JP2005501308A6 - Unique email message indexing system, search method and use - Google Patents

Abstract

A system and method for identifying unique email messages in a large enterprise utilizing an external server and an external database system. The uniqueness of the message is determined by assigning a message tag to each message based on the electronic message properties (500). The message tag (506) is calculated using a hash algorithm (5040) to speed up indexing and comparison operations. The message tag (506) is a message tag index file associated with an existing email message and If a matching email message is found in the index file, the message is not unique, whereas if not found, the email message is unique and its message tag is the index file (406) The system may include an associative database for storing index files, and an archiving system and method that uses the uniqueness check function of the present invention is also disclosed.
[Selection] Figure 5

Description

【Technical field】
[0001]
The present invention generally relates to the management of email messages and messaging systems. More specifically, the present invention relates to the handling of messages extracted from email messaging systems.
[Background]
[0002]
Electronic mail (email) messaging systems have become central applications in many companies. In some organizations, individuals typically send and receive only a few email messages per day, while in other organizations, general users send and receive dozens of messages per day. Email messaging systems can process hundreds or thousands of messages per day, depending on the size of the organization. As the number and size of messages and attachments increased at an astronomical rate, and the amount of business-critical information in the message store increased, managing email services became increasingly difficult. A load exceeding the capacity of the electronic mail server may affect the backup and recovery function, and may cause loss of basic information due to accidental deletion or malfunction of the mail server.
[0003]
In some conventional email systems, the size of the message store is, for example, the number of messages that can be stored in an individual mailbox, the cumulative size of messages stored in the mailbox, the individual message size and the message store. It can be controlled by a certain threshold, such as a limit on the total number of messages that can be made. These thresholds can be controlled by a system administrator and may be “hard-coded” into an email message application. The challenge with such a threshold is to try to maintain the message store within a predefined range without substantially providing management capabilities that allow users to store important messages for the period they need. is there.
[0004]
Another method that has been used in the prior art to reduce the size of the message store is to “archive” messages. Conventional message archiving systems have been incorporated into email messaging applications. However, since such systems are generally proprietary software applications, there is not much room for the email administrator to choose how to archive and retrieve messages. In some systems, if a user needs to read an archive message, he may have to go through a system administrator. In another system, “archiving” is simply downloading the message to the user's local hard drive, which may not be easily accessible or searchable to retrieve the archive message.
[0005]
In these email systems that do not have an integrated archiving function, a system administrator can implement a manual archiving operation through an email backup procedure. In general, backup procedures are designed to fully recover a message store (also known as a “post office”) in the event of a catastrophic failure. However, in general, much of the functionality desired for an archive system is not provided by such a backup procedure. For example, in some backup procedures, the email administrator may have to restore the entire post office simply to retrieve one or more messages from the individual user's mailbox. Another challenge with typical backup procedures is that email administrators may not be allowed to search for specific messages based on the content of messages from the backup file. Without a full text search function, it is more difficult to determine whether a particular email message has been archived.
[0006]
To further complicate e-mail administrators, e-mail archiving requirements can vary from organization to organization. For example, a “comprehensive” archiving scheme may be necessary if the archiving process is required to capture all messages in “real time” before the user has the opportunity to delete any messages. One way to implement a comprehensive archive is to capture a message when the message is sent or received and a copy of the message is placed in the archive. In this aspect, messages are captured and archived before being delivered to all recipients. Thus, the archive file generally stores only a single copy of each archive message. By doing so, the size of the archive file is reduced.
[0007]
In other organizations, comprehensive archiving may not be required depending on the company's policy, but instead, archiving may be performed on a weekly or other cycle. Such an archiving process does not capture all messages processed by the email system, but only captures messages on the system that have not been deleted by the time the process is performed. Unlike a real-time archive system, in a periodic archive system, messages are captured only after delivery to individual recipients. A third party, or external periodic message archiving system, basically operates by reading all messages stored in each mailbox in the system. Each message that is read is subsequently replicated to an archive file. Since each mailbox is read separately, the archive file generated by such a conventional archive system becomes a file of an unnecessary size. Therefore, since messages distributed to a plurality of mailboxes are handled as separate messages in the archive processing, duplicate messages are stored in the archive file. If the archiving system has accessed the internal structure of the message store, it is possible on the archiving system to archive only a single copy of each message, but in general such access is subject to the ownership of the email system. Due to its nature, it is not permitted by third parties.
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0008]
Accordingly, there is a need for a system and method for indexing unique email messages extracted from email messaging systems.
[0009]
The present invention provides a system and method for indexing unique email messages extracted from email messaging systems. The method includes reading a message from a mailbox on the email messaging system, where the message comprises a plurality of message properties. Examples of the message property include a sender name, a transmission time by the sender, and a subject. When the source e-mail messaging system is an external messaging system, for example, the sender name may be an e-mail address, and when the e-mail messaging system is a destination messaging system, a standard name may be used. The transmission time is preferably in accordance with the transmission time set by the transmission source e-mail messaging system, and may be displayed, for example, in microseconds.
[0010]
The present invention then calculates a unique identifier or message tag, preferably consisting of a data string using message properties. For example, the sender name and the transmission time by the sender can be used to calculate the message tag. If the message is unique, that is, the message tag is not already stored in the index file, the message tag is stored in the index file associated with the message archive. If a message tag already exists in the index file, the message is not unique.
[0011]
In order to speed up the process of determining whether a message is unique, a hash algorithm can be applied to the message tag to obtain a “signature” of a predetermined message length. Therefore, the comparison between the newly calculated message tag and the message tag already stored in the index file is further quickened by unifying the lengths of the index records.
[0012]
The present invention further comprises an archiving system and method in which only unique messages are stored in the message archive.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
The present invention provides systems and methods for indexing unique email messages extracted from single or multiple email messaging systems. The present invention further provides systems and methods that minimize or avoid duplicate archiving for multiple copies of the same email message by archiving only unique messages extracted from the message store. .
[0014]
The present invention uses an index file to store information about messages already extracted from the email messaging system. The index file can be stored using any suitable format that allows easy searching and comparison of entries in the file. The index file can be, for example, a text file, a spreadsheet, a relational database table, or a table set. Each time an email message is added to the archive, a “message tag” is always generated and stored in the index file. The message tag conforms to email properties or attributes sufficient to create a unique identifier for each email message.
[0015]
The system and method of the present invention may be used in any application suitable for identifying duplicate messages on an email messaging system. For example, the system and method of the present invention can be effectively incorporated into an email archiving application to reduce or minimize the size of the archive message store. When the present invention is used in an archiving system, a temporary message tag is created for an email message before the message is added to the archive. This temporary message tag is then compared with each message tag already stored in the index file. If the temporary message tag is an existing tag that matches an entry in the index file, the email message has already been archived. In this case, the message need not be archived.
[0016]
In the following sections, two embodiments of the present invention are described. The method for creating (that is, calculating) a message tag for an electronic mail message used in each embodiment is different.
[0017]
First embodiment:
A first embodiment of the present invention will be described with reference to FIG. In this example, the message tag can be calculated by combining selected message properties to form a single text string. For example, if the e-mail messaging system is a Microsoft Exchange system, the message may include properties of “Client_Submit_Time” in box 10, “Sent_Representing_Email_Address” in box 12, and “PR_Subject” in box 14. Boxes 16, 18 and 20 show the corresponding data formats associated with each of these properties. Boxes 22, 24 and 26 show examples of effective values that these properties can have for a particular message. For example, the value for “Client_Submit_Time” in box 10 is displayed as “OxOlcl9el38106580” in box 22. The transmission time in the present embodiment represents the time when the message is transmitted by the message sender. The time format is the same format created by the system clock on the sender's email messaging server. Only when the format for the transmission time is standardized for each server, the format for the transmission time is not important. That is, the same time format should be used to calculate the message tags for all messages received from a particular server.
[0018]
The box 24 includes the value of the exchange property “Sent_Email_Address” in the box 12, “/ o = sqa / ou = dogwood / cn = Recipients / cn = Crowen”. This property has been widely referred to as the “full authority name” of the sender. A message tag created according to the sender's transmission time and the sender's full authority name is sufficient for the unique identification of most email messages. By combining each value (as shown in link 30), a message tag 40 is generated. As described above, if the transmission time and the sender name are used, it is usually possible to uniquely identify the e-mail message sufficiently. However, other properties can be added to the column to improve the likelihood that the message tag represents a unique message. For example, as shown in FIG. 1, the PR_Subject property of box 14 may be included. In this embodiment, as indicated by box 26, the value of this property is "This is a test message." At link 32, all three types of properties are combined to form message tag 42.
[0019]
The message tag generation method described above can be modified in various ways without departing from the spirit of the present invention. For example, the combination order may be changed so that the obtained message tag is formed by combining the transmission time string and the sender name string. Alternatively, the subject may be placed before the sender name or the transmission time. In yet another method, the sender name may include other properties to identify the sender of the email message. For example, the sender name may be displayed as an Internet e-mail name such as “Jdoe@acme.com”. This value is then used as described above. Furthermore, a message tag can be generated without using sender information according to other message properties such as message size and header information.
[0020]
The message tag generated according to this embodiment has a variable length. That is, the message tag for the first message extracted from the email messaging system may be different in length from the message tag of the second message extracted from the email messaging system. This is especially because the sender name and the length of the subject field of the email message can be different. Furthermore, different email messaging systems may use different implementation methods to calculate the transmission time. If the index file is very large, searching in the index file can be a redundant operation due to the variable length of the message tag. In a second embodiment described below, an improved message tag is provided that optimizes such a search.
[0021]
Second embodiment:
In the second embodiment, a variable-length message tag is converted into a message tag having a predetermined length by applying a hash algorithm. In general, a hash algorithm is commonly used in the encryption technology field to generate a key for encrypting a message. The hash algorithm is also used to create an electronic “signature” of a message that can be used to authenticate the validity of the message. Such a signature is also known as the “fingerprint” or “message digest” of the message. One principle behind such a hash algorithm is that it is “uncomputable” to apply the algorithm to two different messages to obtain the same result. Another principle of the hash algorithm is that the generated message digest has a uniform length. It is this second principle that is useful as a background to the present invention. That is, when different message tags created as described above are processed through a hash algorithm, the generated message tags represent a unique email message with a uniform length.
[0022]
FIG. 2 is a schematic diagram showing the operation of the second embodiment of the present invention. Item numbers 10 to 42 will be described in association with FIG. As described with reference to FIG. 2, message tag 42 is generated by combining selected properties to form a variable length column. This sequence is then used as input to the hash algorithm 50. In the present embodiment, the output of the hash algorithm 50 is 64 bits and is represented by a hexadecimal string “Ox4764eOccl21642b5” shown in the box 60. As is known in the art, these columns ultimately represent a 64-bit set (multiple 1s and 0s) that can be converted into a variety of different representations.
[0023]
By generating message tags of uniform length, the performance of search and comparison operations on the index file can be significantly improved. In the preferred embodiment, the well-known “MD5” hash algorithm is used. The MD5 hash algorithm is defined in RFC 1321, www.faqs.org/rfcl321.html, but is incorporated herein by reference in its entirety. Message tags generated using the MD5 hash algorithm have a uniform length of 128 bits (ie, 16 characters (when converted to ASCII characters), or 32 hexadecimal numbers).
[0024]
·Construction:
FIG. 3 illustrates a configuration that can be used to implement an embodiment of the present invention. The corporate email messaging system 300 includes an email server 301 that provides email services to clients 302 and 304. The email messaging system 300 can be a Microsoft Exchange server, and communication between the archive server 330 and the email messaging server 300 can be handled via the well-known message application program interface (MAPI) protocol. As is well known, MAPI is a messaging structure and a client interface component. MAPI as a messaging structure allows interaction between multiple applications and multiple messaging systems across various hardware platforms. MAPI as a client interface component is a complete combination of the object-oriented interface with the functions that form the basis of the client application and service provider interface of the MAPI subsystem. In a comparison between simple MAPI, Common Messaging Call (CMC) and CDO libraries, MAPI provides the highest performance and best controllability for messaging-based applications and service providers. Alternatively, the email messaging system 300 can be a Lotus Notes mail server, and communication can be handled via the Lotus Notes Application Program Interface (API) protocol. Similarly, if the email messaging system is a simple mail transfer protocol (SMTP) mail server, communications can be handled via SMTP.
[0025]
In the embodiment shown in FIG. 3, the communication lines 306 and 308 may use MAPI, SMTP or other protocols depending on the capacity of the client system 302 and 304. The e-mail can be received from the external system 320 via the communication line 321 via the Internet 322 via SMTP. In one embodiment of the present invention, archive server 330 initiates an archive session with email server 301 on a periodic basis via communication line 332. This periodic basis may be, for example, daily, weekly, monthly, or any other suitable time interval depending on the company's archiving requirements. The communication line 332 may use any suitable network protocol such as, for example, the well-known transmission control / Internet protocol (TCP / IP). In another embodiment of the present invention, archive server 330 retrieves email in real time or near real time.
[0026]
As is well known in the art, the email messaging server 301 may include multiple mailboxes, directories, folders, or other “storage compartments” that are used to associate messages with individual users. As used herein, the term “mailbox” refers to a collection of messages associated with a particular user, which the user creates to organize his email messages. Contains any suitable subfolders or directories. In some embodiments, the mailbox may include an “inbox” for storing newly arrived email messages and an “outbox” for storing messages sent by the user. .
[0027]
In one embodiment where archive server 330 extracts messages on a periodic basis, archive server 330 reads all messages in each mailbox on email server 301. In another example, archive server 330 may be configured to read only new messages that have been created or delivered after the completion of the previous periodic session. In another embodiment, the archive server 330 can be configured to read only messages in the mailbox inbox and outbox. Regardless of the message reading scheme implemented, the archive server examines the index file to determine the uniqueness of the message.
[0028]
The “uniqueness check” function may be built in the archive server 330 or may be executed on another server. In any case, the uniqueness check function includes the calculation of the message tag described above. The message tag for the newly read message is compared with the index file in database 334. The index file includes a message tag list corresponding to all messages stored in the message archive of database 334. If the calculated message tag matches an item in the index file, the message is not unique. That is, since the message is already stored in the message archive, the second storage is unnecessary. Alternatively, if the calculated message tag does not match any record in the index file, the message is unique and should be stored in the message archive. In this case, the message tag is also added to the index file.
[0029]
Once the message is archived on the archive server 330, the data can be transferred to another storage medium without affecting the performance of the email server 301. For example, data can be moved to a tape library system 335, an optical jukebox 336, a CD / DVD optical device 337, and the like. Since these media are less expensive than other magnetic storage media, moving archive data to these storage media can reduce long-term storage costs for the organization.
[0030]
FIG. 4 is a flowchart illustrating an e-mail message archiving process according to an embodiment of the present invention. Steps 400 to 406 are initialization steps and are intended to clarify the processing. That is, once the message archive and index file are present, the process performs steps 408-420. In step 400, a first message is read from the mailbox of the email messaging server. In step 402, a message tag for the first message is calculated, and in step 404, the first message is stored in a message archive. In step 406, the calculated message tag for the first message is stored in the index file. In step 408, a second (ie, next) message is read from the mailbox of the email messaging server. The mailbox may be the same mailbox as the one that has read the first message, or may be a different mailbox. At step 410, a message tag for the second message is calculated, and at step 412, the second message tag is compared to the first message tag (ie, the second message tag is already stored in the index file). Compared to all message tags).
[0031]
In step 414, the process branches according to the result of step 412. If the second message tag matches the first message tag (ie, if the second message tag already exists in the index file), the second message is not unique and processing goes to step 420. Move on. If the message is unique (ie, if the message tag did not match any item in the index file), the second message is stored in the message archive at step 416, and the second message tag is In step 418, it is stored in the index file.
[0032]
At step 420, the process checks to see if there are other messages to be read from the email messaging server. If there are more messages, processing returns to step 408 to read the next message. Conversely, if there are no more messages, the process is complete.
[0033]
FIG. 5 is a schematic diagram showing how a message tag can be calculated in the second embodiment of the present invention. In FIG. 5, an email message property 500 is selected from the email message. As described herein, the combination of sender name and transmission time is sufficient to uniquely identify an email message in most applications. Selected properties are combined to form a single column. The column may or may not include white space. The column is converted to a suitable bit representation in box 502. In box 504, a hash algorithm is applied to the bit string to determine the message tag in box 506.
[0034]
As described herein, the present system and method for archiving and retrieving email messages is used in large enterprise environments that use a dedicated archive server and a database system such as SQL or ORACLE (trademark brand). In another aspect, the archive server may be on the same platform as the email messaging server, and as described above, the email messaging server may be, for example, Microsoft Outlook ™ or Lotus Notes ™, Any suitable email messaging system, such as an authorized email messaging system or a non-copyrighted email messaging system, may be followed.
[0035]
・Embodiments including application programs:
One embodiment of the present invention further includes an application program recorded on any magnetic or electronic medium and a computer system programmed with the program. In this embodiment, the computer system is programmed to search the mailbox of the email messaging server to identify messages added to the archive. Such a program may operate to process messages delivered to the email messaging system before the program of the present invention is executed. In this approach, the program identifies and extracts existing email messages for archiving. The program may be further configured to archive messages in real time. That is, when the message is processed by the email messaging system, a copy for archiving is retrieved by the archive server. Embodiments of the present invention can include an embedded relational database to assist in fast retrieval of message metadata. In such an embodiment, the full text of a keyword or message is added to a message index file for quick message retrieval. Furthermore, a summary of a certain attached file may be added to the message index. For example, the archive server can read an attached file conforming to a general language processing application in order to enable full text search in the attached file.
[0036]
The present invention provides a comprehensive solution for external archiving email messages from email messaging systems. The present invention can be used by organizations that are obligated to store email messages over time. For example, certain financial institutions have been ordered by the Federal Securities and Exchange Commission (SEC) to ensure that all records, including email messages, are archived for five years. The records must be stored in such a way that individual records can be retrieved if required. By storing e-mail messages in an external archive along with full-text search function messages, implementations of the present invention can resolve these and other requirements. Further, the size of the archive message store can be maintained at a manageable level by examining duplicate messages.
[0037]
The following preferred embodiments of the present invention have been disclosed for purposes of illustration and description. It is not an exhaustive objective and does not limit the invention to the precise form disclosed. Many modifications and variations of the embodiments described herein will be apparent to those skilled in the art in view of the above disclosure. The scope of the present invention is defined only by the claims appended hereto and their equivalents. Further, in describing exemplary embodiments of the present invention, the specification may have presented the method and / or process of the present invention as a particular series of steps. However, to the extent that the method or process does not depend on the specific process sequence described herein, the method or process will not be limited to the specific process sequence described. Other process sequences may be possible, as will be apparent to those skilled in the art. Accordingly, the specific process sequences described herein are not to be considered as limiting in the claims. Furthermore, claims directed to the methods and / or processes of the present invention should not be limited to the performance of the steps in the order described, the order can be variable, and Those skilled in the art will readily understand that it can be within the scope.
[Brief description of the drawings]
[0038]
FIG. 1 is a schematic diagram illustrating a message tag calculation method according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating a message tag calculation method according to a second embodiment of the invention.
FIG. 3 is a schematic diagram showing a representative structure in an embodiment of the present invention.
FIG. 4 is a flow chart showing the process of an archive email message in one embodiment of the present invention.
FIG. 5 is a schematic diagram illustrating a configuration of a uniqueness check according to an embodiment of the present invention.

Claims (44)

A method for identifying a unique email message in a plurality of email messages extracted from an email messaging system, comprising:
Retrieving a message including a plurality of message properties from a mailbox of the email messaging system;
Calculating a message tag from at least some of the plurality of message properties;
Examine the list of message tags stored in the index file,
A method comprising determining whether the message is unique based on whether the message tag can be found in an index file. The method according to claim 1, wherein the message tag is calculated by combining at least two types of properties selected from the plurality of message properties. The method of claim 2, wherein the message tag is further calculated by applying a hash algorithm to the message tag to form a uniform sequence having a predetermined length. 4. The method of claim 3, wherein the hash algorithm is an MD5 hash algorithm. The method according to claim 1, wherein the plurality of message properties include a sender name and a transmission time by the sender, and the message tag includes the sender name and a transmission time by the sender. A method that is calculated by combining. The method of claim 1, wherein the plurality of message properties include a sender name, a transmission time by a sender, and a subject, and the message tag includes the sender name, the subject, and a transmission by the sender. A method calculated by combining time. The method of claim 1, wherein the index file is stored in a relational database system. A method for archiving multiple email messages in a system external to an email messaging system comprising:
Reading a first message comprising at least a first sender name and at least a time of transmission by the first sender from a first mailbox of the email messaging system;
Calculating a first message tag from the first sender name and the transmission time by the first sender;
Storing the first message in a message archive and storing the first message tag in an index file associated with the message archive;
Reading a second message comprising at least a second sender name and at least a time of transmission by the second sender from a second mailbox of the email messaging system;
Calculating a second message tag from the second sender name and the transmission time by the second sender;
Comparing the second message tag with the first message tag;
Storing the second message in the message archive and storing the second message tag in the index file if the first message tag and the second message tag are not identical. 9. The method of claim 8, wherein the first message tag combines the first sender name and a transmission time by the first sender to form a first message string. And the second message tag is calculated by combining the second sender name and the transmission time by the second sender to form a second message string. Method. 10. The method of claim 9, wherein the first message tag further applies a hash algorithm to the first message sequence to form a first uniform sequence having a predetermined length. The second message tag is further calculated by applying a hash algorithm to the second message sequence to form a second uniform sequence having a predetermined length. . The method of claim 10, wherein the hash algorithm is an MD5 hash algorithm. 9. The method of claim 8, wherein the first mailbox and the second mailbox are different mailboxes on the email messaging system. 9. The method of claim 8, wherein the index file is stored in a relational database system. 9. The method of claim 8, wherein the message archive is a relational database system. A system external to an email messaging system that identifies a unique email message,
Means for reading an email message including a plurality of message properties from a mailbox of the email messaging system;
Means for calculating a message tag from at least two types of properties selected from the plurality of message properties;
Means for comparing the message tag with a list of message tags stored in an index file;
And means for determining that the message tag is unique if the message tag is not present in the index file. 16. The system according to claim 15, wherein the at least two types of properties include a sender name and a sender transmission time. 16. The system of claim 15, wherein the message tag is calculated by combining at least two types of properties to form a first message sequence. 18. The system according to claim 17, wherein the message tag is further calculated by applying a hash algorithm to the message sequence to form a uniform sequence having a predetermined length. The system of claim 18, wherein the hash algorithm is an MD5 hash algorithm. 16. The system according to claim 15, wherein the index file is stored in a relational database system. An external system of an email messaging system that identifies a unique email message,
A uniqueness checker in communication with the email messaging system;
An index file including a plurality of predetermined message tags,
The uniqueness checker is configured to read a message from the email messaging system, the message includes a plurality of properties associated with the message, and the uniqueness checker uses at least two of the properties. The message tag for the message is calculated, the calculated message tag is compared with the index file, and if the calculated message tag matches an entry in the index file, the uniqueness checker A system that determines that a message is not unique and if the calculated message tag does not match an entry in the index file, the calculated message tag is added to the index file. The system according to claim 21, wherein the message tag is calculated by combining at least two types of the properties to form a message string. 23. The system of claim 22, wherein the message tag is further calculated by applying a hash algorithm to the message sequence to form a uniform sequence having a predetermined length. 24. The system of claim 23, wherein the hash algorithm is an MD5 hash algorithm. 24. The system of claim 21, wherein the uniqueness checker reads the message from a mailbox of an email messaging system. The system according to claim 21, wherein the plurality of properties include a sender name and a sender transmission time. 27. The system of claim 26, wherein the plurality of properties further includes a subject column, and the message tag includes the sender name, a transmission time by the sender, and the subject to form a message sequence. A system that is calculated by joining columns of 28. The system of claim 27, wherein the message tag is further calculated by applying a hash algorithm to the message sequence to form a uniform sequence having a predetermined length. 16. The system according to claim 15, wherein the index file is stored in a relational database system. An external system of an email messaging system that archives multiple email messages,
Means for reading a first message including at least a first sender name and a transmission time by the first sender from a first mailbox of the email messaging system;
Means for calculating a first message tag from the first sender name and a transmission time by the first sender;
Means for storing the first message in a message archive and storing the first message tag in an index file associated with the message archive;
Means for reading from the second mailbox of the electronic mail messaging system a second message including at least a second sender name and a transmission time by the second sender;
Means for calculating a second message tag from the second sender name and the transmission time by the second sender;
Means for comparing the second message tag with the first message tag;
A system comprising: storing the second message in the message archive and storing the second message tag in an index file if the first message tag and the second message tag are not identical; . 31. The system of claim 30, wherein the first message tag combines the first sender name and a transmission time by the first sender to form a first message string. The second message tag is calculated by combining the second sender name and the transmission time by the second sender to form a second message string. . 32. The system of claim 31, wherein the first message tag further applies a hash algorithm to the first message tag to form a first uniform sequence having a predetermined length. And the second message tag is further calculated by applying a hash algorithm to the second message tag to form a second uniform sequence having a predetermined length. 33. The system of claim 32, wherein the hash algorithm is an MD5 hash algorithm. 31. The system of claim 30, wherein the first message further includes a first subject string, and the second message further includes a second subject string, and the first message tag is: Calculated by combining the first sender name, the transmission time by the first sender, and the first subject string to form a first message string, the second message tag being , A system calculated by combining the second sender name, the transmission time by the second sender, and the second subject string to form a second message string. 32. The system of claim 30, wherein the index file is stored in a relational database system. 32. The method of claim 30, wherein the message archive is a relational database system. A system for externally archiving a plurality of email messages selected from an email messaging system,
An archive server in communication with the email messaging system;
A uniqueness checker in communication with the archive server;
An archive message store in communication with the archive server;
When the archive server reads a message from the email messaging system, a plurality of properties associated with the message are sent from the archive server to the uniqueness checker,
The uniqueness checker calculates a message tag of the message using at least two types of the properties, compares the calculated message tag with an index file, and the calculated message tag is stored in the index file. If the entry matches, the uniqueness checker indicates to the archive server that the message is not unique, and if the calculated message tag does not match the entry in the index file, the calculation A message tag added to the index file, and if the message is unique, the archive server stores the message in the archive message store. 38. The system of claim 37, wherein the message tag is calculated by combining at least two types of the properties to form a message string. 40. The system of claim 38, wherein the message tag is further calculated by applying a hash algorithm to the message sequence to form a uniform sequence having a predetermined length. 40. The system of claim 39, wherein the hash algorithm is an MD5 hash algorithm. 38. The system of claim 37, wherein the archive server reads a message from a mailbox of the email messaging system. 42. The system according to claim 41, wherein the plurality of properties include a sender name and a transmission time by the sender. 43. The system of claim 42, wherein the plurality of properties further includes a subject string, and the message tag includes the sender name, a transmission time by the sender, and the subject to form a message string. A system calculated by combining. 44. The system of claim 43, wherein the message tag is further calculated by applying a hash algorithm to the message sequence to form a uniform sequence having a predetermined length.

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