Hi On trying to open an old index using lucene 10.0.0 I'm getting this exception:
Exception in thread "main" org.apache.lucene.index.IndexFormatTooOldException: Format version is not supported (resource BufferedChecksumIndexInput(MemorySegmentIndexInput(path="/whatever.../segments_3"))): This index was initially created with Lucene 8.x while the current version is 10.0.0 and Lucene only supports reading the current and previous major versions. This version of Lucene only supports indexes created with release 9.0 and later by default. at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:351) at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:295) at org.apache.lucene.index.StandardDirectoryReader$1.doBody(StandardDirectoryReader.java:88) at org.apache.lucene.index.StandardDirectoryReader$1.doBody(StandardDirectoryReader.java:77) at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:807) at org.apache.lucene.index.StandardDirectoryReader.open(StandardDirectoryReader.java:110) at org.apache.lucene.index.StandardDirectoryReader.open(StandardDirectoryReader.java:67) at org.apache.lucene.index.DirectoryReader.open(DirectoryReader.java:60) which is clear enough and I can rebuild but the live indexes are big and 24x7 and I'm intrigued by "only supports ... by default". Is there something I can do to allow 10.0.0 to read 8.x indexes? That would help here. -- Ian.
