Hi, > On Jun 23, 2023, at 2:34 PM, Yixun Xu <yix...@gmail.com> wrote: > > Hello, > > I have a service that creates and manages Lucene indices. The service is > using Lucene 8 and I want to upgrade to Lucene 9, and I would like to be > able to rollback the upgrade in case I encounter any issues (*). The > problem is that the older version of the service won't be able to read the > segments created after the upgrade because they would be created using > Lucene 9's codec. > > One potential solution is to keep writing new indices using Lucene 8's > codecs after upgrading to Lucene 9, and only start using Lucene 9's codec > after some time. However this doesn't seem to be officially supported: the > lucene-backward-codecs package provides older codecs, but they are > read-only. > > My questions are: > 1. I can try copying over the actual codecs from Lucene 8 instead of using > lucene-backward-codecs, but is this actually supposed to work, or will > there be undefined behaviors when the codec is used with Lucene 9? > 2. Is there an alternative solution to support rollbacks?
This is probably not the solution you are looking for, but the way we manage this is to have a higher level logical version (including Lucene codes, backwards-incompatible document format changes, etc). We read all indexing operations off of a Kafka topic, and each index format version independently keeps Kafka offsets. So, after upgrading to index format X+1, rolling back to index format X will also rewind the Kafka consumers and they will replay any missed indexing operations immediately. > > Any help would be greatly appreciated! > > Best regards, > Yixun Xu --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
