MoodleDocs - User contributions [en]

Feedback settings

2009-09-17T14:27:39Z

Deanthayer: Changed section heading to Site after submit / Page after submit

{{Feedback}}After selecting Feedback from the Activities menu, you will be presented with a list of options for '''setting up a Feedback'''.

=== Name ===

Give your Feedback a title.

=== Description ===

This text will be displayed to users before they enter the feedback.

=== Open and Close Feedback ===

This allows you to set a time period during which the Feedback will be available to responses.

=== Record User Names ===

Choose from the following options:
* Anonymous
* Users' Names Will Be Logged and Shown With Answers

=== Show analysis to students ===

Yes/No. The summary results can be shown to respondents, or shown only to teachers.

=== Send E-Mail-Notifications ===

Yes/No. Notifications will be sent to the Moodle site administrators upon the submission.

=== Multiple submit ===

Yes/No, for anonymous polls allow unlimited answers for every user, for polls where the user name is logged this allow users to resubmit their answers.

=== Site after submit / Page after submit ===

This allows you to present users with a message after completion. If you want students to be sent somewhere or to see something other than "Your answers have been saved" after completing a Feedback activity, you can put a URL in '''Site after submit''' and/or some text in '''Page after submit''' respectively. If you fill them both in, the students will first see whatever text you put in '''Page after submit''', then click '''Continue''' and be sent to the URL in '''Site after submit'''. If you leave them both blank, the students will just see a "Your answers have been saved" message. Neither of these fields are required for a student to answer the questions, but they must click the '''Answer the questions...''' link to start the Feedback activity.

=== Group mode ===

The group mode can be one of three levels:

* No groups - There are no sub groups, everyone is part of one big community
* Separate groups - Each group can only see their own group, others are invisible
* Visible groups - Each group works in their own group, but can also see other groups

The group mode can be defined at two levels:

* Course level - The group mode defined at the course level is the default mode for all activities defined within that course
* Activity level - Each activity that supports groups can also define its own grouping mode. If the course is set to [[Force group mode|"force group mode"]] then the setting for each activity is ignored.

=== Visible to students ===

You can hide the activity from students by selecting "Hide" here. It is useful if you wouldn't like to make the activity available immediately.

[[Category:Feedback]]
[[Category:Teacher]]

Feedback settings

2009-09-17T14:23:58Z

Deanthayer: Added more detail about how Site after submit and Page after submit work.

{{Feedback}}After selecting Feedback from the Activities menu, you will be presented with a list of options for '''setting up a Feedback'''.

=== Name ===

Give your Feedback a title.

=== Description ===

This text will be displayed to users before they enter the feedback.

=== Open and Close Feedback ===

This allows you to set a time period during which the Feedback will be available to responses.

=== Record User Names ===

Choose from the following options:
* Anonymous
* Users' Names Will Be Logged and Shown With Answers

=== Show analysis to students ===

Yes/No. The summary results can be shown to respondents, or shown only to teachers.

=== Send E-Mail-Notifications ===

Yes/No. Notifications will be sent to the Moodle site administrators upon the submission.

=== Multiple submit ===

Yes/No, for anonymous polls allow unlimited answers for every user, for polls where the user name is logged this allow users to resubmit their answers.

=== Page after submit ===

This allows you to present users with a message after completion. If you want students to be sent somewhere or to see something other than "Your answers have been saved" after completing a Feedback activity, you can put a URL in '''Site after submit''' and/or some text in '''Page after submit''' respectively. If you fill them both in, the students will first see whatever text you put in '''Page after submit''', then click '''Continue''' and be sent to the URL in '''Site after submit'''. If you leave them both blank, the students will just see a "Your answers have been saved" message. Neither of these fields are required for a student to answer the questions, but they must click the '''Answer the questions...''' link to start the Feedback activity.

=== Group mode ===

The group mode can be one of three levels:

* No groups - There are no sub groups, everyone is part of one big community
* Separate groups - Each group can only see their own group, others are invisible
* Visible groups - Each group works in their own group, but can also see other groups

The group mode can be defined at two levels:

* Course level - The group mode defined at the course level is the default mode for all activities defined within that course
* Activity level - Each activity that supports groups can also define its own grouping mode. If the course is set to [[Force group mode|"force group mode"]] then the setting for each activity is ignored.

=== Visible to students ===

You can hide the activity from students by selecting "Hide" here. It is useful if you wouldn't like to make the activity available immediately.

[[Category:Feedback]]
[[Category:Teacher]]

Arguments in favour of PostgreSQL

2008-07-28T20:17:02Z

Deanthayer: Spelling and sentence structure corrections.

Martin Langhoff argues '''in favour of PostgreSQL''' (source: [http://moodle.org/mod/forum/discuss.php?d=24831#121862 Moodle over webct and LNLS at Athabasca University?] forum posting)

There are several reasons to go with Postgres, I'll try to make a brief outline. We run a variety of RDBMSs at Catalyst, and have a lot of in-house experience with them: Oracle, Postgres, MySQL and Progress, plus a few others. We also have experience with replicated databases, clustering and other tricks -- which we use for the backend of the .nz root domain servers as well as a few other mission-critical systems.

On the performance side, Postgres requires a bit more up-front configuration than MySQL. A well tuned Postgres is pretty close on SELECT performance to MySQL with small databases. With large tables MySQL has some bad performance problems, and Postgres performs much better.

Write performance is also an issue with MySQL -- with a lot of traffic, it has serious problems with concurrent writes. Under heavy load, Postgres performs much better.

But to tell you the truth, the real reason for choosing Postgres is reliability. We maintain a lot of databases, and Postgres is rock-solid reliable and has a focus on ACID-correctness: when it returns from a commit, the data is safely on disk and won't be lost -- barring actual disk problems, which we offset using RAID-1.

No matter how hard we try, MySQL databases with a lot of usage have recurring index corruption issues. If you look at the startup scripts for MySQL on most Linux distributions, they check for data corruption on every startup -- this is to mask the fact that it is a frequent occurrence.

And while this is passable with small installations where the data isn't mission critical, you have to consider how much you can trust such approch. And with large datasets, runing isamchk/myisamchk can take hours -- we cannot afford that.

The clustering solution for MySQL is being touted a lot, and I think it is a red herring. My main concern about is that it writes "asynchronously" -- that is, there is no guarantee that your data is on-disk safely. It'll get to the disk sometime. It'll get to the slaves... sometime. Hmmm.

Given that the MySQL cluster uses async writes, splitting read/writes between the master and the slaves breaks down in cases where we write some data, and read it back in immediately (or soon after). And this does happen in quite a few places.

And you also have to consider the performance boost of using async writes: if you tell a standalone Postgres or MySQL to use async writes, it'll scale much better (should be able to handle up to 3-4 times more simultaneous writes). Once you do that, the performance advantage of the MySQL cluster mostly vanishes. It still has semi-hot takeover in case the master goes down, but Postgres can do that using Slony, and with better guarantees of consistency of the data in the slave.

In a nutshell, MySQL isn't normally very solid when it comes to ensuring my data is safely stored on-the-disk, even if it theoretically guarantees that it's been saved. And MySQL Cluster says up-front that there isn't a guarantee any more. Riiiiiight wink

Michael is talking about having UPSs. We have a car-sized UPS and a container-sized on-site generator that auto-starts. And yet, I wouldn't depend on that for my DB consistency on a large Installation. So many things other than power can (and do) go amiss. If a process has a problem storing the data, the right thing is to tell that back to the user. With async writes, you end up with a queue of data that hasn't been stored yet, but you already told the user it was.

That's not what a database is supposed to do.

I am currently exploring some techniques similar to those being used in livejournal and slashdot. We should be able to increase Moodle scalability by cutting down on DB load by about 50%. This is happening slowly in the gaps between more urgent projects. Feel free to ping Richard or me if you're interested in that track.

===See Also===
* [https://docs.moodle.org/en/Step-by-step_Install_Guide_for_Ubuntu#Install_Postgresql_.28skip_MySQL.29 Installing Postgres on Ubuntu(Debian)]
[[Category:Administrator]]
[[Category:Performance]]

[[pl:Argumenty za PostgreSQL]]
[[ja:PostgreSQLを使う理由]]

Groups

2007-10-09T12:58:36Z

Deanthayer: According to the Groups FAQ, there is no way to assign specific activities to specific groups.

{{Course admin}}
The '''Groups''' feature allows a teacher to assign teachers and students to a group within a course. Participants in a course can belong to more than one group (Moodle 1.6 onwards).

==Groups pre-1.9==
The Groups edit page has three columns:

* ''People in the course'' - both assigned and unassigned participants.

* ''Groups'' - A list of groups available for this course.

* ''Members of selected group'' - When you select a group this column will display the members of that group

Underneath each column are the options for that column.

[[Image:000.jpg|frame|left|groups administration page]]
<br style="clear:both;">

To create new groups, type the group name in the text box and click the adjacent ''Add new group'' button. You can add a description to this group using the ''Edit group settings'' button.

To add a participant(s) to a group you need to select their name in the first column (use shift or ctrl for multiple selections), select the group you wish to add them to from the centre column, and then click the ''Add selected to group ->'' button.

To remove participants from a group, select the appropriate group to view members, select the participants to remove and click the ''Remove selected members'' button.

==Group modes==

The group mode can be defined at two levels:

* Course level - the group mode defined at the course level is the default mode for all activities defined within that course. This is determined in the course [[Settings|settings]]

* Activity level - each activity that supports groups can also have its own group mode defined. If the course setting "Force group mode" is set to "Yes" then the option to define the group mode for individual activities is not available i.e. there is no Groups icon [[Image:Groupn.gif]] next to activities on the course page.

There are three group modes:

;No groups
:There are no sub groups, everyone is part of one big community.

;Separate groups
:Each group can only see their own group, others are invisible.

;Visible groups
:Each group works in their own group, but can also see other groups.

==Groups in Moodle 1.9 onwards==
{{Moodle 1.9}}

An attempt to add groupings to Moodle 1.8 was made; however, it was decided to remove this functionality until it can be better tested and integrated with other parts of Moodle (i.e. modules, gradebook, etc.). The initial interface has been modified so that groupings no longer appear as part of the user interface in Moodle 1.8.

In Moodle 1.9, the concept of Groupings will be introduced: a way of organizing various groups in a hierarchical structure. While this approach may prove to be more powerful, using groups is no longer as intuitive. For example, a teacher teaches four sections of the same class. The teacher could have 4 groupings (i.e. one for each section). Within those sections the teacher could assign various students to various groups within the groupings.

=== How to add students to groups in Moodle 1.9 ===
To add students to a group, the teacher must follow these steps.
# [[Create grouping|Create a grouping]]
## Click the "Create grouping" button.
## Enter the "Grouping name" and optionally a description.
## Click the "Create grouping" button.
# [[Create group|Create a group]] in the grouping
## Select the title in "Groupings" that you just created.
## Click the "Create group in grouping" button.
## Enter the "Group name" and optionally a description.
## Optionally, enter an Enrollment key. (If you define a '''group enrolment key''' then not only will entering that key let the user into the course, but it will also automatically make them a member of this group.)
## Click the "Create group" button.
# [[Assign users to group|Assign users to the group]].
## Select the title in "Groups in: Groupings" that you just created
## Click the "Add/remove users" button.
## In the "Potential members" list, select the students you want to add to the group.
## Click the arrow button that points towards the "Existing members" list.
## That's all
### Click the "Back to groups" button to return for more editing.
### Click the "Participants" link to see the participants list and the pull-down menu to see "Separate groups."

=== Screen shot (Beta Version?)===
It looks slightly different now.

[[Image:Groups_screenshot_18.jpg|frame|left|groups administration page]]
<br style="clear:both;">

When the user clicks on the Add/Remove users button, they are brought to the [[Assign users to group]] page with a list of the potential users that can be added to the group. The user then has the option of hitting the return button to go back and view the groupings, groups in groupings and the members of the groups.

===Orphan groups===
Groups can be created outside of groupings. A pseudo-grouping is provided as "Not in a grouping", and contains all groups that do not belong to any grouping (i.e. orphan groups). This functionality is there to handle imports of groups from previous versions or other sources. It is advised that all groups created using this interface are created within groupings.

==See also==

*[[Groups FAQ]]
*[http://moodle.org/mod/forum/view.php?id=1490 Using Moodle: Groups] forum

[[Category:Groups]]

[[fr:Groupes]]
[[ja:グループ]]