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[LDM #WSP-283484]: latency between receiving and writing NNEXRAD

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  • Subject: [LDM #WSP-283484]: latency between receiving and writing NNEXRAD
  • Date: Tue, 23 Oct 2007 09:33:14 -0600
Gerry,

> First, I was wrong: the pwact does have a -close associated with it.

Some do; some don't.  The ones that do have the string "file: -close"
in their log messages.  Whether the "-close" option is used or not,
however, doesn't appear to be relevant (see below).

> An
> excerpt of the log is here:
> Oct 22 20:00:31 dc-ldm2 pqact[25409] INFO:      232 20071022184554.512
> NNEXRAD 40870431  SDUS56 KEKA 221836 /pNVLBHX
> Oct 22 20:00:31 dc-ldm2 pqact[25402] INFO:                file:
> data/SCOOP/RTSTATS/level3.michiganwxsystem.net/NNEXRAD/jackie.unidata.ucar.edu_v_bigbird.tamu.edu

The above indicates that "pqact" process 25409 filed a data-product
at 2000 UTC that was created at 1845 UTC -- yielding a delay of 1
hour and 45 minutes between creation and filing.  You've indicated
that the data-products are arriving with minimal latency, so it's
likely that the "pqact" process in question is just that far behind
in its processing of the product-queue.  I suspect, therefore, that
your computer just isn't sized right for the task at hand.  The CPU
could be too slow, there might be insufficient memory (swapping the
product-queue leads to poor performance), or the disks could be too
slow.

Can you reduce the load you're placing on the computer to see if
it catches up?  One way would be to reduce the amount of data that
it receives.  Also, check the amount of swapping that being done.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: WSP-283484
Department: Support LDM
Priority: Normal
Status: Closed