Function cdbCopySendData

src/backend/cdb/cdbcopy.c:241–277

* sends data to a copy command on a specific segment (usually * the hash result of the data value). */

 * the hash result of the data value).
 */
void
cdbCopySendData(CdbCopy *c, int target_seg, const char *buffer,
				int nbytes)
{
	SegmentDatabaseDescriptor *q;
	Gang	   *gp;
	int			result;

	/*
	 * NOTE!! note that another DELIM was added, for the buf_converted in the
	 * code above. I didn't do it because it's broken right now
	 */

	gp = getCdbCopyPrimaryGang(c);
	Assert(gp);
	q = getSegmentDescriptorFromGang(gp, target_seg);

	/* transmit the COPY data */
	result = PQputCopyData(q->conn, buffer, nbytes);

	if (result != 1)
	{
		if (result == 0)
		{
			/* We don't use blocking mode, so this shouldn't happen */
			ereport(ERROR,
					(errcode(ERRCODE_IO_ERROR),
					 errmsg("could not send COPY data to segment %d, attempt blocked",
							target_seg)));
		}
		else
			ereport(ERROR,
					(errcode(ERRCODE_IO_ERROR),
					 errmsg("could not send COPY data to segment %d: %s",
							target_seg, PQerrorMessage(q->conn))));
	}
}

/*
 * gets a chunk of rows of data from a copy command.