Sybase IQ going to Unresponsive Mode

[former_member246062]

Hi All,

We r using  Sybase IQ 16.0 SP11 on HP-UX  as a Simplex environment with '20' RLV enabled tables.

Its been 4 to 5 times this IQ server went to Unresponsive Mode within a span of one month since we moved this into Prodcution .

This had created a panic situation wherein which now we had a doubt that , is this really a Stable Product or not?

If someone had gone through the same , help us to overcome this situation.

Thanks,

Yuavraj Subramani

[tayeb_hadjou · Accepted solution]

Hi Yuvaraj,

First of all, make sure IQ total memory configured (iqlm, iqtc, iqmc, ch) is less than 80% of total available physical memory before startin IQ.

At least 20% should be left to OS and other tasks, otherwise risk of overload.

Also, we recommend  SWAP =Total physical memory or upper.

By the way, I'd advise review guidlines below

SAP Sybase IQ 16 Hardware Sizing Guide: http://scn.sap.com/docs/DOC-41455

Regards

[markmumy · Accepted solution]

For systems dedicated to IQ and with 256gb RAM or more, I would make sure that -iqmc, -iqtc, and -iqlm are each 30% of total RAM.  That leaves 10% for the OS and its needs.  As you grow about 1 TB of RAM, the 10% can be lowered even more as most unix variants don't need 10%, but rather 20-50 GB of RAM for such large systems.

Also, make sure that -gn is set to 1.5x the value of -gm.  This can cause slowdowns and even hanging as IQ waits on resources.

What is your use case for RLV?  Do you need row level locking for multiple concurrent write operations?

Mark

[former_member246062 · Accepted solution]

Hi Mark,

Thanks for the info. This is our CFG parameters having Physical Memory 287 GB.

-c 10240m

-gc 20

-gd all

-gl all

-gm 1000

-gn 1500

-gp 4096

-ti 5

-tl 0

-iqmc 51200

-iqtc 51200

-iqlm 51200

-iqrlvmem 51200

We do multiple writes on around 10 tables concurrently , but the number of users hitting @ same time will be less than 50.

swapinfo

	Kb	Kb	Kb	PCT	START/	Kb
TYPE	AVAIL	USED	FREE	USED	LIMIT	RESERVE	PRI	NAME
dev	452984832	0	452984832	0%	0	-	1	/dev/vg00/lvol2
reserve	-	113360248	-113360248
memory	287130752	49741944	237388808	17%

Memory Information:

    physical page size = 4096 bytes, logical page size = 4096 bytes

    Physical: 301873952 Kbytes, lockable: 226619984 Kbytes, available: 256844412 Kbytes