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https://issues.apache.org/jira/browse/IGNITE-6663?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vladimir Ozerov updated IGNITE-6663:
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Labels: performance (was: )
> SQL: optimize primary key equality lookup
> -----------------------------------------
>
> Key: IGNITE-6663
> URL: https://issues.apache.org/jira/browse/IGNITE-6663
> Project: Ignite
> Issue Type: Task
> Security Level: Public(Viewable by anyone)
> Components: sql
> Reporter: Vladimir Ozerov
> Labels: performance
> Fix For: 2.4
>
>
> H2 perform every index search through {{BaseIndex.find}} method. It contains
> both {{first}} and {{last}} rows. If condition looks like {{attr = ?}}, then
> both bounds are the same. When this call is propagated to our {{BPlusTree}},
> then two index lookups occur:
> - Lower bound: {{BPlusTree#findInsertionPoint}}
> - Upper bound: {{BPlusTree.ForwardCursor#findUpperBound}}
> This is done for a reason because we do not know in advance how many elements
> are in between the bounds, so one lookup + scan is not an option in general
> case. But in case of PK lookup with equality condition, when we know in
> advance that only one row will be returned, this leads to additional
> unnecessary comparisons.
> Suggested fix:
> 1) Make sure that all rows in {{GridH2PlainRowFactory}} has correct
> {{equals}} implementation.
> 2) Inside {{H2TreeIndex#find}}: if this is PK index (see constructor args)
> and {{lower.equals(upper)}}, then use {{BPlusTree.findOne}} instead of
> {{BPlusTree.find}}.
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