diff options
Diffstat (limited to 'src/backend/utils/adt/numeric.c')
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 69 |
1 files changed, 65 insertions, 4 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 7e51873fd10..19fc4d45055 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -14,7 +14,7 @@ * Copyright (c) 1998-2007, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.99 2007/01/16 21:41:13 neilc Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.100 2007/02/17 00:55:57 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -2165,6 +2165,40 @@ do_numeric_accum(ArrayType *transarray, Numeric newval) return result; } +/* + * Improve avg performance by not caclulating sum(X*X). + */ +static ArrayType * +do_numeric_avg_accum(ArrayType *transarray, Numeric newval) +{ + Datum *transdatums; + int ndatums; + Datum N, + sumX; + ArrayType *result; + + /* We assume the input is array of numeric */ + deconstruct_array(transarray, + NUMERICOID, -1, false, 'i', + &transdatums, NULL, &ndatums); + if (ndatums != 2) + elog(ERROR, "expected 2-element numeric array"); + N = transdatums[0]; + sumX = transdatums[1]; + + N = DirectFunctionCall1(numeric_inc, N); + sumX = DirectFunctionCall2(numeric_add, sumX, + NumericGetDatum(newval)); + + transdatums[0] = N; + transdatums[1] = sumX; + + result = construct_array(transdatums, 2, + NUMERICOID, -1, false, 'i'); + + return result; +} + Datum numeric_accum(PG_FUNCTION_ARGS) { @@ -2175,6 +2209,18 @@ numeric_accum(PG_FUNCTION_ARGS) } /* + * Optimized case for average of numeric. + */ +Datum +numeric_avg_accum(PG_FUNCTION_ARGS) +{ + ArrayType *transarray = PG_GETARG_ARRAYTYPE_P(0); + Numeric newval = PG_GETARG_NUMERIC(1); + + PG_RETURN_ARRAYTYPE_P(do_numeric_avg_accum(transarray, newval)); +} + +/* * Integer data types all use Numeric accumulators to share code and * avoid risk of overflow. For int2 and int4 inputs, Numeric accumulation * is overkill for the N and sum(X) values, but definitely not overkill @@ -2219,6 +2265,22 @@ int8_accum(PG_FUNCTION_ARGS) PG_RETURN_ARRAYTYPE_P(do_numeric_accum(transarray, newval)); } +/* + * Optimized case for average of int8. + */ +Datum +int8_avg_accum(PG_FUNCTION_ARGS) +{ + ArrayType *transarray = PG_GETARG_ARRAYTYPE_P(0); + Datum newval8 = PG_GETARG_DATUM(1); + Numeric newval; + + newval = DatumGetNumeric(DirectFunctionCall1(int8_numeric, newval8)); + + PG_RETURN_ARRAYTYPE_P(do_numeric_avg_accum(transarray, newval)); +} + + Datum numeric_avg(PG_FUNCTION_ARGS) { @@ -2232,11 +2294,10 @@ numeric_avg(PG_FUNCTION_ARGS) deconstruct_array(transarray, NUMERICOID, -1, false, 'i', &transdatums, NULL, &ndatums); - if (ndatums != 3) - elog(ERROR, "expected 3-element numeric array"); + if (ndatums != 2) + elog(ERROR, "expected 2-element numeric array"); N = DatumGetNumeric(transdatums[0]); sumX = DatumGetNumeric(transdatums[1]); - /* ignore sumX2 */ /* SQL92 defines AVG of no values to be NULL */ /* N is zero iff no digits (cf. numeric_uminus) */ |