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https://issues.apache.org/jira/browse/VCL-1082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16249810#comment-16249810
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Mike Jennings commented on VCL-1082:
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This issue occurs because the monitor_vcld.pl program compares the epoch time
returned form the management node operating system to the date/time value
returned from the lastcheckin time on the managementnode table in the database
which is converted from a datetime column value to epoch.
The DATETIME column type stores date and time as a static value where the
TIMESTAMP column is stored as a UTC and then converted for display based on the
Local Timezone setting in mysql. Because information is not stored in MySQL in
a TIMESTAMP column there is no way for the monitor_vcld.pl program to know that
the date and time being returned from MySQL has actually been rolled back a
hour and things that the epoch time is one hour in the past.
I have solved this issue, but changing the DATETIME value to TIMESTAMP in the
database using the following query below.
ALTER TABLE managementnode MODIFY COLUMN lastcheckin TIMESTAMP;
I then modified the code to update the lastupdate time using the NOW() method,
so that we use the current time of the database server when updating the
timestamp. I also modified the epoch timestamp check to return the
lastmodified timestamp as a epoch value from MySQL by leveraging the
UNIX_TIMESTAMP function in MySQL. This lets MySQL take care of managing
daylights savings time and timezones for the system.
I am attaching a patch of the code changes that I performed.
> monitor_vcld.pl throws incorrect lastcheckin time exception after Daylight
> Savings Time Roles Back
> --------------------------------------------------------------------------------------------------
>
> Key: VCL-1082
> URL: https://issues.apache.org/jira/browse/VCL-1082
> Project: VCL
> Issue Type: Bug
> Components: vcld (backend)
> Affects Versions: 2.5
> Reporter: Mike Jennings
> Priority: Minor
> Labels: patch
>
> When Daylight Savings time rolled back one hour on Nov 5th, the
> monitor_vcld.pl program started reporting critical exceptions where the
> management node has not been checked in, in over a hour.
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