topic performance in QlikView

performance

Mon, 26 Jan 2026 18:19:17 GMT

Hello

By idea of Rob I make very simple qvw document:

Load Recno( ) as A, Rand() as B autogenerate(10000000);

Reload on my local notebook is about 25 sec long.

Reload on our huge servers is about 46 sec long ! (servers are iddling before starting reload).

Offer:

Can other users respond how long is reloading this simple qvw on yours servers ?

Thanks

performance

pover — Sun, 03 Oct 2010 04:52:38 GMT

Hugo,

19 sec in a notebook with Windows 7, 8 GB RAM and 8 CPU system threads, but my notebook is also faster than some of the bigger servers. See the my following post.

http://community.qlik.com/forums/t/33509.aspx

Regards.

performance

Sun, 17 Oct 2010 09:20:31 GMT

Hello

Using 10 version reload duration on local PC is 15 sec !

good reason to upgrade to 10 version.

best regards

Hugo

performance

Sun, 17 Oct 2010 22:34:17 GMT

Just tried this test on my machine and it takes 9 seconds 😛

Whilst I am using QV10 and using all cores (i7 920 cpu which has a clock speed of 2.67GHz), I would also mention that the bus speed between CPU and RAM is 1GHz so it should be fast....... not to mention having overclocked RAM 🙂

Some of these servers are quite big and have lots of resources, but they are usually tailored to throughput and capacity rather than sheer response speed. A reload that is CPU heavy and is trying very hard to load things into RAM might take longer on a server that has a lot of cores but with lower clock speeds/specifications. However when scaling and serving hundreds of users it will do a better job than a small desktop with a single core running at 3.2GHz. Horses for courses.

performance

Mon, 18 Oct 2010 09:25:34 GMT

Laptops are optimized for low power usage = slow disks, narrow buses, slow memory, small CPU cache.

If the "idle big servers" are slower than a notebook, throw them away.

-Alex

performance

Tue, 19 Oct 2010 20:39:32 GMT

I agree with Alex, makes no sense having better response times on laptop. We are experiencing this kind of behaviour in a customer right now, and I can tell you the customer is pissed off. We ran testing software on the server to discard any failure on hardware, the test did not show any failure, on the other hand I showed that the server was performing better on cpu intensive calculations and access to RAM, since the processor has a 4-memory-channel. I'm suspecting that the current implementation of QlikView has problems dealing with several cores and multi-threading, my theory is that probably the software is dividing the task into so many threads that the amount of actual work for every thread is little and the overhead of communication probably is over killing performance. On the other hand, it might not be QlikView itself, but the Windows scheduler that might not be ready to successfully allocate this type of tasks.

Regards

performance

Thu, 21 Oct 2010 12:52:58 GMT

Hi,

Disable CPU hyperthreading. Suppose there is sizeable amount of memory, so don't let Windows automatically manage the size of the pagefile. Use a fixed amount of pagefile, ex 2 GB. The old mantra swap = two times the memory does not apply for a tool called "in memory analytics"; you really need data to fit in memory.

To do a one-to-one comparison with laptop, limit QVS service from using all CPU cores from QEMC : System : Setup: QlikView Servers : Performance : CPU affinity. Choose same amount of cores as in the laptop. Use the Windows task manager to really see the rest of the CPU cores idle.

-Alex

performance

Thu, 21 Oct 2010 15:12:19 GMT

Hi Alex, we have tried disabling hyper threading and reducing the CPU affinity, the results we got were better but not really what we expected. We have run test in 5 different servers, so far we have had the best results on xeon quad core processors. The next step is try in another server with several quad core processors and see if the performance improve comparing the single quad core cpu architectures we had tried. I suppose having cpu with more than four cores mess up performance because of the shared cache memory, imagine every core trying to write on the shared buffer at once. Anyway, we will let you know how this issue ends.

Regards.

performance

Fri, 22 Oct 2010 07:06:04 GMT

Instead of setting affinity 11110000 00000000, set 10001000 10001000 . That uses only real CPU cores, not threads

-Alex

performance

Fri, 22 Oct 2010 15:20:23 GMT

Thanks Alexandru, for some reason QlikView will only allow to reduce the number of cores by half maximum. I'll continue do testing.

Regards

performance

Wed, 03 Nov 2010 09:01:00 GMT

Same thing here :

- My laptop is Core 2 Duo @ 2.33 GHz with 2 Gb of RAM (Windows XP) : 24 seconds to reload (QV 9 SR 6).

- My client server has 16 cores with 32 Gb of RAM (Windows 2008 Server SP 2) : 36 seconds to reload (QVS 9 SR 6).

I tried to disable hyperthreading, that makes the process slightly slower.

performance

Wed, 03 Nov 2010 09:29:29 GMT

To make a fair comparison, set your idle server to use only 2 out of 16 cores with affinity mask = 00000001 00000001 (binary) = 0101 (hexa)

Schedule a batch file OR type every now an than during the testing in PowerShell


powershell -command "& { get-process qvb | foreach{ $_.processoraffinity=0x0101} }"

-Alex

performance

Wed, 03 Nov 2010 09:34:52 GMT

QV server does logging, job scheduling etc. 12 seconds overhead to a 30 seconds job is just noise.

Problem is when reload takes four hours in laptop, and eight hours in server.

-Alex

performance

pover — Wed, 03 Nov 2010 19:23:47 GMT

Alex has a good point about 12 seconds being noise, so what would happen if nmartin adds a couple zeros to the autogenerate?

Regards.

performance

prieper — Sun, 07 Nov 2010 20:37:04 GMT

On my notebook (2*2.4GHz Processors): 26s
On the server (8*2.5Ghz): 28s, but some other processes running in parallel

Peter

performance

Fri, 20 Apr 2012 09:00:19 GMT

Hello

Reload process is single core (single CPU) ?

in version 10 it is running connect64 process and qvb process.

Newer see 100% CPU using when reloading.