How to find packages installed on a Sitecore Instance

Few years back, one of the questions that I got from my manager was "Is there a way to detect/backtrack which packages are installed on a sitecore instance ?"

My answer was "No" to him at that time.

But, recently when I'm going through google, I found a blog post which describe a way to achieve this. Actually, this feature is already there in sitecore. We only have to know the where to look.

Login to Sitecore Desktop
Change database to "Core"
Open Content Editor and expand "/sitecore/system/packages/installation history" node

Here, you can view all the packages installed in the sitecore instance.
One thing to note that is, when you create the packages, remember to use the "Package name", "Author", "Version" fields as needed. Those field values are stored in the package installation history items.

For example, keeping "Package Name" as same for same type packages will store them under the same parent node in sitecore "/sitecore/system/packages/installation history" node.


Following blog post is about a simple tool/webpage to see the above information in a graphical way.
http://sitecorebasics.wordpress.com/2013/11/11/package-history-user-guide/


http://kirkegaard-at.blogspot.com/2013/10/sitecore-package-installation-history.html

Use of EnableEventQueue setting

When an item is updated and published, it did not get reflected on the website. But, when IIS cache is cleared, this new changes started to reflect on the website.

So, I looked into the code and could not find any issue. Then, I moved my focus to the sitecore configurations. Following are the steps that I tried/look.

1. Checked current website name is included in the <event name="publish:end"> node and <event name="publish:end:remote"> node.
    What this setting does is, it says to sitecore clear html cache of the sites specified in that event section, on publish.

2. Then, I looked into EventQueue table in the web database. It does not had any entries. So, that was the issue. So, I change "EnableEventQueues" setting to "true" on CM instance. This did the trick.

Reason for our issue was that sitecore is using EventQueue table entry to clear the cache on publish. Since there were no entries in the table, sitecore did not clear any cache.

Read following blog entries which describe the use of EventQueue table and settings in details to get a better understanding.

http://sitecorebasics.wordpress.com/2011/03/19/basics-of-sitecore-event-queue/
http://www.sitecore.net/Community/Technical-Blogs/Getting-to-Know-Sitecore/Posts/2010/07/Introducing-the-Sitecore-Event-Queue.aspx

Sitecore IDTable

Recently when I'm trying to clear some of my old documents, I found "Student handbook Web Site .NET developer" handbook. When I go through that document quickly, I saw an entry about "IDTable" in sitecore. Eventhough I have seen this table, I was not aware of the use of that table till now. So, I thought of writing a post regarding the IDTable table.

The IDTable

You can store persistent mappings of arbitrary keys to Sitecore IDs in the Sitecore IDTable. 

By default, this is only used by the Sitecore CMS WebDAV functionality to keep locks on media items in the CM environment and does not need to be synchronized with the CD environment

You configure the location of the IDTable in the web.config file in the IDTable section in the connectionStringName parameter:

<IDTable type="Sitecore.Data.$(database).$(database)IDTable, Sitecore.Kernel" singleInstance="true">   <param connectionStringName="master" />

  <param desc="cacheSize">500KB</param>

</IDTable>

To synchronize the contents of the IDTable between the CM and CD environments, change the connectionStringName parameter in the IDTable configuration section to point to a Core database that is shared or replicated between the environments. Alternatively, it can point to a shared Web database

          Quote "Sitecore CMS 6.6 or later - Scaling Guide"
          http://sdn.sitecore.net/upload/sitecore6/66/scaling_guide_sc66-a4.pdf


IDTable can be used for tasks like keeping track of duplicate items when doing a custom import from another third-party application to sitecore.
   Sitecore.Data.IDTables.IDTable.Add(string prefix, string key, ID id);
By keeping IDs of items that has already imported to sitecore, if you run the import more than once, you have the option of skipping the IDs that already had imported to the system by keeping/monitoring the IDTable entries.

You can find an old blog entry about IDTable from following url :
http://sitecoredev.blogspot.com/2005/11/idtable.html

Updated:
http://sitecorejunkie.com/2014/03/01/synchronize-idtable-entries-across-multiple-sitecore-databases-using-a-composite-idtableprovider/