The "changeToken" is an attribute that is present in the TIBCO Data Virtualization (TDV) Server's 'server_values.xml' file. It is present only in clustered environments i.e., if that particular TDV Server is part of a cluster, only then will this attribute be present and it will not be present on a TDV Server, which has never been connected to a cluster.
The use of 'changeToken' in TDV is explained below.

• The 'changeToken' is used to keep track of the changes made in TIBCO Data Virtualization (TDV), in a clustered environment. The changes made could be any server-level configuration changes.
• It helps in scenarios where TDV needs to identify when data (configurations) has been modified, added, or deleted, allowing for more efficient data synchronization between the clusters.
• It is a unique identifier that helps keep track of the last modification or change to that particular entity/configuration.
• For example, in a clustered environment, if the default value of "VARCHAR Max Length" for the REST data source is changed from 'Studio>Administration>Configuration>Data Sources>REST Sources' of TDV 8.8 node, the below changes can be observed in the server_values.xml file of that particular node.

  <common:attribute>
    <common:name>/sources/rest/varCharMaxLength</common:name>
    <common:type>INTEGER</common:type>
    <common:changeToken>2493026153648881668</common:changeToken>
    <common:value>4001</common:value>
  </common:attribute>

• Some other examples that can be observed in the server_values.xml file are:

<common:attribute>
    <common:name>/server/sql/defaultSqlOptions</common:name>
    <common:type>MAP</common:type>
    <common:changeToken>-2549831644508848127</common:changeToken>
    <common:valueMap></common:valueMap>
  </common:attribute>

<common:attribute>
    <common:name>/server/sql/logging/resource/enableLogging</common:name>
    <common:type>STRING</common:type>
    <common:changeToken>-7781179665909022399</common:changeToken>
    <common:value>INFO</common:value>
  </common:attribute>

<common:attribute>
    <common:name>/server/webservices/baseURI</common:name>
    <common:type>STRING</common:type>
    <common:changeToken>-2549831644508848127</common:changeToken>
    <common:value/>