Re: Next Steps with Hash Indexes - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Next Steps with Hash Indexes
Date
Msg-id CANbhV-FN4xP7ssDK01zmcUZTxG3dRd4=P1KL+k2RsEkufgJEAA@mail.gmail.com
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In response to Re: Next Steps with Hash Indexes  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
On Tue, Jul 20, 2021 at 1:26 PM Amit Kapila <amit.kapila16@gmail.com> wrote:

> One more thing we need to think about here is when to find the right
> bucket page in the chain where we can insert the new tuple. Do we
> first try to complete the uniqueness check (which needs to scan
> through the entire bucket chain) and then again scan the bucket with
> space to insert or do we want to do it along with uniqueness check
> scan and remember it?

The latter approach, but that is just a performance tweak for later.

On a unique hash index, regular splitting means there are almost no
bucket chains more than 2 long (bucket plus overflow), so it seems
like mostly wasted effort at this point.

-- 
Simon Riggs                http://www.EnterpriseDB.com/



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