Re: execute table query in backend

[Anh Pham <atpham.wpi@xxxxxxxxx>]

Thank you for you suggestion.

I actually took a look at SPI_ functions before. However, I believe using this will bring quite an overhead.

I am trying to modify the Sequence scan node such that: each time the scan returns a tuple,
we'll take some information from this tuple. And finally issue another scan operation on a different table based on these information

On Thu, Mar 6, 2014 at 12:36 AM, Amit Langote <amitlangote09@xxxxxxxxx> wrote:

On Tue, Mar 4, 2014 at 12:38 AM, Anh Pham <atpham.wpi@xxxxxxxxx> wrote:
> Hi,
> I am trying to extend the server backend by writing a new module.
> Basically, it tries to retrieve tuples from a specific table using some
> predefined qualifications (equivalent to "SELECT FROM WHERE" client sql
> statement ).
> Is there any quick or efficient way to do this?

Assuming you're trying to write a server extension (and NOT a client
application), this is where you can start:

http://www.postgresql.org/docs/9.3/static/server-programming.html

Specifically, an interface called "server programming interface"
(chapter 44 on the above page) can be used to issue SQLs from a server
extension module. Read more about it here (documentation also includes
few examples to get started with):

http://www.postgresql.org/docs/9.3/static/spi.html

--
Amit

--

Anh T Pham

Computer Science

Worcester Polytechnic Institute