Hi, We (at Amazon product search) have customized TieredMergePolicy to
1. make it easy to configure merge-on-commit merges 2. to ensure no merged segment is accidentally too big a percentage of the total index thus harming effective within-query concurrency and long-pole query latencies. If this community feels this is useful, I am happy to open a jira and contribute a patch that will add it to Lucene's sandbox module. Thanks, Anand
