Apply the "nodeAgg" optimization to more of the builtin transition
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
parent
a6bbfedcf7
commit
be2f825d51
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.113 2005/02/11 04:08:58 neilc Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.114 2005/04/06 23:56:07 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1902,8 +1902,6 @@ float8_accum(PG_FUNCTION_ARGS)
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float8 N,
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sumX,
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sumX2;
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Datum transdatums[3];
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ArrayType *result;
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transvalues = check_float8_array(transarray, "float8_accum");
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N = transvalues[0];
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@ -1914,15 +1912,35 @@ float8_accum(PG_FUNCTION_ARGS)
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sumX += newval;
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sumX2 += newval * newval;
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transdatums[0] = Float8GetDatumFast(N);
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transdatums[1] = Float8GetDatumFast(sumX);
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transdatums[2] = Float8GetDatumFast(sumX2);
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/*
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* If we're invoked by nodeAgg, we can cheat and modify our first
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* parameter in-place to reduce palloc overhead. Otherwise we
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* construct a new array with the updated transition data and
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* return it.
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*/
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if (fcinfo->context && IsA(fcinfo->context, AggState))
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{
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transvalues[0] = N;
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transvalues[1] = sumX;
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transvalues[2] = sumX2;
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result = construct_array(transdatums, 3,
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FLOAT8OID,
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sizeof(float8), false /* float8 byval */ , 'd');
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PG_RETURN_ARRAYTYPE_P(transarray);
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}
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else
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{
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Datum transdatums[3];
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ArrayType *result;
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PG_RETURN_ARRAYTYPE_P(result);
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transdatums[0] = Float8GetDatumFast(N);
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transdatums[1] = Float8GetDatumFast(sumX);
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transdatums[2] = Float8GetDatumFast(sumX2);
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result = construct_array(transdatums, 3,
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FLOAT8OID,
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sizeof(float8), false /* float8 byval */ , 'd');
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PG_RETURN_ARRAYTYPE_P(result);
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}
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}
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Datum
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@ -1935,8 +1953,6 @@ float4_accum(PG_FUNCTION_ARGS)
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sumX,
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sumX2,
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newval;
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Datum transdatums[3];
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ArrayType *result;
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transvalues = check_float8_array(transarray, "float4_accum");
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N = transvalues[0];
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@ -1950,15 +1966,35 @@ float4_accum(PG_FUNCTION_ARGS)
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sumX += newval;
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sumX2 += newval * newval;
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transdatums[0] = Float8GetDatumFast(N);
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transdatums[1] = Float8GetDatumFast(sumX);
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transdatums[2] = Float8GetDatumFast(sumX2);
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/*
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* If we're invoked by nodeAgg, we can cheat and modify our first
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* parameter in-place to reduce palloc overhead. Otherwise we
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* construct a new array with the updated transition data and
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* return it.
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*/
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if (fcinfo->context && IsA(fcinfo->context, AggState))
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{
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transvalues[0] = N;
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transvalues[1] = sumX;
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transvalues[2] = sumX2;
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result = construct_array(transdatums, 3,
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FLOAT8OID,
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sizeof(float8), false /* float8 byval */ , 'd');
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PG_RETURN_ARRAYTYPE_P(transarray);
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}
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else
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{
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Datum transdatums[3];
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ArrayType *result;
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PG_RETURN_ARRAYTYPE_P(result);
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transdatums[0] = Float8GetDatumFast(N);
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transdatums[1] = Float8GetDatumFast(sumX);
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transdatums[2] = Float8GetDatumFast(sumX2);
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result = construct_array(transdatums, 3,
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FLOAT8OID,
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sizeof(float8), false /* float8 byval */ , 'd');
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PG_RETURN_ARRAYTYPE_P(result);
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}
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}
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Datum
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@ -14,7 +14,7 @@
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* Copyright (c) 1998-2005, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.82 2005/04/04 23:50:27 neilc Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.83 2005/04/06 23:56:07 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -2357,7 +2357,6 @@ numeric_stddev(PG_FUNCTION_ARGS)
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Datum
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int2_sum(PG_FUNCTION_ARGS)
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{
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int64 oldsum;
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int64 newval;
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if (PG_ARGISNULL(0))
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@ -2370,22 +2369,39 @@ int2_sum(PG_FUNCTION_ARGS)
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PG_RETURN_INT64(newval);
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}
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oldsum = PG_GETARG_INT64(0);
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/*
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* If we're invoked by nodeAgg, we can cheat and modify out first
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* parameter in-place to avoid palloc overhead. If not, we need to
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* return the new value of the transition variable.
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*/
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if (fcinfo->context && IsA(fcinfo->context, AggState))
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{
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int64 *oldsum = (int64 *) PG_GETARG_POINTER(0);
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/* Leave sum unchanged if new input is null. */
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if (PG_ARGISNULL(1))
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PG_RETURN_INT64(oldsum);
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/* Leave the running sum unchanged in the new input is null */
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if (!PG_ARGISNULL(1))
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*oldsum = *oldsum + (int64) PG_GETARG_INT16(1);
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/* OK to do the addition. */
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newval = oldsum + (int64) PG_GETARG_INT16(1);
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PG_RETURN_POINTER(oldsum);
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}
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else
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{
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int64 oldsum = PG_GETARG_INT64(0);
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PG_RETURN_INT64(newval);
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/* Leave sum unchanged if new input is null. */
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if (PG_ARGISNULL(1))
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PG_RETURN_INT64(oldsum);
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/* OK to do the addition. */
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newval = oldsum + (int64) PG_GETARG_INT16(1);
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PG_RETURN_INT64(newval);
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}
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}
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Datum
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int4_sum(PG_FUNCTION_ARGS)
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{
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int64 oldsum;
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int64 newval;
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if (PG_ARGISNULL(0))
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@ -2398,16 +2414,34 @@ int4_sum(PG_FUNCTION_ARGS)
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PG_RETURN_INT64(newval);
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}
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oldsum = PG_GETARG_INT64(0);
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/*
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* If we're invoked by nodeAgg, we can cheat and modify out first
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* parameter in-place to avoid palloc overhead. If not, we need to
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* return the new value of the transition variable.
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*/
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if (fcinfo->context && IsA(fcinfo->context, AggState))
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{
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int64 *oldsum = (int64 *) PG_GETARG_POINTER(0);
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/* Leave sum unchanged if new input is null. */
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if (PG_ARGISNULL(1))
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PG_RETURN_INT64(oldsum);
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/* Leave the running sum unchanged in the new input is null */
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if (!PG_ARGISNULL(1))
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*oldsum = *oldsum + (int64) PG_GETARG_INT32(1);
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/* OK to do the addition. */
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newval = oldsum + (int64) PG_GETARG_INT32(1);
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PG_RETURN_POINTER(oldsum);
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}
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else
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{
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int64 oldsum = PG_GETARG_INT64(0);
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PG_RETURN_INT64(newval);
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/* Leave sum unchanged if new input is null. */
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if (PG_ARGISNULL(1))
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PG_RETURN_INT64(oldsum);
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/* OK to do the addition. */
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newval = oldsum + (int64) PG_GETARG_INT32(1);
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PG_RETURN_INT64(newval);
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}
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}
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Datum
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@ -2426,6 +2460,12 @@ int8_sum(PG_FUNCTION_ARGS)
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PG_RETURN_DATUM(newval);
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}
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/*
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* Note that we cannot special-case the nodeAgg case here, as we
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* do for int2_sum and int4_sum: numeric is of variable size, so
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* we cannot modify our first parameter in-place.
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*/
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oldsum = PG_GETARG_NUMERIC(0);
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/* Leave sum unchanged if new input is null. */
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