Ejemplo n.º 1
0
/*
 * utility routine for *_rank functions.
 */
static bool
rank_up(WindowObject winobj)
{
	bool		up = false;		/* should rank increase? */
	int64		curpos = WinGetCurrentPosition(winobj);
	rank_context *context;

	context = (rank_context *)
		WinGetPartitionLocalMemory(winobj, sizeof(rank_context));

	if (context->rank == 0)
	{
		/* first call: rank of first row is always 1 */
		Assert(curpos == 0);
		context->rank = 1;
	}
	else
	{
		Assert(curpos > 0);
		/* do current and prior tuples match by ORDER BY clause? */
		if (!WinRowsArePeers(winobj, curpos - 1, curpos))
			up = true;
	}

	/* We can advance the mark, but only *after* acccess to prior row */
	WinSetMarkPosition(winobj, curpos);

	return up;
}
Ejemplo n.º 2
0
/*
 * rank
 * Rank changes when key columns change.
 * The new rank number is the current row number.
 */
Datum
window_rank(PG_FUNCTION_ARGS)
{
	WindowObject winobj = PG_WINDOW_OBJECT();
	rank_context *context;
	bool		up;

	up = rank_up(winobj);
	context = (rank_context *)
		WinGetPartitionLocalMemory(winobj, sizeof(rank_context));
	if (up)
		context->rank = WinGetCurrentPosition(winobj) + 1;

	PG_RETURN_INT64(context->rank);
}
Ejemplo n.º 3
0
/*
 * percent_rank
 * return fraction between 0 and 1 inclusive,
 * which is described as (RK - 1) / (NR - 1), where RK is the current row's
 * rank and NR is the total number of rows, per spec.
 */
Datum
window_percent_rank(PG_FUNCTION_ARGS)
{
	WindowObject winobj = PG_WINDOW_OBJECT();
	rank_context *context;
	bool		up;
	int64		totalrows = WinGetPartitionRowCount(winobj);

	Assert(totalrows > 0);

	up = rank_up(winobj);
	context = (rank_context *)
		WinGetPartitionLocalMemory(winobj, sizeof(rank_context));
	if (up)
		context->rank = WinGetCurrentPosition(winobj) + 1;

	/* return zero if there's only one row, per spec */
	if (totalrows <= 1)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8((float8) (context->rank - 1) / (float8) (totalrows - 1));
}
Ejemplo n.º 4
0
/*
 * cume_dist
 * return fraction betweeen 0 and 1 inclusive,
 * which is described as NP / NR, where NP is the number of rows preceding or
 * peers to the current row, and NR is the total number of rows, per spec.
 */
Datum
window_cume_dist(PG_FUNCTION_ARGS)
{
	WindowObject winobj = PG_WINDOW_OBJECT();
	rank_context *context;
	bool		up;
	int64		totalrows = WinGetPartitionRowCount(winobj);

	Assert(totalrows > 0);

	up = rank_up(winobj);
	context = (rank_context *)
		WinGetPartitionLocalMemory(winobj, sizeof(rank_context));
	if (up || context->rank == 1)
	{
		/*
		 * The current row is not peer to prior row or is just the first, so
		 * count up the number of rows that are peer to the current.
		 */
		int64		row;

		context->rank = WinGetCurrentPosition(winobj) + 1;

		/*
		 * start from current + 1
		 */
		for (row = context->rank; row < totalrows; row++)
		{
			if (!WinRowsArePeers(winobj, row - 1, row))
				break;
			context->rank++;
		}
	}

	PG_RETURN_FLOAT8((float8) context->rank / (float8) totalrows);
}
Ejemplo n.º 5
0
/*
 * ntile
 * compute an exact numeric value with scale 0 (zero),
 * ranging from 1 (one) to n, per spec.
 */
Datum
window_ntile(PG_FUNCTION_ARGS)
{
	WindowObject winobj = PG_WINDOW_OBJECT();
	ntile_context *context;

	context = (ntile_context *)
		WinGetPartitionLocalMemory(winobj, sizeof(ntile_context));

	if (context->ntile == 0)
	{
		/* first call */
		int64		total;
		int32		nbuckets;
		bool		isnull;

		total = WinGetPartitionRowCount(winobj);
		nbuckets = DatumGetInt32(WinGetFuncArgCurrent(winobj, 0, &isnull));

		/*
		 * per spec: If NT is the null value, then the result is the null
		 * value.
		 */
		if (isnull)
			PG_RETURN_NULL();

		/*
		 * per spec: If NT is less than or equal to 0 (zero), then an
		 * exception condition is raised.
		 */
		if (nbuckets <= 0)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_ARGUMENT_FOR_NTILE),
					 errmsg("argument of ntile must be greater than zero")));

		context->ntile = 1;
		context->rows_per_bucket = 0;
		context->boundary = total / nbuckets;
		if (context->boundary <= 0)
			context->boundary = 1;
		else
		{
			/*
			 * If the total number is not divisible, add 1 row to leading
			 * buckets.
			 */
			context->remainder = total % nbuckets;
			if (context->remainder != 0)
				context->boundary++;
		}
	}

	context->rows_per_bucket++;
	if (context->boundary < context->rows_per_bucket)
	{
		/* ntile up */
		if (context->remainder != 0 && context->ntile == context->remainder)
		{
			context->remainder = 0;
			context->boundary -= 1;
		}
		context->ntile += 1;
		context->rows_per_bucket = 1;
	}

	PG_RETURN_INT32(context->ntile);
}
Ejemplo n.º 6
0
static Datum
kmeans_impl(PG_FUNCTION_ARGS, bool initial_mean_supplied)
{
	WindowObject winobj = PG_WINDOW_OBJECT();
	kmeans_context *context;
	int64		curpos, rowcount;

	rowcount = WinGetPartitionRowCount(winobj);
	context = (kmeans_context *)
		WinGetPartitionLocalMemory(winobj,
			sizeof(kmeans_context) + sizeof(int) * rowcount);

	if (!context->isdone)
	{
		int			dim, k, N;
		Datum		arg;
		bool		isnull, isout;
		myvector	inputs, mean, maxlist, minlist;
		int		   *r;
		int			i, a;
		ArrayType  *x;

		arg = WinGetFuncArgCurrent(winobj, 0, &isnull);
		if (!isnull)
			x = DatumGetArrayTypeP(
					WinGetFuncArgCurrent(winobj, 0, &isnull));
		KMEANS_CHECK_V(x, ARR_DIMS(x)[0], isnull);

		dim = ARR_DIMS(x)[0];
		k = DatumGetInt32(WinGetFuncArgCurrent(winobj, 1, &isnull));
		/*
		 * Since window function ignores STRICT mark,
		 * return NULL simply.
		 */
		if (isnull || k <= 0)
		{
			context->isdone = true;
			context->isnull = true;
			PG_RETURN_NULL();
		}

		N = (int) WinGetPartitionRowCount(winobj);
		inputs = (myvector) palloc(SIZEOF_V(dim) * N);
		maxlist = (myvector) palloc(SIZEOF_V(dim));
		minlist = (myvector) palloc(SIZEOF_V(dim));
		for (i = 0; i < N; i++)
		{
			x = DatumGetArrayTypeP(
					WinGetFuncArgInPartition(winobj, 0, i,
						WINDOW_SEEK_HEAD, false, &isnull, &isout));
			KMEANS_CHECK_V(x, dim, isnull);
			memcpy(&inputs[i * dim], ARR_DATA_PTR(x), SIZEOF_V(dim));
			/* update min/max for later use of init mean */
			for (a = 0; a < dim; a++)
			{
				if (i == 0 || maxlist[a] < inputs[i * dim + a])
					maxlist[a] = inputs[i * dim + a];
				if (i == 0 || minlist[a] > inputs[i * dim + a])
					minlist[a] = inputs[i * dim + a];
			}
		}

		/*
		 * initial mean vectors. need improve how to define them.
		 */
		mean = (myvector) palloc(SIZEOF_V(dim) * k);
		/* only the result is stored in the partition local memory */
		r = context->result;
		if (initial_mean_supplied)
		{
			ArrayType	   *init = DatumGetArrayTypeP(
								WinGetFuncArgCurrent(winobj, 2, &isnull));

			/*
			 * we can accept 1d or 2d array as mean vectors.
			 */
			if (isnull || ARR_HASNULL(init) ||
				!((ARR_NDIM(init) == 2 && ARR_DIMS(init)[0] == k &&
					ARR_DIMS(init)[1] == dim) ||
					(ARR_NDIM(init) == 1 &&
						ARR_DIMS(init)[0] == k * dim)))
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
						 errmsg("initial mean vector must be 2d without NULL element")));
			memcpy(mean, ARR_DATA_PTR(init), SIZEOF_V(dim) * k);
		}
		else
		{
			initialize_mean(inputs, dim, N, k, mean, r);
			kmeans_debug(mean, dim, k);
		}
		/* run it! */
		calc_kmeans(inputs, dim, N, k, mean, r);
		context->isdone = true;
	}

	if (context->isnull)
		PG_RETURN_NULL();

	curpos = WinGetCurrentPosition(winobj);
	PG_RETURN_INT32(context->result[curpos]);
}