I've moved indexes from the indexing module to the core module, but I did not move H2Mvcc*IO classes that are responsible for storing MVCC data in indexes. Also for other indexes code I've skipped some blocks with if-condition that checks if cache is MVCC or not.
Actually, there isn't so much code to back if we decide to not drop MVCC support for indexes right now. But maybe it is better to implement a checker that checks that there are still MVCC indexes and fails to start with a link on a migration doc? On Thu, Mar 25, 2021 at 3:13 PM Alexei Scherbakov < alexey.scherbak...@gmail.com> wrote: > Maksim, > > It seems to me from the description "Patch completely breaks MVCC" the > proposed patch should be postponed until at least the public API for > MVCC will be removed. > > Or can you clarify the impact of the patch ? Does the existing MVCC > functionality will remain unbroken ? > > > чт, 25 мар. 2021 г. в 14:52, Andrey Mashenkov <andrey.mashen...@gmail.com > >: > > > Hi Maksim, > > > > Do you mean MVCC will not work at all or MVCC will not support indices > > after your changes? > > Anyway, this looks like a major change and may be too harmful for the > minor > > version (10.1). > > > > Before break MVCC index (or MVCC mode) we should force the user first to > > drop all MVCC indices (or even MVCC caches) before switching to the > version > > with a fix. > > The migration process should be well-documented as well. > > > > I believe a user should be able to migrate to the new Ignite version with > > exited persistence with no issues. E.g. > > * Ignite shouldn't start if existed persistence has a MVCC index (cache) > > and maybe other internal persistent MVCC structures. > > * Even if the user dropped all MVCC indices/caches before the upgrade, > > probably there can be an incomplete checkpoint and there are WAL records > > related to MVCC in WAL that should be correctly processed. > > > > > > > > > > On Thu, Mar 25, 2021 at 1:27 PM Maksim Timonin <timonin.ma...@gmail.com> > > wrote: > > > > > Hi, Igniters! > > > > > > the MVCC feature marked as IgniteExperimental and this annotation is > more > > > weaker than deprecated. So we can remove this functionality in any > > moment. > > > So I propose: > > > 1. Now I leave all affected tests marked as ignored. > > > 2. Create a ticket for removing TRANSACTIONAL_SNAPSHOT from > > > CacheAtomicityMode for a future minor release 10.1. > > > 3. There is a ticket for removing all MVCC code [1]. So we can finish > it > > in > > > any release for future. > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-13871 > > > > > > WDYT? > > > > > > > > > On Mon, Mar 15, 2021 at 9:58 PM Maksim Timonin < > timonin.ma...@gmail.com> > > > wrote: > > > > > > > Hi, Igniters! > > > > > > > > I'm working on a feature (moving indexes to the core module) and skip > > > > specific implementation for MVCC as it is considered deprecated (the > > vote > > > > result [1]). Am I right that now there is no need to support MVCC? > Then > > > > there are a lot of tests (both Java, C++) that fail because they run > > with > > > > TRANSACTIONAL_SNAPSHOT atomicity mode. > > > > > > > > There are 2 cases: > > > > 1. MVCC mode is just a parameter of a test. I just removed it from a > > > > parameters list; > > > > 2. There are tests that run only for MVCC. I marked them with the > > @Ignore > > > > annotation. > > > > > > > > But would it better just completely remove all such tests that are > > broken > > > > by the patch? > > > > > > > > [1] > > > > > > > > > > http://apache-ignite-developers.2346864.n4.nabble.com/RESULT-VOTE-Removing-MVCC-public-API-td50705.html#a50706 > > > > > > > > > > > > > -- > > Best regards, > > Andrey V. Mashenkov > > > > > -- > > Best regards, > Alexei Scherbakov >
