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Horrible performance in 1.90

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6 years 3 months ago #52305 by tdaplyn
Hi all,
We recently upgraded our LimeSurvey install from 1.85 to 1.90 version.
Since then we have experienced massive performance problems.
The system is installed on Win Server 2008 with SQL Express 2005 DB.
As a temporary solution while we try to understand what is happening, our hosting company added an extra CPU for us (virtual machine) and doubled the RAM to 2gb but we've seen DB use of CPU hit 100% again.
We're getting survey responses in the tens, hundreds at most, not thousands.
I can't believe we're the only ones to be experiencing this problem?
A quick and dirty trace of the DB looks like a huge number of cursor calls retrieveing hierarchical sub-question data.
It it possible that the re-design around sub-questions has caused this issue?
Is it possible that the upgrade script has removed or failed to add some critical indexes?
We've obviously going to undertake some major structured performance testing starting with a downgrade back to 1.85 and work up from there but this will take time and in the mean time we're suffering badly!

Any ideas for quick fixes we could try?

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6 years 3 months ago #52306 by holch
Hmm, I have the impression, that whenever those issues come up, that a windows server is involved. Maybe there is an issue with Limesurvey and windows server? (that is just my impression that I got being on the forum quite frequently, but it might be something to look at).

I'm not a LimeSurvey GmbH member. I answer at the LimeSurvey forum in my spare time. No support via private message.
Some helpful links: Manual (EN) | Question Types | Workarounds

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6 years 3 months ago #52325 by tdaplyn
Hmmm. Us Windows platform users tend to be a little reticent to reveal that we're using it, as it's all too easy to point at Windows and identify that as the issue.
We will certainly test the survey on fresh linux and win installs as part of tracking down the issue.
It's just strange that it's happenned since the upgrade to 1.90 and the DB heat seems to be around 'subquestion' queries. Remember - it's SQL Server that's hogging CPU, not the PHP process. It's possible that something has gone wrong with the SQL Express setup. Alternatively, limesurvey is asking it to do silly things.

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6 years 3 months ago #52328 by holch
Hi Tdaplyn,

I am not saying it IS Windows. I just have seen quite a few posts with performance issues and problems that usually do not appear. In my impression most of them were either using a windows server / mssql.

I think most LS developers use a Linux/Apache/PHP/MySQL combination. I can imagine that sometimes there might slip something through for MSSQL.

Was just thinking that this could be an issue that needs to be look at.

I'm not a LimeSurvey GmbH member. I answer at the LimeSurvey forum in my spare time. No support via private message.
Some helpful links: Manual (EN) | Question Types | Workarounds

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6 years 3 months ago #52369 by Mazi
it is always hard to track these errors but if we can narrow it down, we can try to solve it. Some testing recommendations:
- test a simple, small survey
- test if conditions might be the cause
- try to track problems down by manually removing different question types from the survey
- switch to different survey modes (question by question vs all in one)

Every feedback is welcome!


Best regards/Beste Grüße,
Dr. Marcel Minke
(Limesurvey Head of Support)
Need Help? We offer professional Limesurvey support
Contact: marcel.minke(at)survey-consulting.com'"

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6 years 1 week ago #56940 by johnnyp112
Did you resolve this performance issue? We are currently running v1.90+ Build 9642 and each page loads up very slow from the Administration page as well as the surveys. We're running this on Windows Server 2003 and MySQL.

Any recommendations?

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6 years 1 week ago #56942 by Mazi
Can you test the recommendations I made above so we can try to track down the error?


Best regards/Beste Grüße,
Dr. Marcel Minke
(Limesurvey Head of Support)
Need Help? We offer professional Limesurvey support
Contact: marcel.minke(at)survey-consulting.com'"

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6 years 1 week ago #56998 by johnnyp112
Yes, I've tried what you suggested but it's not specific to any one survey but the issue is with the site as a whole. I've just tried updating PHP and the performance issue persists. I'm thinking about bringing up another server with Windows 2008 R2 and see if that helps any.

Also, I just learned that FastCGI was enabled on this server so that may be the culprit.

Thanks!

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6 years 1 week ago #57002 by Mazi
MS software sometimes seems to cause such problems. Using Apache and MySQl might be an alternative solution.


Best regards/Beste Grüße,
Dr. Marcel Minke
(Limesurvey Head of Support)
Need Help? We offer professional Limesurvey support
Contact: marcel.minke(at)survey-consulting.com'"

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5 years 11 months ago #58104 by johnnyp112
I resolved this.

When upgrading to 1.90 there were added configuration changes that needed to be updated in config.php. After adding the new configuration and restarting IIS the performance is back to normal.

So Windows wasn't an issue.

Thanks for everyone's advice/suggestions.

Johnny

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5 years 11 months ago #58120 by DenisChenu

johnnyp112 wrote: were added configuration changes that needed to be updated in config.php.

What is the change you have to made to reslove this issue ?

Assistance on LimeSurvey forum and LimeSurvey core development are on my free time.
I'm not a LimeSurvey GmbH member, professional service on demand (or search sondages pro).

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5 years 11 months ago #58144 by johnnyp112
I had the bare minimum configuration that worked well for 1.87. The defaults from defaults_config.php was used and we just updated our information into it.

I suspect it had to do with the Advanced Setup where it explicitly lists where the admin scripts, tmp, and images are located.

I didn't have that listed before and LimeSurvey may have took some time looking for those directories.

See the attached for all the additional configurations that were added.
Attachments:

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