In practice what would this mean? We relax the restriction that David mentions, and we keep old codecs around in backwards-codecs for two major releases instead of one? Are there other implications? Suppose we had a Query that relied on a specific index format, which gets retired. We keep the index format code around - do we also need to remember to maintain the old Query?
-Mike On Wed, Jan 6, 2021 at 4:41 AM Simon Willnauer <[email protected]> wrote: > > Hello all, > > Currently Lucene supports reading and writing indices that have been > created with the current or previous (N-1) version of Lucene. Lucene > refuses to open an index created by N-2 or earlier versions. > I would like to propose that Lucene adds support for opening indices > created by version N-2 in read-only mode. Here's what I have in mind: > > - Read-only support. You can open a reader on an index created by > version N-2, but you cannot open an IndexWriter on it, meaning that > you can neither delete, update, add documents or force-merge N-2 > indices. > > - File-format compatibility only. File-format compatibility enables > reading the content of old indices, but not more. Everything that is > done on top of file formats like analysis or the encoding of length > normalization factors is not guaranteed and only supported on a > best-effort basis. > > The reason I came up with these limitations is because I wanted to > make the scope minimal in order to retain Lucene's ability to move > forward. If there is consensus to move forward with this, I would like > to target Lucene 9.0 with this change. > > Simon > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
