Problem with ps command

[Blackbug]

I have a problem is executing few commands in my script.

i will describe steps to reproduce it.

1. set a variable PID's with 218 PIDS.

PIDs=4092092,4096180,4100336,4104412,4108416,4112630,4116536,4120794,4124888,4133020,4136982,4141290,4145288,4153372,4157504,4161578,4165774,4169780,4174010,4178052,4182200,4186186,4190404,4194394,4198608,4202634,4206610,4210920,4214846,4219066,4223048,4227172,4231384,4235398,4239472,4243680,4247742,4251860,4255948,4263978,4268234,4276348,4280326,4284512,4288720,4292638,4296842,4301048,4305032,4309134,4313134,4317194,4321364,4325390,4329570,4333790,4337914,4341958,4345918,4349952,4354112,4358386,4366380,4370656,4374734,4382764,4387042,4390942,4395242,4399184,4403258,4407388,4411552,4415514,4419678,4423708,4427808,4431940,4436146,4440222,4444322,4448316,4452456,4456658,4460642,4468932,4472900,4476974,4481040,4489308,4493474,4501526,4505744,4509710,4514046,4517952,4522104,4526254,4530340,4534422,4538552,4542646,4546714,4550684,4554956,4558870,4563048,4567266,4571348,4575426,4579542,4583480,4587588,4591830,4595920,4600038,4604116,4608234,4612340,4616390,4620302,4624480,4628498,4632598,4636900,4641006,4645118,4649214,4653290,4657272,4661468,4665466,4669694,4673554,4677662,4681802,4685826,4689960,4694044,4698132,4702268,4706306,4710478,4714506,4718600,4722710,4726800,4731056,4734986,4739136,4743196,4747272,4751438,4755468,4759594,4763866,4767784,4771900,4775996,4780212,4784174,4788272,4792372,4796638,4800586,4808764,4812940,4817102,4821016,4825340,4829416,4833514,4837402,4841588,4845746,4849856,4853878,4858092,4861998,4866072,4870162,4874414,4878486,4882564,4890658,4894940,4898900,4903158,4907144,4911310,4915286,4919386,4923398,4927720,4935716,4939948,4944008,4948016,4952196,4956298,4960462,4964584,4968462,4972750,4976730,4980764,4984986,4989016,4993274,4997122,5001470,5005398,5009532,5021850,5025866,5030078,5034194,5038146

2. Now use command ps to check

ps -o pidvsz -p ${PIDs} |wc -l

You can clearly see the difference in output. there are 218 pids but last command display only 128..

any idea why?

I am using AIX and ksh..

[Bachstelze]

Are you certain that a process exists for all the PIDs in your list? If there is no process for some PIDs, ps wil not print anything about them.