A 5.x Solr could have indices that are still in a 4.x format, right? That would be one point where it's not "fully back compatible."
On Tue, Feb 23, 2016 at 12:27 PM, Shai Erera <[email protected]> wrote: > Wait, what do you mean by Lucene not supporting back-compat? Lucene 6.0 > will be able to read Lucene 5.0 indexes. The only thing that we don't > guarantee support for is API, which isn't the case here. > > So what's in 6.0 that can't read a 5.x Solr. It can't be the index format > since that's supported by Lucene. Is it the ZK format? If so, should we try > to "version" it so that a 6.0 code can read a 5.x version? Is it something > else / additionally? > > Shai > > On Tue, Feb 23, 2016 at 7:06 PM Mark Miller <[email protected]> wrote: > >> Yes, we are allowed wide berth to break backcompat across major versions >> and we cannot support rolling updates for the same reason Lucene stopped >> trying to do full back compat across major versions. Without, we can't >> properly innovate in the code or fix past mistakes and would also burn lots >> of cycles we don't have on crazy, "sophisticated" back compat layers. >> >> We don't even really support rolling updates between major versions. We >> make a simple best effort. Until we have tests, it's going to be a shaky >> affair. There is a JIRA open now working on some testing I believe. >> >> - Mark >> >> On Tue, Feb 23, 2016 at 11:29 AM Shai Erera <[email protected]> wrote: >> >>> Hi >>> >>> I read in few emails/issue comments that rolling upgrades from 5.x to >>> 6.0 isn't supported. Is it really the case? Does it mean that anyone who >>> has a 5.x Solr cluster *must* incur down time when upgrading to 6.0? >>> >>> If this is really the case, can someone list the known issues/reasons >>> for that?Can we do something about it, e.g. in a subsequent 5.6 release >>> that will allow rolling upgrades (like the 5.4.1 fix that allowed rolling >>> upgrades from pre-5.4 to 5.4)? >>> >>> I feel it's odd (and may not be taken well) if we force users to take >>> down their entire cluster if they want to upgrade to 6.0. Definitely feels >>> like it will also slow down 6.0 adoption. >>> >>> And if nothing can be done, what's the recommended way then to upgrade >>> to 6.0? >>> >>> Shai >>> >> -- >> - Mark >> about.me/markrmiller >> >
