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Configuring a Server Framework for Cloudscape
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Setting Cloudconnector PropertiesNOTE: The rest of this chapter applies only to Cloudconnector users. You can set system-wide (persistent) Cloudconnector properties using the weblogic.properties file, or you can set temporary Cloudconnector properties by specifying them in the database connection URL. For information about temporary Cloudconnector properties, see Setting Session-Level WebLogic Properties on the URL in chapter 4. This section discusses using the weblogic.properties file. To set persistent Cloudconnector properties, modify the weblogic.properties file. The only property that you must modify before starting the server is the password property, as discussed in Setting a Password. The weblogic.properties file requires no additional modification prior to running Cloudconnector, however there are several optional Cloudconnector properties you may want to specify or modify. You can set optional Cloudconnector properties in this file or in the Cloudscape client database connection URL. Cloudconnector properties specified on a connection URL are valid only for that connection. To set cloudscape.system.home when using Cloudconnector, set it when starting Cloudconnector in the startCS script. You add it as a parameter to the JVM command in the script: -Dcloudscape.system.home=c:\cloudscape\serverDIR Alternatively, you can set cloudscape.system.home by uncommenting the setting java.system.property.cloudscape.system.home in the weblogic.properties file. Configuring Multi-ThreadingCloudconnector automatically multi-threads operations. When the value of the weblogic.system.executeThreadCount property is larger than 1, Cloudconnector uses multiple threads to handle incoming JDBC requests. The default value of the Cloudconnector configuration is 15. NOTE: Execute threads are used by client JDBC requests, but not by embedded requests in servlets. The higher the number of threads, the greater the possible concurrency. Users running under a JVM with poor threading capabilities may want to disable multi-threading. To disable multi-threading, modify the property in the weblogic.properties file: weblogic.system.executeThreadCount=1 However, if you disable multi-threading, concurrency is drastically reduced and deadlock becomes more likely. For example, consider the following scenario: Client transaction A inserts into the People table and thus obtains a lock on that table. Cloudconnector assigns one thread to that action. When the action completes, Cloudconnector releases the execute thread while still holding the lock. A few seconds later, client transaction B tries to select from the People table and must wait for A to release the lock. Cloudconnector assigns the one available thread to that action. This thread waits along with the waiting SELECT statement. A few seconds later, transaction A commits. There is no other Cloudconnector thread to assign to that thread, however, because the one available thread is tied to the waiting SELECT statement. Finally, transaction B aborts because of a deadlock timeout. The thread in Cloudconnector becomes available, and transaction A can commit. Transaction B must resubmit the SELECT. (See the Cloudscape Developer's Guide for more information on deadlocks.) You cannot set the executeThreadCount property at the session level on the database connection URL. You must set it in the weblogic.properties file before starting up Cloudconnector. You can see the values of all Cloudconnector properties for the current server through the administrative servlet; see Cloudconnector Administration for details. Disabling HTTP ServicesBy default, HTTP services are enabled in Cloudconnector. To disable HTTP services, set: weblogic.httpd.enable=false in the weblogic.properties file. NOTE: The WebLogic default setting of weblogic.httpd.enable is false, but the Cloudconnector customization of WebLogic sets it to true. You can also control the number of HTTP threads by setting the weblogic.system.httpdThreadCount property. The default value is 5. |
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![]() Cloudscape Version 3.6 For information about Cloudscape technical support, go to: www.cloudscape.com/support/.Copyright © 1998, 1999, 2000 Informix Software, Inc. All rights reserved. |