Around 6 months ago I started a project, and part of that project was to move us away from an old search tool to use elasticsearch.

I recently created a small utility that is ran in jenkins to create indicies in ElasticSearch.

The first versions took around 5 hours to index our massive data into elasticsearch. This was still better than the 9 hours, our old solution took, so no one was complaining.

One of the major slowdowns was a .Where() on a List<T>. When I wrote the tool this TODO was written

//TODO: use some kind of key lookup here, but we need non-unique keys and Dictionaries are unique only