USER MANUALS

Changing Settings of Virtual DataPort and the Web Container

The command SET adds, modifies or deletes a property from the configuration file of Virtual DataPort (<DENODO_HOME>/conf/vdp/VDBConfiguration.properties).

The command WEBCONTAINER SET adds or modifies a property of the configuration file of the web container of Denodo (<DENODO_HOME>/resources/apache-tomcat/conf/tomcat.properties).

You can change almost all settings of Virtual DataPort from the administration tool (dialog Administration > Server Configuration). However, there a few settings that involve modifying these files. Although you can edit the file directly, we strongly recommend doing it with the commands SET and WEBCONTAINER SET instead. The benefits of using these commands over modifying the files directly are:

  1. When you change the value of some of properties, the value may be applied immediately (this is only true for some properties). However, if you change the file directly, you always have to restart the Virtual DataPort server to apply the change.

  2. If you enabled the feature Storing the Metadata on an External Database, the new value is propagated, when is necessary, to the other servers that share the same external database.

  3. It is more convenient because you can execute the command from the VQL Shell of Design Studio, the Administration Tool or any other tool; you do not have to connect with SSH to the host where the server runs.

  4. If you change the amount of memory allocated for the Virtual DataPort server directly in the file, then you have to execute the script <DENODO_HOME>/bin/regenerateFiles. If you modify this with the command SET, you do not need to execute this script (you still have to restart Virtual DataPort to apply the change).

Syntax of the command SET
; This adds/replaces a property
SET <property name:literal> = <value:literal>

; This removes a property
SET <property name:literal> = NULL
Syntax of the command WEBCONTAINER SET
WEBCONTAINER SET <property name:literal> = <value:literal>

Considerations

  • When changing the value of certain properties, you may need to restart the Virtual DataPort server. For others, the new value is applied immediately. The documentation of the property mentions this.

  • Only administrators can execute the commands SET and WEBCONTAINER SET.

Examples

Example 1

Execute this to allocate 4 gigabytes of memory for the Virtual DataPort server and change other settings of the Java Virtual Machine:

SET 'java.env.DENODO_OPTS_START' = '-server -Xms4g -Xmx4g -XX:+DisableExplicitGC -XX:+UseConcMarkSweepGC -XX:NewRatio=4 -XX:CMSInitiatingOccupancyFraction=60 -XX:ReservedCodeCacheSize=256m';

This changes the value of the property “java.env.DENODO_OPTS_START” and invokes the script <DENODO_HOME>/bin/regenerateFiles. If you changed this property directly on the file, the change does not apply until you execute this script and restart.

You need to restart the Virtual DataPort server to apply this change.

Example 2

Execute this to allocate 2 gigabytes of memory for the web container of Denodo and to change other settings of the Java Virtual Machine:

WEBCONTAINER SET 'java.env.DENODO_OPTS_START' = '-Xmx2g -Dorg.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true -Dorg.apache.catalina.connector.CoyoteAdapter.ALLOW_BACKSLASH=true';

You need to restart the web container to apply any change to a property of the web container.

Example 3

Delete a property from the configuration of Virtual DataPort.

SET 'com.denodo.vdb.util.tablemanagement.sql.insertion.HdfsInsertWorker.parquet.compression' = NULL;

Note that to remove a property, the value has to be NULL without quotes. If you put quotes, the value of the property will be the character string “NULL”.

WEBCONTAINER SET does not support this; it can only be used to add or modify properties, not delete them.

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