On Sat, Oct 4, 2014 at 12:35 PM, Jack Krupansky <[email protected]> wrote: > I tried to follow all of the trunk 6/branch 5x discussion, but... AFAICT > there was no explicit decision or even implication that a release 5.0 would > be imminent or that there would not be a 4.11 release. AFAICT, the whole > trunk 6/branch 5x decision was more related to wanting to have a trunk that > eliminated the 4x deprecations and was no longer constrained by > compatibility with the 4x index – let me know if I am wrong about that in > any way! But I did see a comment on one Jira referring to “preparation for a > 5.0 release”, so I wanted to inquire about intentions. So, is a 5.0 release > “coming soon”, or are 4.11, 4.12, 4.13... equally likely?
I created a branch_5x because 3.x index support was responsible for multiple recent corruption bugs, some of which starting impacting 4.x indexes. Especially bad were: LUCENE-5907: 3.x back compat code corrupts (not just can't read) your index. LUCENE-5934: 3.x back compat code corrupts (not just can't read) your 4.0 index. LUCENE-5975: 3.x back compat code reports a false corruption (was indeed a bug in those versions of lucene) for 3.0-3.3 indexes. Whenever I see patterns in corruptions then I see it as a systemic problem and aggressively work to do something about it. I've seen several lately, but these are the relevant ones: 3.x back compat: 3.x didn't have a codec API, so its wedged in, and pretty hard. Its not that we were lazy, its that its radically different: doesn't separate data by fields, sorts terms differently, uses shared docstores, writes field numbers implicitly, ... We try to emulate it the best we can for testing, but the emulation can't really be perfect, so in such places: surprise, bugs. The only way to stop these corruptions is to stop supporting it. test infrastructure: IMO lucene 4 wasn't really ready to support multiple index formats from a test perspective, so we cheated and try to emulate old formats and rotate them across all tests. This works ok, but its horrible to debug (since these are essentially integration tests), the false failure rate is extremely high, and the complexity of the implementation is high. Its not just that it misses to find some bugs, it was actually directly responsible for corruption bugs like LUCENE-5377. But throughout 4.x, we have fixed the situation and added BaseXYZFormat tests for each part of an index format. Now we have reliable unit tests for each part of the abstract codec API: adding new tests here finds old bugs and prevents new ones in the future. For example I fixed several minor bugs in 4.x's CFS code just the last few days with this approach. there are also other patterns like deleting files, commit fallback logic, exception handling, addIndexes, etc that we have put substantial work into recently for 5.0. Whatever was safe to backport to bugfix releases, we tried, but some of these kinds of "fixes" are just too heavy for a bugfix branch, and many just cannot even be done as long as 3.x support exists. There is also some hardening in the 5.0 index format itself that really could not happen correctly as long as we must support 3.x. So its not just that 3.x causes corruption bugs, it prevents us from moving forward and actually tackling these other issues. This is important to do or we will just continue to "tread water" and not actually get ahead of them. So I did something about it and created a 5.x branch. Worse case, nobody would follow along, but I guess I just assumed the situation was widely understood. > > Open questions: What is Heliosearch up to, and what are Elasticsearch’s > intentions? > I don't see how this is relevant. The straw the broke the camel's back for me was LUCENE-5934, and it doesn't impact elasticsearch. --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
