ignite-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ivan Pavlukhin (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (IGNITE-8841) MVCC TX: Read transactions remap when coordinator fails.
Date Mon, 04 Feb 2019 13:48:00 GMT

    [ https://issues.apache.org/jira/browse/IGNITE-8841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16759857#comment-16759857
] 

Ivan Pavlukhin commented on IGNITE-8841:
----------------------------------------

[~gvvinblade] please find my comments below.
# Can we get rid of {{MvccUtils.requestSnapshot as it mostly delegates to }}{{GridNearTxLocal}}?
# I did not get why do we need to call {{PreviousQueries.init}} from {{onLocalJoin}} callback?
It worth adding a comment explaining the idea.

> MVCC TX: Read transactions remap when coordinator fails.
> --------------------------------------------------------
>
>                 Key: IGNITE-8841
>                 URL: https://issues.apache.org/jira/browse/IGNITE-8841
>             Project: Ignite
>          Issue Type: Bug
>          Components: mvcc, sql
>            Reporter: Roman Kondakov
>            Assignee: Igor Seliverstov
>            Priority: Major
>              Labels: failover
>          Time Spent: 50m
>  Remaining Estimate: 0h
>
> At the moment read transactions that don't acquire topology lock will be forcibly rolled
back on topology change as read tx can be in fly while topology being change.
>  This is done to prevent having active transaction with stale snapshots on new topology
in cases of TX coordinator or Near node were lost.
>  
> It would be nice to remap it somehow until they locked a topology or at least throw some
meaningful exception to user.
>  For example, it is possible to obtain a new "write" mvcc version from the new coordinator
and use this version for all further writes while using "old" version for reads. In this case
we need to change visibility rules a little: "old" version should see "own" updates made
by "new" "write" version.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Mime
View raw message