JP2000181843A - Information repeater and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an average response time in the case the updating frequency of original contents is high and, besides, an information providing request is outputted from a client to an unspecified number of multiple servers. SOLUTION: An information repeater 122 is arranged on a network 121 and is provided with a relay function for transferring the data providing request from a client computer to a server computer and transferring provided data from the server computer to the client computer. The repeater 122 is provided with replication means 113, 110, 109, 111 and 108 for copying and holding request data by asynchronization with the data providing request concerning data on the server computer, which is requested providing from the client computer before and a copy returning means 113 for returning copy data 110 held by the replication means to the client computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information relay apparatus and a storage medium, and more particularly, to information generated by a server computer on a network, which is interposed between a client computer that refers to the information and relays information exchange between the two. The present invention relates to a relay device and a storage medium.

[0002]

2. Description of the Related Art WWW (World Wide Wed)
b) or FTP (File Transfer Prot)
In a distributed computer system typified by an ocol) service, a unique identification character string that specifies a block of information (hereinafter, referred to as content) is associated with each content in the form of a URL. Client system (hereafter,
By specifying a URL from a client, the content can be extracted from a server system (hereinafter, referred to as a server).

When using such a system, there is a case where an information relay device called a proxy server is interposed between a client and a server. The proxy server has several functions, one of which is a caching function.

[0004] By using this caching function, the content once referred by the client is stored in its cache area when passing through the proxy server. With this data cache, when a client requests to see the content again,
Since the data in the cache is returned, network data transfer between the proxy server and the server can be omitted, and the request of the client can be answered at high speed.

The operation of a general caching proxy server currently implemented is as follows. Here W
The example of WW is shown.

[0006] 1. Upon receiving a display request from the client,
Examine the cache area.

[0007] 2. If a copy of the content requested by the client exists in the cache area, the copy is returned if the copy is within the validity period. The expiration date is sent together with content acquisition from the server.

[0008] 3. If the expiration date has passed, the WWW server where the original is placed is inquired of the latest update date and time of the content in order to confirm whether or not it is the latest one.

4. If the last update date and time of the original match the update date and time of the copy, the contents in the cache are returned to the client.

[0010] 5. If the original last update date is newer than the cache, the original content is downloaded again, returned to the client, and the cache is updated.

Hereinafter, the situation 2 or 4 is referred to as "cache hit".

Here, conditions for hitting the cache in response to an information provision request from a client are summarized as follows.

The content of the requested URL exists in the cache (hereinafter referred to as existence).

The content in the cache is the same as that of the server (hereinafter, referred to as up-to-date).

Due to the nature of these conditions, the cache hits only when both the existence and the freshness conditions are satisfied for the duplicated data on the cache.

On the other hand, in a technique called a database replication system or a push (Push) technology, a change is notified to a client having a copy when the content on the server is updated with respect to the content set in advance, and the copy is notified. Is changed to the latest state.

By using the push technology for the cache management of the proxy server, a predetermined U
For the contents of the RL, the latest one is always held in the cache area. Therefore, the probability of a cache hit for a request from the client is higher than that of a general proxy server, and the average response time as seen from the client is shorter. This effect is significant if the content on the server is updated frequently.

Although not strictly speaking, it is not a push technology, but a technology generally called a push technology is a technology called intelligent pull.
While the push technology described above actively sends content from the server side, this intelligent pull tries to achieve the same state as apparently using push technology by periodically acquiring content from the client side. I do.

As an example in which this intelligent pull technology is applied to a proxy server, US
Asanet.

The Marimba's Castanet comprises a transmitter having a server function and a tuner having a client function. The tuner periodically checks whether the contents of the URL set on the tuner in advance have been updated on the transmitter, downloads the updated content, and updates the duplicate file on the tuner.

When there is a content reference request from the user, the copy content on the tuner is displayed. Therefore, when the tuner is used as a proxy server of a WWW browser, a high-speed response can be realized. In this case, if the reference request from the WWW browser is the content cached on the tuner, a copy is returned; otherwise, the content is downloaded from the original server.

Since the contents cached in the tuner are regularly updated to the latest state, there is a higher probability that the freshness of the cache is established as compared with the case where a general proxy server is used.

In JP-A-10-21134, two proxy processes are prepared, and the first proxy process has a normal proxy function, and the second proxy has the first proxy process. A technique is described in which URLs described in an access log generated by a proxy are sequentially read from an original in a Web server and stored in a cache. In other words, if the target content that the client is trying to retrieve is not found in the proxy cache, or if it is found and the expiration date has expired, the original can be read and the target content that is within the expiration date can be found. If it does, it returns it to the client.

[0024]

However, when the above-described caching function of the caching proxy server is used, the caching function of the caching proxy server is effectively enabled when the content update frequency of the original content placed on the server is low. work. However, when the update frequency of the original content is high, the probability of the cache being up-to-date is low, so that the cache hit rate is reduced and the effect of caching by the proxy server is reduced.

When the above-mentioned push technology or intelligent pull technology is used, only a preset content is copied. Therefore, W
In a system in which the original content is unspecified such as WW, there is a problem that the probability of the existence of the cache is reduced and the hit rate is reduced. If the existence is improved by setting a sufficiently large number of contents as push targets in advance, there arises a problem that a required cache size becomes too large, which is not realistic.

Further, according to the technique described in Japanese Patent Application Laid-Open No. H10-21134, the timing for caching
Since the access log of the second proxy increases based on the access log, the cache is not updated unless there is a request from the client, even if the original content has been changed within the expiration date, It may happen that new content is not available to the client.

The present invention has been made in view of such circumstances, and the frequency of updating the original content is high.
It is still another object of the present invention to provide an information relay device and a storage medium that can improve the average response time when a client provides an information provision request to an unspecified number of servers.

[0028]

In order to solve the above problems, the invention according to claim 1 is arranged on a network connecting a server computer as an information provider and a client computer as an information user. An information relay apparatus having a relay function of transferring a data providing request from a client computer to a server computer and transferring provided data from the server computer to the client computer.

In this information relay apparatus, the replication means replicates and holds the requested data of the data on the server computer to which the data provision request was previously made from the client computer, asynchronously with the data provision request.

Further, when a data provision request is made from the client computer, the copy returning means returns the duplicate data held by the replication means to the client computer.

According to the present invention, since the copy update is performed asynchronously with the data provision request, it is possible to appropriately return the copy even when the original content is frequently updated. Since the data requested to be transmitted is copied, it is possible to improve the average response time when an information provision request is output from a client to an unspecified number of servers.

Next, the invention according to claim 2 is the invention according to claim 1, wherein the replication means comprises:
Update the replication data to the latest state at set time intervals.

Therefore, the copy data can be returned more efficiently.

Next, a third aspect of the present invention is directed to the second aspect of the present invention, wherein a replication interval determining unit is provided, and the update interval for each of a plurality of replicated data is set by the interval determining unit. , Based on the frequency of data provision requests from the client computer for each data.

Therefore, it is possible to perform appropriate copy update according to the data request frequency.

Next, according to a fourth aspect of the present invention, in the invention according to the second or third aspect, each of the update time intervals for the plurality of replicated data is set to the server computer for each data by the replication interval determining means. It is changed based on the above data change frequency.

Therefore, it is possible to perform the copy update in consideration of not only the client's request but also the situation on the server side.

Next, a fifth aspect of the present invention is the invention according to the first to fourth aspects, wherein when a data provision request is received by the replica use determining means, the replicated data held by the replication means is valid. It is determined whether it is within the time limit.

If the replica usage determining means determines that the replicated data is out of the validity period, the replicating means further inquires of the server computer about the attribute information of the data corresponding to the replicated data. When it is determined that the data has been updated on the server computer, the data is reacquired from the server computer and the acquired data is transferred to the relay function.

Therefore, when the data on the server side is not actually changed, it is possible to prevent the data from being redundantly transmitted between the server and the relay device, and to perform efficient data transfer. it can.

Next, according to a sixth aspect of the present invention, in the first aspect of the invention, when a change occurs in the data to be provided, the server computer registers the data registered for data provision. This is applied to the information relay device when the updated data is to be transmitted to the data providing target. The server computer uses, for example, a push technology.

In this case, upon receiving a data provision request for data that does not hold duplicate data from the client computer, the replication means registers with the server computer to provide the requested data.

Therefore, by acting to register the data to be pushed from the information relay device to the server computer using the push technology or the like, the same effect as the first aspect of the invention can be obtained.

Next, according to a seventh aspect of the present invention, in accordance with the first aspect of the present invention, the replication means acquires and holds the access restriction information on the duplicated data together with the duplicated data. .

Further, based on the access restriction information, the copy return means returns copy data only to a data provision request from a client to which access is permitted.

Therefore, it is possible to return data only to a client having access authority.

Next, an eighth aspect of the present invention is a recording medium storing a program for causing a computer to implement the first aspect of the present invention.

The computer controlled by the program read from the recording medium functions as the information relay device of the present invention.

Next, a ninth aspect of the present invention is a recording medium storing a program for causing a computer to implement the second aspect of the present invention.

The computer controlled by the program read from the recording medium functions as the information relay device of the present invention.

Next, a tenth aspect of the present invention is a recording medium on which a program for causing a computer to realize the sixth aspect of the invention is recorded.

The computer controlled by the program read from the recording medium functions as the information relay device according to the present invention.

[0053]

Embodiments of the present invention will be described below. (First Embodiment of the Invention) FIG. 1 is a block diagram showing a configuration example of a network system including a proxy server to which an information relay device according to a first embodiment of the present invention is applied.

This network system has a public line 1
The Internet is a network in which a number of server nodes 114 and client nodes 101 are connected via the Internet 21.
Further, the client node 101 is connected to the public line 121 via the proxy server node 103, and transmits a content request to the server node 114 to the proxy server 1
03. The information relay device 122 of the present embodiment is incorporated in the proxy server node 103.

In this embodiment, each of the nodes 101 and 10
3 and 114 will be described.
The intervening network is not an essential requirement of the invention. For example, the client node 101 and the information relay device can exist as software processes in the same computer.

In FIG. 1, each node 101, 103,
Although only one 114 is described, the client node 101 and the server node 114 may have a plurality of devices having the same configuration. Further, each node 1
Reference numerals 01, 103, and 114 each comprise a computer system having a communication function, and constitute various function realizing means shown in FIG. 1 from hardware resources such as a CPU and a memory and software resources such as a control program. FIG. 1 shows various data necessary for realizing the functions, which are stored in a storage unit (not shown) such as a memory or a hard disk in each computer (not shown).

The configuration of each of the above components will be described below.

The client node 101 has a content display unit 10 having an information display function such as a WWW browser.
2 are provided. The content display unit 102 performs a content acquisition request 1 from the client to the server.
17 and displays the content sent from the server.

Next, the server node 114 includes a content transmitting section 115 having an information transmitting function, such as a WWW server, and content data 116.

The content transmitting section 115 receives the request 117 from the client or the proxy server 103.
Alternatively, upon receiving 118, the corresponding content is transmitted.

The contents data 116 is a set of contents transmitted from the contents transmitting section 115 in response to a request 117 or 118 from the client or the information relay device, and is stored in a storage means (not shown). Also, an ID for identifying individual contents
(URL for WWW) and a content content entity represent one content. In the following description, I
A case where D is a URL will be described.

FIG. 2 is a diagram showing an example of a URL and a transmission source ID.

The information shown in FIG.
01 is an example of the form of the identification information included in the request data 117 or 118 specifying the content to be acquired.

Next, the proxy server node 103 is a server that performs communication with the Internet and the like on behalf of the client node 101. In the present embodiment, the information relay device 122 is provided therein.

The information relay device 122 holds the input information statistical data 105, the replication strategy knowledge 107, the replica content URL 109, the URL-specific replication interval 108, and the replica content data 110. Also, based on these data and the request data 117, the input analysis unit 104, the replication strategy determination unit 107, the replica use determination unit 112, and the request / content transfer unit 1 that execute predetermined processing.
13 and a replica updating unit 111.

First, the input analysis unit 104 analyzes the request 117 sent from the client, and creates the input information statistical data 105. In addition, all information of the request is sent to the replica use determination unit 112.

The input information statistical data 105 is obtained by storing analysis information of past requests and the like in storage means (not shown). For example, for the item of FIG. 3A, the statistical information of the request is held in the form shown in FIG.

FIG. 3 is a diagram showing an example of the contents of the input information statistical data and the data used in the replication strategy determining unit.

FIG. 4 is a diagram showing an example of the storage form of the input information statistical data.

Note that, among the items shown in FIG.
The RL (1), the latest request issue time (2), the total number of requests (3), and the request occurrence frequency (4) are analyzed or calculated and updated based on the request 117 received by the input analysis unit 104. It is.
The replica usage count (5) is incremented when a replica is used by a replica usage determination unit 112 described later.

The replication strategy determining unit 106 uses the input information statistical data 105 based on the replication strategy knowledge 107 to determine which content is to be replicated and at what intervals the replica is updated to the latest state. Then, the result is output to the URL-specific replication interval 108. Here, the replication strategy knowledge 107 is the replication strategy determining unit 1
06 is the knowledge data used, and holds the knowledge in the form shown in FIG. 5, for example.

FIG. 5 is a diagram showing an example of the content of the replication strategy knowledge.

The replication strategy knowledge 10 shown in FIG.
7, the replication strategy determination unit 10
The following describes what kind of replication interval is determined by No.6.

The replication strategy determining unit 106 determines that the replica corresponding to each URL has the processing # 1 to # 4 shown in FIG.
It is checked whether any of the processing conditions is satisfied, and if the condition is satisfied, the replication interval specified for the processing is output to the URL-specific replication interval 108. In the case of replication registration deletion, the corresponding URL is deleted from the replica content URL 109.

The replication strategy determining unit 106
Prior to the replication strategy decision processing, FIG.
The replica usage rate (6) shown in (b) is calculated and held during the strategy determination processing.

Processing # 1 in FIG. 5 is performed when the latest request issue time (2) is earlier than three hours from the current time and the replica usage rate (6) is larger than 0.5. The replication interval for the URL is set to 5 hours. The reason why the interval is set to 5 hours, which is a relatively long time under this condition, is that the replica held by the information relay device 122 is used as it is with a high probability for the request frequency. This is because the change frequency can be expected to be relatively low. In other words, in this case, the request frequency is relatively higher than the content change frequency.

In the process # 2 in FIG. 5, the latest request issuance time (2) is earlier than three hours from the current time,
And when the replica usage rate (6) is 0.5 or less,
The replication interval for the URL is two hours. The reason for setting the interval to 2 hours, which is a relatively short time under this condition, is that the usage rate of the replica held by the information relay device 122 is low for the request frequency, and the change frequency of the corresponding content in the server node 114 is relatively low Because it can be expected to be high. In other words, in this case, the request frequency is relatively lower than the content change frequency.

In the process # 3 in FIG. 5, when the request occurrence frequency (4) per unit time is larger than 5, and the replica usage rate (6) is smaller than 0.8, the replication interval for the URL Is set to 1/3 of the frequency measurement unit time. This is not to set the replication interval by mere time, but to define it in accordance with the concept of request occurrence frequency and replica usage rate. The process # 3 corresponds to the case where the request request is high and the content change frequency on the server side is high.

The process # 4 in FIG.
If there is no request for more than a day, the replication is terminated. In this case, the replication registration is deleted, and the replication strategy determination unit 1
Reference numeral 06 deletes related information about the URL from the replica content URL 109, the URL-based replication interval 108, and the replica content data 110.

The replication strategy knowledge 107 shown in FIG. 5 is an example of various possible strategy knowledge.
Other strategic knowledge can also be applied. For example, a condition "whether or not the content is not fixed" may be added to the process # 4 as an AND condition, and "replication end" may be set only when both of these conditions are satisfied. In this case, the registration is deleted only when the content is not requested for three days and the content is not fixedly requested by the client.

The replication interval 108 for each URL is
UR determined by the replication strategy determining unit 106
The data of the replication interval for each L is held. For example, the value of the replication interval for each URL is held in the form shown in FIG.

FIG. 6 is a diagram showing an example of the contents of a replication interval for each URL.

The replica content URL 109 holds the URL list of the content to be replicated, which is determined by the replication strategy determining unit 106. For example, the URL of the content to be replicated is held in a form as shown in FIG.

FIG. 7 is a diagram showing an example of the replica content URL.

The replica content data 110 holds the replica entity of the content corresponding to the URL listed in the replica content URL 109. For example, the replica content entity is held in the form shown in FIG.

FIG. 8 is a diagram showing an example of the replica content data.

The replica update unit 111 transmits each URL at the interval described in the replication interval 108 for each URL.
The request is made to the server node via the request / content transfer unit 113 so as to update the replica content data 110 for the content.

The replica use determining unit 112 compares the time included in the request data 117 with the expiration date or the update time of the content entity corresponding to the request in the replica content data 110, and notifies the client node 101 of the replica. Return or server node 11
4 to determine whether to newly obtain data and return data. When it is determined that the replica is to be returned to the client node 101, the number of times the replica is used in the input information statistical data 105 is incremented for the corresponding URL.

The request / content transfer unit 113
A content acquisition request 118 is sent to the server node 114 based on the determination result of the replica usage determining unit 112, and the content data returned from the server node 114 is returned to the client node 101. When the replica use determining unit 112 determines to return the replica, the replica is returned to the client node 101.

The request / content transfer unit 11
3 stores the content data acquired from the server node 114 in the replica content data 110 and the replica content URL 109. Therefore, the request / content transfer unit 113 performs not only the update of the replica but also the storage and the UR of the newly requested content.
L holding is also performed.

The replication means in the claims includes, for example, a replica update unit 111, a URL-specific replication interval 108, and a replica content data 11.
0, replica content URL 109 and request /
The content transfer unit 113 and the like correspond.
The replica use determining unit 112 and the request / content transfer unit 113 correspond.

Next, the operation of the information relay apparatus according to the present embodiment configured as described above will be described with reference to FIGS. 9, 10 and 11.

FIG. 9 is a flowchart for explaining the request relay processing in the present embodiment.

FIG. 10 is a flowchart for explaining the replication strategy decision processing in this embodiment.

FIG. 11 is a flowchart for explaining the replica update processing in this embodiment.

Of these processes, the request relay process, the replication strategy decision process, and the replica update process are asynchronous operations that proceed independently.

First, the request relay processing will be described.

This request relay process is a process mainly performed by the information relay device 122 when the request data 117 is issued from the client node 101, as shown in FIG.

First, when the user specifies a URL to the content display unit 102, a content display request is output from the client node 101 (S
1).

The display request issued by the user is transmitted in the form of request data 117 from the content display unit 102 to the input analysis unit 104 of the information relay device 122 (S2).

The contents of the request data 117 are analyzed by the input analysis unit 104, and the contents (1) of the input information statistical data 105 are based on the information on the time when the request was received.
(4) is updated (S3). After the update of the input information statistical data (S3), the process proceeds to a replication strategy determination process described later.

On the other hand, in response to the processing in step S 2, the UR stored in the replica content data 110 is determined based on the request received via the input analysis unit 104.
The expiration date of the L replica content is calculated by the replica usage determining unit 112 (S4).

Here, various methods can be used for calculating the expiration date. For example, when the content is transmitted from the server node 114, an expiration time is attached,
Since the last change time is attached, a method of calculating from the value is adopted.

Next, if the replica content corresponding to the request has not expired (S5), the corresponding replica content is read from the replica content data 113. This read content is requested /
From the content transfer unit 113 to the client node 101
(S6).

Further, the replica usage determining unit 112 increases the number of replica uses (5) in the input information statistical data 106 by "1" (S7), and the process becomes a replication strategy determination process.

If the replica content corresponding to the request has passed its expiration date or is a request for content that has not been replicated (S5), the request / request is performed based on the server node name included in the request data 117. The request data 11 is transmitted from the content transfer unit 113 to the server node 114.
8 is transferred. The content specified by the request data 118 is transmitted from the server node 114 to the information relay device 1.
03 (S8).

The content returned from the server node 114 is transferred from the request / content transfer unit 113 of the information relay device 122 to the client node 101 (S9), and the request / content transfer unit 11
By the process of 3, the content of the replica content data 110 is updated with the same content (S10). In the case of content that has not been replicated, data (content, U
RL) and will be replicated thereafter.

After the content of the replica content data 110 is updated (S10), the process proceeds to the determination of the replication strategy.

Next, the flow of the replication strategy decision processing will be described. The replication strategy determination processing is the request relay processing in FIG. 9; S3 or S7, S10
It starts after receiving the processing of.

First, in step S3 or S7 in FIG.
After S10, the replication strategy determining unit 106 generates a URL-specific replication interval 108 based on the input information statistical data 105 and the replication strategy knowledge 107 (t1).

Specifically, for example, in the case of the input information statistical data as shown in FIG. 4 and the replication strategy knowledge as shown in FIG. 5, the replication interval is determined as follows.

First, the input information statistical data of the URL specified by the request data 117 is extracted. For example, in the request data, http: // www / foo. h
When tml is specified, the information on the first line in FIG. 4 is extracted.

Next, the replication strategy determining unit 106
Calculates the replica usage rate (6),
Knowledge having conditions matching the extracted input information statistical data is retrieved from the replication strategy knowledge 107. For example, if the current time is 1998/09/07/10: 0
When it is 0, when the data on the first line in FIG. 4 is searched, the knowledge on the first line in FIG. 5 matches.

Next, the replication interval described in the found knowledge is set as the replication interval of the URL, and the replication strategy determining unit 106 updates the replication interval 108 for each URL.

The above is the case where a new replication interval is set. It should be noted that cases corresponding to other processes are as described above.

On the other hand, if the replication interval described in the found knowledge indicates the end of the replication, the replication strategy determination unit 10
6 deletes the URL and the corresponding replica content data from the data of the URL-specific replication interval 108, replica content URL 109, and replica content data 110 (t2).

As another method of terminating the replication, when the replica content data 110 becomes larger than a predetermined size, the content priority information (not shown) is referred to and the need for the content is reduced. Content may be excluded from replication targets. As this priority information, for example, the latest request issue time is used. Further, the user may set the priority separately. Further, in this case, the proxy server node 1 that deletes the replica having the lower priority.
The replica content may be deleted using the replica deletion function 03.

In the present embodiment, the method of determining the replication interval based on the rule base has been described. However, the form of the input information statistical data and the replication strategy knowledge is not limited to this. Calculation of an interval value or the like is also conceivable.

Next, the flow of the replica update process will be described. The replica update process operates asynchronously with the request relay process and the replication strategy determination process.

First, the replica update unit 111 compares the last replica creation time stored in the replica content URL 109 with the replication interval stored in the URL-specific replication interval 108.
As a result, if there is a URL whose current time is more than the replication interval time from the last replica creation time, the replica update unit 111 requests the request / content transfer unit 113 to download the content from the server node 114. Is done.

The request / content transfer unit 113 downloads the content, replaces the replica content data 110 with the download data,
The replica is updated (u1).

After updating the replica, the replica updating unit 111 stops for a certain period of time, and then the process of step u1 is repeated (u2).

As described above, the information relay device according to the embodiment of the present invention is provided with the replica updating unit 111, executes the replication process asynchronously with the request relay process, and updates the replica content in advance. Therefore, it is possible to increase the probability that the replica content data in the information relay device is kept up to date,
The hit rate for client requests can be improved.

The replication strategy determining unit 106
The content to be replicated is increased or decreased according to the frequency of requests, so that content with a high client request frequency is replicated to a limited capacity replica storage area, and the The hit rate for a specific content acquisition request can be improved.

Further, in the conventional Push platform (such as Castanet), only preset contents are subject to Push, and it is not possible to flexibly cope with a change in a request on the client side. Since the content that has not been used is automatically pushed afterward, flexible caching processing (replication) can be realized.

Further, in the conventional Push platform, in order to prevent the cache area from becoming insufficient,
It was necessary to manually remove all unnecessary contents from the Push target. On the other hand, in the present invention, Pu is automatically set based on the priority set for each content.
Since the cache area (replica content data 110) is excluded from sh targets, it does not overflow. (Second Embodiment of the Invention) In the first embodiment, when the replica usage determining unit 112 determines that the replica has expired, the request 117 is sent to the server node 114 unconditionally. The request was forwarded as 118.

On the other hand, in the present embodiment, unnecessary content download from the server node 114 is eliminated by checking whether or not the replica content is the same as the original content on the server node. is there.

The information relay apparatus of the present embodiment has the first processing in addition to the modification of the processing of the request / content transfer unit 113.
The configuration is the same as that of the first embodiment.

The request / content transfer unit 113
In addition to the configuration of the first embodiment, the server node 1
When the content is downloaded from the server 14, only the content attribute information is acquired first, and the entire content is acquired only when the replica content is not the latest based on the content attribute information.

As the contents of the request data 118 for this purpose, two types are prepared as shown in FIGS.

FIG. 12 is a diagram showing an example of a request for acquiring only the content attribute information used in the second embodiment of the present invention.

In the request shown in the figure, the request type is “only attribute information”, and the URL is “http”.
p: // www. aaa. bbb / foo. html "
Is shown.

Here, as the attribute information of the content,
At least "the content last change time (creation time for new content)" is included.

FIG. 13 is a diagram showing an example of a request for acquiring the entire content.

In the request shown in the figure, the request type is “entire content” and its URL is “ht”.
tp: // www. aaa. bbb / foo. htm
l ".

The request / content transfer section 11
No. 3 adds the change frequency information of the original content to the input information statistical data 105. This information is obtained, for example, by the following equation.

Change frequency information = total number of content acquisition requests / content attribute acquisition requests The replication strategy knowledge 107 can include the change frequency of the original content as a condition. For example, if the change frequency of the original content is within a predetermined value range, the replication interval is set to a certain value.

Next, the operation of the information relay apparatus according to the present embodiment configured as described above will be described with reference to FIG.

FIG. 14 is a flowchart for explaining the request relay processing in this embodiment.

In the operation of the present embodiment, the request relay processing is changed as compared with the first embodiment.

First, when the replica content is within the expiration date, the same processing as in the first embodiment is executed (v1 to v7). That is, steps S1 to S1 shown in FIG.
Since S7 is the same as steps v1 to v7, a description thereof will be omitted.

Next, when it is determined that the replica has expired (v5), the request / content transfer unit 118 transmits a content attribute acquisition request 118 to the server node 114, and the attribute information of the content is acquired. (V8).

The request / content transfer unit 113 compares the last modification time included in the acquired attribute information with the last replica creation time of the corresponding replica, and determines whether the original content is newer than the replica (v9). .

When it is determined that the original content is newer than the replica (v9), the entire content is obtained from the server (v10), and the replica content data 1 is obtained.
10 is updated (v11), and further, the input information statistical data relating to the URL is changed.

Also, after the entire content is obtained (v
10), the content is returned to the client node (v12).

On the other hand, if the last replica creation time is later than the last change time of the original content in step v9, it is determined that the replica is the same as the latest original content, and the replica content is returned to the client node 101 (v13). . Thereafter, the replica usage count is incremented (v14).

As described above, the information relay apparatus according to the embodiment of the present invention checks whether or not the replica content is the same as the original content on the server node. It is possible to eliminate the download of the content, and to expect a reduction in the response time for the content that does not change even after the expiration date.

Further, since the replication interval can be adjusted based on the update frequency of the original content, it is necessary to appropriately set the replica update interval of the content for which the expiration date is not explicitly set in a probabilistic sense. And a situation in which the entire content must be acquired during the request relay processing is less likely to occur.

In the present embodiment, a description has been given only of a case in which a request 117 for attribute information is made in advance from the client node 101. However, this advance request for attribute information is not limited to request relay processing but also to replica update processing. It may be applied to the case. In this case, when the replica updating unit 111 determines that the replica should be updated, a request for the attribute information is made in advance, and the content is downloaded only when the content is changed. (Third Embodiment of the Invention) The first and second embodiments are
Although a technology called an intelligent pull is applied, a push technology is used in the present embodiment. In connection with the use of the push technology, a multicast technology is used in a communication path between a request / content transfer unit and a content transmission unit, whereby data is actively transmitted from a server node to a plurality of information relay devices. You can do it.

FIG. 15 is a block diagram showing a configuration example of a network system including a proxy server to which the information relay device according to the third embodiment of the present invention is applied. Note that the information relay device 203 shown in the figure is included in the proxy server, but since the relationship between them is the same as in the first embodiment, the display of the proxy server is omitted here.

The network used in the present embodiment, the relationship between the client node 201, the proxy server node and the server node 211, and the basic functions of these components are described in the respective nodes 101, 101 of the first embodiment.
Since it is the same as the case of 103 and 114, detailed description is omitted here.

First, the client node 201 has the same configuration as the client node 101. The request data 208 sent from the client node is the same as the request data 117.

The information relay device 203 includes a replication target URL 206, replica content data 207,
Each data of the replication strategy knowledge 221 and the input information statistical data 222 is stored in a storage unit (not shown).
Further, based on each of these data and the request data 208, the replica use determining unit 20 that executes a predetermined process.
4, a request / content transfer unit 205 and a registration / deletion determination unit 223 are provided.

Here, first, the replica use determining unit 204
Returns the content from the replica content data 207 to the client node if the content of the URL included in the request data 208 exists in the replication target URL 206, and adds the URL to the replication target URL 206 if the content does not exist, and A request 209 to register as new replication target content is sent.

Further, based on the request data 208, the replica use determining unit 204 holds the latest request issue time as input information statistical data 222 for each URL.

The request / content transfer unit 205
Of the content data 210 sent from the server node 211, only the content of the URL registered in the replication target URL 206 is recorded in the replica content data 207.

The replication target URL 206 is a data area in which the URL of the content to be replicated by the information relay device 203 is recorded. For example, it has a data structure shown in FIG.

FIG. 16 is a diagram showing an example of a data structure of a replication target URL in the present embodiment.

[0159] Replica content data 207 is a data area for recording replica content. For example, it has the data structure shown in FIG.

FIG. 17 is a diagram showing an example of the data structure of the replica content data in this embodiment.

The replication strategy knowledge 221 is data indicating a condition for deleting the replica content in the replica content data 207. The conditions include "the latest request occurred three days before the current time" and "the latest request occurred three days before the current time AND AND the URL is not fixed content".

The registration deletion judging unit 223 judges the URL to be deleted from the latest request issue time of the input information statistical data 222 and the registration deletion condition of the replication strategy knowledge 221. When the determination unit 223 determines that a certain replica content should be registered and deleted, it deletes the corresponding data from the replication target URL 206 and the replica content data 207, and transmits the registration deletion data to the server node 211.

On the other hand, the server node 211 holds the data of the content data 214, the URL 216 to be replicated, and the data of the replication destination device 217 in a storage means (not shown), and performs the content processing for performing a certain process related to these data. A transmission unit 212, an update detection unit 213, and a replication target URL registration unit 215 are provided.

Replication target URL registration unit 215
Registers the URL included in the request data 209 in the replication target URL 216, and registers the name of the information relay device of the transmission source of the request data 209 in the replication delivery device name 217.

The replication target URL registration unit 215 is a registration deletion judgment unit 223 of the information relay apparatus 203.
Receives the deletion request data 224 from the
4 to be replicated URL 21
6 and the corresponding data is deleted from the replication delivery destination device name 217.

The replication target URL 216 is a URL list of contents transmitted from the server node 211 to the information relay apparatus 203 for replication. Request data 2 from a plurality of information relay devices 203
If the information relay device 09 has been received, the information is recorded without distinguishing each information relay device. For example, the UR to be replicated by the information relay device
It has the form of FIG. 16 similar to L206.

The content data 214 is a set of content data in which the server node 211 has original data.

The update detection unit 213 determines the content data 2
14 changes are detected, and this is the UR to be replicated.
If it is included in the L216, the URL and the content data entity are sent to the content transmission unit 212.

As a method of detecting a change in the content data in the update detection unit 213, for example, the following several methods can be considered.

A. The last update time of all contents is confirmed at regular time intervals, and contents updated after the previous confirmation time are found.

B. From the tool used to change the content, the changed content is stored in the content data 21.
4 is notified to the update detection unit 213.

C. If the OS or hardware has a function of detecting that data has changed on the storage device, the update detection unit 213 detects the data change.
Inform

The content transmitting section 212 is the update detecting section 2
13 is transmitted to all the information relay apparatuses 203 registered in the replication destination apparatus name 217.

Next, the operation of the information relay apparatus according to the present embodiment configured as described above will be described with reference to FIGS.
This will be described with reference to FIG. 9, FIG. 20 and FIG.

FIG. 18 is a flowchart for explaining the request relay processing in this embodiment.

FIG. 19 is a flowchart for explaining the replica object registration processing in this embodiment.

FIG. 20 is a flowchart for explaining the replica distribution processing in this embodiment.

FIG. 21 is a flowchart for explaining the registration deletion processing in this embodiment.

Here, the processing in FIGS. 18 and 19 proceeds as a series of flows, while FIGS. 20 and 21 are independent processing flows.

First, the flow of the operation shown in FIGS. 18 and 19 will be described.

Step w1 is the same processing as step S1 in FIG.

Next, the request data 208 from the client node 201 is received by the replica use determining unit 204 (w2), and it is checked whether the URL included in the request has been registered in the replication target URL 206 (w3).

When the user has already been registered (w3),
The replica usage determining unit 204 returns the replica of the replica content data 207 to the client node 201 (w4), and ends.

On the other hand, if it has not been registered (w3),
The URL included in the request is added to the replication target URL 206 (w5). Further, a request 209 for registering a replication target URL and acquiring a content is transmitted to the server node 211 (w
6).

Content transmitting section 2 of server node 211
12, the content of the URL included in the request 209 is returned to the information relay device 203, and further transferred to the client node 201 by the information relay device 203. (W7) In conjunction with the request relay processing, the replica target registration processing is executed as shown in FIG.

First, the URL included in the request 209
Is transferred to the replication target URL registration unit 215, and this URL is added to the replication target URL of the server node 211 (x1). Further, the identifier of the transmission source device of the request 209 is added to the replication destination device name 217 by the replication target URL registration unit 215 (x2). Next, the replica distribution process will be described.

First, a change or new creation of the content in the content data 214 is detected by the update detection unit 213 (y1).

The update detection unit 213 determines whether the content whose change has been detected is a content included in the replication target URL 216 (y2).

Here, if the content is to be replicated, the content 210 is transmitted to the device registered in the replication destination device name 217 through the content transmitting unit 212 (y3). When sending this,
Multicast technology is used, whereby data is actively transmitted from the server node to the plurality of information relay devices 203. FIG. 15 shows one of the plurality of information relay devices 203.

In the information relay apparatus 203, the URL of the content 210 sent from the server node 211 is
Is included in the replication target URL 206 by the request / content transfer unit 205 (y4). If it is included in the replication target URL, the replica content data 207 is updated with the content 210 (y5).

As described above, the replica object is registered in the server node 211 using the push technology by the replica object registration process, and the registered URL is distributed to the information relay device 203 by the replica distribution process.

Here, in order to prevent the number of replication target URLs registered in the server node 211 from increasing too much, the information relay apparatus 203 executes a registration deletion process.

In the registration deletion process shown in FIG. 21, first, the registration deletion judgment unit 223 starts the registration deletion judgment.
Therefore, the latest request issue time of the input information statistical data 222 and the registration deletion condition of the replication strategy knowledge 221 are read (z1).

Subsequently, it is determined whether or not each URL satisfies the registration deletion condition based on the latest request issuance time (z2).

As a result, if there is a URL that satisfies the registration deletion condition, the replication target U related to the URL
The RL 206 and the replica content data 207 are deleted (z3), and the deletion request data 224 is output to the server node 211 (z4).

In the server node 211, the replication target URL receiving the deletion request data 224
The URL included in the data 224 by the registration unit 215
The information about the replication target URL 216 and the replication delivery destination device name 217 is deleted (z5).

As described above, in the information relay device according to the embodiment of the present invention, the replication process is performed in conjunction with the change of the original content data in the server node 211. Replica content data is always kept up to date,
It can respond quickly to requests from client nodes.

That is, since the Proxy server only retains the content once obtained as it is, if the original is updated, it must be transferred again from the server when accessing from the next browser. However, in the present invention, since the content of Proxy is always the latest, improvement in the average response time viewed from the browser can be expected.

In this embodiment, the server node 21
1, the changed content itself is transmitted to the information relay apparatus 203 when the content data 214 is changed, but the present invention is not limited to such a form. For example, in combination with the second embodiment, when the content data 214 is changed, only the attribute information, not the content itself, is transmitted to the request / content transfer unit 205. The transfer / transfer unit 205 determines whether or not the replica content is the latest, and only when the replica is not the latest, the request / content transfer unit 205 requests the content 1
18 may be issued to update the replica. (Fourth Embodiment of the Invention) In the first, second, and third embodiments, the replication of only the URL and the entity of the content has been described. However, in the present embodiment, the replication is set for each content. Access control information is stored together with replica content.

The information relay apparatus of the present embodiment is provided with an access control judging unit so that the access control information is held in the replica content data 110 and 207. It is configured similarly.

Here, the access control information is
Information such as "A user can see this content" can be used to limit the content that can be accessed for each client node user.

[0202] The access control judging unit executes content access restriction based on the access control information.

As an operation of the information relay apparatus of the present embodiment thus configured, first, a user identification name is added to request data from a client.

The access control information registered in the replica content data in the information relay device is compared with the client user identification name by the access control determining unit. As a result, the replica content is returned only to the user permitted to access.

As described above, the information relay device according to the embodiment of the present invention distributes access control information along with the content. Response time when viewed can be shortened.

In a similar case, in the first to third embodiments, it is necessary to make an inquiry to the server node in order to obtain access control information for each user. (Fifth Embodiment of the Invention) The first to fourth embodiments have been described with respect to an example in which the information relay device is applied to a proxy server on the Internet. In this embodiment, a case where the information relay device is applied to a file server system is described. explain.

FIG. 22 is a diagram showing an example of the overall configuration of a file server system to which the information relay device according to the fifth embodiment of the present invention is applied.

In this system, a large-scale file server 302 is installed at a head office 301, which corresponds to the server nodes 114 and 211 of the first to fourth embodiments. The large-scale file server 302 is connected to small-scale file servers 303 and 304 provided in each section of the head office 301 via a relatively low-speed LAN, and is connected to a small-scale file server of each branch office via a public line. 305 and 306 are connected.

[0209] These small file servers 303-3
In 06, information relay devices 122 and 203 are provided.

Each of the small file servers 303 to 306
Is a relatively small-capacity file server that can provide file information to clients in the department or branch office over a high-speed LAN. Also, when the information requested by the user is not requested, the information is requested to the large-scale file server 302. This information is the first to fourth
It corresponds to the content of the embodiment. The file search information corresponds to a URL.

The large-scale file server 302 stores all information, and transmits data in response to requests from the small-scale file servers 303 to 306.

In the file server system thus configured, the relationship between the client, the small file, and the large file server is the same as that between the client node, the proxy server node, and the server node in the first to fourth embodiments. Becomes

Therefore, information that is used at a certain frequency or more in the department or branch office is stored in a small-scale database having a small capacity, and information not used is excluded from the small-scale database.

As described above, the information relay device according to the embodiment of the present invention has the same configuration as that of the first to fourth embodiments in the file server system. In the case where the small file server provided in the server goes to an inquiry, the same effect as in the first to fourth embodiments can be obtained.

The scope of application of the present invention is not limited to the Internet or a file server system, but can be variously applied to a computer or communication system in which a situation similar to the situation described in the embodiment occurs. It is.
For example, it can be applied to FTP and the like.

Further, the apparatus described in the embodiment can be realized by causing a computer to read a program stored in a storage medium.

Here, as the storage medium in the present invention,
Magnetic disk, floppy disk, hard disk,
Any storage medium that can store a program and can be read by a computer, such as an optical disk (CD-ROM, CD-R, DVD, etc.), a magneto-optical disk (MO, etc.), a semiconductor memory, etc. It may be.

Further, an OS (Operating System) running on the computer based on instructions of a program installed in the computer from the storage medium,
MW for database management software, network software, etc.
(Middleware) or the like may execute a part of each process for realizing the present embodiment.

Further, the storage medium in the present invention is not limited to a medium independent of a computer, but also includes a storage medium in which a program transmitted via a LAN or the Internet is downloaded and stored or temporarily stored.

Further, the number of storage media is not limited to one, and the case where the processing in the present embodiment is executed from a plurality of media is also included in the storage media of the present invention, and the media configuration may be any configuration.

The computer according to the present invention executes each process in the present embodiment based on a program stored in a storage medium.
Any configuration such as a single device, a system in which a plurality of devices are connected to a network, or the like may be used.

The computer in the present invention is
It is not limited to a personal computer, but also includes a processing device, a microcomputer, and the like included in an information processing device, and generically refers to a device and a device capable of realizing the functions of the present invention by a program.

[0223]

As described above in detail, according to the present invention, when the frequency of updating the original content is high and the client provides a request for providing information to an unspecified number of servers, the average response time is reduced. An information relay device and a storage medium that can be improved can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a network system including a proxy server to which an information relay device according to a first embodiment of the present invention is applied.

FIG. 2 is a diagram showing an example of a URL and a transmission source ID.

FIG. 3 is a diagram showing an example of contents of input information statistical data and data used in a replication strategy determining unit.

FIG. 4 is a diagram showing an example of a storage form of input information statistical data.

FIG. 5 is a diagram showing an example of the content of replication strategy knowledge.

FIG. 6 is a diagram showing a content example of a replication interval for each URL.

FIG. 7 is a view showing an example of a replica content URL.

FIG. 8 is a diagram showing an example of replica content data.

FIG. 9 is a flowchart illustrating request relay processing in the embodiment.

FIG. 10 is an exemplary flowchart for explaining a replication strategy determining process according to the embodiment;

FIG. 11 is a flowchart illustrating a replica update process according to the embodiment;

FIG. 12 is a view showing an example of a request for acquiring only content attribute information used in the second embodiment of the present invention.

FIG. 13 is a view showing an example of a request for acquiring the entire content.

FIG. 14 is a flowchart illustrating request relay processing in the embodiment.

FIG. 15 is a block diagram showing a configuration example of a network system including a proxy server to which an information relay device according to a third embodiment of the present invention is applied.

FIG. 16 shows a replication target U in the embodiment.
The figure which shows the example of a data structure of RL.

FIG. 17 is an exemplary view showing an example of the data structure of replica content data in the embodiment.

FIG. 18 is a flowchart illustrating request relay processing in the embodiment.

FIG. 19 is a flowchart illustrating a replica target registration process according to the embodiment;

FIG. 20 is a flowchart illustrating replica distribution processing in the embodiment.

FIG. 21 is a flowchart illustrating registration deletion processing in the embodiment.

FIG. 22 is a diagram showing an example of an overall configuration of a file server system to which an information relay device according to a fifth embodiment of the present invention is applied.

[Explanation of symbols]

Reference Signs List 101 client node 103 proxy server node 104 input analysis unit 105 input information statistical data 106 replication strategy determination unit 107 replication strategy knowledge 108 replication interval by URL 109 replica content URL 110 replica content data 111 replica Update unit 112 ... Replica use determination unit 113 ... Request / content transfer unit 114 ... Server node 115 ... Content transmission unit 116 ... Content data 117,118 ... Content acquisition request 121 ... Public line 122 ... Information relay device 201 ... Client node 202 ... Content display unit 203: information relay device 204: replica use determination unit 205: request / content transfer unit 206: replication pair URL 207 replica data 208 request data 209 request data 210 data 211 server node 212 content transmitting unit 213 update detecting unit 214 content data 215 replication target URL registration unit 216 replication target URL 217 Replication delivery destination device name 221 Replication strategy knowledge 222 Input statistical data 223 Registration / deletion judgment unit 301 Head office 302 Large-scale file server 303, 304, 305, 306 Small-scale file server

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B089 GA19 GA21 HA01 JA22 JB15 KA05 KB06 KD04 5K030 GA03 HA04 HC01 HD01 KA07 LD17 LD20 9A001 JJ04 JJ25 JJ27

Claims (10)

[Claims] Claims 1. An information provider, which is arranged on a network connecting a server computer serving as an information provider and a client computer serving as an information user, transfers a data providing request from the client computer to the server computer, and provides data provided from the server computer. An information relay apparatus having a relay function of transferring data to a client computer, wherein, for data on the server computer for which data provision has been requested in the past from the client computer, replication means for copying and retaining the requested data asynchronously with the data provision request An information relay device comprising: a replication returning unit that returns, to the client computer, replication data held by the replication unit when a data provision request is received from the client computer. 2. The information relay device according to claim 1, wherein said replication means updates the copy data to the latest state at set time intervals. 3. A replication interval determining means for changing each update time interval for a plurality of replicated data based on the frequency of a data provision request from a client computer for each data.
Information relay device as described. 4. The system according to claim 2, further comprising a replication interval determining unit that changes each update time interval of the plurality of replicated data based on a data change frequency of each data on a server computer. 3. The information relay device according to 3. 5. When the data providing request is received, the replica means includes replica use determining means for determining whether or not the replicated data held by the replication means is within the expiration date. If the replica usage determining means determines that the replicated data is out of the validity period, the server computer is inquired of attribute information of the data corresponding to the replicated data, and it is determined that the data is updated on the server computer from the attribute information. 5. The information relay device according to claim 1, wherein when it is determined, the data is reacquired from the server computer and the acquired data is transferred to the relay function. 6. The server computer according to claim 1, wherein when the data to be provided changes, the server computer transmits the updated data to the data providing target for which the registered data has been registered. 2. The method according to claim 1, wherein upon receiving a data provision request for data not holding duplicate data from a client computer, the replication means registers the server computer to provide the requested data. Information relay device as described. 7. The replication means acquires and holds access restriction information about the duplicate data together with the duplicate data, and the copy return means, based on the access restriction information,
7. The information relay apparatus according to claim 1, wherein the duplicated data is returned only in response to a data provision request from a client to which access is permitted. 8. A server provided on a network connecting a server computer serving as an information provider and a client computer serving as an information user, transferring a data providing request from the client computer to the server computer, and providing data provided by the server computer. Is a program for controlling an information relay device having a relay function of transferring the data to a client computer, comprising: a computer, for data on a server computer for which data provision has been requested in the past from the client computer, asynchronously with the data provision request; A computer-readable storage medium storing a program having replication means for copying and holding request data, and replication returning means for returning the replication data held by the replication means to the client computer when requested to provide data from the client computer. A removable storage medium. 9. The storage medium according to claim 8, wherein said replication means updates the copy data to the latest state at set time intervals. 10. The server computer according to claim 1, wherein when the data to be provided changes, the updated data is transmitted to the registered data providing target for the data registered for data provision. 10. The method according to claim 8, wherein the replication unit, upon receiving a data provision request from a client computer for data that does not hold replicated data, causes the server computer to register to provide the requested data. The storage medium according to the above.