[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[LDM #MWC-865643]: PQACT Utility



LB,

> Steve,
> 
> Thanks for responding.

No worries. That's why were here. :-)

> We have the EXEC statements defined and they work for other experimental 
> products.  Just so I understand, I cannot use pqact from the command-line to 
> process a product that is currently in the queue?

You can use pqact(1) from the command-line -- it's just not intended to be used 
that way for performance reasons. When a data-product is inserted into the 
product-queue by a downstream LDM process, a SIGCONT is sent to the LDM 
server's process-group and received by all pqact(1) processes that were creates 
as a result of EXEC entries in the LDM configuration-file. This signal causes a 
pqact(1) process to "wake up" and check the product-queue for the added 
product. This type of "even driven" design performs much better than having the 
pqact(1) processes poll the product-queue for added products.

As a fail-safe measure, a pqact(1) process *will poll* the product-queue if it 
doesn't receive a SIGCONT for 15 seconds. So a pqact(1) process that's external 
to the LDM process-group will still work -- just not as efficiently (there will 
be, on average, a 7.5 second delay in processing data-products). This 
polling-interval is settable via the "-i" option (a polling-interval of 0 will 
cause the pqact(1) process to terminate when it reaches the end of the 
product-queue).

I hope this helps.

> lb

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: MWC-865643
Department: Support LDM
Priority: Normal
Status: Closed


NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.