within the time range β, the block is placed in a result set;

Step b3: When the search finds that the 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 the time range β, the running width-first algorithm is terminated.

The technical solution adopted in the embodiment of the present application further includes: in the step c, the reading the root node information of the tree-type index structure based on the Merkle tree and the kd tree in the header of the block that meets the time range. Searching for key data that conforms to the spatial range specifically includes: obtaining the root node of the tree-type index structure based on the Merkle tree and the kd tree from the block header of the time range, and starting from the root node to Next, the spatial range is compared with the tree node along a simple path; if the spatial range is larger than the tree node, the path enters the right subtree of the tree, and if the spatial range is smaller than the tree node, then The path enters the left sub-tree of the tree until a super rectangle that meets the spatial range is accessed, and the hash value data in the super rectangle is returned.

The technical solution adopted in the embodiment of the present application further includes: In the step c, the obtaining the corresponding spatio-temporal data according to the key data is specifically: finding a Merkle Patricia-trie technology-based The root node of the key-value pair index, and according to the key-value pair index based on the Merkle Patricia-trie technology, convert the hash value data into the original spatio-temporal data, and return the original spatio-temporal data.

Another technical solution adopted in the embodiments of the present application is: a blockchain spatio-temporal data query system, including:

Blockchain module: used to store block data;

Data insertion module: Connected to the blockchain module, used to insert spatio-temporal data in the blockchain system into a tree-shaped index structure based on a combination of Merkle tree and kd tree, and stored in the blockchain module ; For each block in the blockchain module, introducing temporal meta information in the block header;

Time range search module: It is connected with the blockchain module and is used to give the time range and space range corresponding to the time and space data. The time meta information in the block header of each block in the blockchain module is The topological structure G of the ring graph searches for blocks that match the time range;

Spatial range search module: connected to the time range search module, for reading the root node information of the tree index structure based on the combination of the Merkle tree and the kd tree in the block header of the time range, and searching Output key data that conforms to the spatial range, and then obtain corresponding space-time data according to the key data;

The node set of the topology G is V, and the edge set of the topology G is E.

The technical solution adopted in the embodiment of the present application further includes: the time range search module uses 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 for a time range that matches the time range. The block is specifically: searching for the blocks of the directed acyclic graph according to the time range is implemented by a width-first algorithm, and the topology G has multiple source nodes s for each v ∈ V, and the source Node s starts querying, and all subsequent queries are considered to trace back to the nearest previous node of the current node.

The technical solution adopted in the embodiment of the present application further includes: the time range search module searches the topology structure G (V, E) of the directed acyclic graph by using the time meta information in the block header of each block in the blockchain module. The generation of blocks that meet the time range specifically includes: given a time range β, using the current latest verification block returned by the GetRobustAccepted function to start running the width-first algorithm; during the execution of the width-first algorithm, if the block header If the time meta-information is within the time range β, then the block is put into the result set; when the search finds that the 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 are If it is less than the start time of the time range β, the running width-first algorithm is terminated.

The technical solution adopted in the embodiment of the present application further includes: the spatial range search module reads 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 block header that matches the time range, and searches for a matching space The key data in the range specifically includes: obtaining the root node of the tree-type index structure based on the combination of the Merkle tree and the kd tree from the block header that conforms to the time range, starting from the root node and moving down a row A simple path always compares the spatial range with a tree node; if the spatial range is larger than the tree node, the path enters the right subtree of the tree, and if the spatial range is smaller than the tree node, the path enters The left sub-tree of the tree until a super rectangle that meets the spatial range is accessed, and the hash value data in the super rectangle is returned.

The technical solution adopted in the embodiment of the present application further includes: obtaining the corresponding spatio-temporal data by the spatial range search module according to the key data is specifically: finding a key-value pair based on the Merkle Patricia-trie technology in the block header that conforms to the time range The root node of the index, and according to the key-value pair index based on the Merkle Patricia-trie technology, the hash value data is converted into the original spatio-temporal data, and the original spatio-temporal data is returned.

Another technical solution adopted in the embodiments of the present application is: an electronic device, including:

At least one processor; and

A memory connected in communication with the at least one processor; wherein,

The memory stores instructions executable by the one processor, and the instructions are executed by the at least one processor, so that the at least one processor can perform the following operations of the above-mentioned method of querying the space-time data of the blockchain. :

Step c: Read the root node information based on the tree index structure combining the Merkle tree and the kd tree in the block header of the time range, and search for key data that matches the spatial range, and then according to the Said key data obtains the corresponding spatiotemporal data.

Compared with the prior art, the embodiment of the present application has the beneficial effect that the method, system and electronic device for querying the spatiotemporal data of the blockchain in the embodiment of the present application form a new tree index by combining the Merkle tree and the kd tree. Spatio-temporal data in the blockchain system is stored on the acyclic graph structure. Based on this, the blocks that match the time range are screened in the directed acyclic graph, and the data that matches the spatial 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 query of data by the blockchain system, is designed for spatiotemporal data, which can meet the application scenarios of the blockchain in spatiotemporal data management;

2. The spatio-temporal data query method of this application is very efficient, and it can achieve "online" to quickly return results that meet the given requirements, and the speed of block generation to verification of this application has been greatly improved. Efficient indexes are lightweight, occupy a small space, and meet the requirements of the space-time blockchain;

3. The query response process is simple and easy to implement, and can be applied to a variety of mainstream spatio-temporal data queries such as knn and range queries;

4. This application uses specific time meta-information in the header of each block to record the time interval of the spatiotemporal data in the block. When querying, you can quickly find the block that meets the limit through the given time limit. The index combining the Merkle tree and the kd tree can locate the corresponding data in the block, improving each query response in the prior art requires traversing each block and reading the data in each block is very inefficient ;

5. Improve the lack of non-complicated index structure for multi-dimensional data in the blockchain system. For Merger Tree and KD Tree, a tree-based index for spatial data is created. For each spatio-temporal data, use Merkle Patricia-trie to make Key-value pairs, so that the key-values obtained through the tree index can be quickly located to the original data;

6. For the scenario where spatio-temporal data is mostly used in frequent updates, the blockchain used in this application uses a directed acyclic graph structure (DAG) with faster verification time, which has a better verification time than a chain structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a method for querying time and space data of a blockchain according to an embodiment of the present application; FIG.

2 is a directed acyclic graph according to an embodiment of the present application;

3 is a flowchart of a time range search according to an embodiment of the present application;

4 is a flowchart of a spatial range search according to an embodiment of the present application;

FIG. 5 is an example response diagram of spatiotemporal range query on a directed acyclic graph;

6 is a schematic structural diagram of a blockchain spatio-temporal data query system according to an embodiment of the present application;

FIG. 7 is a schematic structural diagram of a hardware device of a method for querying time and space data of a blockchain according to an embodiment of the present application.

detailed description

In order to make the purpose, technical solution, and advantages of the present application clearer, the present application is 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 application, and are not used to limit the application.

Please refer to FIG. 1, which is a flowchart of a method for querying time and space data of a blockchain according to an embodiment of the present application. The method for querying the spatiotemporal data of the blockchain in the embodiment of the present application includes the following steps:

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

In step 100, the structure of the spatio-temporal data in the blockchain is based on a tree-type index structure based on a combination of a Merkle tree and a kd tree. Among them, the Merkle tree is a tree structure for storing hash values, and its leaves are the hash values of the data, and non-leaf nodes are the hash values of its corresponding child node concatenated strings. The kd tree is a binary tree constructed by multi-dimensional Euclidean space segmentation, 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 super rectangle. Combining the two, that is, the data in the kd tree nodes, performs hash processing according to the Merkle tree rules. Merkle Patricia-trie is used to store the key-value pairs of spatio-temporal 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, you can quickly find the block that matches the time range through the given time range. According to the Merkle tree and kd The tree-type index structure combined with trees can locate the corresponding data in the block.

Step 200: During the spatio-temporal data query process, given the time range and space range corresponding to the time-space data, the time meta-information in the block header of each block in the blockchain module is used in the directed acyclic graph (DAG) topology. G (V, E) searches for blocks that match the time range; among them, the node set of the topology G is V, and the edge set of the topology 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 the parallel production of blocks in the network, and verify the required Less time. In the DAG network, each transaction is confirmed, and it is necessary to link to a newer transaction that already exists in the network for link confirmation. In this way, the width of the network is maintained within a certain range, and new transactions can be confirmed more quickly. time. The directed acyclic graph is shown in Figure 2.

In order to implement fast time search on DAG, this application introduces time meta-information contained in each block header. Given a time range β, first, a block that satisfies the conditions is searched on the DAG topology G (V, E) according to β. As shown in FIG. 2, the topology G has a plurality of source nodes s for each v∈V (the node v belonging to the node set V). The source node s is a node with a degree of zero in the directed acyclic graph. For each node v in the topology G, they are verified by subsequent nodes, and subsequent nodes are verified by more subsequent nodes. By analogy, it can be known that the block nodes newly added to the topology G have no subsequent nodes to verify them, so they are the source nodes s to be verified. Using the source node s, it is possible to trace its previously verified nodes, and it is convenient to traverse the topology G of the entire directed acyclic graph.

The source node s starts the query, and for the subsequent queries, the closest previous node of the current node is considered. The time-range search for the blocks of each directed acyclic graph is implemented with the width-first algorithm (BFS). Specifically, please refer to FIG. 3, which is a flowchart of a time range search according to an embodiment of the present application. The steps for time range search include:

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

Step 202: During the execution of the 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 the search finds that the 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 BFS operation 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 kd tree combined tree-type index structure, searches for key data that fits within the spatial range, and then obtains the corresponding original spatiotemporal data according to the key data through the Merkle Patricia-trie technology;

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 one area in the s time period". The main process of the spatial range search is a tree traversal process. For details, please refer to FIG. 4, which is a flowchart of the spatial range search in the embodiment of the present application. The steps of a spatial search include:

Step 301: Obtain the root node of the tree-type index structure based on the combination of the Merkle tree and the kd tree from the block header of the block that conforms to the time range. Starting from the root node and following a simple path, the given space range and tree are always Nodes for comparison;

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

Step 303: For the returned data, because they are all hash values, the root node of the key-value pair index based on the Merkle Patricia-trie technology needs to be found in the block header;

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

Note that the spatial range search process will process all the 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. 5 is an example response diagram of spatiotemporal range query on a directed acyclic graph. First, according to the given time range, the blocks within the time range are obtained. Then, according to the given space range, the matching super rectangle is found in each block, and the data result in the super rectangle is returned.

Please refer to FIG. 6, which is a flowchart of a blockchain spatio-temporal data query system according to an embodiment of the present application. The blockchain time-space data query system in the embodiment of the present application includes a blockchain module, a data insertion module, a time range search module, and a space range search module.

Blockchain module: used to store block data;

Data insertion module: Connected with the blockchain module, used to insert the spatiotemporal data in the blockchain system into the tree-based index structure based on the combination of the Merkle tree and the kd tree during the blockchain block update process, and store it In the blockchain module; at the same time, for each block in the blockchain module, time meta information is introduced in the block header; in the embodiment of this application, the structure of the spatiotemporal data in the blockchain is based on the Merkle tree A tree-type index structure combined with a kd tree. Among them, the Merkle tree is a tree structure for storing hash values, and its leaves are the hash values of the data, and non-leaf nodes are the hash values of its corresponding child node concatenated strings. The kd tree is a binary tree constructed by multi-dimensional Euclidean space segmentation, 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 super rectangle. Combining the two, that is, the data in the kd tree nodes, performs hash processing according to the Merkle tree rules. Merkle Patricia-trie is used to store key-value pairs of spatio-temporal 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, you can quickly find the block that matches the time range through the given time range. According to the Merkle tree and kd The tree-type index structure combined with trees can locate the corresponding data in the block.

Time range search module: It is connected with the blockchain module. It is used to give the time range and space range corresponding to the time and space data during the query of the spatiotemporal data. The time meta information in the block header of each block in the blockchain module is used to The topological structure G (V, E) of the directed acyclic graph (DAG) searches for blocks that meet the time range. In the embodiment of the present application, in the blockchain technology, a directed non-directed graph that requires a shorter verification time is selected. Ring Graph (DAG), which can improve the efficiency of the blockchain, make it possible to produce blocks in parallel in the network, and the time required for verification is small. In the DAG network, each transaction is confirmed, and it is necessary to link to a newer transaction that already exists in the network for link confirmation. In this way, the width of the network is maintained within a certain range, and new transactions can be confirmed faster time.

In order to implement fast time search on DAG, this application introduces time meta-information contained in each block header. Given a time range β, first, a block that satisfies the conditions is searched on the DAG topology G (V, E) according to β. The topology G has multiple source nodes s for each v ∈ V (that is, newly added nodes to be verified in the directed acyclic graph), and the source node starts the query. For subsequent queries, the closest previous node that traces the current point is considered. . The time-range search for the blocks of each directed acyclic graph is implemented with the width-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 to start running BFS; in During the execution of BFS, if the temporal meta information in the block header is within a given time range β, that is,

Then the block is put into the result set; when the search finds that the 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 BFS operation is terminated.

Spatial range search module: Connected with the time range search module, it is 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 time range block, and then from top to bottom Access the entire Merkle tree and kd tree tree index structure, search for key data that fits within the spatial range, and then obtain the corresponding original spatio-temporal data based on the key data through the Merkle Patricia-trie technology; this application proposes a high-efficiency zone for spatio-temporal data The block chain query response method enables it to support queries such as "all data in the l area in the s time period".

Specifically, the spatial range search method of the spatial range search module is: from the block header of the block, the root node of the tree-type index structure based on the combination of the Merkle tree and the kd tree is obtained, starting from the root node and following a simple path all the way Compare the given spatial range with the tree node; if the given spatial range is larger than the tree node, the path enters the right subtree of the tree, and if the given spatial range is smaller than the tree node, the path enters the left subtree of the tree until Access a super rectangle that meets the spatial range, and return the data in the super rectangle; for the returned data, because they are all hash values, you need to find the root node of the key-value pair index based on the Merkle Patricia-trie technology in the block header. ; According to the key-value pair index based on 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 the tangle (based on directed acyclic graph) of iota, and uses the spatiotemporal data on Pokemon Go to test. It can be found that in the test network, the user uses the method proposed in this application , "Online" query can meet the qualified spatiotemporal data, and its query response time is fast. For the query method, the experiment uses a variety of mainstream query methods: knn query, ball-point query, range query and bounded knn query. The results obtained are that the response speed meets the "online" query.

FIG. 7 is a schematic structural diagram of a hardware device of a method for querying time and space data of a blockchain according to 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 may be connected through a bus or other methods. In FIG. 7, the connection through the bus is taken as an example.

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 non-transitory software programs, instructions, and modules stored in the memory, that is, the processing method of the foregoing method embodiment is implemented.

The memory may include a storage program area and a storage data area, where the storage program area may store an operating system and application programs required for at least one function; the storage data area may store data and the like. In addition, the memory may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include memory remotely set relative to the processor, and these remote memories may be connected to the processing system via a network. Examples of the above network 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 inputted numeric or character information and generate a 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 c: Read the root node information based on the tree-type index structure of the Merkle tree and the kd tree in the block header of the time range, and search for key data that conforms to the spatial range. Said key data obtains the corresponding spatiotemporal data.

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

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

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. When the program instructions are executed by a computer, To cause the computer to:

The method, system, and electronic device for querying the spatiotemporal data of the blockchain in 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 a directed acyclic graph structure. Based on this, the blocks that match the time range are screened in the directed acyclic graph, and the data that matches the spatial 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 query of data by the blockchain system, is designed for spatiotemporal data, which can meet the application scenarios of the blockchain in spatiotemporal data management.

2. The spatio-temporal data query method of this application is very efficient, and it can achieve "online" to quickly return results that meet the given requirements, and the speed of block generation to verification of this application has been greatly improved. Efficient indexes are lightweight and occupy a small space, which meets the requirements of the space-time blockchain.

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

4. This application uses specific time meta-information in the header of each block to record the time interval of the spatiotemporal data in the block. When querying, you can quickly find the block that meets the limit through the given time limit. The index combining the Merkle tree and the kd tree can locate the corresponding data in the block, improving each query response in the prior art requires traversing each block and reading the data in each block is very inefficient .

5.Improve the lack of non-complex index structure for multi-dimensional data in the blockchain system. For the spatial data, establish a tree index combining the Merkle tree and the kd tree. For each spatio-temporal data, use Merkle Patricia-trie Key-value pairs are used to quickly locate the key-values obtained through the tree index to the original data.

Although the present invention has been described with reference to the current preferred embodiments, those skilled in the art should understand that the above preferred embodiments are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the scope of the spirit and principle of the invention shall be included in the scope of protection of the rights of the present invention.

Claims

A method for querying the spatiotemporal data of a blockchain is characterized in that it includes the following steps:

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

Step b: Given the time range and space range corresponding to the time-space 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 for the time Range of blocks

Step c: Read the root node information based on the tree index structure combining the Merkle tree and the kd tree in the block header of the time range, and search for key data that matches the spatial range, and then according to the Said key data to obtain corresponding spatiotemporal data;

The node set of the topology G is V, and the edge set of the topology G is E.
The method for querying space-time data of a blockchain according to claim 1, characterized in that in said step b, said utilizing the time meta-information in a block header of each block in a blockchain module in a directed acyclic graph The search for a block that fits the time range in the topology G of is specifically: searching for the block of the directed acyclic graph according to the time range is implemented by a width-first algorithm, and the topology G for each v ∈ V There are multiple source nodes s, and the source node s starts to query, and all subsequent queries are considered to trace the closest previous node of the current node.
The method for querying the spatio-temporal data of a blockchain according to claim 2, characterized in that in said step b, said utilizing the time meta-information in a block header of each block in a blockchain module in a directed acyclic graph The blocks in the topology G that are found to meet the time range specifically include:

Step b1: Given the time range β, use the current latest verification block returned by the GetRobustAccepted function to start running the width-first algorithm;

Step b2: In the running process of the width-first algorithm, if the time meta-information in the block header is within the time range β, the block is placed in a result set;

Step b3: When the search finds that the 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 the time range β, the running width-first algorithm is terminated.
The method for querying the spatiotemporal data of a blockchain according to claim 3, characterized in that in said step c, said reading the block header of a block that conforms to the time range is based on the combination of the Merkle tree and the kd tree. The root node information of the tree-type index structure, and searching for key data that conforms to the spatial range specifically includes: obtaining the root node of the tree-type index structure based on the combination of the Merkle tree and the kd tree from the block header that conforms to the time range. Starting from the root node and comparing the spatial range with the tree node along a simple path; if the spatial range is larger than the tree node, the path enters the right subtree of the tree, and if the The space range is smaller than the tree node, then the path enters the left subtree of the tree until a super rectangle that meets the space range is accessed, and the hash value data in the super rectangle is returned.
The method for querying the spatio-temporal data of a blockchain according to claim 4, characterized in that, in the step c, the obtaining the corresponding spatio-temporal data according to the key data is specifically: in the block header of the block that conforms to the time range Find the root node of the key-value pair index based on the Merkle Patricia-trie technology, and convert the hash value data into the original spatio-temporal data according to the key-value pair index based on the Merkle Patricia-trie technology, and return the original spatio-temporal data .
A blockchain time-space data query system, which is characterized by:

Blockchain module: used to store block data;

Data insertion module: Connected to the blockchain module, used to insert spatio-temporal data in the blockchain system into a tree-shaped index structure based on a combination of Merkle tree and kd tree, and stored in the blockchain module ; For each block in the blockchain module, introducing temporal meta information in the block header;

Time range search module: It is connected with the blockchain module and is used to give the time range and space range corresponding to the time and space data. The time meta information in the block header of each block in the blockchain module is The topological structure G of the ring graph searches for blocks that match the time range;

Spatial range search module: connected to the time range search module, for reading the root node information of the tree index structure based on the combination of the Merkle tree and the kd tree in the block header of the time range, and searching Output key data that conforms to the spatial range, and then obtain corresponding space-time data according to the key data;

The node set of the topology G is V, and the edge set of the topology G is E.
The query system of spatio-temporal data of a blockchain according to claim 6, wherein the time range search module utilizes the topology of the time meta-information in the block header of each block in the blockchain module in a directed acyclic graph Searching for a block that meets the time range in G is specifically: searching for the block of the directed acyclic graph according to the time range is implemented by a width-first algorithm, and the topology G has multiple for each v ∈ V The source node s starts querying from the source node s, and for the subsequent queries, the closest previous node that traces the current point is considered.
The query system of spatio-temporal data for a blockchain according to claim 7, characterized in that the time range search module utilizes the topological structure of the time meta-information in the block header of each block in the blockchain module in a directed acyclic graph The blocks searched in G that meet the time range specifically include: given a time range β, using the current latest verification block returned by the GetRobustAccepted function to start running the width-first algorithm; during the execution of the width-first algorithm, if the area When the time meta-information in the block header is within the time range β, the block is placed in the result set; when the search finds that the block is outside the time range β or in all the time meta-information in the block header of the next block If the end time is less than the start time of the time range β, the running width-first algorithm is terminated.
The query system of spatio-temporal data for a blockchain according to claim 8, wherein the spatial range search module reads a tree-type index based on a combination of the Merkle tree and a kd tree in a block block header that conforms to a time range The root node information of the structure, and searching for key data in a consistent spatial range specifically includes: obtaining the root node of the tree-type index structure based on the Merkle tree and the kd tree from the block header of the time range. The root node starts to compare the spatial range with the tree node along a simple path; if the spatial range is larger than the tree node, the path enters the right subtree of the tree, and if the spatial range is Smaller than the tree node, the path enters the left sub-tree of the tree until a super rectangle that meets the spatial range is accessed, and the hash value data in the super rectangle is returned.
The query system of spatio-temporal data for a blockchain according to claim 9, wherein the spatial range search module obtains corresponding spatio-temporal data according to key data is specifically: finding a Merkle-based The root node of the key-value pair index of the Patricia-trie technology, and according to the key-value pair index based on the Merkle Patricia-trie technology, the hash value data is converted into the original spatio-temporal data, and the original spatio-temporal data is returned.
An electronic device includes:

At least one processor; and

A memory connected in communication with the at least one processor; wherein,

The memory stores instructions executable by the one processor, and the instructions are executed by the at least one processor, so that the at least one processor can execute the block according to any one of the above 1 to 5 The following operations of the chain spatio-temporal data query method:

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

Step b: Given the time range and space range corresponding to the time-space 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 for the time Range of blocks

Step c: Read the root node information based on the tree index structure combining the Merkle tree and the kd tree in the block header of the time range, and search for key data that matches the spatial range, and then according to the Said key data obtains the corresponding spatiotemporal data.