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Apply the "nodeAgg" optimization to more of the builtin transition

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functions. This patch optimizes int2_sum(), int4_sum(), float4_accum()
and float8_accum() to avoid needing to copy the transition function's
state for each input tuple of the aggregate. In an extreme case
(e.g. SELECT sum(int2_col) FROM table where table has a single column),
it improves performance by about 20%. For more complex queries or tables
with wider rows, the relative performance improvement will not be as
significant.
This commit is contained in:
Neil Conway
2005-04-06 23:56:07 +00:00
parent a6bbfedcf7
commit be2f825d51
2 changed files with 112 additions and 36 deletions
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74
src/backend/utils/adt/float.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.113 2005/02/11 04:08:58 neilc Exp $ * $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.114 2005/04/06 23:56:07 neilc Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1902,8 +1902,6 @@ float8_accum(PG_FUNCTION_ARGS)
float8 N, float8 N,
sumX, sumX,
sumX2; sumX2;
Datum transdatums[3];
ArrayType *result;
transvalues = check_float8_array(transarray, "float8_accum"); transvalues = check_float8_array(transarray, "float8_accum");
N = transvalues[0]; N = transvalues[0];
@ -1914,15 +1912,35 @@ float8_accum(PG_FUNCTION_ARGS)
sumX += newval; sumX += newval;
sumX2 += newval * newval; sumX2 += newval * newval;
transdatums[0] = Float8GetDatumFast(N); /*
transdatums[1] = Float8GetDatumFast(sumX); * If we're invoked by nodeAgg, we can cheat and modify our first
transdatums[2] = Float8GetDatumFast(sumX2); * parameter in-place to reduce palloc overhead. Otherwise we
* construct a new array with the updated transition data and
* return it.
*/
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
transvalues[0] = N;
transvalues[1] = sumX;
transvalues[2] = sumX2;
result = construct_array(transdatums, 3, PG_RETURN_ARRAYTYPE_P(transarray);
FLOAT8OID, }
sizeof(float8), false /* float8 byval */ , 'd'); else
{
Datum transdatums[3];
ArrayType *result;
PG_RETURN_ARRAYTYPE_P(result); transdatums[0] = Float8GetDatumFast(N);
transdatums[1] = Float8GetDatumFast(sumX);
transdatums[2] = Float8GetDatumFast(sumX2);
result = construct_array(transdatums, 3,
FLOAT8OID,
sizeof(float8), false /* float8 byval */ , 'd');
PG_RETURN_ARRAYTYPE_P(result);
}
} }
Datum Datum
@ -1935,8 +1953,6 @@ float4_accum(PG_FUNCTION_ARGS)
sumX, sumX,
sumX2, sumX2,
newval; newval;
Datum transdatums[3];
ArrayType *result;
transvalues = check_float8_array(transarray, "float4_accum"); transvalues = check_float8_array(transarray, "float4_accum");
N = transvalues[0]; N = transvalues[0];
@ -1950,15 +1966,35 @@ float4_accum(PG_FUNCTION_ARGS)
sumX += newval; sumX += newval;
sumX2 += newval * newval; sumX2 += newval * newval;
transdatums[0] = Float8GetDatumFast(N); /*
transdatums[1] = Float8GetDatumFast(sumX); * If we're invoked by nodeAgg, we can cheat and modify our first
transdatums[2] = Float8GetDatumFast(sumX2); * parameter in-place to reduce palloc overhead. Otherwise we
* construct a new array with the updated transition data and
* return it.
*/
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
transvalues[0] = N;
transvalues[1] = sumX;
transvalues[2] = sumX2;
result = construct_array(transdatums, 3, PG_RETURN_ARRAYTYPE_P(transarray);
FLOAT8OID, }
sizeof(float8), false /* float8 byval */ , 'd'); else
{
Datum transdatums[3];
ArrayType *result;
PG_RETURN_ARRAYTYPE_P(result); transdatums[0] = Float8GetDatumFast(N);
transdatums[1] = Float8GetDatumFast(sumX);
transdatums[2] = Float8GetDatumFast(sumX2);
result = construct_array(transdatums, 3,
FLOAT8OID,
sizeof(float8), false /* float8 byval */ , 'd');
PG_RETURN_ARRAYTYPE_P(result);
}
} }
Datum Datum

74
src/backend/utils/adt/numeric.c
View File

@ -14,7 +14,7 @@
* Copyright (c) 1998-2005, PostgreSQL Global Development Group * Copyright (c) 1998-2005, PostgreSQL Global Development Group
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.82 2005/04/04 23:50:27 neilc Exp $ * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.83 2005/04/06 23:56:07 neilc Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -2357,7 +2357,6 @@ numeric_stddev(PG_FUNCTION_ARGS)
Datum Datum
int2_sum(PG_FUNCTION_ARGS) int2_sum(PG_FUNCTION_ARGS)
{ {
int64 oldsum;
int64 newval; int64 newval;
if (PG_ARGISNULL(0)) if (PG_ARGISNULL(0))
@ -2370,22 +2369,39 @@ int2_sum(PG_FUNCTION_ARGS)
PG_RETURN_INT64(newval); PG_RETURN_INT64(newval);
} }
oldsum = PG_GETARG_INT64(0); /*
* If we're invoked by nodeAgg, we can cheat and modify out first
* parameter in-place to avoid palloc overhead. If not, we need to
* return the new value of the transition variable.
*/
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
int64 *oldsum = (int64 *) PG_GETARG_POINTER(0);
/* Leave sum unchanged if new input is null. */ /* Leave the running sum unchanged in the new input is null */
if (PG_ARGISNULL(1)) if (!PG_ARGISNULL(1))
PG_RETURN_INT64(oldsum); *oldsum = *oldsum + (int64) PG_GETARG_INT16(1);
/* OK to do the addition. */ PG_RETURN_POINTER(oldsum);
newval = oldsum + (int64) PG_GETARG_INT16(1); }
else
{
int64 oldsum = PG_GETARG_INT64(0);
PG_RETURN_INT64(newval); /* Leave sum unchanged if new input is null. */
if (PG_ARGISNULL(1))
PG_RETURN_INT64(oldsum);
/* OK to do the addition. */
newval = oldsum + (int64) PG_GETARG_INT16(1);
PG_RETURN_INT64(newval);
}
} }
Datum Datum
int4_sum(PG_FUNCTION_ARGS) int4_sum(PG_FUNCTION_ARGS)
{ {
int64 oldsum;
int64 newval; int64 newval;
if (PG_ARGISNULL(0)) if (PG_ARGISNULL(0))
@ -2398,16 +2414,34 @@ int4_sum(PG_FUNCTION_ARGS)
PG_RETURN_INT64(newval); PG_RETURN_INT64(newval);
} }
oldsum = PG_GETARG_INT64(0); /*
* If we're invoked by nodeAgg, we can cheat and modify out first
* parameter in-place to avoid palloc overhead. If not, we need to
* return the new value of the transition variable.
*/
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
int64 *oldsum = (int64 *) PG_GETARG_POINTER(0);
/* Leave sum unchanged if new input is null. */ /* Leave the running sum unchanged in the new input is null */
if (PG_ARGISNULL(1)) if (!PG_ARGISNULL(1))
PG_RETURN_INT64(oldsum); *oldsum = *oldsum + (int64) PG_GETARG_INT32(1);
/* OK to do the addition. */ PG_RETURN_POINTER(oldsum);
newval = oldsum + (int64) PG_GETARG_INT32(1); }
else
{
int64 oldsum = PG_GETARG_INT64(0);
PG_RETURN_INT64(newval); /* Leave sum unchanged if new input is null. */
if (PG_ARGISNULL(1))
PG_RETURN_INT64(oldsum);
/* OK to do the addition. */
newval = oldsum + (int64) PG_GETARG_INT32(1);
PG_RETURN_INT64(newval);
}
} }
Datum Datum
@ -2426,6 +2460,12 @@ int8_sum(PG_FUNCTION_ARGS)
PG_RETURN_DATUM(newval); PG_RETURN_DATUM(newval);
} }
/*
* Note that we cannot special-case the nodeAgg case here, as we
* do for int2_sum and int4_sum: numeric is of variable size, so
* we cannot modify our first parameter in-place.
*/
oldsum = PG_GETARG_NUMERIC(0); oldsum = PG_GETARG_NUMERIC(0);
/* Leave sum unchanged if new input is null. */ /* Leave sum unchanged if new input is null. */