How to form a self-defined TupleTableSlot

On Thu, Jul 26, 2012 at 11:39 PM, <Chaoyong.Wang@emc.com> wrote:

Here is my task situation:

I have a TupleTableSlot, with its own TupleDesc. Now I want to extract
several attributes to form a new TupleTableSlot, how can I define my own
TupleDesc and the ProjectionInfo?

You might get more helpful advice if you describe more specifically
what you're trying to do. I mean, here's one way to create a
TupleDesc (from contrib/adminpack) but it may or may not be suitable
for your purposes:

tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);

As ProjectInfo, maybe ExecBuildProjectionInfo?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company