Re: Compress Object command -- MIDRANGE-L

Mike Cunningham wrote:

Early this week I had asked about using the CHGPGM command to remove
observability and compress program sizes that all responders said to
forget about. One mentioned using the Compress Object CPROBJ command to
save on space usage and speed up backups. Is anyone using this command
on a regular basis to reduce the size of objects that can be compressed
that only get used infrequently like year-end processes? If you do run
it do you only compress your own objects or do you do a system wide

compress?


Mike:

I run CPROBJ under various circumstances and get excellent results,especially when I want to create savefiles to ship to other systems.As you found, it only works on some object types; but it can do verywell for the objects that work.

Keep in mind that it's a _temporary_ compression and that it cantechnically increase the amount of storage in use on your systemunder some odd circumstances. That's because both temporarilydecompressed versions of the objects can exist at the same time asthe compressed versions. (Usually that's only a few of the variousobjects at a time.)

However, I'm not yet clear on why you wouldn't use CHGPGM RMVOBS()first. Did you actually test it?

I can get a lot of space savings in *PGM objects via RMVOBS() atleast up to V5R3, both OPM and ILE. And it's not 'temporary' in thesame sense as CPROBJ.

Note that you can chose RMVOBS(*ALL) or some subset ofobservability, particularly for ILE programs. Also note that somecreation data might be retained for programs created V5R1 or laterregardless of what you specify. When you remove observability, youmust recompile to get the observability back if you need it.


Tom Liotta

I am considering running this CPROBJ OBJ(*ALLUSR/*ALL) OBJTYPE(*ALL)
DAYS(90) every week end when system use is low.  Or would CPROBJ
OBJ(*ALL/*ALL) OBJTYPE(*ALL) DAYS(90) be a better choice.

I did a test on our development library which has 2,915 objects. 2,901

were scanned by CPROBJ, 464 were able to be compressed and space usage
for the library went from 3,924,838,912 down to 3,833,350,656. Not a big
change.  But, of the 464 objects that were compressed space usage went

from 150,269,952 down to 58,781,696. Not bad.