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[TIGGE #LGY-600646]: Re: Missing fields from CMA


> Regarding the Product Queue, I really appreciate the concept
> and implementation of the Prouct Queue, I understand it in
> this way: based on the LDM Design, the size of Product Queue
> must be smaller than the size of RAM. My question is, would
> it be possible for LDM to use a Product Queue lager than the
> RAM, or the Product Queue will not be tightly mapped to the
> phisical memmory.

The LDM product-queue can be larger than physical memory *in
theory*.  In practice, however, this can greatly reduce the
performance of the LDM due to time spent swapping the product-
queue into and out of physical memory.  This is especially true
in high-volume situations such as yours.  We therefore
strongly recommend that you have sufficient memory to prevent
the product-queue from swapping to and from disk.

> I also have two more suggestions for the mechanisms of the
> Product Queue: one is, would it be possible for LDM to run
> multiple Product Queues concurrently, in order to seperate
> data regarding different characteristics, for example,
> incoming data go into one PQ, sending data be ingested into
> another PQ, or further seperate sending data to multiple
> sending PQ based on different feed type or some other
> properties, and so on? If yes, each PQ then only hold
> certain part of the complete data set that be handled by
> one PQ today.

Unfortunately, the LDM system is designed around one, and
only one, product-queue.  It is possible, however, to run
more than one LDM system on a single computer (each LDM
would have its own user account, of course).  A cleaner,
more direct solution, however, would be to have multiple
computers each running their own LDM.

> The other is, would it be possible to change the PQ to
> handle only metadata of each product, such as feed
> type, product file location, etc. Thus, the PQ probably
> is able to deal with much more products than when each
> complete product data be put into the PQ.

Good idea.  We've thought about it here.  Unfortunately,
it would take some months to implement.

> >     * run UPC's "uptime" script so that we can view time-series plots of
> >       operational parameters (we can install this monitoring tool whenever
> >       permission is granted)

> How does this tool work? What is the prerequisite for
> the installation and the "uptime" script to run?
> I mean do I need to prepare something?

The "uptime" tool is a python script that's run out
of the LDM user's "crontab" file --- usually, once
per minute.  It collects operational parameters such
as the age of the oldest product in the queue, the
number of connections, etc., and appends that
information to a file.  This allows us to make time
series plots in order to understand how the LDM is

Steve Emmerson

Ticket Details
Ticket ID: LGY-600646
Department: Support IDD TIGGE
Priority: Normal
Status: On Hold