Thanks Robert! Tom
> Start at SegmentMerger in both places. > > In 4.10.x you can see how it just validates every part of every reader > in a naive loop: > > https://github.com/apache/lucene-solr/blob/lucene_solr_4_10/lucene/core/src/java/org/apache/lucene/index/SegmentMerger.java#L58 > > in 5.x it is not done with this loop, instead responsibility for the > merge is in the codec API. > So this is done "fine-grained" for each part of the index, for example > in stored fields, we verify each reader's stored fields portion right > before we merge it in that individual piece: > > https://github.com/apache/lucene-solr/blob/branch_5x/lucene/core/src/java/org/apache/lucene/codecs/StoredFieldsWriter.java#L82 > > Note the default codec optimizes merge() more for stored fields and > term vectors with a bulk byte copy that verifies as it copies. > This bulk copy case is the typical case, when you aren't "upgrading" > old segments, using something like SortingMergePolicy, etc: > > https://github.com/apache/lucene-solr/blob/branch_5x/lucene/core/src/java/org/apache/lucene/codecs/compressing/CompressingStoredFieldsWriter.java#L355 > >
