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https://issues.apache.org/jira/browse/IGNITE-7015?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16504989#comment-16504989
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Nick Pordash commented on IGNITE-7015:
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[~vozerov] do you have a rough ETA when this might be released? The performance
implications are so critical that I'm considering manually applying the PR to
each release and rolling a custom build until then, which is obviously not a
great situation to be in. For context, without this optimization in place I
would need to have a cluster 3x-4x bigger just to absorb the excessive B+Tree
updates.
> SQL: Index should be updated only when relevant values changed
> --------------------------------------------------------------
>
> Key: IGNITE-7015
> URL: https://issues.apache.org/jira/browse/IGNITE-7015
> Project: Ignite
> Issue Type: Task
> Components: sql
> Reporter: Vladimir Ozerov
> Assignee: Roman Kondakov
> Priority: Major
> Labels: iep-19, performance
>
> See {{GridH2Table.update}} method. Whenever value is updated, we propagate it
> to all indexes. Consider the following case:
> 1) Old row is not null, so this is "update", not "create".
> 2) Link hasn't changed
> 3) Indexed fields haven't changed
> If all conditions are met, we can skip index update completely, as state
> before and after will be the same. This is especially important when
> persistence is enabled because currently we generate unnecessary dirty pages
> what increases IO pressure.
> Suggested fix:
> 1) Iterate over index columns, skipping key and affinity columns (as they are
> guaranteed to be the same);
> 2) Compare relevant index columns of both old and new rows
> 3) If all columns are equal, do nothing.
> Fields should be read through {{GridH2KeyValueRowOnheap#getValue}}, because
> in this case we will re-use value cache transparently.
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