CN1238792C - Data bank accessing method and client machine/server system for realizing same - Google Patents

Abstract

The invention provides a database access method in a client/server system. A data requester obtains data in the database by sending a data access request. The access method includes the following steps to process the data access request: (1) according to the data access The content of the request searches for data stored in a cache memory located between the database and the data requester, wherein the cache memory stores data with a high frequency of access requests; and (2) if the memory stores the requested data data, then read the data and return to the data requesting party, otherwise, access the database according to the content of the data access request and return the access operation result to the data requesting party, and the system uses steps (1) and ( 2) The following steps are regularly executed in a parallel manner: (3) The data stored in the memory is updated with the data frequently accessed by the data requester within a period of time in the database. The above method reduces the access pressure of the database and enables the data requester to always maintain a high hit rate when accessing the memory.

Description

A database access method and client/server system for realizing the method

technical field

The present invention relates to a client/server system and a database access method, in particular to a method for improving database system access stability and response speed in a client/server (Client/Server, hereinafter referred to as C/S) system and a method for realizing the method client/server system.

Background technique

The early client/server system adopts a two-tier architecture, which is mainly composed of the client end and the database server end. Perform an operation and return the result of the operation to the client side. The disadvantage of this system structure is that the scalability is not good enough. As the application business logic and complexity continue to increase, its development work becomes more and more difficult. In addition, the applications running on the client consume a lot of system and network resources.

For this reason, a client/server system with a three-tier (multi-layer) architecture has emerged, which can satisfy scalability (or scalability) and Internet/Intranet applications. Figure 1 is a schematic diagram of a three-tier (multi-tier) architecture. In this three-tier (multi-tier) structure, business logic is extracted from the client side and the database server side to form an independent layer or layers, thus forming It includes the customer interface layer of the client, the middle business logic layer (which can be subdivided into multiple layers) and the data service layer of the back end. When the application program is running on the client, the middle business logic layer will work with it to complete the corresponding business logic. If necessary, the middle business logic layer will request data from the database, and the data request 1 will be sent to the data service layer. This layer accesses the database according to the data request 1 and returns the query data 2 to the business logic layer.

It is worth pointing out that the hierarchical division in the client/server system mentioned in this specification should not be understood in a narrow sense as a physical division, but should be broadly understood as a logical functional division.

However, under the above-mentioned two-tier or three-tier (multi-tier) architecture, since each data request will access the database, that is, the data service layer will perform corresponding operations on the database, so that the performance of the system (such as processing speed or Response time, etc.) is inversely proportional to the number and frequency of data requests for concurrent access, and often fluctuates as the data access requirements increase and decrease, resulting in poor system stability. In some extreme cases of overload , It will even cause the database processing speed to drop and then crash, the client side responds slowly, does not respond or the connection times out, etc., which is intolerable for customers. In addition, there is no simple and effective means to adjust system performance when the system is under huge data access pressure.

Contents of the invention

The object of the present invention is to provide a database access method in a client/server system, which can effectively alleviate the pressure of database access in a multi-client and high-frequency data query environment, and ensure the stability and response efficiency of the entire system.

In the database access method of the present invention, the data requester obtains the data in the database by sending a data access request, and the access method includes the following steps to process the data access request:

(1) according to the content of the data access request, search for the data stored in the buffer memory between the database and the data requester, wherein the buffer memory stores data with high frequency of access requests in the database; and

(2) If the buffer memory stores the data requested by access, read the data and return it to the data requester, otherwise, access the database according to the content of the data access request and return the access operation result to the data requester,

Also, the access method performs the following steps in parallel with steps (1) and (2):

(3) Updating the data stored in the buffer memory with data that is frequently accessed by the data requester within a period of time in the database.

In the above database access method, preferably, the system executes step (3) regularly, and more preferably, the time interval for regularly executing step (3) is dynamically changed. Another object of the present invention is to provide a client/server system that implements the above-mentioned database access method, which can effectively alleviate the pressure of database access in a multi-client, high-frequency data query environment, and ensure the stability and response of the entire system efficiency.

In the client/server system of the present invention, the system includes a data requester for obtaining data and a database for storing data, and the data requester obtains data in the database by sending a data access request, and the system includes:

a buffer memory, located between the data requester and the database, for storing data with high frequency of access requests in the database;

A data request management module, connected to the data requester, the buffer memory and the database, for searching the data stored in the buffer memory according to the content of the data access request, if the buffer memory stores the requested data , read the data and return it to the data requester, otherwise, send the data access request to the database, access the database according to the content of the data access request and return the access operation result to the data requester;

The data update management module is connected to the buffer memory and the database, and is used to store data in the buffer memory in parallel with the data request management module in the database with data that is frequently accessed by the data requester within a period of time data update.

In the above client/server system, the data update management module regularly updates the buffer memory, and more preferably, the time interval for regularly updating the buffer memory is dynamically changed.

In the above-mentioned database access method of the present invention and the client/server system implementing the method, the frequently accessed data is stored in the buffer memory for calling by the data requester, thus reducing the access pressure on the database, and also setting up a buffer The update mechanism of the memory content enables the data requester to always maintain a high hit rate when accessing the buffer memory, ensuring the stability of the entire system performance and response efficiency.

Description of drawings

FIG. 1 is a schematic diagram of a client/server system with a multi-tier architecture.

FIG. 2 is a schematic diagram of a client/server system according to a preferred embodiment of the present invention.

Detailed ways

In a client/server system, usually, the frequency of data requests in the database is not evenly distributed. Some of the data have high frequency of access, while others have low frequency of access, and even some of the data have frequent access. Extremely low data. The core idea of the present invention is to copy the part of data with high access frequency from the database to the buffer memory, and on the one hand, when the data requester accesses the data, first access the buffer memory, if the memory does not store the data that needs to be called , then access the database instead, which will greatly reduce the access pressure of the database and improve the processing speed and stability of the system; content, and also establishes an update mechanism of the buffer memory, and updates the contents of the buffer memory regularly or irregularly.

The core idea of the present invention has nothing to do with whether the client/server system adopts a two-layer architecture or a three-layer (multi-layer) architecture. ) architecture, the data requester is the logic business processing module in the logic business layer. Buffer memory, data request processing and data update processing are separately listed as an independent level in terms of the implemented logic functions, whether in a two-tier architecture or a three-tier (multi-layer) architecture, they are all located in the data Between the requester and the database, this layer is hereinafter referred to as the data buffer layer.

In the above method, the data request processing and data update processing in the data buffer layer are two processes completed in parallel, and the update process can adopt various methods, for example, in the irregular method, the hit rate of the access buffer memory can be significantly improved. When it is reduced, the buffer memory is updated according to the access frequency within a period of time, and the data with high access frequency of the data requester is transferred from the database to the buffer memory to replace the data in it. Update the data in the buffer memory with the data with high access frequency at a fixed time interval.

A preferred embodiment of the present invention is described below with the aid of Fig. 2, and in this embodiment, client computer/server system adopts two-layer architecture, so the data request party here is the client computer in the customer interface layer, and the database is located in the data service layer.

As shown in Figure 2, this system comprises a plurality of client computers and a database storing a large amount of data, according to the principle of the present invention, an intermediate layer called a data buffer pool is set between the client computer and the database of the common two-tier structure. The data buffer pool includes a large-capacity buffer memory and two management modules, wherein the buffer memory stores data frequently requested by clients, and the data update management module and the data request management module implement their respective functions in parallel. The data update management module regularly queries the database for data with high access frequency, and the database returns the stored data according to the query request to refresh the data in the buffer memory. The refresh time interval can be preset and changed dynamically. The data request management module receives the data request from the client, first accesses the buffer memory to read the requested data, if it is read, it returns the read data to the client, otherwise, it transfers the read request to the database for corresponding processing. deal with. After receiving the read request, the database reads the required data and returns the result to the client.

In the above-mentioned system, instead of using the regular update method, when the hit rate of accessing the buffer memory is significantly reduced, the buffer memory can be updated according to the access frequency within a certain period of time, and the data requester with a higher access frequency The data from the database is transferred to the buffer memory to replace the data in it. In addition, the client/server system in the above example adopts a two-tier architecture, but it can be extended to a three-tier (multi-tier) architecture. In the three-tier (multi-tier) architecture, the data requester is the logical business layer In the logical business processing module, the data buffer pool is located between the logical business processing module and the database.

In the above method and system, the data buffer pool can satisfy most of the data requests, so that the access pressure of the database will not fluctuate greatly with the change of the number of data requesters, thus ensuring the stable operation of the system. In addition, most of the data requests obtain data from the faster buffer memory in the data buffer pool, which saves time-consuming database query operations, so the system responds faster. Finally, the access pressure of the database can also be adjusted by changing the update speed of the data in the buffer memory. For example, when the database access pressure is high, the update frequency can be appropriately increased to improve the hit rate of the buffer memory and reduce the access pressure of the database. On the contrary, The update frequency can be reduced to avoid frequently updating the data in the buffer memory.

Claims (8)

1. data bank access method, request of data square tube are crossed and are sent data access request and obtain data in the database, it is characterized in that described access method comprises the following steps the deal with data request of access:

(1) data of storing in the memory buffer of content search between described database and described request of data side according to data access request, wherein said buffer memory stores have the high data of request of access frequency in the database; And

(2) if described buffer memory stores has the data of accessed request, then read these data and return to request of data side, otherwise, return to request of data side according to the access to content database of this data access request and with the accessing operation result,

And described access method is to carry out the following step with the parallel mode in step (1) and (2):

(3) with a period of time in the database at interval in the high data of request of data side's visiting frequency with the Data Update of described memory buffer stored.

2. data bank access method as claimed in claim 1 is characterized in that, described system is execution in step (3) regularly.

3. data bank access method as claimed in claim 2 is characterized in that, regularly the time interval of execution in step (3) is dynamic change.

4. client/server system, described system comprises the request of data side that obtains data and the database of storage data, described request of data square tube is crossed and is sent data access request and obtain data in the database, it is characterized in that described system comprises:

Memory buffer between described request of data side and described database, is used for the high data of request of access frequency in the stored data base;

The request of data administration module, link to each other with described request of data side, described memory buffer and described database, be used for the data of storing according to the content search memory buffer of data access request, if described buffer memory stores has the data of accessed request, then read these data and return to request of data side, otherwise, this data access request is delivered to database, return to request of data side according to the access to content database of this data access request and with the accessing operation result;

The Data Update administration module, link to each other with described memory buffer and described database, be used for with the parallel mode of request of data administration module with a period of time in the database at interval in the high data of request of data side's visiting frequency with the Data Update of described memory buffer stored.

5. client/server system as claimed in claim 4 is characterized in that, described Data Update administration module regularly upgrades memory buffer.

6. client/server system as claimed in claim 5 is characterized in that, the time interval of regularly upgrading memory buffer is dynamic change.

7. as each described client/server system among the claim 4-6, it is characterized in that, described client/server system is two layer architectures that comprise customer interface layer and data service layer, described request of data side is the client computer that belongs to the customer interface layer, described database belongs to data service layer, and described memory buffer, request of data administration module and Data Update administration module are between described client computer and described database.

8. as each described client/server system among the claim 4-6, it is characterized in that, described client/server system is the multi-tier systematic structure that comprises customer interface layer, Business Logic and data service layer, described request of data side is the business logic processing module that belongs to Business Logic, described database belongs to data service layer, and described memory buffer, request of data administration module and Data Update administration module are between described business logic processing module and described database.

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