Vladimir Ozerov created IGNITE-7015:
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Summary: 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
Fix For: 2.4
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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