Re: Learning to hack Postgres - Keeping track of ctids

On 30 September 2016 at 04:15, Emrul <emrul@emrul.com> wrote:
> Hi,
>
> I'm working on an idea to implement a graph database in Postgres.  At the
> moment its just a learning exercise.
>
> What I'd like to do is store a reference to all the links from one record
> using an array type that stores links to all related tables.
>
> At first, I've succeeded in doing this using primary key Ids and this works
> fine.  However, I'd like to be able to bypass the index lookup altogether by
> storing the ctids in my array instead of the primary key ids.
>
> Trouble of course is that ctids can get changed (like for instance
> vacuuming).  So my question is: how can I keep my ctid references up to date
> - is there any way to detect when a ctid is changed?

I expect that you'd have to teach the heapam code, vacuum, etc to do
the required housekeeping.

-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services