Neil Conway wrote:
On Fri, 2006-11-24 at 11:08 +1300, Mark Kirkwood wrote:
- Modifies do_numeric_accum to have an extra bool parameter and does not
calc sumX2 when it is false.
I think it would be clearer to reorganize this function slightly, and
have only a single branch on "useSumX2". On first glance it isn't
obviously that transdatums[2] is defined (but unchanged) when useSumX2
is false.
Right - new patch attached that adds a new function do_numeric_avg_accum
that only uses N and sum(X). This means I could amend the avg aggregates
for numeric, int8 to have a initvalues of {0,0}.
Cheers
Mark
? gmon.out
Index: src/backend/utils/adt/numeric.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/numeric.c,v
retrieving revision 1.96
diff -c -r1.96 numeric.c
*** src/backend/utils/adt/numeric.c 4 Oct 2006 00:29:59 -0000 1.96
--- src/backend/utils/adt/numeric.c 25 Nov 2006 00:00:58 -0000
***************
*** 2097,2102 ****
--- 2097,2136 ----
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)
{
***************
*** 2107,2112 ****
--- 2141,2158 ----
}
/*
+ * 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
***************
*** 2151,2156 ****
--- 2197,2218 ----
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)
{
***************
*** 2164,2174 ****
deconstruct_array(transarray,
NUMERICOID, -1, false, 'i',
&transdatums, NULL, &ndatums);
! if (ndatums != 3)
! elog(ERROR, "expected 3-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) */
--- 2226,2235 ----
deconstruct_array(transarray,
NUMERICOID, -1, false, 'i',
&transdatums, NULL, &ndatums);
! if (ndatums != 2)
! elog(ERROR, "expected 2-element numeric array");
N = DatumGetNumeric(transdatums[0]);
sumX = DatumGetNumeric(transdatums[1]);
/* SQL92 defines AVG of no values to be NULL */
/* N is zero iff no digits (cf. numeric_uminus) */
Index: src/include/catalog/pg_aggregate.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_aggregate.h,v
retrieving revision 1.58
diff -c -r1.58 pg_aggregate.h
*** src/include/catalog/pg_aggregate.h 4 Oct 2006 00:30:07 -0000 1.58
--- src/include/catalog/pg_aggregate.h 25 Nov 2006 00:01:01 -0000
***************
*** 80,89 ****
*/
/* avg */
! DATA(insert ( 2100 int8_accum numeric_avg 0 1231 "{0,0,0}" ));
DATA(insert ( 2101 int4_avg_accum int8_avg 0 1016 "{0,0}" ));
DATA(insert ( 2102 int2_avg_accum int8_avg 0 1016 "{0,0}" ));
! DATA(insert ( 2103 numeric_accum numeric_avg 0 1231 "{0,0,0}" ));
DATA(insert ( 2104 float4_accum float8_avg 0 1022 "{0,0,0}" ));
DATA(insert ( 2105 float8_accum float8_avg 0 1022 "{0,0,0}" ));
DATA(insert ( 2106 interval_accum interval_avg 0 1187 "{0 second,0 second}" ));
--- 80,89 ----
*/
/* avg */
! DATA(insert ( 2100 int8_avg_accum numeric_avg 0 1231 "{0,0}" ));
DATA(insert ( 2101 int4_avg_accum int8_avg 0 1016 "{0,0}" ));
DATA(insert ( 2102 int2_avg_accum int8_avg 0 1016 "{0,0}" ));
! DATA(insert ( 2103 numeric_avg_accum numeric_avg 0 1231 "{0,0}" ));
DATA(insert ( 2104 float4_accum float8_avg 0 1022 "{0,0,0}" ));
DATA(insert ( 2105 float8_accum float8_avg 0 1022 "{0,0,0}" ));
DATA(insert ( 2106 interval_accum interval_avg 0 1187 "{0 second,0 second}" ));
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_proc.h,v
retrieving revision 1.428
diff -c -r1.428 pg_proc.h
*** src/include/catalog/pg_proc.h 24 Nov 2006 21:18:42 -0000 1.428
--- src/include/catalog/pg_proc.h 25 Nov 2006 00:01:20 -0000
***************
*** 2697,2708 ****
--- 2697,2710 ----
DATA(insert OID = 1832 ( float8_stddev_samp PGNSP PGUID 12 f f t f i 1 701 "1022" _null_ _null_ _null_ float8_stddev_samp - _null_ ));
DESCR("STDDEV_SAMP aggregate final function");
DATA(insert OID = 1833 ( numeric_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 1700" _null_ _null_ _null_ numeric_accum - _null_ ));
+ DATA(insert OID = 2858 ( numeric_avg_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 1700" _null_ _null_ _null_ numeric_avg_accum - _null_ ));
DESCR("aggregate transition function");
DATA(insert OID = 1834 ( int2_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 21" _null_ _null_ _null_ int2_accum - _null_ ));
DESCR("aggregate transition function");
DATA(insert OID = 1835 ( int4_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 23" _null_ _null_ _null_ int4_accum - _null_ ));
DESCR("aggregate transition function");
DATA(insert OID = 1836 ( int8_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 20" _null_ _null_ _null_ int8_accum - _null_ ));
+ DATA(insert OID = 2857 ( int8_avg_accum PGNSP PGUID 12 f f t f i 2 1231 "1231 20" _null_ _null_ _null_ int8_avg_accum - _null_ ));
DESCR("aggregate transition function");
DATA(insert OID = 1837 ( numeric_avg PGNSP PGUID 12 f f t f i 1 1700 "1231" _null_ _null_ _null_ numeric_avg - _null_ ));
DESCR("AVG aggregate final function");
Index: src/include/utils/builtins.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/utils/builtins.h,v
retrieving revision 1.282
diff -c -r1.282 builtins.h
*** src/include/utils/builtins.h 18 Sep 2006 22:40:40 -0000 1.282
--- src/include/utils/builtins.h 25 Nov 2006 00:01:23 -0000
***************
*** 833,841 ****
--- 833,843 ----
extern Datum text_numeric(PG_FUNCTION_ARGS);
extern Datum numeric_text(PG_FUNCTION_ARGS);
extern Datum numeric_accum(PG_FUNCTION_ARGS);
+ extern Datum numeric_avg_accum(PG_FUNCTION_ARGS);
extern Datum int2_accum(PG_FUNCTION_ARGS);
extern Datum int4_accum(PG_FUNCTION_ARGS);
extern Datum int8_accum(PG_FUNCTION_ARGS);
+ extern Datum int8_avg_accum(PG_FUNCTION_ARGS);
extern Datum numeric_avg(PG_FUNCTION_ARGS);
extern Datum numeric_var_pop(PG_FUNCTION_ARGS);
extern Datum numeric_var_samp(PG_FUNCTION_ARGS);
---------------------------(end of broadcast)---------------------------
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