Managing Report Server Database Connections

Transcription

1 Guideline Managing Report Server Database Connections Product(s): IBM Cognos 8 Area of Interest: Infrastructure

2 Managing Report Server Database Connections 2 Copyright Copyright 2008 Cognos ULC (formerly Cognos Incorporated). Cognos ULC is an IBM Company. While every attempt has been made to ensure that the information in this document is accurate and complete, some typographical errors or technical inaccuracies may exist. Cognos does not accept responsibility for any kind of loss resulting from the use of information contained in this document. This document shows the publication date. The information contained in this document is subject to change without notice. Any improvements or changes to the information contained in this document will be documented in subsequent editions. This document contains proprietary information of Cognos. All rights are reserved. No part of this document may be copied, photocopied, reproduced, stored in a retrieval system, transmitted in any form or by any means, or translated into another language without the prior written consent of Cognos. Cognos and the Cognos logo are trademarks of Cognos ULC (formerly Cognos Incorporated) in the United States and/or other countries. IBM and the IBM logo are trademarks of International Business Machines Corporation in the United States, or other countries, or both. All other names are trademarks or registered trademarks of their respective companies. Information about Cognos products can be found at This document is maintained by the Best Practices, Product and Technology team. You can send comments, suggestions, and additions to cscogpp@ca.ibm.com.

3 Managing Report Server Database Connections 3 Contents 1 INTRODUCTION PURPOSE APPLICABILITY EXCLUSIONS AND EXCEPTIONS LIMITED DATABASE CONNECTIONS BEING OVERUSED TERMINOLOGY AND ARCHITECTURE TERMINOLOGY ARCHITECTURE COMPARISON OF REPORTNET 1.X TO IBM COGNOS REPORTNET 1.X IBM COGNOS CONCLUSION... 7

4 Managing Report Server Database Connections 4 1 Introduction 1.1 Purpose This document is aimed at IBM Cognos 8 server administrators who have used the ReportNet 1.x warpproperties.xml parameters to tune database connection handling. This document contrasts the ReportNet 1.x and IBM Cognos 8 behaviour and notes ReportNet equivalents in IBM Cognos Applicability This document applies to IBM Cognos 8 (8.1). 1.3 Exclusions and Exceptions The behaviour and properties discussed in this document are subject to change. 2 Limited Database Connections Being Overused Some databases licences restrict the number of concurrent connections. The default ReportNet configuration that was contained in the ReportNet 1.x warpproperties.xml file could be modified to minimize the connection period. The warpproperties.xml file and configuration switches no longer exist in IBM Cognos 8. This document provides equivalent settings for IBM Cognos 8. In most environments there is no need to adjust the default connection settings. These properties should only be modified with care and clear intent. 3 Terminology and Architecture 3.1 Terminology Request A report to be executed. Logical Connection A virtual database connection between the report server and query engine Database Connection An physical connection from IBM Cognos software to the query database made via the database API. 3.2 Architecture For the execution of a report there is a specific flow to the process of establishing a database connection and retrieving results. In a short form the process is as follows: 1. The report server receives a Request (to execute a report).

5 Managing Report Server Database Connections 5 2. The report server establishes a Logical Connection to the query engine passing a query definition to be executed. 3. The RDBMS provider is the part of the query engine. The query engine converts the query definition to one or more native database SQL queries 4. The query engine establishes one or more Database Connections based on the native SQL required for the query definition. 5. The Native SQL is passed down to the database for execution. 6. The query engine retrieves results or messages from the database connection. To specify this process further, each report server can execute multiple simultaneous requests. One and only one Logical Connection is established per Request from the report server to the query engine. Each request may contain one or more query definitions. In both the ReportNet 1.x and IBM Cognos 8 (8.1) release, queries within a report are executed serially assuring that only a single query can be executed concurrently for each request. i.e. one Request = one concurrent database query. Each query definition may result in one or more SQL queries to the database. The RDBMS provider will cache and re-use Database Connections within the limits of the database. For example some databases allow multiple SQL queries to be executed through the same connection, while other databases will allow only one connection per query. Some databases allow the user credentials in a database connection to be changed (i.e. re-use the database connection across users). Others require different connections for each different user. Please see your database vendor documentation for more information on the connection pooling capabilities and restrictions. The end result of these database-specific restrictions is that by controlling the report server Requests you can only indirectly control the Database Connections.

6 Managing Report Server Database Connections 6 In order to ensure that users can continue to interact with a request for operations such as page down, requests are kept alive in the report server after the user obtains their report output. Properties are used to control how many requests are active and when they are released. 4 Comparison of ReportNet 1.x to IBM Cognos ReportNet 1.x ReportNet request handling and behaviour is as follows: Two properties, RequestCacheLength and RequestReleaseTimeout, control the behaviour of request handling in ReportNet 1.x. Each report server process can execute RequestCacheLength (default 10) number of concurrent requests. In the event that an additional request is initiated, report server will start the new request and then find an existing older request to delete. Generally, this means the request with the longest inactive time will be purged. The effect of this is that the report server request list can momentarily grow past the RequestCacheLength until report server trims the request list. All requests become stale after RequestReleaseTimeout seconds (default 300) and will be deleted along with their associated logical and database connections. Therefore, in time, all requests will be deleted and none will be active. The RequestCacheLength and RequestReleaseTimeout properties are in the warpproperties.xml file: <structure> <!-- Setting number of seconds for request release timeout. value=number of seconds; can be any positive integer. --> <!-- <property>requestreleasetimeout</property> <value type="long">300</value> --> </structure> <structure> <!-- Setting number of entries in the Context Handler request cache. value=number of entries.; can be any positive integer. --> <!-- <property>requestcachelength</property> <value type="long">10</value> --> </structure> 4.2 IBM Cognos 8 The IBM Cognos 8 behaviour is somewhat different than ReportNet. Like ReportNet, IBM Cognos 8 uses two properties to control the behaviour of request handling. The properties have different names: SessionCacheSize equivalent to ReportNet RequestCacheLength

7 Managing Report Server Database Connections 7 SessionInactivityTimeout equivalent to ReportNet RequestReleaseTimeout IBM Cognos 8 behaviour also differs from ReportNet as so: 5 Conclusion Each report server has a fixed limit of SessionCacheSize (default 10) requests which cannot be exceeded. In the event that an additional request is initiated, report server will delete an existing request before starting the new request. The effect of this is that the report server request list should never exceed the SessionCacheSize. All requests will become stale after the Inactivity Timeout in Second interval (default 3600 seconds) set in IBM Cognos Connection and will be deleted along with their associated logical and database connections. Therefore, in time all requests will be purged and none will be active. SessionInactivityTimeout can be used optionally to override the Inactivity Timeout in Second interval set in IBM Cognos Connection. The properties are defined in the rsvpproperties.xml file. <structure> <!-- The amount of time (in seconds) a session can be inactive before it is removed from the session cache maintained by Report Server. Can be any non-negative integer. If this property is not specified the value for SessionInactivityTimeout will be retrieved from the IBM Cognos Series8 configuration. --> <!-- <property>sessioninactivitytimeout</property> <value type="long">3600</value>--> </structure> <structure> <!-- The maximum size of the session cache maintained by Report Server. value=number of entries.; can be any nonnegative integer greater than 0. If a value of less than 1 is given, the session cache size will default to a size of 1. --> <!--<property>sessioncachesize</property> <value type="long">10</value>--> </structure> There properties should be adjusted with care. Only make changes with a specific result in mind. Make small changes and test each change to ensure that it meets the given need. The judicious use of these properties allows you to fine-tune the Database Connection handling as required.

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