row hash locks

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Enthusiast

row hash locks

When tpump update a row, I understand that it does a row hash lock. Based on this, I suspect that this means that all the rows with the pi values that hash to the same value as the pi being updated will be locked.
(Please correct me if I'm wrong) I can see where this may cause blocking.

When tpump does inserts however, I don't understand why there are blockers.

Can someone explain this?
Thank you.
2 REPLIES
Enthusiast

Re: row hash locks

Inserts require row hash write locks.

This required for purposes such as duplicate row checking, duplicate value checking(for unique) and not to mention to avoid any read transactions from occurring on the same row hash etc.
Enthusiast

Re: row hash locks

That was perfect.
thank you very much.