* Zardosht Kasheff <zardosht@stripped> [10/04/22 16:03]:
> If I understand correctly, the flag HA_EXTRA_WRITE_CAN_REPLACE implies
> that handler::write_row can overwrite existing rows, if a duplicate is
> found. That is what the comment states, and that is what I heard NDB
> does in MySQL Cluster. If this is the case, then I assume that
> handler::write_row returns success even when the row is overwritten.
You can treat it in two ways:
- it is merely a hint, and the server doesn't expect any change
in the contract if it is set
- it never actually worked.
Both MyISAM and InnoDB engines ignore it,
(check storage/myisam/mi_extra.c,
storage/innobase/handler/ha_innodb.cc), which means you should do
it as well.
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