[jira] [Commented] (IGNITE-8723) Detect index corruption at runtime

["Vladimir Ozerov (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-8723?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16503349#comment-16503349 ] 

Vladimir Ozerov commented on IGNITE-8723:
-----------------------------------------

[~agoncharuk], I doubt it would work for MVCC. Consider an {{UPDATE}} or {{SELECT FOR UPDATE}} query which needs to take a lock on a key. All such queries must lock a kay on a primary node. 

I think more generic approach here is to disable an index cluster-wide. This is common practice in other databases - indexes could be switched off ("offline") either manually, or automatically in case of corrupt. We already has necessary infrastructure for this - exchange-like consensus protocol to initiate DDL change, and hidden indexes, which are not used in queries, but are still updated (we can disable it if needed). 

I think this would be better solution than adding more complexity to request routing logic which is already non trivial (partitioned vs replicated, multicast vsunicast, update w/ and w/o reducer, MVCC cases, etc).

> Detect index corruption at runtime
> ----------------------------------
>
>                 Key: IGNITE-8723
>                 URL: https://issues.apache.org/jira/browse/IGNITE-8723
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Alexey Goncharuk
>            Priority: Major
>             Fix For: 2.6
>
>
> Several times Ignite users faced a situation when SQL indexes were corrupted (linked to invalid or removed data).
> I think it makes sense to slightly rework such errors during index dereference, and
> 1) Fail all ongoing and further SQL queries assigned to this node. SQL mapper should cache this and try to re-route SQL requests to other OWNING nodes
> 2) After index corruption is detected, all or only corrupted indexes should be deallocated (the decision depends on what is faster) and rebuilt
> 3) After indexes are rebuilt, we should notify other nodes that the node is available for queries again



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