I want to set default value of token to be * on the drilldown before clicking the field value.
$COUNT$= "*" > On clicking $click.value$= field value
<row>
<panel>
<viz type="treemap_app.treemap">
<title>Top 15 Result</title>
<search base="health_rules">
<query>|stats count AS "Result Count" BY count value |head 15</query>
</search>
<drilldown>
<set token="VALUES">$row.value$</set>
<set token="COUNTS">$row.count$</set>
</drilldown>
</viz>
</panel>
</row>
Have you tried init?
<init>
<set token="COUNTS">*</set>
</init>
https://docs.splunk.com/Documentation/Splunk/latest/Viz/tokens#Set_tokens_on_page_load