Hi,
Version 6.11.7 of the LDM has just been released. It fixes a bug that
caused the NOAAPORT ingest component to crash.
Here's the story:
The NOAAPORT Satellite Broadcast System contains a lot of GRIB-2 messages.
Such messages require external tables in order to be interpreted. The
NOAAPORT ingest component of the LDM uses the tables that come with GEMPAK
to interpret GRIB-2 messages in order to generate meaningful LDM
product-identifiers. Unfortunately, not all tables are complete and
creators of GRIB-2 messages are free to add data for which no corresponding
table-entry exists.
Stuff like that drives us crazy. So I added a diagnostic log message to the
GEMPAK function that interprets level or layer data to let us know when a
table entry was missing. In such a case, it would log the table lookup
information and the last entry in the table (for reference purposes).
Unfortunately, I thought a table would always have *some* entries in it.
I was wrong.
On February 25th, a GRIB-2 message was broadcast that resulted in a
completely empty table being given to the level/layer interpretation
function. The subsequent attempt to log the diagnostic message resulted in
the NOAAPORT ingestion process receiving a segmentation violation signal
(i.e., SIGSEGV). The rest of the LDM system then did what it's supposed to
when a child-process terminates abnormally: it shutdown.
The fix was easy once the cause was determined. A diagnostic message will
still be logged, but no SIGSEGV will occur.
Those of you who use the LDM to ingest NOAAPORT should upgrade to this new
version before another such GRIB-2 message is broadcast. As always, the
relevant URL is
<http://www.unidata.ucar.edu/software/ldm/<http://www.unidata.ucar.edu/software/ldm/index.html>
>.
Regards,
Steve Emmerson
