Re: [PATCH] SQL assertions prototype

David Fetter <david(at)fetter(dot)org> wrote:
> On Mon, Nov 25, 2013 at 11:04:23AM -0800, Kevin Grittner wrote:

>> As soon as we are out of this CF, I am planning to write code to
>> capture deltas and fire functions to process them "eagerly"
>> (within the creating transaction).  There has been suggestions
>> that the changeset mechanism should be used for that, which I
>> will look into; but my gut feel is that it will be better to
>> build a tuplestore of tids flagged with "old" or "new" around
>> the point that "after triggers" fire.  How close does that sound
>> to what CREATE ASSERTION (as currently envisioned) would need?
>
> It sounds *extremely* close to what we'd need for row access in
> per-statement triggers, as in probably identical.  The SQL syntax
> of this sub-feature is described in Foundation section 11.49 and
> called REFERENCING in CREATE TRIGGER.
>
> Do you have any prototypes I could use for that purpose?

No, but it is at the top of my list after the CF.  I will also need
an execution node type or two to produce the referenced rows for
the appropriate contexts, which is probably also very close to what
you need for per-statement triggers.  I will be happy to coordinate
work with you.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company