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20040110: how often dcnldn writes?

Neil,

The -m 25000 allows 25,000 maximum entries in a file.
The default action I provide uses 30 minute file naming
with 5 minute bins for the data (since the data can exceed 30,000
strikes in an hour which would be the maximum number of points
in a GEMPAK file).

NLDN products are issued for the IDD every 5 minutes, but that doesn't mean
they contain any strikes. Null messages containing no strike data
are still sent when no strikes are being detected. If you have
very few decoders running, you man not have pqact close the connection to
the decoder, and with null reports every 5 minutes, you may see the decoder 
stay open.

The decoder will flush every 500 reports, or at the end of a bulletin.

The provided entry in $NAWIPS/ldm/etc/templates is:
NLDN    .*
        PIPE    decoders/dcnldn -m 25000 -b 30 -s minute05
        -d data/gempak/logs/dcnldn.log
        -e GEMTBL=@GEMTBL@
        data/gempak/nldn/YYYYMMDDHHNN_nldn.gem

This will result in  files named YYYYMMDDHHNN_nldn.gem, where the
-b 30 will result in "NN" breaks every 30 minutes. The -s
option will accumulate strikes witin a 5 minute period
as a GEMPAK time for plotting.

This entry matches the file naming expected in $GEMTBL/datatyle/datatype.tbl.

Steve Chiswell





>From: Neil Smith <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200401102238.i0AMclp2011216

>I'm watching NLDN come in on our ldm (6.0.14), and logging (-v2)  our
>dcnldm (5.6j) actions. The output data file naming is YYMMDDHH.gem.
>The output file is not being refreshed; in fact it  currently hasn't 
>been
>updated in 3 hrs. We've created gempak product gif scripts searching
>for filnames of above format and those are not finding files for a 
>'current'
>time to open.
>
>How often is dcnldn supposed to generate a new YYMMDDHH.gem file and
>what induces it to do so?
>
>What is the -s option default? What does the -n 30 mean in the example
>pqact entry?
>
>Is the -m option units in bytes? What is the result when this is 
>exceeded?
>
>
>
>Our current setup:
>pqact entry -
>NLDN    .*
>         PIPE    /unidata/nawips/bin/freebsd/dcnldn -v 2 -m 25000
>         -d /unidata/ldm/logs/dcnldn.log
>         -p /unidata/nawips/gempak/tables/pack/nldn.pack
>         /data/gempak/nldn/YYMMDDHH.gem
>
>hear's a grep for a current dcldm PID from the log file:
>[87340] 040110/1555 [DC 3] Version 5.6.j
>[87340] 040110/1555 [DC 2] read 84/102399 bytes strt 0 newstrt 84
>[87340] 040110/1555 [DCGNLDN 0] Header len 3 nflash 0
>[87340] 040110/1555 [DCGNLDN 0] iret dcb_getb 0
>[87340] 040110/1601 [DC 2] read 84/102316 bytes strt 84 newstrt 168
>[87340] 040110/1601 [DCGNLDN 0] Header len 3 nflash 0
>[87340] 040110/1601 [DCGNLDN 0] iret dcb_getb 0
>[87340] 040110/1607 [DC 2] read 84/102232 bytes strt 168 newstrt 252
>[87340] 040110/1607 [DCGNLDN 0] Header len 3 nflash 0
>[87340] 040110/1607 [DCGNLDN 0] iret dcb_getb 0
>[87340] 040110/1613 [DC 2] read 84/102148 bytes strt 252 newstrt 336
>[87340] 040110/1613 [DCGNLDN 0] Header len 3 nflash 0
>[87340] 040110/1613 [DCGNLDN 0] iret dcb_getb 0
>[87340] 040110/1619 [DC 2] read 84/102064 bytes strt 336 newstrt 420
>[87340] 040110/1619 [DCGNLDN 0] Header len 3 nflash 0
>[87340] 040110/1619 [DCGNLDN 0] iret dcb_getb 0
>[87340] 040110/1622 [DC 2] read 0/101980 bytes strt 420 newstrt 420
>[87340] 040110/1622 [DCGNLDN -9] time out or end of data
>[87340] 040110/1622 [DC 5]
>[87340] 040110/1622 [DC 2] Number of bulletins read and processed: 0
>[87340] 040110/1622 [DC 6]
>
>What is the significance ot the 'time out or end of data' statement?
>
>If there are no bulletins read or processed in an hour's time, is this
>unusual, and would no file be created/added to for that hour?
>
>Thanks. -Neil
>--
>Neil R. Smith                          address@hidden
>Comp.Sys.Mngr.                 (979)845-6272
>Dept. Atmospheric Sciences/Texas A&M University
>