Refresh Tree, Partial Re-Indexing

I've been doing a lot of work recently with large data loads, and I've been trying to find ways to optimize the time that my site has to spend rebuilding indexes.

It used to be, after each data import I would kick off a full index rebuild programmatically. Because of the large amounts of data and computed fields, each rebuild was taking a long time and led to me using Hot Swappable Indexes.

An optimization I found that helped with this was how to only re-index the new data that I just added. You can call the method IndexCustodian.RefreshTree() on a folder, and only it and its children will be re-indexed.

The code for this...

     var database = Sitecore.Data.Database.GetDatabase("master");
     Item dataFolder = database.GetItem(new ID(Settings.GetSetting("CourseFolderId")));
     SitecoreIndexableItem indexableFolder = new SitecoreIndexableItem(dataFolder);
     Sitecore.ContentSearch.Maintenance.IndexCustodian.RefreshTree(indexableFolder);

This is essentially the same functionality as clicking the Re-Index Tree button in the Developer ribbon.

Doing this reduced the time spent on re-indexing after an import by a large amount.

One side-note, the RefreshTree() method returns a collections of Jobs that you could then monitor their progress if you wanted. You can read more about Jobs here.