Steven, >Date: Mon, 20 Sep 2004 10:12:07 -0500 >From: "Steven Danz" <address@hidden> >Organization: Aviation Weather Center >To: Steve Emmerson <address@hidden> >Subject: Re: 20040918: Possible pqact issue in LDM? >Keywords: 200409091803.i89I3pnJ023109 The above message contained the following: > Sure... the story goes something like this. > > AWC has a NorthupGrumman NOAAPort receiver system, which is pretty > much just a stripped down AWIPS CP. On this system, we have some > software from FSL that can talk to the AWIPS CP software and for each > product received on the NOAAPort, insert it into the LDM queue. So, > we also have LDM running on this system, configured as a pure data > source (no 'request' lines in ldmd.conf) to feed the NOAAPort data to > other systems in the center. Now, to make a record of the time that > each product reaches the center on NOAAPort, the LDM on the receiver > has a small pqact.conf that, for each AWC product, EXEC's a script to > put a one-line product in the queue that contains the current wall > clock time, the server name, product name, etc. to give us a record of > the time that the product arrived from NOAAPort. > > Now, down stream from the NOAAPort receiver, there is an LDM client > with a pqact configured that stores all these 'receive notification' > in to a file by product, by day. We also keep a similar log of every > transmit of every product from the center. Then, we have a script > that takes the send log entries and matches them up with the receive > log entries to determine delay and to monitor if the NWSTG drops a > product When ever there is a missing receive entry that is 'too old', > an alarm goes up on our monitoring software (Nagios is the package we > are using). So, when there is an alarm on Nagios (and I catch it in > time before things are flushed from the queue) I quickly log into the > NOAAPort receiver to check > 1) is the product in the queue > 2) is the receive notice in the queue > 3) is there a log entry from the receive notice script that it attempted > to put a notice in the queue > 4) and when I was running pqact -v, was there an entry that pqact saw > the product go by > > So far, each time there has been a problem reported 1) has been fine, > the product was in the queue, but 2) was not and there was no entry > in 3) indicating that the script had attempted to run. When I was > running 'pqact -v' over the weekend I noticed that there were 'chunks' > of headers missing when comparing the list of headers to what 'pqcat' > displayed in the queue. For example, looking over about 40 minutes > of the queue, there were about 255 products in 13 'chunks' that pqcat > listed in the queue, that the 'pqact -v' didn't report seeing. > > Probably too much detail :-) Not at all. Are you checking the product-queue too soon after being notified? Is the missed data-product later acted-upon by pqact(1), indicating that it was merely delayed? Do you have a saved product-queue that pqcat(1) indicates contains data-products that pqact(1) missed? If so, if you manually execute pqact(1) on this product-queue, does it find the "missed" data-products, e.g., echo '<<feedtype>> (<<pattern>>) EXEC -wait echo \1' >conf pqact -vl- -o <<time>> -q <<pq>> conf where <<feedtype>> Is the feedtype of a data-product that pqact(1) missed. <<pattern>> Is the pattern of a data-product that pqact(1) missed. <<time>> Is the age of the oldest data-product in the product-queue in seconds (use pqmon(1) to determine this). <<pq>> Is the pathname of the saved product-queue. Are there non-printing characters in the product-identifier of the "missed" data products that cause them to not be matched? You can check the product-identifiers with pqcat -vl- -f <<feedtype>> -p <<pattern>> -q <<pq>> -i 0 | od -c Regards, Steve Emmerson
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