Request for additional SPI functions.

From: "Thomas Hallgren" <thhal(at)mailblocks(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Request for additional SPI functions.
Date: 2004-01-12 14:59:39
Message-ID: btucog$bjl$1@news.hub.org
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Short story:
I need two new functions in the Server Programming Interface (SPI) when
mapping an ExecutionPlan to a Java prepared statement (pljava project).

Long story:
My problem is that once a plan is prepared and I want to execute it, I send
an array of java objects for the arguments. The SPI_cursor_open/SPI_execp of
course expects the arguments to be Datum's and the mapper must convert java
objects. Knowing the Oid of each type, this is not a problem. Those are
hidden in the opaque execution plan (a void*). I'm all in favor of data
hiding and reluctant to use spi_priv.h so I propose that you add the
following two functions:

/*
* Returns the number of arguments for the prepared plan.
*/
int SPI_getargcount(void* plan)
{
if (plan == NULL)
{
SPI_result = SPI_ERROR_ARGUMENT;
return -1;
}
return ((_SPI_plan*)plan)->nargs;
}

/*
* Returns the Oid representing the type id for argument at argIndex. First
* parameter is at index zero.
*/
Oid SPI_getargtypeid(void* plan, int argIndex)
{
if (plan == NULL || argIndex < 0 || argIndex >=
((_SPI_plan*)plan)->nargs)
{
SPI_result = SPI_ERROR_ARGUMENT;
return InvalidOid;
}
return ((_SPI_plan*)plan)->argtypes[argIndex];
}

Regards,

Thomas Hallgren

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