Re: Do we actually need an ItemId array on nbtree pages containingfixed-width tuples? - Mailing list pgsql-hackers

From Andrey Borodin
Subject Re: Do we actually need an ItemId array on nbtree pages containingfixed-width tuples?
Date
Msg-id 92DDB751-189E-4AA2-9703-C94371B6A98D@yandex-team.ru
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In response to Do we actually need an ItemId array on nbtree pages containingfixed-width tuples?  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Do we actually need an ItemId array on nbtree pages containingfixed-width tuples?
List pgsql-hackers
Hi, Peter!

> 4 дек. 2017 г., в 4:55, Peter Geoghegan <pg@bowt.ie> написал(а):
> Thoughts?

I like the idea of more compact B-tree.
Chances are that I didn't understood all your ideas.

But ItemId's let you insert a tuple among two existing tuples without data movement. New tuple is places wherever free
spacestarts. You just shift bytes in ItemId array. 
And you always have to insert tuple in specific position, since B-tree relies on tuple order.

Best regards, Andrey Borodin.

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