[jira] [Created] (IGNITE-7015) SQL: index should be updated only when relevant values changed

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

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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