DualListSelector - tree variant performance improvements

[kmcfaul]

Large data sets for DualListSelector have a large amount of latency as well (same structure as TreeView). Memoization similar to TreeView (PR #6362) should be implemented here as well. Potentially also investigate using a non-recursive solution for further performance improvements.

[ddonahue007]

We are seeing latency in Cost Management when we have large data sets (40,000 or so children under one folder). I will pull together more details on what we are seeing if it is helpful.

[dlabrecq]

I did some performance testing with the dual-list in our settings page. Tested the page loading time for 1k, 5k, 10k, 20k, and 40k items.

When adding items to the available list, the page loads in about 600ms. It didn't seem to matter if there were 1k or 40k items. However, when those same items are added to the chosen list; instead, there is a huge performance hit.

For 40k chosen items (i.e., our current use case), I'm seeing page loads of 55 seconds.

• 40k is about 55s
• 20k is 12s
• 10k is 6s
• 5k is 3s
• 1k is less than 2s.

Note that there is also a performance hit just to select, move, and sort options client-side. When selecting and moving between lists, I'm selecting just the folder.

Not sure if string lengths make a difference, but here is an example of what I used: