Oozie Coordinator not running at specified frequency interval

Question

I have defined an Oozie coordinator job as follows:

<coordinator-app name="edu-apollogrp-DFE" frequency="${coord:minutes(15)}" start="${start}" end="${end}" timezone="${timezone}" xmlns="uri:oozie:coordinator:0.1">
    <controls>
            <concurrency>1</concurrency>
    </controls>
    <action>
            <workflow>
                    <app-path>${nameNode}/user/${user}/oozie/apps/DFE/queryGenerator-wf</app-path>
                    <configuration>
                            <property>
                                    <name>nameNode</name>
                                    <value>${nameNode}</value>
                            </property>
                            <property>
                                    <name>jobTracker</name>
                                    <value>${jobTracker}</value>
                            </property>

                    </configuration>
            </workflow>
    </action>
</coordinator-app>

As you can see, I've defined the frequency as 15 minutes, and concurrency as 1.

However, the job is running every 5 minutes, and it launches 4 instances of my workflow at the same time, as seen in the below screenshot:

I don't understand why this is happening, I would really appreciate some insights!

Answer 1

In this case i imagine your start time was in the past - if you look at the materialized instance column you will see they have a 15 minutes interval between then. What OOZIE is doing in the case where the start time is in the past is it will effectively 'back-schedule' all the tasks up to the current time, generating each materialized instance 5 minutes apart.