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[LDM #DBK-582040]: 6.10.1 how to diagnose pqact memory leak?



Daryl,

> I stumbled back onto this today while diagnosing a filesystem issue.  For
> example:
> 
> # lsof /mesonet | grep 8681 | wc -l
> 288
> 
> where 8681 is a pqact process.  An example output is:
> 
> pqact    8681     ldm  295w   REG  9,127    849138  14697353
> /mesonet/data/text/sao/12111100.sao
> pqact    8681     ldm  296w   REG  9,127    843784  14702371
> /mesonet/data/text/sao/12111315.sao
> pqact    8681     ldm  297w   REG  9,127       108  14705360
> /mesonet/data/text/sao/12111317.sao
> 
> This seems problematic.

Seems OK to me.

> I thought pqact was limited to 32 file descriptors

The maximum number of open file descriptors is guaranteed by the POSIX standard 
to be at least 32.

The actual number can be found via the command "ulimit -a" or "getconf 
OPEN_MAX". On my system, the value is 1024.

> and would start recycling them once it reached this limit.

That's correct.

> Is there a need
> for these old descriptors to lay around or are they reused when possible ?

The "need" is that the LDM user didn't specify a "-close" option -- so they 
think a similar data-product that needs to be written to the same file or piped 
to the same decoder is likely to arrive very soon.

Nevertheless, if the pqact(1) process needs another file-descriptor and they're 
all in-use, then it will recycle the least-recently-used file-descriptor by 
closing it and reopening it to the new file or decoder.

> thanks for the education,

You're most welcome.

> daryl

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: DBK-582040
Department: Support LDM
Priority: Normal
Status: Closed