End-side-based global database connection number control method and system

Abstract

The invention relates to the technical field of power system automation, and provides a global database connection number control method and system based on an end side, and the method comprises the steps: calling a database connection assembly to achieve the access to a multi-type heterogeneous database service; the method comprises the following steps: transforming a heterogeneous database access component, adding a database connection handle state monitoring function module, and traversing heterogeneous database connection handles and releasing idle overtime database connection according to the current read-write state of the connection handles; when the non-idle database connection handle reaches the timeout time, the database connection is not forcibly released; after the database connection handle is automatically disconnected, the database connection is recovered when the current database connection handle generates the read-write request again; judging whether the current global connection number is out of limit or not, if yes, waiting until idle connection occurs, and then establishing new database connection; and setting the connection timeout time of the request database, and returning the timeout time. The method can be compatible with various types of heterogeneous databases.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system automation, and in particular to a global database connection number control method and system based on an end side. BACKGROUND

[0002] In recent years, with the wide application of power station monitoring systems, database connection management has become a key technical challenge. Especially under the background of the continuous expansion of application scale, how to effectively control the number of database connections has become an important problem to be solved in the design of monitoring systems.

[0003] To ensure that a large number of power station monitoring applications can still maintain efficient and orderly database access under the condition of limited database connection number, a perfect database connection management mechanism needs to be established. For this purpose, a large amount of research work has been carried out in the related field. The current mainstream solution is to use a database application to access a database proxy service, and to realize effective control of the number of connections through a connection pool mechanism on the proxy service side. However, there are still significant defects: first, the database access interface of the existing system needs to be completely reformed, which has high implementation cost and large engineering quantity; second, the centralized proxy architecture has a single point of failure risk, and the system reliability is difficult to guarantee; finally, the additional proxy layer increases the network communication overhead, resulting in a decrease in database access performance. Therefore, it is urgent to explore a new solution that can effectively control the number of connections while maximizing the preservation of the original architecture and performance of the system. SUMMARY

[0004] The present application aims to solve at least one of the technical problems in the background art, and provides a global database connection number control method and system based on an end side.

[0005] To achieve the above-mentioned purpose, the present application provides a global database connection number control method based on an end side, comprising:

[0006] In each database application process, the access to multiple types of heterogeneous database services is realized by calling a database connection component;

[0007] The heterogeneous database access component is reformed, and a database connection handle state monitoring function module is added, according to the current read-write state of the connection handle, to realize:

[0008] Iterate through the heterogeneous database connection handle and release the idle timeout database connection;

[0009] For the database connection handle that is currently executing a transaction operation or processing a long-time read-write request, when it reaches the timeout time, it is not forced to release its database connection;

[0010] The current database connection handle restores the database connection when a read / write request occurs again after the database connection handle is automatically disconnected;

[0011] When a database connection request is created, it is determined whether the current global connection number is over the limit, and if so, the establishment of a new database connection is waited until an idle connection appears;

[0012] A request database connection timeout time is set, and a timeout is returned.

[0013] According to an aspect of the present application, the access to the multiple types of heterogeneous database services in each database application process is realized by calling a database connection component, which includes:

[0014] The database connection component function and the database application run in the same process space to realize the end-side connection number control function;

[0015] The database application and the database connection component are distributed on multiple servers.

[0016] The database connection component provides unified connection and access support for multiple types of heterogeneous databases.

[0017] According to an aspect of the present application, the heterogeneous database connection handles are traversed, and the idle timeout database connections are released, which includes:

[0018] A new database connection handle monitoring thread is created.

[0019] All database connection handles in the current process are traversed in the handle monitoring thread at regular intervals, and the database connection is forcibly closed when the current database connection handle is idle for more than a set threshold.

[0020] According to an aspect of the present application, for the database connection handle that is currently executing a transaction operation or processing a long-time read / write request, when it reaches the timeout time, the database connection is not forcibly released, which includes:

[0021] In the handle monitoring thread state monitoring process, if the current database connection is executing a transaction operation, the connection is not forcibly released even if it is idle for a timeout.

[0022] In the handle monitoring thread state monitoring process, if the current database connection is executing a certain read / write request that takes a long time, the connection is not forcibly released.

[0023] According to an aspect of the present application, after the database connection handle is automatically disconnected, the current database connection handle restores the database connection when a read / write request occurs again, which includes:

[0024] When a read or write operation occurs, determine whether the current database connection handle is automatically released. If it is released, reactivate the database connection.

[0025] After activating the database connection, activate the database read and write streams at the same time;

[0026] After the database connection and read / write stream activation are successful, the read / write operation is performed.

[0027] According to one aspect of the present invention, when creating a database connection request, determining whether the current number of global connections exceeds the limit, and if so, waiting until an idle connection appears before establishing a new database connection, includes:

[0028] Connect to the database and determine the current data source connection usage. If the connection usage is less than the threshold, a successful connection is directly returned.

[0029] If the number of connections exceeds the threshold, the connection is released and the system enters the waiting-for-retry state;

[0030] After a preset interval, the current connection occupancy status is determined again, and based on the connection occupancy status, it is determined whether the connection is returned to be successful.

[0031] According to one aspect of the present invention, the setting of a database connection request timeout and a timeout return includes:

[0032] When the current number of database connections exceeds the threshold, the system enters the waiting-for-retry state.

[0033] If the cumulative waiting retry time exceeds the set threshold but there is no idle connection, the connection failure is returned.

[0034] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a terminal-side global database connection number control system, comprising:

[0035] The database access module, in each database application process, implements access to multiple types of heterogeneous database services by calling database connection components;

[0036] The database connection control module transforms the heterogeneous database access component and adds a database connection handle status monitoring function module. Based on the current read and write status of the connection handle, it implements the following:

[0037] Traverse heterogeneous database connection handles and release idle timed-out database connections;

[0038] For database connection handles that are currently executing transaction operations or processing long read / write requests, when the timeout period is reached, the database connection is not forcibly released;

[0039] After the database connection handle is automatically disconnected, the current database connection handle resumes the database connection when a read-write request occurs again;

[0040] When a database connection request is created, it is determined whether the current global connection number is over the limit, and if it is over the limit, it is waited until an idle connection occurs, and then a new database connection is established;

[0041] The request database connection timeout time is set, and the timeout is returned.

[0042] Further, in order to achieve the above-mentioned purpose, the application further provides an electronic device, comprising a processor, a memory and a computer program stored on the memory and executable on the processor, wherein the computer program is executed by the processor to implement the end-side-based global database connection number control method as described above.

[0043] Further, in order to achieve the above-mentioned purpose, the application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the end-side-based global database connection number control method as described above.

[0044] According to the scheme of the application, the end-side-based global database connection number control method provided by the application can be compatible with multiple types of heterogeneous databases; by directly obtaining the current data source connection number and the maximum connection number information from the database service, global connection number monitoring and control in a multi-application, multi-server environment can be realized; by modifying the internal implementation of the existing heterogeneous database access component, connection number management can be realized while maintaining the existing database access architecture and calling interface unchanged to the maximum extent; database connection control is implemented on the end side, which can effectively avoid the problem of system overall database access failure caused by single point failure in the proxy architecture, thereby improving the reliability and stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 The principle block diagram of the end-side-based global database connection number control method according to an embodiment of the application is schematically represented;

[0046] Figure 2 The database connection idle timeout release flowchart according to an embodiment of the application is schematically represented;

[0047] Figure 3 The database connection and read-write flow recovery flowchart according to an embodiment of the application is schematically represented;

[0048] Figure 4 The database connection creation flowchart according to an embodiment of the application is schematically represented. DETAILED DESCRIPTION

[0049] The present application will now be discussed with reference to the exemplary embodiments. It should be appreciated that the discussed embodiments are merely meant to better enable one of ordinary skill in the art to understand and thus implement the present application, and are not meant to imply any limitation on the scope of the present application.

[0050] As used herein, the term "includes" and its variants are to be read to mean "comprising but not limited to." The term "based on" is to be read as "based, at least in part, on." The terms "one embodiment" and "an embodiment" are to be read as "at least one embodiment."

[0051] Figure 1 An illustrative representation of a principle block diagram of an end-side based global database connection number control method according to an embodiment of the present application is shown. As shown in Figure 1 In the present embodiment, the end-side based global database connection number control method includes:

[0052] In each database application process, access to multiple types of heterogeneous database services is achieved by calling a database connection component;

[0053] The heterogeneous database access component is modified to add a database connection handle state monitoring function module, and according to the current read-write state of the connection handle, the following is achieved:

[0054] The heterogeneous database connection handles are traversed and idle timeout database connections are released;

[0055] For a database connection handle that is currently performing a transaction operation or processing a long-time read-write request, when it reaches the timeout time, it is not forced to release its database connection;

[0056] After the database connection handle is automatically disconnected, when the current database connection handle again has a read-write request, the database connection is restored;

[0057] When a database connection request is created, it is determined whether the current global connection number is over the limit, and if it is over the limit, it is waited until an idle connection appears before a new database connection is established;

[0058] A request database connection timeout time is set, and a timeout is returned.

[0059] Further, according to an embodiment of the present application, in each database application process, access to multiple types of heterogeneous database services is achieved by calling a database connection component, including:

[0060] The database connection component function and the data application (such as APP1, APP2, etc.) run in the same process space, and the end-side connection number control function is achieved;

[0061] Database applications and database connection components are distributed on multiple servers; as Figure 1 shown, multiple database applications are distributed on servers 1-3.

[0062] The database connection component provides uniform connection and access support for multiple types of heterogeneous databases.

[0063] Further, according to an embodiment of the present application, the heterogeneous database connection handle is traversed, and idle timeout database connections are released, including:

[0064] A new database connection handle monitoring thread is created;

[0065] As Figure 2 shown, all database connection handles in the current process are traversed in the handle monitoring thread at regular intervals, and after the current database connection handle has been idle for more than a set threshold, the database connection is forcibly closed.

[0066] Further, according to an embodiment of the present application, for a database connection handle that is currently performing a transaction operation or processing a long-time read-write request, when it reaches the timeout time, the database connection is not forcibly released, as Figure 2 shown, including:

[0067] In the handle monitoring thread state monitoring process, if the current database connection is performing a transaction operation, even if it is idle for a timeout, the connection is not forcibly released;

[0068] In the handle monitoring thread state monitoring process, if the current database connection is performing a read-write request that takes a long time, the connection is not forcibly released.

[0069] Further, according to an embodiment of the present application, after the database connection handle is automatically disconnected, the database connection is restored when a read-write request occurs again, as Figure 3 shown, including:

[0070] When a read-write operation occurs, it is determined whether the current database connection handle database connection has been automatically released, and if it has been released, the database connection is reactivated;

[0071] After the database connection is activated, the database read-write stream is also activated;

[0072] After the database connection and the read-write stream are activated successfully, the read-write operation is performed again.

[0073] Further, according to an embodiment of the present application, when a database connection request is created, it is determined whether the current global connection number is over the limit, and if it is, the new database connection is not established until an idle connection appears, as Figure 4As shown, comprising:

[0074] The connection database is connected, the current data source connection number occupation is determined, if the connection number occupation is less than the threshold value, the connection success is directly returned;

[0075] If the connection number exceeds the threshold value, the connection is released, and the waiting retry state is entered;

[0076] After a preset interval time, the current connection number occupation is determined again, and whether the connection success is returned is determined according to the connection number occupation.

[0077] Further, according to an embodiment of the application, a request database connection timeout time is set, and a timeout is returned, as shown in Figure 4 As shown, comprising:

[0078] After the current database connection number occupation exceeds the threshold value, the waiting retry state is entered;

[0079] After the waiting retry time accumulation exceeds the set threshold value, but there is no idle connection, the connection failure is returned.

[0080] Further, according to an embodiment of the application, the application further comprises: a new interface supports obtaining the current connection number and the maximum connection number information of various heterogeneous databases, and the specific method is as follows:

[0081] Determine the current database type;

[0082] Select a suitable database current connection number query sql statement, and execute a query operation;

[0083] Select a suitable database maximum connection number query sql statement, and execute a query operation.

[0084] According to the above scheme of the application, the application provides a kind of global database connection number control method based on end side, can be compatible with multiple types of heterogeneous databases;By directly obtaining current data source connection number and maximum connection number information from database service, global connection number monitoring and control under multiple application, multiple server environment can be realized;By reforming the internal implementation of existing heterogeneous database access component, connection number management can be realized under the premise of keeping existing database access architecture and calling interface unchanged to the maximum extent;Database connection control is implemented on the end side, can effectively avoid the system overall database access failure problem caused by single point failure in proxy architecture, to improve the reliability and stability of system.

[0085] Further, to achieve the above object, the application further provides a kind of global database connection number control system based on end side, comprising:

[0086] The database access module, in each database application process, implements access to multiple types of heterogeneous database services by calling database connection components;

[0087] The database connection control module transforms the heterogeneous database access component and adds a database connection handle status monitoring function module. Based on the current read and write status of the connection handle, it implements the following:

[0088] Traverse heterogeneous database connection handles and release idle timed-out database connections;

[0089] For database connection handles that are currently executing transaction operations or processing long read / write requests, when the timeout period is reached, the database connection is not forcibly released;

[0090] After the database connection handle is automatically disconnected, the database connection is restored when the current database connection handle has a read or write request again;

[0091] When creating a database connection request, determine whether the current global connection number exceeds the limit. If so, wait until an idle connection appears before establishing a new database connection.

[0092] Set the timeout for requesting database connection, and return if timeout occurs.

[0093] Furthermore, according to an embodiment of the present invention, in each database application process, access to multiple types of heterogeneous database services is achieved by calling a database connection component, including:

[0094] The database connection component function and data applications (such as APP1, APP2, etc.) run in the same process space to implement the terminal-side connection number control function;

[0095] Database applications and database connection components are distributed across multiple servers; e.g. Figure 1 As shown, multiple database applications are distributed on servers 1 to 3;

[0096] The database connection component provides unified connection and access support for multiple types of heterogeneous databases.

[0097] Furthermore, according to an embodiment of the present invention, traversing heterogeneous database connection handles and releasing idle timed-out database connections includes:

[0098] Create a new database connection handle monitoring thread;

[0099] like Figure 2 As shown, all database connection handles in the current process are periodically traversed in the handle monitoring thread. When the idle time of the current database connection handle exceeds the set threshold, the database connection is forcibly closed.

[0100] Further, according to an embodiment of the present application, for the database connection handle which is currently executing transaction operation or processing long time read-write request, when it reaches the timeout time, it is not forced to release its database connection, such as Figure 2 as shown, comprising:

[0101] In the handle monitoring thread state monitoring process, if the current database connection is executing transaction operation, even if the idle timeout, the connection is not forced to be released;

[0102] In the handle monitoring thread state monitoring process, if the current database connection is executing a read-write request which takes a long time, the connection is not forced to be released.

[0103] Further, according to an embodiment of the present application, after the database connection handle is automatically disconnected, when the current database connection handle occurs read-write request again, the database connection is restored, such as Figure 3 as shown, comprising:

[0104] When the read-write operation occurs, it is determined whether the database connection of the current database connection handle is automatically released, if it is released, the database connection is reactivated;

[0105] After the database connection is activated, the database read-write flow is activated at the same time;

[0106] After the database connection and the read-write flow are activated successfully, the read-write operation is executed.

[0107] Further, according to an embodiment of the present application, when creating a database connection request, it is determined whether the current global connection number is over limit, if it is over limit, it is waited until the idle connection appears, and then a new database connection is established, such as Figure 4 as shown, comprising:

[0108] Connect the database, determine the current data source connection number occupation, if the connection number occupation is less than the threshold value, return the connection success directly;

[0109] If the connection number exceeds the threshold value, release the connection and enter the waiting retry state;

[0110] After a preset interval time, the current connection number occupation is determined again, and according to the connection number occupation, it is determined whether to return the connection success.

[0111] Further, according to an embodiment of the present application, the timeout time of the request database connection is set, and the timeout is returned, such as Figure 4 as shown, comprising:

[0112] After the current database connection number occupation exceeds the threshold value, enter the waiting retry state;

[0113] After the waiting retry time accumulation exceeds the set threshold, but there is no idle connection, the connection fails.

[0114] Further, according to an embodiment of the present application, the present application further comprises: a newly added interface supports obtaining current connection number and maximum connection number information of various heterogeneous databases, and the specific method is as follows:

[0115] Judging the current database type;

[0116] Selecting a suitable database current connection number query sql statement to perform a query operation;

[0117] Selecting a suitable database maximum connection number query sql statement to perform a query operation.

[0118] According to the above scheme of the present application, the global database connection number control system based on the end side provided by the present application can be compatible with various types of heterogeneous databases; by directly obtaining the current data source connection number and the maximum connection number information from the database service, global connection number monitoring and control in a multi-application, multi-server environment can be realized; by modifying the internal implementation of the existing heterogeneous database access component, connection number management can be realized on the premise of maintaining the existing database access architecture and calling interface unchanged to the maximum extent; the database connection control is implemented on the end side, which can effectively avoid the problem of system overall database access failure caused by single point failure in the proxy architecture, thereby improving the reliability and stability of the system.

[0119] Further, to achieve the above-mentioned purpose, the present application further provides an electronic device, comprising a processor, a memory and a computer program stored on the memory and executable on the processor, and the computer program is executed by the processor to realize the global database connection number control method based on the end side as described above.

[0120] Further, to achieve the above-mentioned purpose, the present application further provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the global database connection number control method based on the end side as described above.

[0121] Those skilled in the art can realize that the modules and algorithm steps described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0122] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the apparatus and device described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0123] In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented by other manners. For example, the apparatus embodiments described above are only schematic, for example, the division of the modules is only a logical function division, and actual implementation can have another division manner, for example, a plurality of modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed modules can be indirect coupling or communication connection through some interfaces, apparatuses or modules, and can be electrical, mechanical or other forms.

[0124] The modules described as separate components can or can not be physically separated, and the components displayed as modules can or can not be physical modules, that is, can be located in one place, or can be distributed to a plurality of network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0125] In addition, each functional module in the embodiments of the present application can be integrated in one processing module, or each module can exist physically separately, or two or more modules can be integrated in one module.

[0126] If the functions are realized in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the energy-saving signal transmission / reception method of the embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, and various program code storage media.

[0127] The above description is only the preferred embodiment of the present application and the explanation of the technical principles applied. It should be understood by those skilled in the art that the application scope of the present application is not limited to the technical solutions formed by the specific combinations of the technical features described above, and should also cover other technical solutions formed by the combinations of the technical features described above or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features with similar functions disclosed in the present application (but not limited to).

[0128] It should be understood that the size of the serial number of each step in the summary and the embodiments of the present application does not absolutely mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claims

1. A method for controlling the number of global database connections based on the terminal side, characterized in that: include: In each database application process, access to multiple types of heterogeneous database services is achieved by calling database connection components; Transform heterogeneous database access components and add a database connection handle status monitoring module. Based on the current read and write status of the connection handle, achieve the following: Traverse heterogeneous database connection handles and release idle timed-out database connections; For database connection handles that are currently executing transaction operations or processing long read / write requests, when the timeout period is reached, the database connection is not forcibly released; After the database connection handle is automatically disconnected, the database connection is restored when the current database connection handle has a read or write request again; When creating a database connection request, determine whether the current global connection number exceeds the limit. If so, wait until an idle connection appears before establishing a new database connection. Set the timeout for requesting database connection, and return if timeout occurs.

2. The method for controlling the number of global database connections based on the terminal side according to claim 1, characterized in that: In each database application process, access to multiple types of heterogeneous database services is achieved by calling database connection components, including: The database connection component runs in the same process space as the database application, enabling end-side connection control. Database applications and database connection components are distributed across multiple servers; The database connection component provides unified connection and access support for multiple types of heterogeneous databases.

3. The method for controlling the number of global database connections based on the terminal side according to claim 1, characterized in that: The traversing of heterogeneous database connection handles and releasing idle timed-out database connections includes: Create a new database connection handle monitoring thread; In the handle monitoring thread, all database connection handles in the current process are periodically traversed. When the idle time of the current database connection handle exceeds the set threshold, the database connection is forcibly closed.

4. The method for controlling the number of global database connections based on the terminal side according to claim 1, characterized in that: The database connection handle that is currently executing a transaction operation or processing a long read / write request is not forcibly released when the timeout period is reached, including: During the handle monitoring thread status monitoring process, if the current database connection is executing a transaction operation, the connection will not be forcibly released even if the idle timeout occurs; During the handle monitoring thread status monitoring process, if the current database connection is executing a time-consuming read or write request, the connection is not forcibly released.

5. The method for controlling the number of global database connections based on the terminal side according to claim 1, characterized in that: After the database connection handle is automatically disconnected, restoring the database connection when the current database connection handle generates a read or write request again includes: When a read or write operation occurs, determine whether the current database connection handle is automatically released. If it is released, reactivate the database connection. After activating the database connection, activate the database read and write streams at the same time; After the database connection and read / write stream activation are successful, the read / write operation is performed.

6. The method for controlling the number of global database connections based on the terminal side according to claim 1, characterized in that: When creating a database connection request, determining whether the current global number of connections exceeds the limit, and if so, waiting until an idle connection appears before establishing a new database connection, including: Connect to the database and determine the current data source connection usage. If the connection usage is less than the threshold, a successful connection is directly returned. If the number of connections exceeds the threshold, the connection is released and the system enters the waiting-for-retry state; After a preset interval, the current connection occupancy status is determined again, and based on the connection occupancy status, it is determined whether the connection is returned to be successful.

7. The method for controlling the number of global database connections based on the terminal side according to any one of claims 1 to 6, characterized in that: The setting of request database connection timeout and timeout return includes: When the current number of database connections exceeds the threshold, the system enters the waiting-for-retry state. If the cumulative waiting retry time exceeds the set threshold but there is no idle connection, the connection failure is returned.

8. The global database connection number control system based on the terminal side is characterized by: include: The database access module, in each database application process, implements access to multiple types of heterogeneous database services by calling database connection components; The database connection control module transforms the heterogeneous database access component and adds a database connection handle status monitoring function module. Based on the current read and write status of the connection handle, it implements the following: Traverse heterogeneous database connection handles and release idle timed-out database connections; For database connection handles that are currently executing transaction operations or processing long read / write requests, when the timeout period is reached, the database connection is not forcibly released; After the database connection handle is automatically disconnected, the database connection is restored when the current database connection handle has a read or write request again; When creating a database connection request, determine whether the current global connection number exceeds the limit. If so, wait until an idle connection appears before establishing a new database connection. Set the timeout for requesting database connection, and return if timeout occurs.

9. An electronic device, characterized in that The method comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for controlling the number of global database connections based on the end side is implemented as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the end-side-based global database connection number control method according to any one of claims 1 to 7.

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