CN112966001A - BCTkPQ query method based on block chain - Google Patents

Abstract

The invention discloses a BCTkPQ query method based on a block chain, which comprises the following steps of 1: constructing a collaborative query framework CQM; step 2: constructing a source-destination S-D index, and constructing a business logic relation in each transaction; and step 3: on the basis of the S-D index, constructing a path-score P-SC index according to a query request sent by a user, 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; and 4, step 4: and acquiring the first k transactions with the highest score of the weight W on the attribute O in the transaction of the path p in the query request. Based on the CQM model and the secondary index, the block chain-based BCTkPQ quick query can be realized, and the query efficiency is improved along with the increase of the number of CP nodes and the number of users.

Description

BCTkPQ query method based on block chain

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 high degree of attention from the industry and academia as the cornerstone of cryptocurrency systems. Blockchains have been successfully applied in various realistic scenarios, such as internet of things, smart medicine, supply chain, database architecture, data service outsourcing, and the like. A blockchain may be viewed as a distributed database maintained by nodes that are not fully trusted by each other through a consensus protocol. According to different scenes, the blockchain can design a specific transaction model according to specific business logic. Among them, a common transaction model is based on financial transactions, which represent transfer information between banks or financial institutions. Obviously, in a financial transaction scenario, the blockchain may safely and completely store the user's financial bills and daily transfer records. All transaction data contain useful information and knowledge, express 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, there is an increasing demand for diversified query processing.

The traditional query method is to send a query request to a complete node that maintains a complete block and transaction, and to obtain a eligible transaction by traversing all blocks of the entire blockchain. Obviously, the efficiency of this solution is too low to meet the large number of query requirements. The main reason for the inefficiency is that the entire node needs to traverse all the blockchain data stored in the local storage, resulting in a too high 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 a top-k transaction Path Query (BCTkPQ) in a block chain, the first k transactions in a given Query Path p that satisfy a specified condition are returned.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a BCTkPQ query method based on a block chain comprises the following steps:

step 1: constructing a collaboration Query framework CQM (collaborative Query model) comprises three key parts, namely an application programming interface API, a collaboration network CN (collaborative network) maintained by a group of collaboration peers CP (collaborative peer), and a block chain BC (Block chain) for storing original transaction data; wherein the API comprises a distributor and a responder;

step 2: constructing a Source-Destination S-D (Source-Destination) index, and constructing a business logic relationship in each transaction, wherein the process comprises the following steps:

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

step 2.2: definition of T_xDefining T for transactions on blockchains, according to a general financial transfer operation between accounts_xHas the structure of T_x＝{ID，T_xHash, from, to, O }, where ID denotes T_xSerial number of (1), T_xHash represents T_xThe hash value of (a) of (b),<from,to>the field being a representation of T_xThe business logic of the transmission operation is called a transaction path p, O is the rest attribute of the transaction when the block chain transaction T_xWith m attributes, O is { attr₁,attr₂,……,attr_mAttr is a certain attribute;

step 2.3: traversing all transactions on the blockchain, and dividing T_xThe from field and the to field of (1) 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 >.

And step 3: on the basis of the S-D index, according to a query request < P, k, W, O > sent by a user, a Path-Score P-SC (Path-Score) index is constructed, a mapping relation between the Path and the transaction Score is established, and the P-SC index and the S-D index form a secondary index; wherein p is a transaction path, O is a set of other attributes of the transaction, W is a weight set, and k is the first k transactions with the highest query score. 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_iWhen the P-SC index does not exist, a new packet is created to store the path P_iI.e. p_i→<Tx_i>Adding to bucket_iPerforming the following steps;

step 3.3: when p is obtained_iWhen the P-SC index exists, acquiring a corresponding bucket and storing P_iCorresponding Tx_iGo to bucket.

And 4, step 4: obtaining the query result, assuming that the user sends the query request < p, k, W, O >, so as to obtain the first k transactions with the highest score of the weight W on the attribute O in the transactions with the path p ═ from, to >, and the process is as follows:

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

step 4.2: each CP gets all the contents P → in the local P-SC index<from*,to*>According to the weight set W in the query condition, the transaction score of the packet is calculated_i；

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

F_s(T_x)＝∑attr_i×w_i

wherein, F_s(T_x) Score for a transaction_i，attr_iFor a transaction T_xThe ith attribute of (1), w_i≧ 0 is the ith value of weight set W in query condition, and is the corresponding attribute attr_iThe weight of (c).

Step 4.3: according to the transactions score, sorting from big to small, adding the first k blockchain transactions with the highest scores in the bucket into a result set resultSet;

step 4.4: calculating digest for the resultSet, and broadcasting the digest to other CPs;

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

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

1. the method for processing the BCTkPQ problem based on the collaborative query model CQM can realize the BCTkPQ fast 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, compared with the traditional query method, the diversified query method based on the secondary index can improve the query efficiency and reduce the number of the nodes, and the whole node needs to traverse all block chain data stored in a local storage, thereby causing overhigh calculation workload. Based on a CQM model and a secondary index, the block chain-based BCTkPQ quick query 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 structural diagram of a collaborative query framework in an embodiment of the present invention;

FIG. 2 is a flow chart of the construction of an S-D index according to an embodiment of the present invention;

FIG. 3 is a flowchart of constructing a P-SC index according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a structure of a secondary index 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 detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In this embodiment, 3 subscribers S are used_U＝{U₁,U₂,U₃Where five nodes CP ═ P₁,P₂,…,P₅The experiment was performed with 100 pieces of data, each in the format of T_x＝{ID，T_xHash, from, to, money }. In this embodiment, a block chain-based BCTkPQ query method is as follows:

step 1: constructing a Collaborative Query Model (CQM), the structure of which is shown in fig. 1, and which includes three key parts, namely an Application Programming Interface (API), a Collaborative Network (CN) maintained by a group of Collaborative Peers (CPs), and a Block Chain (Block Chain, BC) storing original transaction data; wherein the API comprises a distributor and a responder;

the execution flow of the CQM is briefly described as follows: first, the query request is broadcast to all CPs through a dispatcher (dispatcher) in the API. All CPs then respond to the query request synchronously, each CP containing three modules, a parser, an indexer and an executor. These modules may access the BC in a read-only manner, meaning that all modules may read the data objects stored in the blockchain and create an index to complete the query request locally. Finally, after the CN has processed the query request, the CN returns the result through a responder (responder) in the API.

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

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

step 2.2: definition of T_xDefining T for transactions on blockchains, according to a general financial transfer operation between accounts_xHas the structure of T_x＝{ID，T_xHash, from, to, O }, where ID denotes T_xSerial number of (1), T_xHash represents T_xThe hash value of (a) of (b),<from,to>the field being a representation of T_xThe business logic of the transmission operation is called a transaction path p, O is the rest attribute of the transaction when the block chain transaction T_xWith m attributes, O is { attr₁,attr₂,……,attr_mAttr is a certain attribute;

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

step 2.3: traverse all transactions on the chain, will T_xThe from field and the to field of (a) 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 data₁,U₁,U₂,U₂,U₃,U₁The to field D & ltu & gt is extracted from 100 pieces of data₂,U₃,U₁,U₃,U₁,U₃···}；

Step 2.4: the mapping relationship between the current transactions is saved as E set, i.e. p →<from,to>Construction of E ═ tone in 100 pieces of data<U₁,U₂>,<U₁,U₃>,<U₂,U₁>,<U₂,U₃>,<U₃,U₁>H, the structure is shown on the left side of FIG. 4;

and step 3: root on the basis of S-D indexSending a query request according to a user<p,k,W,O>Simulating queries<<U₁,U₃>,2,1,money>Constructing a Path-Score (P-SC) index, and establishing mapping of the Path and the transaction Score, wherein the process is shown in FIG. 3, 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_iWhen not present in the P-SC index, e.g. T_x3Path p₃＝<U₂,U₁>When the P-SC does not exist, a new packet is created to store the path P_i＝<U₂,U₁>I.e. p_i→<Tx₃>Adding to bucket₃Performing the following steps;

step 3.3: when p is obtained_iWhen present in the P-SC index, e.g. T_x6Path p₆＝<U₁,U₃>Obtaining corresponding bucket when the P-SC exists, and storing P₆Corresponding Tx₆Entering a bucket;

and 4, step 4: obtaining the query result, assuming that the user sends the query request<p,k,W,O>＝<<U₁,U₃>,2,1,money>Taking the acquisition path as p ═<from*,to*>＝<U₁,U₃>The top k of the transaction with the highest score of the weight W of 1 on money is 2 transactions, as shown in fig. 5;

step 4.1: user will request through distributor of CQM<p,k,W,O>＝<<U₁,U₃>,2,1,money>Broadcast to all CP ═ P₁,P₂,…,P₅}；

Step 4.2: each CP gets all the contents P → in the local P-SC index<from*,to*>＝<U₁,U₃>The transaction score of the bucket is calculated according to the weight set W in the query condition_i. Transaction score_iIs F_s(T_x)，F_s(T_x)＝∑attr_i×w_i. Wherein, attr_iFor a transaction T_xThe ith attribute of (1), w_i≧ 0 is the ith value of weight set W in query condition, and is the corresponding attribute attr_iThe weight of (c).

In this embodiment, W only includes one attribute money, and its weight is 1, so the transaction T in the E set_xi，score_i＝F_s(T_xi)＝money_i×1；

Step 4.3: according to score, in descending order, adding the 2 transactions with the highest scores in bucket to a result set resultSet, wherein resultSet is { T }_x2＝{2，T_x2Hash，U₁，U3，money2}，T_x6＝{6，T_x6Hash，U₁，U₃，money6}}；

Step 4.4: calculating digest for the resultSet, and broadcasting the digest to other CPs;

step 4.5: when the received digests are all the same and the number exceeds a given threshold, two thirds of the total CP number, a resultSet is returned, the current calculation is terminated and the next call is waited.

Claims (5)

1. A BCTkPQ query method based on a block chain is characterized by comprising the following steps:

step 1: constructing a collaboration query framework CQM comprising three key parts, namely an Application Programming Interface (API), a Collaboration Network (CN) maintained by a group of Collaboration Peers (CP) and a Blockchain (BC) for storing original transaction data; wherein the API comprises a distributor and a responder;

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

and step 3: on the basis of the S-D index, constructing a path-score P-SC index according to a query request < 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;

wherein, p is a transaction path, O is a set of other attributes of the transaction, W is a weight set, and k is the first k transactions with the highest query score;

and 4, step 4: obtaining the query result, assuming the user sendsQuery request<p,k,W,O>Taking the acquisition path as p ═<from^*,to^*>The first k transactions with the highest weight W on attribute O in the transactions of (2).

2. The block chain-based BCTkPQ query method of claim 1, wherein the procedure of step 2 is as follows:

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

step 2.2: definition of T_xDefining T for transactions on blockchains, according to a general financial transfer operation between accounts_xHas the structure of T_x＝{ID，T_xHash, from, to, O }, where ID denotes T_xSerial number of (1), T_xHash represents T_xThe hash value of (a) of (b),<from,to>the field being a representation of T_xThe business logic of the transmission operation is called a transaction path p, O is the rest attribute of the transaction when the block chain transaction T_xWith m attributes, O is { attr₁,attr₂,……,attr_mAttr is a certain attribute;

step 2.3: traversing all transactions on the blockchain, and dividing T_xThe from field and the to field of (1) 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 >.

3. The block chain-based BCTkPQ query method of claim 1, wherein the procedure of step 3 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_iWhen the P-SC index does not exist, a new packet is created^*To store the path p_iI.e. p_i→<Tx_i>Adding to bucket_iPerforming the following steps;

step 3.3: when p is obtained_iWhen the P-SC index exists, acquiring a corresponding bucket and storing P_iCorrespond toTx of_iGo to bucket.

4. The block chain-based BCTkPQ query method 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 CQM;

step 4.2: each CP gets all the contents P → in the local P-SC index<from^*,to^*>According to the weight set W in the query condition, the transaction score of the packet is calculated_i；

Step 4.3: according to the transactions score, sorting from big to small, adding the first k blockchain transactions with the highest scores in the bucket into a result set resultSet;

step 4.4: calculating digest for the resultSet, and broadcasting the digest to other CPs;

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

5. The block chain-based BCTkPQ query method of claim 4, wherein the transaction score is score_iThe calculation method of (2) is as follows:

F_s(T_x)＝∑attr_i×w_i

wherein, F_s(T_x) Score for a transaction_i，attr_iFor a transaction T_xThe ith attribute of (1), w_i≧ 0 is the ith value of weight set W in query condition, and is the corresponding attribute attr_iThe weight of (c).

Images