mongodb/mongo — pull request #608 by dstorch (2014-01-12 21:25:01+00:00)
Title: SERVER-12296 cache a backup plan for blocking sort solutions

If the winning solution chosen by the multi plan runner has a blocking sort, then try and cache a non-blocking sort plan in addition to the winner. The cached plan runner then will fall back on the backup plan if the blocking sort fails due to an out-of-memory error.