Function SerializeParamExecParams

src/backend/executor/execParallel.c:357–407

* Serialize specified PARAM_EXEC parameters. * * We write the number of parameters first, as a 4-byte integer, and then * write details for each parameter in turn. The details for each parameter * consist of a 4-byte paramid (location of param in execution time internal * parameter array) and then the datum as serialized by datumSerialize(). */

 * parameter array) and then the datum as serialized by datumSerialize().
 */
static dsa_pointer
SerializeParamExecParams(EState *estate, Bitmapset *params, dsa_area *area)
{
	Size		size;
	int			nparams;
	int			paramid;
	ParamExecData *prm;
	dsa_pointer handle;
	char	   *start_address;

	/* Allocate enough space for the current parameter values. */
	size = EstimateParamExecSpace(estate, params);
	handle = dsa_allocate(area, size);
	start_address = dsa_get_address(area, handle);

	/* First write the number of parameters as a 4-byte integer. */
	nparams = bms_num_members(params);
	memcpy(start_address, &nparams, sizeof(int));
	start_address += sizeof(int);

	/* Write details for each parameter in turn. */
	paramid = -1;
	while ((paramid = bms_next_member(params, paramid)) >= 0)
	{
		Oid			typeOid;
		int16		typLen;
		bool		typByVal;

		prm = &(estate->es_param_exec_vals[paramid]);
		typeOid = list_nth_oid(estate->es_plannedstmt->paramExecTypes,
							   paramid);

		/* Write paramid. */
		memcpy(start_address, &paramid, sizeof(int));
		start_address += sizeof(int);

		/* Write datum/isnull */
		if (OidIsValid(typeOid))
			get_typlenbyval(typeOid, &typLen, &typByVal);
		else
		{
			/* If no type OID, assume by-value, like copyParamList does. */
			typLen = sizeof(Datum);
			typByVal = true;
		}
		datumSerialize(prm->value, prm->isnull, typByVal, typLen,
					   &start_address);
	}

	return handle;
}

/*
 * Restore specified PARAM_EXEC parameters.