CN105915619A - Access heat regarded cyber space information service high performance memory caching method - Google Patents

Abstract

The invention discloses a high-performance memory caching method for network space information service in consideration of access heat, which comprises the following steps: the server end receives the space data request sent by the client, and obtains the requested access address; uses the address as a key in the global memory cache Retrieve the cache object in the cache object. If the retrieval misses, use the address requested by the client as a key to retrieve the corresponding temporary cache object from the temporary cache. If the retrieval hits, decide whether to add it to the global memory cache according to the number of accesses of the temporary cache object. If If there is a miss, add the current request information to the temporary cache. The method of the invention can control the cache module to only cache the space data whose access heat reaches a certain threshold in the limited server memory, reduce the number of memory cache replacements, avoid excessive elimination of memory cache data, and improve the memory cache performance of the server and the concurrent access performance of cyberspatial information services.

Description

A high-performance memory caching method for cyberspace information services taking into account access heat

technical field

The invention relates to network geographic information system technology, in particular to a high-performance memory caching method for network space information service taking into account access heat.

Background technique

High-performance memory caching of web space information service is one of the important problems to be solved in web geographic information system (WebGIS). Utilizing the high-performance concurrent read and write performance of server memory, the web space information service request data is cached in the high-speed memory of the server , can improve the efficiency of concurrent response to client requests, but the memory resources of the server are limited. For large-scale massive spatial data, only part of the data can be cached in the server's memory. When a large number of users access intensively concurrently, due to a large number Temporary access data is added to the limited memory cache, which will result in frequent elimination of data in the memory cache, reducing the efficiency of the memory cache and the cache hit rate.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-performance memory caching method for cyberspace information services that takes into account the access heat to reduce the elimination frequency of memory caches on servers and improve the performance of memory caching for cyberspace information services in view of the defects in the prior art .

The technical solution adopted by the present invention to solve the technical problem is: a high-performance memory caching method for cyberspace information services that takes into account access heat, which includes the following steps:

Step 1: Set the server-side spatial data request cache threshold (ACT), the maximum number of global memory cache objects (GCT), and the maximum number of temporary cache objects (TCT).

Step 2: The server receives the spatial data request sent by the client, and obtains the requested access address.

Step 3: Use the address as a key to retrieve the cached object from the global memory cache. If the global memory cache is hit, go to step 4; if the global memory cache is not hit, go to step 6.

Step 4: Update the last access time attribute of the hit global memory cache object.

Step 5: directly return the result data stored in the hit cache object to the client, and end.

Step 6: Retrieve the data requested by the client from the spatial database.

Step 7: Return the result data to the client.

Step 8: Use the client request address as a key to retrieve the corresponding temporary cache object from the temporary cache. If the temporary cache is hit, go to step 9; if the temporary cache is not hit, go to step 15.

Step 9: Obtain the access count (RAC) of the temporary cache object. If RAC>ACT, go to step 10; otherwise, go to step 14.

Step 10: Add the result data obtained by the current request to the global memory cache.

Step 11: Delete the temporary cache object of the current request,

Step 12: Obtain the number of caches (GCC) in the global memory cache. If GCC>GCT, go to step 13. If GCC<GCT, end.

Step 13: Delete a cache object that has not been accessed for the longest time in the global memory cache, and end.

Step 14: Add 1 to the access count (RAC) of the temporary cache object, and update the last access time of the temporary cache object, and end.

Step 15: Initialize the access count of the temporary cache object currently requested as 1, and add it to the temporary cache.

Step 16: Obtain the number of cache objects (TCC) in the temporary cache, if TCC>TCT, go to step 17; if TCC<TCT, end.

Step 17: Delete a cache object that has not been accessed for the longest time in the temporary cache, and end.

According to the above solution, both the temporary cache and the global cache in step 1) are stored in the form of key-value pairs, where the key is the requested address, and the values are the temporary cache object and the global cache object respectively.

According to the above scheme, the value of each temporary cache object includes the last access time of the request address corresponding to its key and the number of visits to this address; the value of each global cache object includes the request address corresponding to its key The last access time of and the result data corresponding to the request.

According to the above solution, in the step 9), the result data corresponding to the request address is cached in the global cache only when the number of visits to the request address exceeds the threshold.

The beneficial effect of the present invention is that it is possible to judge whether to cache the requested data in the memory cache of the server according to the access heat of the network space information service access request, so as to avoid storing some data with a small number of temporary visits in the memory cache of the server, Reduce the number of server memory cache conversions, improve server-side memory cache efficiency and cache hit rate, and improve the performance of concurrent request processing for a large number of users of cyberspace information services.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is a flow chart of the method of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1, Figure 1 is a flow chart of a high-performance memory caching method for cyberspace information services that takes into account access heat provided by the present invention, and the method includes the following steps:

Step 1: Set the server-side spatial data request cache threshold (ACT), the maximum number of global memory cache objects (GCT), and the maximum number of temporary cache objects (TCT).

Step 2: The server receives the spatial data request sent by the client, and obtains the HTTP address for the requested access.

Step 3: Use the address as a key to retrieve the cached object from the global memory cache. If the global memory cache is hit, go to step 4; if the global memory cache is not hit, go to step 6.

The global cache object is stored in the form of key-value pairs. The HTTP address of the request is used as the key, and the value is a global cache object class (GlobalCacheItem), which contains the result data of the request (data) and the last access time of the request (lastAccessTime). The global cache object class is defined as follows:

Public class GlobalCacheItem

{

Public byte[] data;

Public DateTime lastAccessTime;

}

Step 4: Obtain the hit global memory cache object (globalCacheObj), update the last access time (lastAccessTime) attribute of globalCacheObj, and update it to the current time.

Step 5: directly return the result data (globalCacheObj.data) stored in the hit cache object to the client, and end.

Step 6: Retrieve the data requested by the client from the spatial database.

Step 7: Return the result data to the client.

Step 8: Use the client request address as a key to retrieve the corresponding temporary cache object from the temporary cache. If the temporary cache is hit, go to step 9; if the temporary cache is not hit, go to step 15.

Temporary cache objects are stored in the form of key-value pairs. The HTTP address of the requested access is used as the key, and the value is a temporary cache object class (TempCacheItem), which contains the number of requested accesses (RAC) and the last access time of the request (lastAccessTime). The temporary cache object class is defined as follows:

Public class TempCacheItem

{

Public int RAC;

Public DateTime lastAccessTime;

}

Step 9: Obtain the hit temporary cache object (tempCacheObj), and obtain the access times of the temporary cache object (tempCacheObj.RAC). If tempCacheObj.RAC>ACT, go to step 10; otherwise, go to step 14.

Step 10: Add the result data of the current request obtained in step 6 to the global memory cache.

Step 11: Delete the temporary cache object (tempCacheObj) of the current request,

Step 12: Obtain the number of caches (GCC) in the global memory cache. If GCC>GCT, go to step 13. If GCC<GCT, end.

Step 13: According to the last access time attribute (lastAccessTime) of each cache object in the global memory cache, delete a cache object that has not been accessed for the longest time in the global memory cache, and end.

Step 14: Add 1 to the access count (tempCacheObj.RAC) of the temporary cache object, and update the last access time (tempCacheObj.lastAccessTime) of the temporary cache object, and end.

Step 15: Create a new temporary cache object for the current request, initialize the access count (RAC) of the temporary cache object of the current request to 1, and initialize the last access time (lastAccessTime) to the current time, and add it to the temporary cache.

Step 16: Obtain the number of cache objects (TCC) in the temporary cache, if TCC>TCT, go to step 17; if TCC<TCT, end.

Step 17: According to the last access time attribute (lastAccessTime) of each cache object in the temporary cache, delete a cache object that has not been accessed for the longest time in the temporary cache, and end.

The most obvious difference of the present invention is the addition of a temporary cache module. When the server receives concurrent access requests from a large number of users, it does not directly add the result data of the new request to the global memory cache, but only adds the requested access times and the last The access time is stored in the temporary cache, and the requested result data is cached in the global memory cache only when the number of accesses exceeds the preset threshold. This method can prevent data with a small number of temporary accesses from being stored in the global memory cache, reduce the replacement frequency of the global memory cache, improve the efficiency and hit rate of the global memory cache, and improve the concurrent processing performance of the network space information service, especially in the server The advantage of this approach is even more pronounced when memory resources are low.

Embodiment one:

In order to illustrate the idea of the present invention more clearly, the following is a further description of the high-performance memory caching method for cyberspace information services that takes into account access heat, using OGC in cyberspace information services Take the GetCapabilities request of the WMS service as an example. The cache threshold for the number of spatial data requests is set to 10, the maximum number of global memory cache objects is set to 10,000, and the maximum number of temporary cache objects is set to 100. Specific steps are as follows:

Step 1: Set the server-side cache threshold for spatial data requests (ACT=10), the maximum number of global memory cache objects (GCT=10000), and the maximum number of temporary cache objects (TCT=100).

Step 2: The server receives the GetCapabilities request of the WMS service sent by the client, and obtains the HTTP address accessed by the GetCapabilities request. The format of the request address is as follows:

http://domain/wms?REQUEST=GetCapabilities&VERSION=1.1.1&SERVICE=WMS

Step 3: Use the address obtained in step 2 as a key to retrieve the cached object from the global memory cache. If the global memory cache is hit, go to step 4; if the global memory cache is not hit, go to step 6.

Step 4: Obtain the hit global memory cache object (globalCacheObj), update the last access time (lastAccessTime) attribute of globalCacheObj, and update it to the current time.

Step 5: directly return the result data (globalCacheObj.data) stored in the hit cache object to the client, and end.

Step 6: Retrieve the data requested by the client from the spatial database, and generate result data that meets the requirements of the GetCapabilities service interface according to the interface specification of the WMS service.

Step 7: Return the result data to the client.

Step 8: Use the client request address as a key to retrieve the corresponding temporary cache object from the temporary cache. If the temporary cache is hit, go to step 9; if the temporary cache is not hit, go to step 15.

Step 9: Obtain the hit temporary cache object (tempCacheObj), and obtain the access times of the temporary cache object (tempCacheObj.RAC). If tempCacheObj.RAC>10, go to step 10; otherwise, go to step 14.

Step 10: Use the client request address obtained in step 2 as a key to create a new instance object (globalItem) of the GlobalCacheItem class, set its lastAccessTime property to the current time, and set its data property to the current request obtained in step 6 The result data, and then add the requested global cache object globalItem to the global memory cache.

Step 11: Delete the temporary cache object (tempCacheObj) of the current request,

Step 12: Obtain the number of caches (GCC) in the global memory cache. If GCC>10000, go to step 13. If GCC<10000, end.

Step 13: According to the last access time attribute (lastAccessTime) of each cache object in the global memory cache, delete a cache object that has not been accessed for the longest time in the global memory cache, and end.

Step 14: Add 1 to the access times (tempCacheObj.RAC) of the temporary cache object, and update the last access time (tempCacheObj.lastAccessTime) of the temporary cache object to the current time, and end.

Step 15: Create a new TempCacheItem instance object (tempItem) for the current request, set its access count (RAC) to 1 initially, and the last access time (lastAccessTime) to the current time, and use the client request address obtained in step 2 as key, add the temporary cache object tempItem of the request to the temporary cache.

Step 16: Obtain the number of cache objects (TCC) in the temporary cache, if TCC>100, go to step 17; if TCC<100, end.

Step 17: According to the last access time attribute (lastAccessTime) of each cache object in the temporary cache, delete a cache object that has not been accessed for the longest time in the temporary cache, and end.

Adopting the high-performance memory caching method of network space information service designed in the present invention, which takes into account the access heat, can prevent the temporary access request data from being added to the global memory cache too much when the server receives concurrent access requests from a large number of users, effectively Minimizing the replacement times of the global memory cache helps to improve the efficiency and hit rate of the global memory cache, and improves the concurrent processing performance of the network spatial information service when a large number of users intensively access concurrently.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should belong to the protection scope of the appended claims of the present invention.

Claims (4)

1. take the cyberspace information service high-performance memory cache method accessing temperature into account for one kind, it is characterised in that it comprises the following steps:

Step 1) arranges spatial data request number of times cache threshold ACT of server end, global memory's cache object maximum number GCT, temporal cache object maximum number TCT；

Step 2) received server-side client send spatial data request, it is thus achieved that the reference address of request；

Cache object is retrieved as keyword in global memory caches in address by step 3), if retrieval hit, goes to step 4) if in retrieval recklessly, going to step 6)；

It is current time that step 4) updates the last time attribute that accesses of global memory's cache object of hit；

The result data of storage in the cache object of hit is directly returned to client by step 5), terminates；

Step 6) retrieves the data of client request from spatial database；

Result data is returned to client by step 7)；

Client request address is retrieved the temporal cache object of correspondence from temporal cache by step 8) as keyword, if temporal cache hit object, goes to step 9)；If temporal cache is miss object, go to step 15)；

Step 9) obtains access times RAC of temporal cache object；If RAC > ACT, go to step 10)；Otherwise then go to step 14)；

The result data that current request is obtained by step 10) increases in global memory's caching；

Step 11) deletes the temporal cache object of current request；

Step 12) obtains caching number GCC in global memory's caching, if GCC>GCT, goes to step 13, if GCC<GCT, terminates；

Step 13: delete in global memory's caching and be not accessed for a global buffer object at most, terminate；

Access times RAC of temporal cache object are added 1 by step 14), and update the last access time of temporal cache object, terminate；

The object of current request is increased to as temporal cache object in temporal cache by step 15), and the access times of this temporal cache object are initially 1；

Step 16) obtain cache object number TCC in temporal cache, if TCC > TCT, go to step 17；If TCC < TCT, terminate；

Step 17) delete in temporal cache and be not accessed for a temporal cache object at most, terminate.

The cyberspace information service high-performance memory cache method taking access temperature into account the most according to claim 1, it is characterized in that, in described step 1), temporal cache and global buffer all use the form of key-value pair to store, wherein, key is the address of request, and value is respectively temporal cache object and global buffer object.

The cyberspace information service high-performance memory cache method taking access temperature into account the most according to claim 2, it is characterized in that, the value of described each temporal cache object includes the last access time of request address and the access times to this address that its key is corresponding；The value of described each global buffer object includes the result data corresponding with this request of the last access time of the request address that its key is corresponding.

The cyberspace information service high-performance memory cache method taking access temperature into account the most according to claim 1, it is characterized in that, in described step 9), only just result data corresponding for request address is cached in global buffer when the access times of request address exceed threshold value.