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Maximum number of questions in the survey

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7 years 5 months ago #165860 by shiva522
Maximum number of questions in the survey was created by shiva522
Hello.

Created a poll where there are several dozen groups, each with several questions. When you reach a certain number of such groups, when I try to activate a poll, I get a message:

The poll response table can not be created. This is usually caused by too many (sub-) questions in the survey. Try to reduce the number of questions.

Tell me please what is the maximum number of questions in the survey can be and why such restrictions are caused (a restriction on the number of columns in the table mysql, restrictions in the limesurvey itself or something else)?
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7 years 5 months ago #165866 by Joffm
Replied by Joffm on topic Maximum number of questions in the survey
Hi,

Read the manual here:
www.limesurvey.org/manual/General_FAQ#Wh...does_LimeSurvey_have ...
regarding survey size and max number of columns.

So, you should try to split your survey.

Regards
Joffm
Volunteers are not paid.
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7 years 5 months ago - 7 years 5 months ago #165872 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
I read the documentation for your link.

Judging from the documentation: the maximum line size can not be more than 65535 bytes. The size of 1 character is 3 bytes. Therefore, 21 844 characters are maximum for the string.

Now we look at my table, with which the question arose.

The first 8 standard fields of the lime_survey_XXXXXX table are approximately 119 characters + the TEXT - ip field of the respondent. Further at me in the table 1617 fields varchar (5). If 1617 * 5 = 8085 characters.

As a result, 8085 + 119 = 8204 characters, which is much less than 21 844 characters. Where did I misunderstand?
Last edit: 7 years 5 months ago by shiva522.
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7 years 5 months ago #165877 by Joffm
Replied by Joffm on topic Maximum number of questions in the survey
What type of table?
MyISAM or InnoDB?
InnoDB has only about 1000 columns.

But nevertheless you have to restructure your survey.

Split it and use end-url.

Joffm
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7 years 5 months ago #165878 by jelo
Replied by jelo on topic Maximum number of questions in the survey

shiva522 wrote: Now we look at my table, with which the question arose.

How do you inspect a table, which LimeSurvey hasn't created?

Since it all depends on your survey structure and your database configuration, a feedback will depend on knowing both. What version of LimeSurvey is used?

I would recommend to copy the survey and remove some parts. Just to find out, where your installation of LimeSurvey is hitting the limit. It might be impossible to create the survey design in LimeSurvey at the moment.

The roadmap acknowledges the limit issue and developers plan to change the database handling in the future.

Refactor answer database to get rid of column limitations.

www.limesurvey.org/manual/LimeSurvey_roa...eased_.28Feb_2018.29
The meaning of the word "stable" for users
www.limesurvey.org/forum/development/117...ord-stable-for-users
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7 years 5 months ago #165923 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
I know that InnoDB allows no more than 1000 columns. MyISAM table type
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7 years 5 months ago - 7 years 5 months ago #165924 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
I use Toad for MySQL 7.3 for inspecting MySql tables.
2.72.2 version of limesurvey which i use.

about the decrease in the number of questions in the survey, I did it when I encountered this problem. if we reduce the number of columns to 8 service + 1554 varchar (5) columns - the table is created

The decision to split the survey into two parts as a way out of this situation I took yesterday. However, I would like to know where I exceeded the limits? Is this related to the limitations in the limesurvey or are these the limitations of Mysql? This is the initial question .. I was asked by my boss and he waiting for an answer from me
Last edit: 7 years 5 months ago by shiva522.
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7 years 5 months ago #165926 by Joffm
Replied by Joffm on topic Maximum number of questions in the survey
It's MySQL

dev.mysql.com/doc/mysql-reslimits-excerp...umn-count-limit.html

Joffm
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7 years 5 months ago #165933 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
I've already read all this. As I understand there is no definite answer. if I did not make a mistake with the calculations, I did not reach the maximum line size of 65535. As a result of the calculation, I get less than 24000+ bytes the size of the string. from which it can be concluded that limesurvey itself limits the number of acceptable questions in polls.
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7 years 5 months ago #165937 by jelo
Replied by jelo on topic Maximum number of questions in the survey

shiva522 wrote: from which it can be concluded that limesurvey itself limits the number of acceptable questions in polls.

The activation error message states that the response table cannot be created correctly. So I would conclude that you cannot inspect a table inside the database which hits the limits.

To learn how the error is triggered, you will need to hope for a core developer to show up.
Or dig inside the code, which is available on GITHUB.
You might start from here: github.com/LimeSurvey/LimeSurvey/blob/ma.../activate_helper.php .
The meaning of the word "stable" for users
www.limesurvey.org/forum/development/117...ord-stable-for-users
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7 years 5 months ago - 7 years 5 months ago #165946 by Joffm
Replied by Joffm on topic Maximum number of questions in the survey
Hi, and what did ddrmoscow tell you in your crosspost in the Russian section?

Please, avoid crossposting at the same time.

I just tried to create your table which you described in the Russian section.
Outside LS, just by running the SQL in phpMyAdmin. If you use TOAD, well, that's the same.
And I failed.


So maybe the best you ask in a MySQL-Forum.

Joffm
Volunteers are not paid.
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Last edit: 7 years 5 months ago by Joffm.
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7 years 5 months ago #166126 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
"ddrmoscow" asked clarifying questions about my topic but he has no answer.

About what to do if Limesurvey reports that the maximum allowed number of questions in the survey is exceeded, this is understandable. Divide the survey into several surveys.

It is not clear why my calculations are the maximum row size and less than what MYSQL allows and the limesurvey table does not allow creating. I assume that the restrictions are from limesurvey and not from MYSQL. But these are only assumptions based on conjectures. But I would like to know for sure.

I think this discussion should be completed, since no one knows the answer and does not waste your time guessing.

Nevertheless, thanks for the help.
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7 years 5 months ago #166138 by Joffm
Replied by Joffm on topic Maximum number of questions in the survey
Just one more answer,

did you try to create your table in MySQL?

As I wrote I tried and failed; you see the screenshot.

So the easy answer to your problem "But I would like to know for sure." is:
If you are able to create it with TOAD or phpMyAdmin outside LS, it's a LS issue, if not, it's a MySQL restriction.


Joffm
Volunteers are not paid.
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7 years 5 months ago #166154 by jelo
Replied by jelo on topic Maximum number of questions in the survey

shiva522 wrote: I think this discussion should be completed, since no one knows the answer and does not waste your time guessing.

Open a bugticket in the tracker with the limit size gap. That way you might get the direct attention of the developers of LimeSurvey. Currently none of them has joined this discussion thread here.
The meaning of the word "stable" for users
www.limesurvey.org/forum/development/117...ord-stable-for-users
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7 years 5 months ago - 7 years 5 months ago #166230 by shiva522
Replied by shiva522 on topic Maximum number of questions in the survey
The question can be considered closed.

Limitations, as far as I understand, come from MySql itself.

 In "Toad for mysql" I tried manually creating a table based on the script of the created table and adding fields of the same type and dimension (varchar (5)) to the number where I encountered the problem. Experimentally (reducing the number of fields) reached the 1575 field, when the table allows creating.

After, I tried varchar (5) instead of varchar (1). The result is the same. 1575 fields - the number at which I was able to create the table.
So Limesurvey has nothing to do with it.

Thank you all for your help.
Last edit: 7 years 5 months ago by shiva522.
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