| From: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
|---|---|
| To: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
| Cc: | Shubham Barai <shubhambaraiss(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Andrew Borodin <amborodin86(at)gmail(dot)com>, Kevin Grittner <kgrittn(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Subject: | Re: GSoC 2017: weekly progress reports (week 4) and patch for hash index |
| Date: | 2017-09-29 14:50:48 |
| Message-ID: | CAPpHfdsCe0_saXKdGXeugjJ6_y8UARAcPjT2ApRpVPCqQ4B3-Q@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Sep 8, 2017 at 4:07 AM, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
wrote:
> Hi Shubham,
>
> On Tue, Jun 27, 2017 at 9:21 PM, Shubham Barai <shubhambaraiss(at)gmail(dot)com>
> wrote:
> > If these two hash keys (78988658 and 546789888) mapped to the same
> bucket, this will result in false serialization failure.
> > Please correct me if this assumption about false positives is wrong.
>
> I wonder if there is an opportunity to use computed hash values
> directly in predicate lock tags, rather than doing it on the basis of
> buckets. Perhaps I'm missing something important about the way that
> locks need to escalate that would prevent that from working.
+1,
Very nice idea! Locking hash values directly seems to be superior over
locking hash index pages.
Shubham, do you have any comment on this?
------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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