PQMON

pqmon - program to monitor the state of an LDM product queue

pqmon [-S] [-l logdest] [-q pqfname] [-i interval] [outputfile]

This program writes to outputfile statistics to monitor the state of a local LDM product queue (see pq(3)). If no outputfile is specified, the data is written to standard output. The program may be used to display the current state of a product queue, to periodically sample the product queue’s state, or to help determine the parameters that should be used for pqcreate, to create a product queue that will not run out of product slots or waste space for unused product slots. After reporting on the current state of the queue, pqmon exits, unless a non zero interval is specified.

pqmon is typically used to verify that the product queue is peforming adequately, is not close to running out of product slots, and is large enough to hold products for a desired time period.

-S

Writes modified output to the standard output stream (the "-l" option is ignored except for error messages). The output comprises a single line of the following parameters, in order:

Whether or not the queue is full (i.e., whether or not an old data-product has been deleted in order to make room for a new data-product).

dataCapacity

The size, in bytes, of the data portion of the queue.

dataHighWater

The high-water usage-mark of the data portion of the queue, in bytes.

dataCurrent

The the current usage of the data portion of the queue, in bytes.

prodCapacity

The number of products the queue can contain.

prodHighWater

The maximum number of products in the queue since it was created.

prodCurrent

The current number of products in the queue.

ageOldest

The age, in seconds, of the oldest data-product in the queue.

ageYoungest

The age, in seconds, of the youngest data-product in the queue.

minVirtResTime

The minimum virtual residence time, in seconds, of data-products in the queue. The virtual residence time of a data-product is the time difference from when the data-product was originally created to when it was removed from the local product-queue. The minimum virtual residence time is the smallest such value over all data-products that have been removed from the queue since this metric was initialized. If the queue is not yet at equilibrium (i.e., if no data-products have been deleted since this parameter was initialized) then this metric will be -1. This parameter can be reset via the pqutil(1) utility.

mvrtSize

The amount of data in the queue, in bytes, when the minimum virtual residence time was determined. This parameter can be reset via the pqutil(1) utility.

mvrtSlots

The number of data-products in the queue when the minimum virtual residence time was determined. This parameter can be reset via the pqutil(1) utility.

−l logdest

Log to logdest. One of ’’ (system logging daemon), ’-’ (standard error stream), or file logdest. Default is the standard error stream if the process has a controlling terminal (i.e., the process isn’t a daemon); otherwise, either the LDM log file or the system logging daemon (execute this program with just the option ’-?’ to determine which).

-q pqfname

The filename of the product queue. The default is $(regutil /queue/path).

−i interval

Polling interval, in seconds. The program sleeps and reports on the state of the product queue every interval seconds. If the interval is 0, the program exits after one report (this is the default if the "-i" option is missing).

SIGTERM

Normal termination.

SIGINT

Immediate termination.

SIGUSR1

Refresh logging (if configure(1) executed without the "--with-ulog" option) and write status and product statistics to log output.

The following invocation will report on the status of the default product queue to stderr and then exit.

pqmon

The following example will emit to stderr information about the current state of the product queue in /tmp/ldm.pq, updated every 5 seconds:

pqmon -q /tmp/ldm.pq -i 5

The following line in the ldmd.conf configuration file will cause a report of the status of the product queue to be logged every 10 minutes.

exec "pqmon -i 600"

ldmd(1), pqact(1), pqutil(1), ulog(3), pq(3), syslogd(8), WWW URL http://www.unidata.ucar.edu/software/ldm/.

If you have problems with this program, then you should first examine the LDM email archive for similar problems and how they were solved. The email archive is available via the following World Wide Web URL:

http://www.unidata.ucar.edu/software/ldm/

If this does not suffice and your site is a member of the Unidata program, then send an inquiry via email -- together will all relevant information -- to

support@unidata.ucar.edu