greenplumn aggregate 源码

  • 2022-08-18
  • 浏览 (464)

greenplumn aggregate 代码

文件路径:/gpcontrib/orafce/aggregate.c

#include "postgres.h"

#include <math.h>

#include "funcapi.h"
#include "builtins.h"

#include "lib/stringinfo.h"
#include "utils/builtins.h"

#include "orafce.h"

PG_FUNCTION_INFO_V1(orafce_listagg1_transfn);
PG_FUNCTION_INFO_V1(orafce_wm_concat_transfn);
PG_FUNCTION_INFO_V1(orafce_listagg2_transfn);
PG_FUNCTION_INFO_V1(orafce_listagg_finalfn);

PG_FUNCTION_INFO_V1(orafce_median4_transfn);
PG_FUNCTION_INFO_V1(orafce_median4_finalfn);
PG_FUNCTION_INFO_V1(orafce_median8_transfn);
PG_FUNCTION_INFO_V1(orafce_median8_finalfn);

typedef struct
{
	int	alen;		/* allocated length */
	int	nextlen;	/* next allocated length */
	int	nelems;		/* number of valid entries */
	union
	{
		float4	*float4_values;
		float8  *float8_values;
	} d;
} MedianState;

int orafce_float4_cmp(const void *a, const void *b);
int orafce_float8_cmp(const void *a, const void *b);

/****************************************************************
 * listagg
 *
 * Concates values and returns string.
 *
 * Syntax:
 *     FUNCTION listagg(string varchar, delimiter varchar = '')
 *      RETURNS varchar;
 *
 * Note: any NULL value is ignored.
 *
 ****************************************************************/
/* subroutine to initialize state */
static StringInfo
makeStringAggState(FunctionCallInfo fcinfo)
{
	StringInfo	state;
	MemoryContext aggcontext;
	MemoryContext oldcontext;

	if (!AggCheckCallContext(fcinfo, &aggcontext))
	{
		/* cannot be called directly because of internal-type argument */
		elog(ERROR, "listagg_transfn called in non-aggregate context");
	}

	/*
	 * Create state in aggregate context.  It'll stay there across subsequent
	 * calls.
	 */
	oldcontext = MemoryContextSwitchTo(aggcontext);
	state = makeStringInfo();
	MemoryContextSwitchTo(oldcontext);

	return state;
}

static void
appendStringInfoText(StringInfo str, const text *t)
{
	appendBinaryStringInfo(str, VARDATA_ANY(t), VARSIZE_ANY_EXHDR(t));
}

Datum
orafce_listagg1_transfn(PG_FUNCTION_ARGS)
{
	StringInfo	state;

	state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);

	/* Append the element unless null. */
	if (!PG_ARGISNULL(1))
	{
		if (state == NULL)
			state = makeStringAggState(fcinfo);
		appendStringInfoText(state, PG_GETARG_TEXT_PP(1));		/* value */
	}

	/*
	 * The transition type for string_agg() is declared to be "internal",
	 * which is a pass-by-value type the same size as a pointer.
	 */
	PG_RETURN_POINTER(state);
}

Datum
orafce_wm_concat_transfn(PG_FUNCTION_ARGS)
{
	StringInfo	state;

	state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);

	/* Append the element unless null. */
	if (!PG_ARGISNULL(1))
	{
		if (state == NULL)
			state = makeStringAggState(fcinfo);
		else
			appendStringInfoChar(state, ',');

		appendStringInfoText(state, PG_GETARG_TEXT_PP(1));		/* value */
	}

	/*
	 * The transition type for string_agg() is declared to be "internal",
	 * which is a pass-by-value type the same size as a pointer.
	 */
	PG_RETURN_POINTER(state);
}


Datum
orafce_listagg2_transfn(PG_FUNCTION_ARGS)
{
	return string_agg_transfn(fcinfo);
}

Datum
orafce_listagg_finalfn(PG_FUNCTION_ARGS)
{
	return string_agg_finalfn(fcinfo);
}

static MedianState *
accumFloat4(MedianState *mstate, float4 value, MemoryContext aggcontext)
{
	MemoryContext oldcontext;

	if (mstate == NULL)
	{
		/* First call - initialize */
		oldcontext = MemoryContextSwitchTo(aggcontext);
		mstate = palloc(sizeof(MedianState));
		mstate->alen = 1024;
		mstate->nextlen = 2 * 1024;
		mstate->nelems = 0;
		mstate->d.float4_values = palloc(mstate->alen * sizeof(float4));
		MemoryContextSwitchTo(oldcontext);
	}
	else
	{
		/* enlarge float4_values if needed */
		if (mstate->nelems >= mstate->alen)
		{
			int	newlen = mstate->nextlen;

			oldcontext = MemoryContextSwitchTo(aggcontext);
			mstate->nextlen += mstate->alen;
			mstate->alen = newlen;
			mstate->d.float4_values = repalloc(mstate->d.float4_values,
									    mstate->alen * sizeof(float4));
			MemoryContextSwitchTo(oldcontext);
		}
	}

	mstate->d.float4_values[mstate->nelems++] = value;

	return mstate;
}

static MedianState *
accumFloat8(MedianState *mstate, float8 value, MemoryContext aggcontext)
{
	MemoryContext oldcontext;

	if (mstate == NULL)
	{
		/* First call - initialize */
		oldcontext = MemoryContextSwitchTo(aggcontext);
		mstate = palloc(sizeof(MedianState));
		mstate->alen = 1024;
		mstate->nextlen = 2 * 1024;
		mstate->nelems = 0;
		mstate->d.float8_values = palloc(mstate->alen * sizeof(float8));
		MemoryContextSwitchTo(oldcontext);
	}
	else
	{
		/* enlarge float4_values if needed */
		if (mstate->nelems >= mstate->alen)
		{
			int	newlen = mstate->nextlen;

			oldcontext = MemoryContextSwitchTo(aggcontext);
			mstate->nextlen += mstate->alen;
			mstate->alen = newlen;
			mstate->d.float8_values = repalloc(mstate->d.float8_values,
									    mstate->alen * sizeof(float8));
			MemoryContextSwitchTo(oldcontext);
		}
	}

	mstate->d.float8_values[mstate->nelems++] = value;

	return mstate;
}

Datum
orafce_median4_transfn(PG_FUNCTION_ARGS)
{
	MemoryContext	aggcontext;
	MedianState *state = NULL;
	float4 elem;

	if (!AggCheckCallContext(fcinfo, &aggcontext))
	{
		/* cannot be called directly because of internal-type argument */
		elog(ERROR, "median4_transfn called in non-aggregate context");
	}

	state = PG_ARGISNULL(0) ? NULL : (MedianState *) PG_GETARG_POINTER(0);
	if (PG_ARGISNULL(1))
		PG_RETURN_POINTER(state);

	elem = PG_GETARG_FLOAT4(1);
	state = accumFloat4(state, elem, aggcontext);

	PG_RETURN_POINTER(state);
}

int
orafce_float4_cmp(const void *_a, const void *_b)
{
	float4 a = *((float4 *) _a);
	float4 b = *((float4 *) _b);

	if (isnan(a))
	{
		if (isnan(b))
			return 0;
		else
			return 1;
	}
	else if (isnan(b))
	{
		return -1;
	}
	else
	{
		if (a > b)
			return 1;
		else if (a < b)
			return -1;
		else
			return 0;
	}
}

Datum
orafce_median4_finalfn(PG_FUNCTION_ARGS)
{
	MedianState *state = NULL;
	int	lidx;
	int	hidx;
	float4 result;

	if (PG_ARGISNULL(0))
		PG_RETURN_NULL();

	state = (MedianState *) PG_GETARG_POINTER(0);

	if (state == NULL)
		PG_RETURN_NULL();

	qsort(state->d.float4_values, state->nelems, sizeof(float4), orafce_float4_cmp);

	lidx = state->nelems / 2 + 1 - 1;
	hidx = (state->nelems + 1) / 2 - 1;

	if (lidx == hidx)
		result = state->d.float4_values[lidx];
	else
		result = (state->d.float4_values[lidx] + state->d.float4_values[hidx]) / 2.0f;

	PG_RETURN_FLOAT4(result);
}

Datum
orafce_median8_transfn(PG_FUNCTION_ARGS)
{
	MemoryContext	aggcontext;
	MedianState *state = NULL;
	float8 elem;

	if (!AggCheckCallContext(fcinfo, &aggcontext))
	{
		/* cannot be called directly because of internal-type argument */
		elog(ERROR, "median4_transfn called in non-aggregate context");
	}

	state = PG_ARGISNULL(0) ? NULL : (MedianState *) PG_GETARG_POINTER(0);
	if (PG_ARGISNULL(1))
		PG_RETURN_POINTER(state);

	elem = PG_GETARG_FLOAT8(1);
	state = accumFloat8(state, elem, aggcontext);

	PG_RETURN_POINTER(state);
}

int
orafce_float8_cmp(const void *_a, const void *_b)
{
	float8 a = *((float8 *) _a);
	float8 b = *((float8 *) _b);

	if (isnan(a))
	{
		if (isnan(b))
			return 0;
		else
			return 1;
	}
	else if (isnan(b))
	{
		return -1;
	}
	else
	{
		if (a > b)
			return 1;
		else if (a < b)
			return -1;
		else
			return 0;
	}
}


Datum
orafce_median8_finalfn(PG_FUNCTION_ARGS)
{
	MedianState *state = NULL;
	int	lidx;
	int	hidx;
	float8 result;

	if (PG_ARGISNULL(0))
		PG_RETURN_NULL();

	state = (MedianState *) PG_GETARG_POINTER(0);

	if (state == NULL)
		PG_RETURN_NULL();

	qsort(state->d.float8_values, state->nelems, sizeof(float8), orafce_float8_cmp);

	lidx = state->nelems / 2 + 1 - 1;
	hidx = (state->nelems + 1) / 2 - 1;

	if (lidx == hidx)
		result = state->d.float8_values[lidx];
	else
		result = (state->d.float8_values[lidx] + state->d.float8_values[hidx]) / 2.0;

	PG_RETURN_FLOAT8(result);
}

相关信息

greenplumn 源码目录

相关文章

greenplumn alert 源码

greenplumn assert 源码

greenplumn assert 源码

greenplumn builtins 源码

greenplumn charlen 源码

greenplumn charpad 源码

greenplumn convert 源码

greenplumn datefce 源码

greenplumn file 源码

greenplumn magic 源码

0  赞