LockObtainFailedException and SwitchOnRebuildLuceneIndex in Sitecore 7

"LockObtainFailedException" is a common error in Sitecore 7. For most of the cases, it will occur when you try to access the index file while the index is still building. The error will looks like something like below,

In Sitecore 7, it introduces the "SwitchOnRebuildLuceneIndex". (Sitecore.ContentSearch.LuceneProvider.SwitchOnRebuildLuceneIndex) It will create a "xxx_sec" .e.g "sitecore_index_web_sec)" index folder and build a new set of indexes for Sitecore to switch on when rebuilding index is happening.

I recommend Sitecore set this as default provider.