CN112966001B - BCTkPQ query method based on blockchain - Google Patents

Abstract

The invention discloses a BCTkPQ query method based on a block chain, which comprises the following steps: constructing a collaborative query framework (CQM); step 2: constructing a source-destination S-D index, and constructing a business logic relationship in each transaction; step 3: constructing a path-score P-SC index according to a query request sent by a user on the basis of the S-D index, and establishing a mapping relation between the path and the transaction score, wherein the P-SC index and the S-D index form a secondary index; step 4: the top k transactions with the highest score of the weight W on attribute O in the transaction of path p in the query request are obtained. The invention can realize BCTkPQ rapid query based on the block chain based on the CQM model and the secondary index, and the query efficiency can be improved along with the increase of the number of CP nodes and the number of users.

Description

BCTkPQ query method based on blockchain

Technical Field

The invention relates to the technical field of path query, in particular to a BCTkPQ query method based on a block chain.

Background

Currently, blockchains have received a great deal of attention from the industry and academia as a basis for cryptocurrency systems. Blockchains have been successfully applied to a variety of real-world scenarios such as internet of things, smart medicine, supply chains, database architecture, data service outsourcing, and the like. Blockchains can be viewed as a distributed database maintained by nodes that are not fully trusted with each other through a consensus protocol. According to different scenarios, the blockchain may design a specific transaction model according to specific business logic. Among them, a common transaction model is based on financial transactions, and is used to represent transfer information between banks or financial institutions. Obviously, in a financial transaction scenario, the blockchain may securely and completely store the user's financial bill and daily transfer records. All transaction data contains useful information and knowledge, expresses business preference of users in different scenes, and can be used for improving the quality of application services such as data analysis, data security, recommendation systems and the like. Thus, the need for diversified query processing is increasing.

The traditional query method is to send a query request to a complete node maintaining the complete block and the transaction, and acquire the transaction meeting the condition by traversing all blocks of the entire blockchain. Clearly, the efficiency of this solution is too low to meet a large number of query requirements. The main reason for inefficiency is that the entire node needs to traverse all of the blockchain data stored in the local store, resulting in excessive computational workload.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a BCTkPQ query method based on a block chain. For top-k transaction path queries (blockchain-kPathQuery, BCTkPQ) in the blockchain, the first k transactions in a given query path p that satisfy the specified condition are returned.

In order to solve the technical problems, the invention adopts the following technical scheme: a BCTkPQ query method based on a block chain comprises the following steps:

step 1: constructing the collaboration query framework CQM (Collaborative QueryModel) includes three key parts, namely an application programming interface API, a collaboration network CN (CollaborativeNetwork) maintained by a set of collaboration peers CP (CollaborativePeer), and a blockchain BC (BlockChain) storing raw transaction data; wherein the API comprises a dispatcher and a responder;

step 2: a Source-Destination S-D (Source-Destination) index is constructed, and business logic relationships in each transaction are constructed as follows:

step 2.1: initializing three sets < S, D, E > for storing logic for each transaction;

step 2.2: definition T _x For transactions on a blockchain, T is defined in accordance with a general inter-account financial transfer operation _x The structure is T _x ＝{ID，T _x Hash, from, to, O }, where ID represents T _x Sequence number T of (1) _x Hash represents T _x Is used to determine the hash value of (c),<from,to>the field is a representation T _x The business logic of the transfer operation, called transaction path p, O is the rest of the attribute of the transaction, when the block chain transaction T _x When m attributes are present, O is { attr ₁ ,attr ₂ ,……,attr _m Attr is a certain attribute;

step 2.3: traversing all transactions on the blockchain, T _x The from field and the to field of (a) are added to the S set and the D set, respectively;

step 2.4: the path of the current transaction is saved to the E set, i.e., p→ < from, to >.

Step 3: constructing a Path-Score P-SC (Path-Score) index on the basis of the S-D index according to query requests < P, k, W, O > sent by a user, and establishing a mapping relation between the Path and the transaction Score, wherein the P-SC index and the S-D index form a secondary index; where p is the transaction path, O is the rest attribute set of the transaction, W is the weight set, and k is the top k transactions with highest query scores. The specific process is as follows:

step 3.1: obtaining newly added path p in E set of S-D index _i ；

Step 3.2: when p is obtained _i Creating a new packet bucket when not present in the P-SC index ^* To store the path p _i I.e. p _i →<Tx _i >Added to socket ^* In (a) and (b);

step 3.3: when p is obtained _i When the P-SC index exists, the corresponding socket is acquired, and P is stored _i Corresponding Tx _i Into the socket.

Step 4: acquiring a query result, and sending a query request by a user<p,k,W,O>The acquisition path is p →<from ^* ,to ^* >The top k transactions with the highest score for weight W on attribute O of (c) are as follows:

step 4.1: the user broadcasts the request < p, k, W, O > to all CPs through the distributor of the CQM;

step 4.2: each CP obtains all the contained P-in the local P-SC index<from ^* ,to ^* >According to the weight set W in the query condition, calculating the transaction score of the packet socket _i ；

The transaction score _i The calculation method of (2) is as follows:

F _s (T _x )＝∑attr _i ×w _i

wherein F is _s (T _x ) Score for transaction _i ，attr _i For transaction T _x Is the ith attribute, w _i 0 is the ith value of the weight set W in the query condition, is the corresponding attribute attr _i Is a weight of (2).

Step 4.3: according to the transaction score, the first k blockchain transactions with the highest scores in the bucket are added into a result set according to the sequence from big to small;

step 4.4: calculating abstract digest for the result set, and broadcasting the digest to other CPs;

step 4.5: when the received digees are all the same and the number exceeds a given threshold (typically the threshold is set to two thirds of the number of all CPs), a resultSet is returned, the current calculation is terminated and the next call is awaited.

The beneficial effects of adopting above-mentioned technical scheme to produce lie in:

1. the method for processing the BCTkPQ problem based on the collaborative query model CQM can realize the BCTkPQ rapid query based on the block chain.

2. The query method constructs a secondary index based on the P-SC index and the S-D index, and compared with the traditional query method, the diversified query method based on the secondary index improves the query efficiency and reduces the cost, and the whole node needs to traverse all the block chain data stored in the local storage, thereby causing excessive calculation workload. Based on the CQM model and the secondary index, BCTkPQ quick query based on the blockchain can be realized, and the query efficiency can be improved along with the increase of the number of CP nodes and the number of users.

Drawings

FIG. 1 is a schematic diagram of a collaborative query framework in an embodiment of the present invention;

FIG. 2 is a flow chart of constructing an S-D index in an embodiment of the invention;

FIG. 3 is a flow chart of constructing a P-SC index in an embodiment of the present invention;

FIG. 4 is a schematic diagram of a secondary index structure according to an embodiment of the present invention;

FIG. 5 is a flow chart of a query process in an embodiment of the invention.

Detailed Description

The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.

In this embodiment, 3 users S are used _U ＝{U ₁ ,U ₂ ,U ₃ Five nodes cp= { P } ₁ ,P ₂ ,…,P ₅ Experiments were performed on 100 data, each in the format T _x ＝{ID，T _x Hash, from, to, money). The BCTkPQ query method based on the blockchain in this embodiment is as follows:

step 1: constructing a Collaborative query framework (CQM), the structure of which is shown in fig. 1, and which includes three key parts, namely an Application Programming Interface (API), a collaboration network (CollaborativeNetwork, CN) maintained by a set of collaboration peers (CollaborativePeer, CP), and a Blockchain (BC) storing raw transaction data; wherein the API comprises a dispatcher and a responder;

the execution flow of the CQM is briefly described as follows: first, a query request is broadcast to all CPs through a distributor (dispatcher) in the API. Then, all CPs synchronously respond to the query request, and each CP contains three modules, namely, a parser, an indexer, and an executor. These modules can access the BC in a read-only manner, meaning that all modules can read the data objects stored in the blockchain and create an index to fulfill the query request locally. Finally, after the CN processes the query request, the result is returned through a responder (responder) in the API.

Step 2: constructing a Source-Destination (S-D) index, constructing a business logic relationship in each transaction, and the flow is shown in FIG. 2;

step 2.1: initializing three sets < S, D, E >, storing logic for each transaction;

step 2.2: definition T _x For transactions on a blockchain, T is defined in accordance with a general inter-account financial transfer operation _x The structure is T _x ＝{ID，T _x Hash, from, to, O }, where ID represents T _x Sequence number T of (1) _x Hash represents T _x Is used to determine the hash value of (c),<from,to>the field is a representation T _x The business logic of the transfer operation, called transaction path p, O is the rest of the attribute of the transaction, when the block chain transaction T _x When m attributes are present, O is { attr ₁ ,attr ₂ ,……,attr _m Attr is a certain attribute;

in this embodiment, only one of the other attributes of the transaction is money;

step 2.3: traversing all transactions on the chain, T _x The from field and the to field of (f) are added to the S set and the D set, respectively, and as shown in fig. 3, the from field s= { U is extracted from 100 pieces of data ₁ ,U ₁ ,U ₂ ,U ₂ ,U ₃ ,U ₁ Extracting to field d= { U from 100 pieces of data ₂ ,U ₃ ,U ₁ ,U ₃ ,U ₁ ,U ₃ ···}；

Step 2.4: storing the mapping relation between the current transactions as E set, i.e. p →<from,to>E= { is constructed in 100 pieces of data<U ₁ ,U ₂ >,<U ₁ ,U ₃ >,<U ₂ ,U ₁ >,<U ₂ ,U ₃ >,<U ₃ ,U ₁ >The structure is shown on the left side of the figure 4;

step 3: based on the S-D index, sending a query request according to the user<p,k,W,O>Simulation query<<U ₁ ,U ₃ >,2,1,money>Constructing a Path-Score (P-SC) index, establishing a mapping of the Path and the transaction Score, wherein the flow is shown in fig. 3, and the P-SC index and the S-D index form a secondary index, and the structure is shown in fig. 4;

step 3.1: obtaining newly added path p in E set of S-D index _i ；

Step 3.2: when p is obtained _i In the absence of P-SC index, e.g. T _x3 Path p ₃ ＝<U ₂ ,U ₁ >Creating a new packet socket when not present in the P-SC ^* To store the path p _i ＝<U ₂ ,U ₁ >I.e. p _i →<Tx ₃ >Added to socket ^* In (a) and (b);

step 3.3: when p is obtained _i When present in the P-SC index, e.g. T _x6 Path p ₆ ＝<U ₁ ,U ₃ >When the P-SC exists, the corresponding socket is acquired, and P is stored ₆ Corresponding Tx ₆ Into a socket;

step 4: acquiring a query result, and sending a query request by a user<p,k,W,O>＝<<U ₁ ,U ₃ >,2,1,money>The acquisition path is p →<from ^* ,to ^* >＝<U ₁ ,U ₃ >The top k=2 transactions with highest score for weight w=1 on data object o=money, as shown in fig. 5;

step 4.1: the user requests through the distributor of CQM<p,k,W,O>＝<<U ₁ ,U ₃ >,2,1,money>Broadcast to all cp= { P ₁ ,P ₂ ,…,P ₅ }；

Step 4.2: each CP obtains all the contained P-in the local P-SC index<from ^* ,to ^* >＝<U ₁ ,U ₃ >According to the weight set W in the query condition, calculating the transaction score of the bucket _i . Transaction score _i Is F _x (T _x )，F _x (T _x )＝∑attr _i ×w _i . Wherein attr _i For transaction T _x Is the ith attribute, w _i 0 is the ith value of the weight set W in the query condition, is the corresponding attribute attr _i Is a weight of (2).

In this embodiment, W contains only one attribute money, and its weight is 1, so transaction T in E set _xi ，score _i ＝F _s (T _xi )＝money _i ×1；

Step 4.3: adding the 2 transactions with the highest scores in the bucket to a result set according to the score in order from big to small,

step 4.4: calculating abstract digest for the result set, and broadcasting the digest to other CPs;

step 4.5: when the received digest is all the same and the number exceeds the given threshold, returning to the resultSet, terminating the current calculation and waiting for the next call.

Claims (3)

1. The BCTkPQ query method based on the blockchain is characterized by comprising the following steps of:

step 1: constructing a collaborative query framework CQM comprising three key parts, namely an application programming interface API, a collaboration network CN maintained by a set of collaboration peers CP, and a blockchain BC storing raw transaction data; wherein the API comprises a dispatcher and a responder;

step 2: constructing a source-destination S-D index, and constructing a business logic relationship in each transaction;

the specific process is as follows:

step 2.1: initializing three sets < S, D, E > for storing logic for each transaction;

step 2.2: definition T _x For transactions on a blockchain, T is defined in accordance with a general inter-account financial transfer operation _x The structure is T _x ＝{ID，T _x Hash, from, to, O }, where ID represents T _x Sequence number T of (1) _x Hash represents T _x Is used to determine the hash value of (c),<from,to>the field is a representation T _x The business logic of the transfer operation, called transaction path p, O is the rest of the attribute of the transaction, when the block chain transaction T _x When m attributes are present, O is { attr ₁ ,attr ₂ ,……,attr _m Attr is a certain attribute;

step 2.3: traversing all transactions on the blockchain, T _x The from field and the to field of (a) are added to the S set and the D set, respectively;

step 2.4: saving the path of the current transaction into the E set, namely p & gtfwdarw < from, to >;

step 3: constructing a path-score P-SC index according to query requests < P, k, W and O > sent by a user on the basis of the S-D index, and establishing a mapping relation between the path and the transaction score, wherein the P-SC index and the S-D index form a secondary index; wherein p is a transaction path, O is the rest attribute set of the transaction, W is a weight set, and k is the first k transactions with highest query scores;

the specific process is as follows:

step 3.1: obtaining newly added path p in E set of S-D index _i ；

Step 3.2: when p is obtained _i Creating a new packet bucket when not present in the P-SC index ^* To store the path p _i I.e. p _i →<Tx _i >Added to socket ^* In (a) and (b);

step 3.3: when p is obtained _i When the P-SC index exists, the corresponding socket is acquired, and P is stored _i Corresponding Tx _i Into a socket;

step 4: acquiring a query result, and sending a query request by a user<p,k,W,O>The acquisition path is p →<from ^* ,to ^* >The top k transactions with the highest scoring for weight W on attribute O.

2. The BCTkPQ query method based on blockchain of claim 1, wherein the procedure of step 4 is as follows:

step 4.1: the user broadcasts the request < p, k, W, O > to all CPs through the distributor of the CQM;

step 4.2: each CP obtains all the contained P-in the local P-SC index<from ^* ,to ^* >According to the weight set W in the query condition, calculating the transaction score of the packet socket _i ；

Step 4.3: according to the transaction score, the first k blockchain transactions with the highest scores in the bucket are added into a result set according to the sequence from big to small;

step 4.4: calculating abstract digest for the result set, and broadcasting the digest to other CPs;

step 4.5: and when the received digees are all the same and the number exceeds a given threshold value, returning to a resultSet, terminating the current calculation and waiting for the next call.

3. The BCTkPQ query method based on blockchain of claim 2, wherein the transaction score _i The calculation method of (2) is as follows:

F _s (T _x )＝∑attr _i ×w _i

wherein F is _s (T _x ) Score for transaction _i ，attr _i For transaction T _x Is the ith attribute, w _i 0 is the ith value of the weight set W in the query condition, is the corresponding attribute attr _i Is a weight of (2).