Re: [HACKERS] GSoC 2017: weekly progress reports (week 6) - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: [HACKERS] GSoC 2017: weekly progress reports (week 6)
Date
Msg-id db9b9447-a1d8-9fa6-6967-c88b6969d7a5@iki.fi
Whole thread Raw
In response to Re: [HACKERS] GSoC 2017: weekly progress reports (week 6)  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
List pgsql-hackers
On 09/04/18 18:04, Alvaro Herrera wrote:
> Heikki Linnakangas wrote:
> 
>> Remember, the purpose of predicate locks is to lock key ranges, not physical
>> pages or tuples in the index. We use leaf pages as handy shortcut for "any
>> key value that would belong on this page", but it is just an implementation
>> detail.
> 
> Hmm ... so, thinking about pending list locking, would it work to
> acquire locks on the posting tree's root of each item in the pending
> list, when the item is put in the pending list? (even if we insert the
> item in the pending list instead of its posting tree).

Hmm, you mean, when inserting a new tuple? Yes, that would be correct. I 
don't think it would perform very well, though. If you have to traverse 
down to the posting trees, anyway, then you might as well insert the new 
tuples there directly, and forget about the pending list.

- Heikki


pgsql-hackers by date:

Previous
From: Magnus Hagander
Date:
Subject: Re: Online enabling of checksums
Next
From: "Joshua D. Drake"
Date:
Subject: Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS