Alexey Goncharuk created IGNITE-6933:
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Summary: Consider executing updates in-place when SQL indexes are
present or object size is smaller than the old object size
Key: IGNITE-6933
URL: https://issues.apache.org/jira/browse/IGNITE-6933
Project: Ignite
Issue Type: Task
Security Level: Public (Viewable by anyone)
Reporter: Alexey Goncharuk
Currently, we are able to execute in-place updates when the new object size
exactly matches the old object size and SQL indexes are absent. This leads to a
significant performance cost because of extra FreeList updates and extra
indexes updates when only one field has changed.
A few possibilities which should be carefully examined:
1) Allow in-place updates if a new object size is smaller than the old object
size (allow some space leak into the data page) and defer FreeList update to
some later time (introduce a threshold?)
2) Examine (or propagate) the list of changed fields and allow in-place updates
if indexed fields did not change
3) Investigate if we can implement an in-place update even with indexed fields
- first, remove the value from indexes, then update, then insert value to
indexes (note that there is a window when the value is not accessible via
indexes in this case, so this is not a safe option). Also, do not update
indexes if the indexed value did not change
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