CN116303574A - Database operation statement optimization and database operation method, equipment and medium - Google Patents

Abstract

The embodiment of the application provides a database operation statement optimization method, a database operation statement optimization device, a database operation statement optimization medium, a database operation statement optimization device and a database operation medium. In the embodiment of the application, based on the abstract syntax tree corresponding to at least one expression in the database operation statement, a common sub-expression is selected from at least one sub-expression, the at least one sub-expression is derived from the at least one expression, and the common sub-expression in the at least one expression is replaced by an execution result mark of the common sub-expression so as to optimize the database operation statement. In this way, in the code execution stage, only the sub-execution codes corresponding to the common sub-expressions need to be executed once, when the execution result marks of the common sub-expressions are included in the codes, the execution results obtained by the sub-execution codes corresponding to the common sub-expressions are multiplexed, and further repeated calculation of repeated sub-expressions is not needed, so that the calculation efficiency is improved, the calculation resources are saved, and the query performance of the database system is improved.

Description

Database operation statement optimization and database operation method, equipment and medium

technical field

The present application relates to the field of database technology, in particular to a database operation statement optimization and database operation method, device and medium.

Background technique

Various relational database systems support data query using SQL (Structured Query Language, Structured Query Language). Specifically, the client submits an SQL statement to the server of the relational database system, and the server parses the SQL statement into an AST (abstract syntax code, abstract syntax tree), and generates a logical execution plan based on the AST, and executes such as data query, Database operations such as data update, data deletion or data insertion, and return the database operation results to the client.

Usually, the logical execution plan includes multiple logical operators, among which logical operators such as Projection (projection) operator and filter (filter) operator need to calculate the expression in the SQL statement. When the SQL statement includes multiple expressions, the probability of repeated sub-expressions in multiple expressions is high, and repeated calculations for repeated sub-expressions result in low calculation efficiency, resulting in waste of computing resources and affecting relational databases. System query performance.

Contents of the invention

Various aspects of the present application provide a database operation statement optimization and a database operation method, device and medium, which are used to optimize the database operation statement and improve the query performance of the database system.

An embodiment of the present application provides a method for optimizing a database operation statement, including: constructing an abstract syntax tree corresponding to at least one expression in the database operation statement; using at least one abstract syntax tree to select a common subexpression from at least one subexpression , at least one subexpression is derived from at least one expression; the common subexpression in at least one expression is replaced by the execution result mark of the common subexpression to optimize the database operation statement, and the execution result mark of the common subexpression is denoted by Indicates the execution result obtained by reusing the sub-execution code corresponding to the common sub-expression in the code execution phase.

The embodiment of the present application also provides a database operation method, including: generating a logical execution plan according to the first abstract syntax tree of the database operation statement, at least one logical operator in the logical execution plan each includes a partial expression in the database operation statement; For at least one expression corresponding to at least one logical operator, construct a second abstract syntax tree corresponding to at least one expression; use at least one second abstract syntax tree to select a common subexpression from at least one subexpression, at least one The subexpression is derived from at least one expression; the common subexpression in at least one expression is replaced with the execution result mark of the common subexpression to optimize at least one logical operator; according to the optimized at least one logical operator and The common subexpression generates execution code; run the execution code to obtain the operation result of the database operation statement, wherein, in the process of running the execution code, the sub execution code corresponding to the common subexpression is reused according to the execution result mark of the common subexpression The obtained execution result.

An embodiment of the present application also provides an electronic device, including: a memory and a processor; the memory is used to store a computer program; the processor is coupled to the memory and used to execute the computer program to perform the steps in the above method.

The embodiment of the present application also provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the processor can implement the steps in the above method.

In this embodiment of the present application, based on the abstract syntax tree corresponding to at least one expression in the database operation statement, a common subexpression is selected from at least one subexpression, at least one subexpression is derived from at least one expression, and The common subexpression in at least one expression is replaced with the execution result flag of the common subexpression to optimize the database operation statement. In this way, in the code execution stage, it is only necessary to execute the sub-execution code corresponding to the common sub-expression once, and when the execution result mark of the common sub-expression is included in the code, the sub-execution corresponding to the common sub-expression is reused The execution results obtained by the code do not need to perform repeated calculations on repeated sub-expressions, which improves calculation efficiency, saves calculation resources, and improves the query performance of the database system.

Description of drawings

The drawings described here are used to provide a further understanding of the application and constitute a part of the application. The schematic embodiments and descriptions of the application are used to explain the application and do not constitute an improper limitation to the application. In the attached picture:

Fig. 1 is a system architecture diagram of an exemplary database system;

Fig. 2 is a flow chart of a method for optimizing a database operation statement provided by an embodiment of the present application;

FIG. 3 is a flow chart of a database operation method provided by an embodiment of the present application;

Fig. 4 is a schematic structural diagram of a database operation statement optimization device provided by the present application;

FIG. 5 is a schematic structural diagram of a database operating device provided by the present application;

FIG. 6 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with specific embodiments of the present application and corresponding drawings. Apparently, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. "And/or", which describes the access relationship of associated objects, means that there can be three kinds of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist at the same time, and B exists alone. A, B can be singular or plural. In the text description of this application, the character "/" generally indicates that the contextual objects are an "or" relationship. In addition, in the embodiment of the present application, "first", "second", "third", etc. are only used to distinguish the contents of different objects, and have no other special meanings.

Usually, the logical execution plan includes multiple logical operators, among which logical operators such as Projection (projection) operator and filter (filter) operator need to calculate the expression in the SQL statement. When the SQL statement includes multiple expressions, the probability of repeated sub-expressions in multiple expressions is high, and repeated calculations for repeated sub-expressions result in low calculation efficiency, resulting in waste of computing resources and affecting relational databases. System query performance.

Based on the foregoing, embodiments of the present application provide a database operation statement optimization and database operation method, device, and medium. In this embodiment of the present application, based on the abstract syntax tree corresponding to at least one expression in the database operation statement, a common subexpression is selected from at least one subexpression, at least one subexpression is derived from at least one expression, and The common subexpression in at least one expression is replaced with the execution result flag of the common subexpression to optimize the database operation statement. In this way, in the code execution stage, it is only necessary to execute the sub-execution code corresponding to the common sub-expression once, and when the execution result mark of the common sub-expression is included in the code, the sub-execution corresponding to the common sub-expression is reused The execution results obtained by the code do not need to perform repeated calculations on repeated sub-expressions, which improves calculation efficiency, saves calculation resources, and improves the query performance of the database system.

The technical solutions provided by various embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

FIG. 1 is a system architecture diagram of an exemplary database system. Referring to Figure 1, the client sends various database operation statements such as SQL statements to the server in the database system, and the management node in the server performs syntax analysis on the database operation statement to construct an abstract syntax tree of the database operation statement. The management node is also based on The abstract syntax tree of the database operation statement generates a logical execution plan, and the logical execution plan usually includes multiple logical operators, such as the projection (projection) operator, filter (filter) operator and other logical operators need to understand the expressions in the database operation statement Calculation. In addition, the management node is also responsible for the allocation of the logical execution plan, that is, assigning each logical operator in the logical execution plan to the computing nodes in the server. Computing nodes execute assigned logical operators to perform various operations such as querying, modifying, or deleting data in the database.

An expression is a combination of one or more values, operators, or functions. Taking the database operation statement as an SQL statement as an example, the SQL statement has three different types of SQL expressions, namely: Boolean expression, number expression and date expression. SQL Boolean expressions are based on matching a single value to fetch data; Numeric expressions are used to perform mathematical operations in any query; Date expressions return the current system date and time value. In practical applications, an expression may include several sub-expressions, and sub-expressions can be understood as expressions contained in an expression. The probability of repeated sub-expressions in database operation statements is relatively high, and the calculation nodes perform repeated calculations on repeated sub-expressions, resulting in low calculation efficiency, resulting in waste of computing resources and affecting the query performance of the database system. For this reason, it is necessary to optimize the database operation statement.

In this embodiment, the client, the management node, or the computing node may be composed of software and/or hardware. In terms of implementation, the client, management node, or computing node can be a terminal device or a server. Wherein, the terminal device or the server may be hardware or software. When the terminal device is hardware, the terminal device is, for example, a mobile phone, a tablet computer, a desktop computer, a wearable smart device, a smart home device, and the like. When the terminal device is software, it can be installed in the hardware devices listed above. In this case, the terminal device is, for example, multiple software modules or a single software module, which is not limited in this embodiment of the present application. Servers can be hardware or software. When the server is hardware, the server is a single server or a distributed server cluster composed of multiple servers. When the server is software, it may be multiple software modules or a single software module, which is not limited in this embodiment of the present application.

FIG. 2 is a flow chart of a method for optimizing a database operation statement provided by an embodiment of the present application. Referring to Figure 2, the method may include the following steps:

201. Build an abstract syntax tree corresponding to at least one expression in the database operation statement.

202. Using at least one abstract syntax tree, select a common subexpression from at least one subexpression, where at least one subexpression originates from at least one expression.

203. Replace the common subexpression in at least one expression with the execution result mark of the common subexpression to optimize the database operation statement, and the execution result mark of the common subexpression is used to indicate that the common subexpression can be reused in the code execution stage The execution result obtained by the sub-execution code corresponding to the expression.

In this embodiment, the database operation statement refers to a statement for performing various operations on the database, such as querying a table, creating a table, modifying a table, etc., and there is no limitation on this. Database operation statements include but not limited to SQL statements, for example.

In this embodiment, the number of expressions in the database operation statement to be optimized may be one or more, and for each expression in the database operation statement, the expression is parsed to construct an abstraction of the expression syntax tree.

In this embodiment, using one or more abstract syntax trees corresponding to the database operation statement, for at least one expression appearing in the database operation statement, a common subexpression is found from at least one subexpression included in the at least one expression. Expressions, common subexpressions can be understood as subexpressions that appear multiple times in database operation statements. For example, the following two expressions appear in the same SQL statement: json_extract_0(json_parse(content),'user')user, and json_extract_0(json_parse(content),'action')action, these two expressions The common subexpression in the formula is json_parse(content).

Further optionally, in order to find out common subexpressions more accurately, each level in the abstract syntax tree can be traversed in order from low to high in the level of the abstract syntax tree, and at least one level corresponding to each level can be updated during the traversal process. The mapping relationship table of at least one sub-expression and the reference count record table that records the reference count of each sub-expression, after traversing the entire abstract syntax tree, find out the reference count from multiple sub-expressions according to the reference count record table More common subexpressions.

Exemplarily, the level of the leaf nodes in the abstract syntax tree is the lowest, and the level of the parent node is one level higher than that of the child nodes. Correspondingly, using at least one abstract syntax tree, an implementation manner of selecting a common subexpression from at least one subexpression is: for any abstract syntax tree in the at least one abstract syntax tree, according to the order of the hierarchy from low to high Traverse each level in the abstract syntax tree, and for the first subexpression corresponding to the node in the current level traversed, query the mapping relationship table according to the current level and the first subexpression, wherein the mapping relationship table includes at least one level. Corresponding at least one sub-expression; according to the query result of the mapping relation table, update the mapping relation table and the reference number recording table used to record the reference times of each sub-expression; after at least one abstract syntax tree is all processed, according to the reference The number of references of each subexpression in the count record table selects a common subexpression from at least one subexpression.

In practical applications, when traversing at least one abstract syntax tree, the current abstract syntax tree can be selected from at least one abstract syntax tree that has not been selected; each level in the current abstract syntax tree can be traversed in order of levels from low to high , and for the first subexpression corresponding to the node in the current level traversed, query the mapping relationship table according to the current level and the first subexpression, the mapping relationship table includes at least one subexpression corresponding to at least one level; according to the mapping For the query result of the relational table, update the mapping relational table and the reference count recording table for recording the reference count of each subexpression, and repeat the above steps until at least one abstract syntax tree is selected.

Exemplarily, in order to accurately find out the common subexpression, when updating the mapping relation table and the reference count recording table used to record the reference counts of each subexpression according to the query result of the mapping relation table, if querying in the mapping relation table When the current level includes the first subexpression, add 1 to the reference count of the first subexpression recorded in the reference count record table; if it is not found in the mapping table that the current level includes the first subexpression, then add The current level and the first sub-expression are associated and stored in the mapping relationship table, and the reference count of the first sub-expression is recorded as 1 in the reference count recording table.

In this embodiment, after at least one abstract syntax tree is completely processed, a subexpression with a reference count greater than 1 in the reference count recording table may be used as a common subexpression.

Further optionally, in order to better optimize the database operation statement, an implementation method of selecting a common subexpression from at least one subexpression according to the reference times of each subexpression in the reference count record table is: if the reference count record If the number of references of the second subexpression in the table is the same as that of the third subexpression, it is determined that the third subexpression is a common subexpression, wherein the second subexpression is any of at least one subexpression One, the node corresponding to the third subexpression is the parent node of the node corresponding to the second subexpression.

For example, there are two candidate common subexpressions in the expression mul(add(add(a,b),c),10) and the expression mul(add(add(a,b),c),20). species, respectively add(a,b) and add(add(a,b),c). Since the reference count of add(a,b) corresponding to the child node is 2, and the reference count of add(add(a,b),c) corresponding to the parent node is 2, it means that add(a,b) is completely nested in add (add(a,b),c), add(add(a,b),c) is the final common subexpression.

For example, the expressions mul(add(add(a,b),c),10), the expressions mul(add(add(a,b),c),20), and the expressions mul(add(add( a, b), d), 20).

The reference count of add(a, b) corresponding to the child node is 3, and the reference count of (add(add(a, b), c) corresponding to parent node 1 is 2, indicating that add(a, b) is not completely nested In add(add(a,b),c), it is impossible to determine whether add(a,b) or (add(add(a,b),c) belongs to the common subexpression at this time.

The reference count of add(a,b) corresponding to the child node is 3, and the reference count of add(add(a,b),d) corresponding to the parent node 2 is 1, indicating that add(a,b) is not completely nested in In add(add(a,b),d), it is impossible to determine whether add(a,b) or add(add(a,b),d) belongs to the common subexpression at this time.

In practical applications, there may be complex functions in expressions, and complex functions are not conducive to accurately finding out more common subexpressions. Further optionally, in order to accurately find out more common subexpressions, before using at least one abstract syntax tree to select a common subexpression from at least one subexpression included in at least one expression, if the fourth subexpression The complex function is included in the formula, and the fourth subexpression is any one of at least one subexpression included in at least one expression, then the complex function in the fourth subexpression is replaced with a composite function, and the composite function can realize the complex function Functions are composed of multiple simple functions obtained by decomposing complex functions.

Specifically, a complex function often includes multiple sub-functions, and the complex function is split into a composite function composed of multiple simple functions that implement the sub-functions. Common complex functions include string data type operation functions and complex data type operation functions such as array (array), map, and Json (JavaScript Object Notation, JS Object Notation). map is a data type in key-value (key-value) pair format.

For example, network link processing functions such as url_extract_host(), url_extract_path(), and url_extract_port() all need to convert strings into URL (Universal Resource Locator, Uniform Resource Locator URL) objects, and these complex functions can be split into composite function. Among them, the url_extract_host() function extracts the Host (host) information from the URL. The url_extract_path() function extracts the access path information from the URL. The url_extract_port() function extracts port information from a URL.

For another example, the json_extract() function is used to extract the value in the original Json string. The json_extract() function needs to convert the string into a Json object. Such complex functions can be split into composite functions. Take the specific json_extract(content,'user') function as an example. When this function is executed, it needs to convert the content (string) into json format first, and then extract user from the data in json format.

This complex function can be split into json_extract_0(json_parse(content),'user')user, where json_parse(content) means converting content (string) into json format.

For another example, the return value of some functions is an array type, and the specific subscript elements of the array are extracted to make a new field. Before such subscript operation functions are executed, a unified Array (array) object needs to be constructed. For such complex functions, it is possible to Split into composite functions.

In this embodiment, after the common subexpression is found out from at least one subexpression of the database operation statement, the common subexpression in at least one expression is replaced with the execution result mark of the common subexpression to optimize In the database operation statement, the execution result flag of the common subexpression is used to indicate the execution result obtained by reusing the sub-execution code corresponding to the common subexpression in the code execution phase.

For example, for the expression json_extract_0(json_parse(content),'user')user, and the expression json_extract_0(json_parse(content),'action')action. Among them, json_parse(content) is a common subexpression. Suppose the common subexpression is marked as cse_exression, and the execution result of the common subexpression is marked as cse_exression_result. The expression json_extract_0(json_parse(content),'user')user is optimized to json_extract_0(cse_exression_result,'user')user, and the expression json_extract_0(json_parse(content),'action')action is optimized to json_extract_0(cse_exression_result,'action' ) action.

In the technical solution provided by the embodiment of the present application, based on the abstract syntax tree corresponding to at least one expression in the database operation statement, a common subexpression is selected from at least one subexpression, at least one subexpression is derived from at least one expression, And replace the common subexpression in at least one expression with the execution result flag of the common subexpression, so as to optimize the database operation statement. In this way, in the code execution stage, it is only necessary to execute the sub-execution code corresponding to the common sub-expression once, and when the execution result mark of the common sub-expression is included in the code, the sub-execution corresponding to the common sub-expression is reused The execution results obtained by the code do not need to perform repeated calculations on repeated sub-expressions, which improves calculation efficiency, saves calculation resources, and improves the query performance of the database system.

FIG. 3 is a flow chart of a database operation method provided by an embodiment of the present application. Referring to Figure 3, the method may include the following steps:

301. Generate a logical execution plan according to the first abstract syntax tree of the database operation statement, where at least one logical operator in the logical execution plan includes a partial expression in the database operation statement.

302. For at least one expression corresponding to at least one logical operator, construct a second abstract syntax tree corresponding to the at least one expression.

303. Using at least one second abstract syntax tree, select a common subexpression from at least one subexpression, where at least one subexpression originates from at least one expression.

304. Replace the common subexpression in the at least one expression with the execution result flag of the common subexpression, so as to optimize at least one logical operator.

305. Generate execution code according to the optimized at least one logical operator and common subexpression.

306. Run the execution code to obtain the operation result of the database operation statement, wherein, during the execution code execution process, multiplex the execution result obtained by running the sub-execution code corresponding to the common sub-expression according to the execution result flag of the common sub-expression.

In this embodiment, the database operation statement to be executed is parsed to obtain an abstract syntax tree of the database operation statement. Here, the abstract syntax tree of the database operation statement is referred to as the first abstract syntax tree. A logical execution plan is generated according to the first abstract syntax tree of the database operation statement. The logical execution plan includes several logical operators, such as Projection (projection) operator, filter (filter) operator, etc., including several expressions in the database operation statement.

For example, the SQL statement is select json_extract(content,'user')user,json_extract(content,'action')action from log where json_extract(content,'id')='xiaowang'.

Among them, the Projection operator includes expressions such as: json_extract(content,'user')user, and json_extract(content,'action')action. The scan operator includes from log. Filter operators include expressions such as json_extract(content,'id')='xiaowang'.

Further optionally, in order to accurately find common subexpressions, complex functions in expressions included in logical operators may also be split. That is, for the sub-expression in the expression, if the sub-expression includes a complex function, replace the complex function in the sub-expression with a compound function. The compound function can realize the function of the complex function. composed of simple functions.

For example, the complex function json_extract() is split into json_extract_0(json_parse(),). then,

The expression json_extract(content,'user')user in the projection operator is replaced with json_extract_0(json_parse(content),'user')user. The expression json_extract(content,'action')action in the projection operator is replaced by json_extract_0(json_parse(content),'action')action. The expression json_extract(content,'id')='xiaowang' in the filter operator is replaced by json_extract_0(json_parse(content),'id')='xiaowang'.

In this embodiment, for at least one expression corresponding to at least one logical operator, an abstract syntax tree corresponding to at least one expression is constructed, and the abstract syntax tree corresponding to the expression is referred to as a second abstract syntax tree herein. Regarding the manner of selecting a common subexpression from at least one subexpression based on the abstract syntax tree corresponding to each of the at least one expression, reference may be made to relevant introductions in the foregoing embodiments, and details are not repeated here.

In this embodiment, after the common subexpression is found, the common subexpression in at least one expression included in the logical operator is replaced with the execution result flag of the common subexpression, so as to optimize at least one logical operator. For example, assuming that the json_parse(content) of the common subexpression is recorded as cse_exression, the execution result of the common subexpression is marked as cse_exression_result.

Therefore, the expression json_extract_0(json_parse(content),'user')user in the projection operator is replaced by json_extract_0(cse_exression_result,'user')user. The expression json_extract_0(json_parse(content),'action')action in the projection operator is replaced by json_extract_0(cse_exression_result,'action')action. The expression json_extract_0(json_parse(content),'id')='xiaowang' in the filter operator is replaced by json_extract_0(cse_exression_result,'id')='xiaowang'.

In this embodiment, after optimizing at least one logical operator, an execution code may be generated according to the optimized at least one logical operator and the common subexpression. Further optionally, a bytecode generation technology such as ASM can be used to compile at least one expression and a common subexpression replaced in at least one logical operator after optimization to obtain a bytecode, which is stored in the memory of the virtual machine Load bytecode in and convert bytecode into executable code. Among them, ASM is a relatively complete java bytecode operation and analysis framework. Through the ASM framework, classes can be dynamically generated or the functions of existing classes can be enhanced.

Specifically, the bytecode mode is used to dynamically load the bytecode into the virtual machine, which effectively avoids virtual function calls, does not require overall compilation and packaging, and meets the real-time requirements of customers.

Optionally, the bytecode is periodically cached, on the premise of ensuring the memory usage rate, avoiding repeated compilation and loading of expressions, and ensuring the real-time performance of the database system.

Optionally, when generating bytecodes, the functions and variables corresponding to public subexpressions are generated separately, and these functions and variables are dynamically generated when they are actually used in a lazy loading manner, which can more effectively ensure that public subexpressions correspond to The sub-execution code is executed only once. In this way, if there is an execution result corresponding to the common subexpression, it is sufficient to reuse the existing execution result corresponding to the common subexpression.

Optionally, in order to make full use of the hardware resources of the database system, according to the sharding rules of the data source, according to the data source corresponding to the input data required by the common sub-expression and the data required by each sub-expression in the optimized logical operator The data source corresponding to the input data dispatches the common sub-expressions and each sub-expression in the optimized logical operator to the computing nodes close to the respective data sources for execution. Among all computing nodes, some computing nodes use the data provided by the data source as input data, such computing nodes can be called computing nodes in the local computing stage; some computing nodes use the output results of other computing nodes as input data, such Computing nodes may be referred to as computing nodes of the global computing stage. In this way, all data can be prevented from being processed on the same computing node, and parallelism can be improved as much as possible under the premise of ensuring correctness.

In this embodiment, after obtaining the execution code corresponding to the database operation statement, run the execution code to obtain the operation result of the database operation statement, wherein, in the process of running the execution code, mark the multiplexing operation according to the execution result of the common subexpression The execution result obtained by the sub-execution code corresponding to the common sub-expression. For example, the sub-execution code corresponding to the common sub-expression json_parse(content) only needs to be executed once, instead of 3 times. In the code execution stage, according to the execution result flag cse_exression_result corresponding to json_parse(content), the execution result obtained by running the sub-execution code corresponding to the common subexpression json_parse(content) once is reused.

In the technical solution provided by the embodiment of the present application, based on the abstract syntax tree corresponding to at least one expression in the database operation statement, a common subexpression is selected from at least one subexpression, at least one subexpression is derived from at least one expression, And replace the common subexpression in at least one expression with the execution result flag of the common subexpression, so as to optimize the database operation statement. In this way, in the code execution stage, it is only necessary to execute the sub-execution code corresponding to the common sub-expression once, and when the execution result mark of the common sub-expression is included in the code, the sub-execution corresponding to the common sub-expression is reused The execution results obtained by the code do not need to perform repeated calculations on repeated sub-expressions, which improves calculation efficiency, saves calculation resources, and improves the query performance of the database system.

FIG. 4 is a schematic structural diagram of a database operation statement optimization device provided by the present application. Referring to Figure 4, the device may include:

A construction module 41, configured to construct an abstract syntax tree corresponding to at least one expression in the database operation statement;

A selection module 42, configured to utilize at least one abstract syntax tree to select a common subexpression from at least one subexpression, at least one subexpression derived from at least one expression;

The replacement module 43 is used to replace the common subexpression in at least one expression with the execution result mark of the common subexpression to optimize the database operation statement, and the execution result mark of the common subexpression is used to indicate The execution result obtained by running the sub-execution code corresponding to the common sub-expression.

Further optionally, the level of the leaf node in the abstract syntax tree is the lowest, and the level of the parent node is one level higher than that of the child node; correspondingly, the selection module 42 utilizes at least one abstract syntax tree to select from at least one subexpression When selecting a common subexpression, it is specifically used to: for any abstract syntax tree in at least one abstract syntax tree, traverse each level in the abstract syntax tree in order of levels from low to high, and target the nodes in the current level traversed For the corresponding first sub-expression, query the mapping relationship table according to the current level and the first sub-expression, wherein the mapping relationship table includes at least one sub-expression corresponding to at least one level; update the mapping according to the query result of the mapping relationship table A relationship table and a reference count recording table for recording the reference counts of each subexpression; after at least one abstract syntax tree is completely processed, the reference counts of each subexpression in the reference count recording table are selected from at least one subexpression Select common subexpressions.

Further optionally, when the selection module 42 selects a common subexpression from at least one subexpression according to the reference times of each subexpression in the reference count record table, it is specifically used for: if the second subexpression in the reference count record table The number of references is the same as that of the third subexpression, then the third subexpression is determined to be a common subexpression, wherein the second subexpression is any one of at least one subexpression, and the third subexpression The corresponding node is a parent node of the node corresponding to the second sub-expression.

Further optionally, when the selection module 42 updates the mapping relationship table and the reference number record table for recording the number of references of each subexpression according to the query result of the mapping relationship table, it is specifically used for: if the query results in the mapping relationship table If the current level includes the first subexpression, add 1 to the reference count of the first subexpression recorded in the reference count record table; The hierarchy and the first sub-expression are associated and stored in the mapping relationship table, and the reference count of the first sub-expression is recorded as 1 in the reference count recording table.

Further optionally, the above device further includes a complex function splitting module, configured to: if the fourth sub-expression includes a complex function, the fourth sub-expression is any one of at least one sub-expression included in at least one expression, Then the complex function in the fourth sub-expression is replaced with a compound function, and the compound function is composed of multiple simple functions obtained by decomposing the complex function.

The device shown in FIG. 4 can execute the method shown in the embodiment shown in FIG. 2 , and its implementation principles and technical effects will not be repeated here. The specific manner of performing operations of each module and unit in the device shown in FIG. 4 in the above embodiment has been described in detail in the embodiment of the method, and will not be described in detail here.

FIG. 5 is a schematic structural diagram of a database operating device provided by the present application. Referring to Figure 5, the device may include:

The first generating module 51 is configured to generate a logical execution plan according to the first abstract syntax tree of the database operation statement, at least one logical operator in the logical execution plan each includes a partial expression in the database operation statement;

A construction module 52, configured to construct a second abstract syntax tree corresponding to at least one expression for at least one expression corresponding to at least one logical operator;

A selection module 53, configured to use at least one second abstract syntax tree to select a common subexpression from at least one subexpression, at least one subexpression derived from at least one expression;

A replacement module 54, configured to replace common subexpressions in at least one expression with execution result marks of common subexpressions, so as to optimize at least one logical operator;

The second generation module 55 is used to generate execution code according to at least one optimized logical operator and common subexpression;

The running module 55 is used to run the execution code to obtain the operation result of the database operation statement, wherein, in the process of running the execution code, according to the execution result mark of the common subexpression, the result obtained by multiplexing and running the sub execution code corresponding to the common subexpression Results of the.

Further optionally, when the second generation module 55 generates the execution code according to the optimized at least one logical operator and the common subexpression, it is specifically used to: replace the expression and the common subexpression in the optimized at least one logical operator The subexpression is compiled to obtain bytecode; the bytecode is loaded in the memory of the virtual machine, and the bytecode is converted into execution code.

Further optionally, the above device also includes a complex function splitting module, configured to: for any subexpression in at least one expression, if the subexpression includes a complex function, replace the complex function in the subexpression with a composite function, Composite functions are composed of multiple simple functions obtained by decomposing complex functions.

The device shown in FIG. 5 can execute the method shown in the embodiment shown in FIG. 3 , and its implementation principles and technical effects will not be described again. The specific manner of performing operations of each module and unit in the apparatus shown in FIG. 3 in the above embodiment has been described in detail in the embodiment of the method, and will not be described in detail here.

It should be noted that the subject of execution of each step of the method provided in the foregoing embodiments may be the same device, or the method may also be executed by different devices. For example, the execution subject of steps 201 to 203 may be device A; for another example, the execution subject of steps 201 and 202 may be device A, and the execution subject of step 203 may be device B; and so on.

In addition, in some of the processes described in the above embodiments and accompanying drawings, multiple operations appearing in a specific order are included, but it should be clearly understood that these operations may not be executed in the order in which they appear herein or executed in parallel , the serial numbers of the operations, such as 201, 202, etc., are only used to distinguish different operations, and the serial numbers themselves do not represent any execution order. Additionally, these processes can include more or fewer operations, and these operations can be performed sequentially or in parallel. It should be noted that the descriptions of "first" and "second" in this article are used to distinguish different messages, devices, modules, etc. are different types.

It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all It is information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose authorization or reject.

FIG. 6 is a schematic structural diagram of an electronic device provided by an embodiment of the present application. As shown in FIG. 6, the electronic device includes: a memory 61 and a processor 62;

The memory 61 is used to store computer programs, and can be configured to store other various data to support operations on the computing platform. Examples of such data include instructions for any application or method operating on the computing platform, contact data, phonebook data, messages, pictures, videos, etc.

Memory 61 can be realized by any type of volatile or nonvolatile storage device or their combination, such as Static Random-Access Memory (Static Random-Access Memory, SRAM), Electrically Erasable Programmable Read-Only Memory (Electrically Erasable Programmable read only memory, EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, EPROM), programmable read-only memory (Programmable read-only memory, PROM), read-only memory (Read-Only Memory, ROM), magnetic memory, flash memory, magnetic or optical disk.

The processor 62, coupled with the memory 61, is used to execute the computer program in the memory 61, so as to: execute the steps in the database operation statement optimization method or the database operation method.

Further, as shown in FIG. 6 , the electronic device further includes: a communication component 63 , a display 64 , a power supply component 65 , an audio component 66 and other components. FIG. 6 only schematically shows some components, which does not mean that the electronic device only includes the components shown in FIG. 6 . In addition, the components in the dotted line box in FIG. 6 are optional components, not mandatory components, which may depend on the product form of the electronic device. The electronic device in this embodiment can be implemented as a terminal device such as a desktop computer, a notebook computer, a smart phone, or an IOT (Internet of things, Internet of things) device, or as a server device such as a conventional server, a cloud server, or a server array. If the electronic equipment of this embodiment is implemented as terminal equipment such as desktop computers, notebook computers, smart phones, etc., it can include the components in the dashed box in Figure 6; if the electronic equipment of this embodiment is implemented as a conventional server, cloud server or server array, etc. The server device may not include the components in the dashed box in FIG. 6 .

For the detailed implementation process of the actions performed by the processor, reference may be made to the relevant descriptions in the foregoing method embodiments or device embodiments, and details are not repeated here.

Correspondingly, an embodiment of the present application further provides a computer-readable storage medium storing a computer program. When the computer program is executed, the steps that can be executed by the electronic device in the above method embodiments can be implemented.

Correspondingly, the embodiments of the present application also provide a computer program product, including computer programs/instructions, which, when executed by a processor, cause the processor to implement the steps executable by the electronic device in the above method embodiments.

The above-mentioned communication component is configured to facilitate wired or wireless communication between the device where the communication component is located and other devices. The device where the communication component is located can access a wireless network based on communication standards, such as WiFi, 2G, 3G, 4G/LTE, 5G and other mobile communication networks, or a combination thereof. In one exemplary embodiment, the communication component receives a broadcast signal or broadcast related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component further includes a Near Field Communication (NFC) module to facilitate short-range communication. For example, the NFC module can be based on Radio Frequency Identification (RFID) technology, Infrared Data Association (The InfraredData Association, IrDA) technology, Ultra Wide Band (Ultra Wide Band, UWB) technology, Bluetooth (Bluetooth, BT) technology and other technology to achieve.

The above-mentioned display includes a screen, and the screen may include a liquid crystal display (Liquid Crystal Display, LCD) and a touch panel (touch panel, TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from a user. The touch panel includes one or more touch sensors to sense touches, swipes, and gestures on the touch panel. The touch sensor may not only sense a boundary of a touch or a swipe action, but also detect duration and pressure associated with the touch or swipe operation.

The above-mentioned power supply component provides power for various components of the equipment where the power supply component is located. A power supply component may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the device in which the power supply component resides.

The aforementioned audio components may be configured to output and/or input audio signals. For example, the audio component includes a microphone (microphone, MIC). When the device where the audio component is located is in an operation mode, such as a calling mode, a recording mode, and a speech recognition mode, the microphone is configured to receive an external audio signal. The received audio signal may be further stored in a memory or sent via a communication component. In some embodiments, the audio component further includes a speaker for outputting audio signals.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

In a typical configuration, a computing device includes one or more central processing units (CPUs), input/output interfaces, network interfaces, and memory.

Memory may include non-permanent memory in computer-readable media, random access memory (Random Access Memory, RAM) and/or non-volatile memory, such as read-only memory (Read Only Memory, ROM) or flash memory (flash RAM). Memory is an example of computer readable media.

Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can be implemented by any method or technology for storage of information. Information may be computer readable instructions, data structures, modules of a program, or other data. The example of the storage medium of computer includes, but not limited to Phase Change RAM (Phase Change RAM, PRAM), Static Random-Access Memory (Static Random-Access Memory, SRAM), Dynamic Random-Access Memory (Dynamic Random-Access Memory, DRAM), Other types of random access memory (Random Access Memory, RAM), read-only memory (Read Only Memory, ROM), electrically erasable programmable read-only memory (Electrically-Erasable Programmable Read-Only Memory, EEPROM), flash RAM or other memory technology, CD-ROM, Digital versatile disc (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any Other non-transmission media that may be used to store information that can be accessed by a computing device. As defined herein, computer-readable media excludes transitory computer-readable media, such as modulated data signals and carrier waves.

It should also be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes Other elements not expressly listed, or elements inherent in the process, method, commodity, or apparatus are also included. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only examples of the present application, and are not intended to limit the present application. For those skilled in the art, various modifications and changes may occur in this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims (10)

1. A method for optimizing database operation statements, comprising:

constructing an abstract syntax tree corresponding to at least one expression in the database operation statement;

selecting, using at least one abstract syntax tree, a common sub-expression from at least one sub-expression, the at least one sub-expression being derived from the at least one expression;

And replacing the common sub-expression in the at least one expression with an execution result mark of the common sub-expression to optimize the database operation statement, wherein the execution result mark of the common sub-expression is used for indicating an execution result obtained by multiplexing and running sub-execution codes corresponding to the common sub-expression in a code execution stage.

2. The method of claim 1, wherein the level of leaf nodes in the abstract syntax tree is lowest and the level of parent nodes is one level higher than the level of child nodes; accordingly, selecting a common sub-expression from the at least one sub-expression using the at least one abstract syntax tree, comprising:

traversing each level in at least one abstract syntax tree according to the sequence from low level to high level, and inquiring a mapping relation table according to a first sub-expression corresponding to a node in a traversed current level and the first sub-expression, wherein the mapping relation table comprises at least one sub-expression corresponding to at least one level;

updating the mapping relation table and a reference number recording table for recording the reference number of each sub-expression according to the query result of the mapping relation table;

And after all the at least one abstract syntax tree is processed, selecting a common sub-expression from the at least one sub-expression according to the reference times of all sub-expressions in the reference times record table.

3. The method of claim 2, wherein selecting a common sub-expression from the at least one sub-expression according to the number of references of each sub-expression in the reference number record table comprises:

and if the reference times of the second sub-expression and the reference times of the third sub-expression in the reference times record table are the same, determining that the third sub-expression is a common sub-expression, wherein the second sub-expression is any one of the at least one sub-expression, and the node corresponding to the third sub-expression is a father node of the node corresponding to the second sub-expression.

4. The method according to claim 2, wherein updating the mapping relation table and a reference number recording table for recording reference numbers of the respective sub-expressions according to the query result of the mapping relation table, comprises:

if the current level is inquired in the mapping relation table to comprise the first sub-expression, adding 1 to the reference number of the first sub-expression recorded in the reference number recording table;

If the current level is not queried in the mapping relation table and comprises the first sub-expression, storing the current level and the first sub-expression in the mapping relation table in a correlated manner, and recording the reference times of the first sub-expression as 1 in the reference times recording table.

5. The method of claim 1, wherein prior to selecting the common sub-expression from the at least one sub-expression using the at least one abstract syntax tree, further comprising:

if the fourth sub-expression includes a complex function, where the fourth sub-expression is any one of at least one sub-expression included in the at least one expression, the complex function in the fourth sub-expression is replaced by a complex function, and the complex function is composed of a plurality of simple functions obtained by decomposing the complex function.

6. A method of database operation, comprising:

generating a logic execution plan according to a first abstract syntax tree of a database operation sentence, wherein at least one logic operator in the logic execution plan respectively comprises partial expressions in the database operation sentence;

constructing a second abstract syntax tree corresponding to at least one expression aiming at the at least one expression corresponding to at least one logical operator;

Selecting, using at least one second abstract syntax tree, a common sub-expression from at least one sub-expression, the at least one sub-expression being derived from the at least one expression;

replacing a common sub-expression in the at least one expression with an execution result label of the common sub-expression to optimize at least one logical operator;

generating an execution code according to the optimized at least one logic operator and the common sub-expression;

and running the execution codes to obtain the operation results of the database operation sentences, wherein in the process of running the execution codes, the execution results obtained by running the sub-execution codes corresponding to the common sub-expressions are marked and multiplexed according to the execution results of the common sub-expressions.

7. The method of claim 6, wherein generating execution code from the optimized at least one logical operator and the common sub-expression comprises:

compiling the expression replaced in the optimized at least one logic operator and the common sub-expression to obtain byte codes;

and loading the byte codes in the memory of the virtual machine, and converting the byte codes into the execution codes.

8. The method of claim 6, further comprising, prior to constructing a second abstract syntax tree for at least one expression for at least one logical operator, for at least one expression:

for any sub-expression in at least one expression, if the sub-expression comprises a complex function, replacing the complex function in the sub-expression with a complex function, wherein the complex function consists of a plurality of simple functions obtained by decomposing the complex function.

9. An electronic device, comprising: a memory and a processor; the memory is used for storing a computer program; the processor is coupled to the memory for executing the computer program for performing the steps in the method of any of claims 1-8.

10. A computer readable storage medium storing a computer program, which when executed by a processor causes the processor to carry out the steps of the method according to any one of claims 1-8.

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