(51) Int Cl.: G06F 17/30 ( ) H04L 29/08 ( )

Transkript

1 (19) TEPZZ_8 4 6_B_T (11) EP B1 (12) EUROPEAN PATENT SPECIFICATION (4) Date of publication and mention of the grant of the patent: Bulletin 14/26 (21) Application number: (22) Date of filing: (1) Int Cl.: G06F 17/ (06.01) H04L 29/08 (06.01) (86) International application number: PCT/US06/ (87) International publication number: WO 06/07802 ( Gazette 06/) (4) SYSTEMS, METHODS, AND SOFTWARE FOR DISTRIBUTED LOADING OF DATABASES SYSTEM, VERFAHREN UND SOFTWARE ZUM VERTEILTEN LADEN VON DATENBANKEN SYSTEMES, PROCEDES ET LOGICIEL POUR CHARGER DES BASES DE DONNEES DE MANIERE REPARTIE (84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR () Priority: US P (43) Date of publication of application: Bulletin 07/38 (73) Proprietor: Thomson Reuters Global Resources 60 Zug (CH) (72) Inventors: BLUHM, Mark A. Cottage Grove, MN 016 (US) VERREAUX, Jon Cottage Grove, MN 016 (US) (74) Representative: Round, Edward Mark et al Marks & Clerk LLP 90 Long Acre London WC2E 9RA (GB) (6) References cited: US-A US-A US-A US-A US-A US-B ALEXANDER KELLER ET AL: "The WSLA Framework: Specifying and Monitoring Service Level Agreements for Web Services", JOURNAL OF NETWORK AND SYSTEMS MANAGEMENT, KLUWER ACADEMIC PUBLISHERS-PLENUM PUBLISHERS, NE, vol. 11, no. 1, 1 March 03 ( ), pages 7-81, XP , ISSN: EP B1 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). Printed by Jouve, 7001 PARIS (FR)

2 1 EP B1 2 Description Technical Field Figure 1 is a block diagram of an exemplary information retrieval system 0 which corresponds to one or more embodiments of the invention. [0001] Various embodiments of the present invention concern information retrieval, particularly systems, methods, and software for loading data into databases. Figure 2 is a block diagram of an exemplary method which corresponds to one or more embodiments of the invention. Background [0002] One problem recognized by the present inventors concerns the loading of new documents onto an online information retrieval system. Loading generally entails indexing the documents to facilitate searching using Boolean or natural language search algorithms and then adding the documents and the corresponding index data to an existing database and index file. [0003] Conventionally, a large and costly server, such as a Sun Microsystems 600 or 6800, was purchased and programmed to specifically serve the loading needs of a given set of databases or collections. Unfortunately, this reliance of a single server makes the system vulnerable to server malfunctions or crashes during the loading process. In many instances, a crash necessitates the reloading of the entire quantity of data, and ultimately delays addition and thus user or subscriber access to new documents. Such delays are particularly significant for time-sensitive data, such as U.S. Supreme Court decisions or breaking news. Accordingly, the inventors have recognized a need for better ways of loading databases in online information retrieval systems. [0004] US04/ discloses an electronic document repository management and access system for distributing and managing a large corpus of electronic documents. The system provides customized services to diverse end users. Summary [000] The present invention provides a system as defined in claim 1 and a method as defined in claim. [0006] In one exemplary system, distributed load domains logically organize and coordinate operation of multiple load servers to meet load capacity needs of a set of one or more databases. The exemplary systems includes two or more (at least two) load monitor servers that not only monitor and ensure completion of load tasks by individual load servers, but also provide for one load monitor to monitor performance of the another. Moreover, the exemplary system provides a service-level-agreement (SLA) data structure for each load server. The SLA data structure governs what types and priority levels of loading tasks will be performed for predetermined time periods. Brief Description of the Drawings [0007] Detailed Description of Exemplary Embodiment(s) [0008] This description, which incorporates the Figures and the claims, describes one or more specific embodiments of an invention. These embodiments, offered not to limit but only to exemplify and teach the invention, are shown and described in sufficient detail to enable those skilled in the art to implement or practice the invention. Thus, where appropriate to avoid obscuring the invention, the description may omit certain information known to those of skill in the art. Exemplary Information Retrieval System [0009] Figure 1 shows an exemplary information retrieval system 0 incorporating teachings of the present invention. System 0 includes a landing skid database 1, a load domain 1, a primary database 1, and a secondary database 1. [00] Landing skid database 1 receives and stores new or updated files for addition to system 0, or primary database 1. In the exemplary embodiment, landing skid database 1 takes the form of a network accessible storage (NAS) device and receives and stores files in an extensible-markup-language (XML) format. The files include documents with a command-script type header information that includes a globally unique document identifier and a database command, such as add or delete. [0011] Load domain 1 includes a set of one or more load servers 122, a set of two or more load monitor servers 124, a set of one or more distribution servers 126, a load queue 128, and a shared directory 129. In the exemplary embodiment each of the servers is logically associated with a load domain, which is itself associated with one or more document collections or databases, such as primary database 1. (In the exemplary embodiment, a load domain includes one or more load boxes that have shared access to a landing skid and load index files. Any load box in a load domain can service any collection that is part of that load domain.) [0012] Servers 122, 124, and 126 include respective processing modules 1221, 1241, and 1261 and respective memory modules 1222, 1242, and Each of the processing modules includes one or more processors or processing circuits, for example dual processors. And, each of the memory modules includes machine-executable instructions (software (SW)) for causing the respective processing modules to perform acts as described below in the exemplary method section. Moreover, in the exemplary embodiment, each of the servers includes the 2

3 3 EP B1 4 instructions of each of the other servers, enabling, for example, a load server (LS) to be readily operated as a load monitor server (LM) or a distribution server (DS). (In some embodiments, each of the servers is implemented as a server blade, that is, a single circuit board populated with components such as processors, memory, and network connections that are usually found on multiple boards. Server blades are more cost-efficient, smaller and consume less power than traditional box-based servers used in other embodiments.) [0013] Additionally, each of load servers 122 includes or is associated with a service-level-agreement (SLA) data structure which governs operational context of the load server. SLA data structure 1223, which is representative, includes a client field 1223A for indicating what databases or database collections the load requests or other work to be accepted by the associated load server must pertain to; a priority field 1223B for indicating a minimum priority of the load requests or other work to accepted by the associated load server; and a temporal indicator 1223C for indicating related temporal aspects of the service level agreement, such as the effective period or duration of the agreement. Some embodiments provide for two SLA data structure, a permanent one and a temporary one, with the temporary one having a life that expires after a predetermined time period and allows the prior SLA data structure to automatically reinstate. Thus, for example, a user, using a GUI (graphical user interface) not shown may establish one or more of the load servers as dedicated to handling load requests for a specific database, such as U.S. Supreme Court, or to handling request of a specific minimum priority. The SLA would be in effect for several, hours, days, weeks, or even longer before automatically expiring and allowing reinstatement of the prior SLA. [0014] In some embodiments, each load monitor server 124 operates using the following parameters: Distributed_Load_Shared_Directory identifies the path to shared directory where heartbeat-type information is written by the load monitors; Distributed_Load_Directory_Monitor_Interval, for example 0000 milliseconds, denotes the amount of time in milliseconds before the non-active or secondary load monitor rechecks the landing skid for new requests; Distributed_Load_Working_File_Monitor_Interval, for example 0000 milliseconds, denotes the amount of time before the non-active Load Monitor rechecks the working file modification time; Distributed_Load_Completed_Requests_Monitor_I nterval, for example 0000 milliseconds, denotes the amount of time in ms before the non-active Load Monitor rechecks load queue 128 for completed requests. [001] Load queue 128 provides a queuing function for use in managing work flow of the load domain. In the exemplary embodiment, the queue is accessible by servers 122, 124, and 126. [0016] Shared directory 129 functions as a communications intermediary, which is accessible to other components or servers in the load domain, such as all the other load monitors in load domain 1. In the exemplary embodiment, the shared directory is part of a network accessible storage (NAS) device and is used to exchange heartbeat information from one load monitor to another as described below. In some embodiments, the shared directory can be a part of the landing skid database. (In some embodiments with multiple load domains, each load domain includes its own set of load monitors that includes its own respective shared directory.) [0017] Primary database 1 and secondary database 1 are redundant or mirror-image databases. In some embodiments they are maintained at separate sites to reduce risk of catastrophic failure. Although not shown in the Figure, users or subscriber access primary database 1 using a client device, such as personal computer over a local or wide-area network. Exemplary Method of Operating an Information Retrieval System [0018] Figure 2 shows a flow chart 0 of an exemplary method of operating an information retrieval system, such as system 0 in Figure 1. Flow chart 0 includes blocks 2-270, which are arranged and described serially. However, other embodiments execute two or more blocks in parallel using multiple processors or processorlike devices or a single processor organized as two or more virtual machines or sub processors. Other embodiments also alter the process sequence or provide different functional partitions or blocks to achieve analogous results. Moreover, still other embodiments implement the blocks as two or more interconnected hardware modules with related control and data signals communicated between and through the modules. Thus, the exemplary process flow applies to software, hardware, and firmware implementations. [0019] At block 2, the exemplary method begins with receiving a file containing documents for addition to a database of an online information-retrieval system. In the exemplary embodiment, this entails landing skid 1 receiving an XML file containing two or more judicial, financial, news, or scientific documents. Execution continues at block 2. [00] Block 2 entails notifying two or more load servers that new documents are available for loading on the database. In the exemplary embodiment, this entails one of load monitor servers 124, specifically a designated active or primary one of the load monitor servers, polling landing skid 1 to determine or detect if new documents for one or more specific collections or databases have been added to the landing skid. If such documents have been added to the landing skid, the active load monitor 3

4 EP B1 6 server adds data regarding the file to load queue 128, and notifies two or more of load servers 122 in response to detecting reception of the file. Additionally, the active load monitor server writes or records a message to shared directory 129, with the message including a time stamp and a load server identifier for the active (primary) load monitor server. (At some point, at least one of the inactive (backup or secondary) load monitor servers will review the message and make a determination of whether the active load monitor is functioning properly.) Execution then advances to block 2. [0021] Block 2 entails indexing the documents in the file using one of the notified load servers. In the exemplary embodiment, each of the load servers that is available and that has an SLA data structure that permits it to process the documents in the file, to access the load queue and attempt to process the documents in the file; however, only the first load server to respond to the notification gets to process the documents. In some embodiments, all non-busy load servers in the load domain respond initially to the notification and respectively assess the files compliance against their SLA data structures only after obtaining rights to process the new file. In other embodiments, the active load monitors are aware of the SLA data structures for each of the load servers and only communicate load-queue additions to those load servers that can process the corresponding documents. After one of the load servers has indexed the documents and generating corresponding index data, it notifies each of distribution servers 126 that distribution work is available by for example sending a message for these servers to check the queue. Additionally, in the exemplary embodiment, the selected load server automatically checks the load queue for any new load work.) Execution proceeds to block 2. [0022] Block 2 entails loading the documents onto a user or subscriber accessible database. In the exemplary embodiment, this entails the load server selected at block 2 notifying two or more of the distribution servers that index data and corresponding files are available for distribution. In response, all non-busy distribution servers 128 attempt to gain rights to perform the distribution, that is, loading the documents and index data onto respective portions of the primary database. However, the first distribution server to respond to the notification is assigned the distribution work. The distribution work entails loading the documents and index data onto primary database 1 and secondary database 1, or more precisely respective portions of databases 1 and 1. In some embodiments, the work of mirroring documents from primary database 1 to secondary database 1 is performed by a separate server or software component other than the selected distribution server. For example, some embodiments use the Oracle Data Guard product. Exemplary execution continues at block. [0023] In block, the selected one of distribution servers 126 notifies two or more load monitors 126 that the documents have been loaded on the database. In the exemplary embodiment, any inactive or secondary load monitors that receive the notification ignore the notification, whereas the active or primary load monitor proceeds as indicated for block 260. (Additionally, in the exemplary embodiment, the selected distribution server automatically checks the load queue for any new work.) [0024] Block 260 entails confirming that the documents have been loaded on the database. In the exemplary embodiment, this confirmation entails the active or primary load monitor attempting to read an "end of file," "end of load," or other analogous indicator from secondary database 1. Successful reading of the indicator is regarded as confirmation that the loading process initiated at block 2 has completed, and the primary loading monitor writes a time-stamped message to the shared directory indicating successful completion of the loading task. (Some embodiments may read the primary database for an indication of whether the loading request has been fulfilled, rather than the secondary database; however, other embodiments may read both the primary and secondary databases for the "end of file" indicator. A failure to read the "end of file" indicator indicates a failure and this status is also communicated to the shared directory using a first one of the notified load monitors. [002] Block 270 entails determining whether the primary or active load monitor is operating properly using one of the secondary or inactive load monitors. In the exemplary embodiment, secondary load monitor reviews one or more messages in the shared directory to determine whether the primary load monitor is operating properly. Specifically, the secondary load monitor ensures that the primary load monitor is up and running (for example, every 60 seconds), ensures that the primary is finding all new files added (for example, every minutes), and ensures that the primary is responding to end of load indicators or statuses. If any of these conditions are not met, the secondary load monitor takes over the primary load monitor status, possible shuts down the failed monitor, begins processing of load requests, and issues a failed-event alert. A normal execution continues with return to block 2 for processing of further requests. Conclusion [0026] The embodiments described above and in the claims are intended only to illustrate and teach one or more ways of practicing or implementing the present invention, not to restrict its breadth or scope. The actual scope of the invention, which embraces all ways of practicing or implementing the teachings of the invention, is defined only by the issued claims. Claims 1. An information retrieval system (0) comprising: a queue (128) for storing load data requests; 4

5 7 EP B1 8 a set of two or more load servers (122) for retrieving data from the queue (128) and indexing documents for retrieval based on the data retrieved from the queue (128); first and second load monitors (124) for monitoring operation of the load servers (122) and providing new data on the queue (128) accessible by the load servers (122), with the first load monitor (124) configured to provide information regarding its operations to the second load monitor (124), and the second load monitor (124) configured to respond to status information indicating failure of the first load monitor (124) to take over monitoring of the load servers and providing new data on the queue (128); wherein each load server (122) is associated with a service-level-agreement data structure (1223), the service-level-agreement data structure (1223) including a first field (1223B) for indicating a minimal priority of document indexing requests that the load server (122) is permitted to accept; a second field (1223A) for identifying for which databases the load server (122) is permitted to index documents; and a third field (1223C) indicating a temporal aspect associated with an effective period or a duration of the service-level agreement data structure (1223). 2. The system of claim 1, wherein to provide status information to the second load monitor (124), the first load monitor (124) is configured to periodically write a time-stamped report to a predetermined portion of a network accessible storage device and the second load monitor (124) is configured to read the timestamped report on the network accessible storage device at predetermined intervals. 3. The system of claim 1, wherein the first load monitor (124) is configured to notify each of the load servers (122) when new data is added to the queue (128), and wherein any of the load servers (122) that is not busy is configured to respond to the notification by attempting to retrieve the new data from the queue (128) and to index the documents based on the new data 4. The system of claim 1, further comprising a set of two or more distribution servers configured to respectively distribute index data generated by the load servers (122) and corresponding documents to a primary index and a primary database (1) for use by subscribers.. The system of claim 4: wherein each load server (122)is configured to provide a loader notification to each of the distribution servers to indicate that it has completed indexing a set of documents based on data retrieved from the queue (128); and wherein any of the distribution servers that is not busy is configured to respond to the loader notification by attempting to distribute index data generated by the load server that provided the loader notification to the primary index and to distribute documents corresponding to the loader notification to the primary database (1). 6. The system of claim, wherein each distribution server is configured to provide a distribution notification to each of the load monitors (124) to indicate that it has completed distributing a set of documents based on data retrieved from the queue (128) to the primary index and to the primary database (1). 7. The system of claim 6, further comprising means, responsive to the distribution notification, for replicating the distributed index data and documents to a secondary index and database (1). 8. The system of claim, wherein each load server (122) is configured to check the queue (128) for new data after providing the loader notification. 9. The system of claim 7, wherein the first load monitor (124) is configured to confirm replication of the distributed index data and documents in the secondary index and database (1) and in response to confirming replication writing a time-stamped load completion message to a network accessible storage device; and wherein the second load monitor (124) is configured to periodically determine whether the network accessible storage device includes messages confirming proper operation of the first load monitor (124).. A method of loading data into an online information retrieval system (0), the method comprising: receiving a file containing documents for addition to a database (1, 1) of an online information-retrieval system (0); notifying two or more load servers (122) in response to receiving the file; indexing the documents in the file using one of the notified load servers (122); loading the indexed documents onto the database (1,1); notifying two or more load monitors (124) that the documents have been loaded on the database (1, 1); confirming that the documents have been loaded on the database (1, 1) using a first one of the notified load monitors (124); and confirming proper operation of a first one of the notified load monitors (124) using a second one

6 9 EP B1 of the notified load monitors (124); wherein each load server (122) is associated with a service-level-agreement data structure (1223), the service-level-agreement data structure (1223) including a first field (1223B) for indicating a minimal priority of document indexing requests that the load server (122) is permitted to accept; a second field (1223A) for identifying for which databases (1,1) the load server (122) is permitted to index documents; and a third field (1223C) indicating a temporal aspect associated with an effective period or duration of the service-level agreement data structure (1223). 11. The method of claim, wherein notifying two or more load servers (122), comprises: detecting reception of the file; adding data regarding the file to a load queue (128); and notifying the two or more load servers (122) that new data has been added to the load queue (128). 12. The method of claim, wherein loading the indexed documents onto the database (1,1), comprises: notifying two or more of distribution servers (126) that index data and corresponding documents are available for loading; and using one of the two or more distribution servers (126) to load the index data and corresponding documents on to the database (1, 1). Patentansprüche 1. Informationsabrufsystem (0), umfassend: eine Warteschlange (128) zum Speichern von Anforderungen für das Laden von Daten; ein Satz von zwei oder mehr Ladeservern (122) zum Abrufen von Daten aus der Warteschlange (128) und zum Indizieren von Dokumenten für den Abruf auf der Grundlage der aus der Warteschlange (128) abgerufenen Daten; ein erster und zweiter Lademonitor (124) für die Überwachung des Betriebs der Ladeserver (122) und die Bereitstellung neuer Daten in der Warteschlange (128), auf die die Ladeserver (122) Zugriff haben, wobei der erste Lademonitor (124) dafür konfiguriert ist, Information bezüglich seiner Betriebsabläufe an den zweiten Lademonitor (124) zu liefern, und der zweite Lademonitor (124) dafür konfiguriert ist, auf Statusinformation, die ein Versagen des ersten Lademonitors (124) anzeigt, zu reagieren, um die Überwachung der Ladeserver und die Bereitstellung neuer Daten in der Warteschlange (128) zu übernehmen; wobei jedem Ladeserver (122) eine dienstniveauvereinbarungsmäßige Datenstruktur (1223) zugeordnet ist, wobei diese dienstniveauvereinbarungsmäßige Datenstruktur (1223) aufweist: ein erstes Feld (1223B) zum Anzeigen einer minimalen Priorität der Dokumentindizierungsanforderungen, die dem Ladeserver (122) zu akzeptieren erlaubt ist; ein zweites Feld (1223A) zum Bestimmen, für welche Datenbanken dem Ladeserver (122) Dokumente zu indizieren erlaubt sind; und ein drittes Feld (1223C), das ein zeitliches Kriterium anzeigt, dem ein effektiver Zeitraum oder eine Dauer der dienstniveauvereinbarungsmäßigen Datenstruktur (1223) zugeordnet ist. 2. System nach Anspruch 1, wobei die Statusinformation an den zweiten Lademonitor (124) zu liefern ist, der erste Lademonitor (124) dafür konfiguriert ist, in regelmäßigen Abständen eine mit Zeitstempel versehene Meldung in einen vorbestimmten Bereich einer für das Netz zugänglichen Speichervorrichtung zu schreiben, und der zweite Lademonitor (124) dafür konfiguriert ist, die mit Zeitstempel versehene Meldung in der für das Netz zugänglichen Speichervorrichtung in vorbestimmten Intervallen zu lesen. 3. System nach Anspruch 1, wobei der erste Lademonitor (124) dafür konfiguriert ist, jeden der Ladeserver (122) zu benachrichtigen, wenn der Warteschlange (128) neue Daten hinzugefügt werden, und wobei jeder der Ladeserver (122), der nicht beschäftigt ist, dafür konfiguriert ist, auf die Benachrichtigung zu reagieren, indem er versucht, die neuen Daten aus der Warteschlange (128) abzurufen und die Dokumente auf der Grundlage der neuen Daten zu indizieren. 4. System nach Anspruch 1, ferner umfassend einen Satz von zwei oder mehr Verteilungsservern, die dafür konfiguriert sind, Indexdaten, die durch die Ladeserver (122) erzeugt werden, und entsprechende Dokumente an einen Primärindex und eine Primärdatenbank (1) zur Verwendung durch Teilnehmer zu verteilen.. System nach Anspruch 4; wobei jeder Ladeserver (122) dafür konfiguriert ist, eine Lader-Benachrichtigung an jeden der Verteilungsserver zu liefern, um anzuzeigen, dass er das Indizieren eines Satzes von Dokumenten auf der Grundlage von Daten, die aus der Warteschlange (128) abgerufen werden, abgeschlossen hat; und wobei jeder der Verteilungsserver, der nicht beschäftigt ist, dafür konfiguriert ist, auf die Lader-Be- 6

7 11 EP B1 12 nachrichtigung zu reagieren, indem er versucht, Indexdaten, die durch den Ladeserver erzeugt werden, der die Lader-Benachrichtigung bereitgestellt hat, an den Primärindex zu verteilen und Dokumente entsprechend der Lader-Benachrichtigung an die Primätdatenbank (1) zu verteilen. 6. System nach Anspruch, wobei jeder Verteilungsserver dafür konfiguriert ist, eine Verteilungsbenachrichtigung an jeden der Lademonitore (124) zu liefern, um anzuzeigen, dass er die Verteilung eines Satzes von Dokumenten auf der Grundlage von Daten, die aus der Warteschlange (128) abgerufen werden, an den Primärindex und die primären Datenbank (1) abgeschlossen hat. 7. System nach Anspruch 6, ferner umfassend ein Mittel, das auf die Verteilungsbenachrichtigung anspricht, zum Replizieren der verteilten Indexdaten und Dokumente an einen Sekundärindex und eine Sekundärdatenbank (1). 8. System nach Anspruch, wobei jeder Ladeserver (122) dafür konfiguriert ist, die Warteschlange (128) nach Bereitstellung der Lader-Benachrichtigung auf neue Daten hin zu überprüfen. 1 2 Bestätigen, dass die Dokumente unter Verwendung eines ersten der benachrichtigten Lademonitore (124) in die Datenbank (1, 1) geladen worden sind; und Bestätigen des ordnungsgemäßen Betriebs eines ersten der benachrichtigten Lademonitore (124) unter Verwendung eines zweiten der benachrichtigten Lademonitore (124); wobei jedem Ladeserver (122) eine dienstniveauvereinbarungsmäßige Datenstruktur (1223) zugeordnet ist, wobei diese dienstniveauvereinbarungsmäßige Datenstruktur (1223) aufweist: ein erstes Feld (1223B) zum Anzeigen einer minimalen Priorität von Dokumentindizierungsanforderungen, die dem Ladeserver (122) zu akzeptieren erlaubt ist; ein zweites Feld (1223A) zum Bestimmen, für welche Datenbanken (1, 1) dem Ladeserver (122) Dokumente zu indizieren erlaubt sind; und ein drittes Feld (1223C), das ein zeitliches Kriterium anzeigt, dem ein effektiver Zeitraum oder eine Dauer der dienstniveauvereinbarungsmäßigen Datenstruktur (1223) zugeordnet ist. 11. Verfahren nach Anspruch, wobei die Benachrichtigung zweier oder mehr Ladeserver (122) umfasst: 9. System nach Anspruch 7, wobei der erste Lademonitor (124) dafür konfiguriert ist, die Replikation der verteilten Indexdaten und Dokumente im Sekundärindex und in der Datenbank (1) zu bestätigen und als Reaktion auf die Bestätigung der Replikation eine mit Zeitstempel versehene Ladeabschlussnachricht in eine für das Netz zugängliche Speichervorrichtung zu schreiben; und wobei der zweite Lademonitor (124) dafür konfiguriert ist, in regelmäßigen Abständen zu bestimmen, ob die für das Netz zugängliche Speichervorrichtung Nachrichten aufweist, die den ordnungsgemäßen Betrieb des ersten Lademonitors (124) bestätigen.. Verfahren zum Laden von Daten in einem Online- Informationsabrufsystem (0), wobei das Verfahren umfasst: Empfangen einer Datei, die Dokumente enthält, zur Hinzufügung zu einer Datenbank (1, 1) eines Online-Informationsabrufsystems (0); Benachrichtigen zweier oder mehr Ladeserver (122) als Reaktion auf den Empfang der Datei; Indizieren der Dokumente in der Datei unter Verwendung eines der benachrichtigten Ladeserver (122); Laden der indizierten Dokumente in die Datenbank (1, 1); Benachrichtigen zweier oder mehr Ladeserver (124), dass die Dokumente in die Datenbank (1, 1) geladen worden sind; Ermitteln des Empfangs der Datei; Hinzufügen von Daten bezüglich der Datei zu einer Ladewarteschlange (128); und Benachrichtigen der beiden oder mehr Ladeserver (122), dass der Ladeschlange (128) neue Daten hinzugefügt worden sind. 12. Verfahren nach Anspruch, wobei das Laden der indizierten Dokumente in der Datenbank (1,1) umfasst: Benachrichtigen zweier oder mehr Verteilungsserver (126), dass Indexdaten und entsprechende Dokumente zum Laden verfügbar sind; und Verwenden eines der beiden oder mehr Verteilungsserver (126), um die Indexdaten und die entsprechenden Dokumente in die Datenbank (11) zu laden. Revendications 1. Système d extraction d informations (0) comprenant : une file d attente (128) destinée à stocker des demandes de chargement de données ; un ensemble de deux serveurs de chargement ou plus (122) destinés à extraire des données de la file d attente (128) et à indexer des documents en vue d une extraction sur la base des 7

8 13 EP B1 14 données extraites de la file d attente (128) ; des premier et second moniteurs de chargement (124) destinés à surveiller le fonctionnement des serveurs de chargement (122) et à fournir de nouvelles données sur la file d attente (128), accessibles par les serveurs de chargement (122), où le premier moniteur de chargement (124) est configuré de manière à fournir des informations concernant ses opérations au second moniteur de chargement (124), et le second moniteur de chargement (124) est configuré de manière à répondre à des informations d état indiquant la défaillance du premier moniteur de chargement (124) s agissant de prendre en charge la surveillance des serveurs de chargement et de fournir de nouvelles données sur la file d attente (128) ; dans lequel chaque serveur de chargement (122) est associé à une structure de données d accord de niveau de service (1223), la structure de données d accord de niveau de service (1223) incluant un premier champ (1223B) destiné à indiquer une priorité minimale de demandes d indexation de documents que le serveur de chargement (122) est autorisé à accepter ; un deuxième champ (1223A) destiné à identifier quelles sont les bases de données pour lesquelles le serveur de chargement (122) est autorisé à indexer des documents ; et un troisième champ (1223C) indiquant un aspect temporel associé à une période effective ou une durée de la structure de données d accord de niveau de service (1223). 2. Système selon la revendication 1, dans lequel, afin de fournir des informations d état au second moniteur de chargement (124), le premier moniteur de chargement (124) est configuré de manière à écrire périodiquement un rapport horodaté sur une partie prédéterminée d un dispositif de stockage accessible par le réseau, et le second moniteur de chargement (124) est configuré de manière à lire le rapport horodaté, sur le dispositif de stockage accessible par le réseau, à des intervalles prédéterminés. 3. Système selon la revendication 1, dans lequel le premier moniteur de chargement (124) est configuré de manière à indiquer à chacun des serveurs de chargement (122) lorsque de nouvelles données sont ajoutées à la file d attente (128), et dans lequel l un quelconque des serveurs de chargement (122) qui n est pas occupé est configuré de manière à répondre à la notification en tentant d extraire les nouvelles données de la file d attente (128) et d indexer les documents sur la base des nouvelles données. 4. Système selon la revendication 1, comprenant en outre un ensemble de deux serveurs de distribution ou plus configurés de manière à distribuer respectivement des données d index générées par les serveurs de chargement (122), et des documents correspondants, à un index principal et à une base de données principale (1), afin qu elles soient utilisées par les abonnés.. Système selon la revendication 4 : dans lequel chaque serveur de chargement (122) est configuré de manière à fournir une notification de chargeur à chacun des serveurs de distribution en vue d indiquer qu il a terminé l indexation d un ensemble de documents, sur la base des données extraites de la file d attente (128) ; et dans lequel l un quelconque des serveurs de distribution qui n est pas occupé est configuré de manière à répondre à la notification de chargeur en tentant de distribuer des données d index, générées par le serveur de chargement qui a fourni la notification de chargeur, à l index principal, et de distribuer des documents correspondants à la notification de chargeur, à la base de données principale (1). 6. Système selon la revendication, dans lequel chaque serveur de distribution est configuré de manière à fournir une notification de distribution à chacun des moniteurs de chargement (124), en vue d indiquer qu il a terminé la distribution d un ensemble de documents, sur la base des données extraites de la file d attente (128), à l index principal et à la base de données principale (1). 7. Système selon la revendication 6, comprenant en outre un moyen, en réponse à la notification de distribution, pour répliquer les documents et données d index distribués, sur un index et une base de données secondaires (1). 8. Système selon la revendication, dans lequel chaque serveur de chargement (122) est configuré de manière à vérifier, dans la file d attente (128), de nouvelles données, suite à la fourniture de la notification de chargeur. 9. Système selon la revendication 7, dans lequel le premier moniteur de chargement (124) est configuré de manière à confirmer la réplication des documents et des données d index distribués dans l index et la base de données secondaires (1), et en réponse à la confirmation de la réplication, à écrire un message d achèvement de chargement horodaté sur un dispositif de stockage accessible par le réseau ; et dans lequel le second moniteur de chargement (124) est configuré de manière à déterminer périodiquement si le dispositif de stockage accessible par le réseau 8

9 1 EP B1 16 comprend des messages confirmant le fonctionnement correct du premier moniteur de chargement (124).. Procédé de chargement de données dans un système d extraction d informations en ligne (0), le procédé consistant à : recevoir un fichier contenant des documents à ajouter à une base de données (1, 1) d un système d extraction d informations en ligne (0) ; notifier deux serveurs de chargement ou plus (122) en réponse à la réception du fichier ; indexer les documents dans le fichier en utilisant l un des serveurs de chargement notifiés (122) ; charger les documents indexés sur la base de données (1, 1) ; indiquer à deux moniteurs de chargement ou plus (124) que les documents ont été chargés sur la base de données (1, 1) ; confirmer que les documents ont été chargés sur la base de données (1, 1) en utilisant un premier des moniteurs de chargement notifiés (124) ; et confirmer le fonctionnement correct d un premier des moniteurs de chargement notifiés (124) en utilisant un second des moniteurs de chargement notifiés (124) ; dans lequel chaque serveur de chargement (122) est associé à une structure de données d accord de niveau de service (1223), la structure de données d accord de niveau de service (1223) incluant un premier champ (1223B) destiné à indiquer une priorité minimale de demandes d indexation de documents que le serveur de chargement (122) est autorisé à accepter ; un deuxième champ (1223A) destiné à identifier les bases de données (1, 1) pour lesquelles le serveur de chargement (122) est autorisé à indexer des documents ; et un troisième champ (1223C) indiquant un aspect temporel associé à une période effective ou une durée de la structure de données d accord de niveau de service (1223) chargement des documents indexés sur la base de données (1, 1) consiste à : signaler à deux des serveurs de distribution ou plus (126) que des données d index et des documents correspondants sont disponibles en vue d un chargement ; et utiliser l un des deux serveurs de distribution ou plus (126) en vue de charger les données d index et les documents correspondants sur la base de données (1, 1). 11. Procédé selon la revendication, dans lequel la notification de deux serveurs de chargement ou plus (122), consiste à : détecter la réception du fichier ; ajouter des données connexes au fichier à une file d attente de chargement (128) ; et signaler aux deux serveurs de chargement ou plus (122) que de nouvelles données ont été ajoutées à la file d attente de chargement (128) Procédé selon la revendication, dans lequel le 9

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12 EP B1 REFERENCES CITED IN THE DESCRIPTION This list of references cited by the applicant is for the reader s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard. Patent documents cited in the description US A [0004] 12