From e7a9ccdb6c5a95bf13a307d44e89a1956914dffc Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Tue, 7 Feb 2006 16:03:50 +0000
Subject: [PATCH] I think that NUMERIC datatype has a problem in the
performance that the format on Tuple(Numeric) and the format to
calculate(NumericVar) are different. I understood that to reduce I/O.
However, when many comparisons or calculations of NUMERIC are executed, the
conversion of Numeric and NumericVar becomes a bottleneck.
It is profile result when "create index on NUMERIC column" is executed:
% cumulative self self total
time seconds seconds calls s/call s/call name
17.61 10.27 10.27 34542006 0.00 0.00 cmp_numerics
11.90 17.21 6.94 34542006 0.00 0.00 comparetup_index
7.42 21.54 4.33 71102587 0.00 0.00 AllocSetAlloc
7.02 25.64 4.09 69084012 0.00 0.00 set_var_from_num
4.87 28.48 2.84 69084012 0.00 0.00 alloc_var
4.79 31.27 2.79 142205745 0.00 0.00 AllocSetFreeIndex
4.55 33.92 2.65 34542004 0.00 0.00 cmp_abs
4.07 36.30 2.38 71101189 0.00 0.00 AllocSetFree
3.83 38.53 2.23 69084012 0.00 0.00 free_var
The create index command executes many comparisons of Numeric values.
Functions other than comparetup_index spent a lot of cycles for
conversion from Numeric to NumericVar.
An attached patch enables the comparison of Numeric values without
executing conversion to NumericVar. The execution time of that SQL
becomes half.
o Test SQL (index_test table has 1,000,000 tuples)
create index index_test_idx on index_test(num_col);
o Test results (executed the test five times)
(1)PentiumIII
original: 39.789s 36.823s 36.737s 37.752s 37.019s
patched : 18.560s 19.103s 18.830s 18.408s 18.853s
4.07 36.30 2.38 71101189 0.00 0.00 AllocSetFree
3.83 38.53 2.23 69084012 0.00 0.00 free_var
The create index command executes many comparisons of Numeric values.
Functions other than comparetup_index spent a lot of cycles for
conversion from Numeric to NumericVar.
An attached patch enables the comparison of Numeric values without
executing conversion to NumericVar. The execution time of that SQL
becomes half.
o Test SQL (index_test table has 1,000,000 tuples)
create index index_test_idx on index_test(num_col);
o Test results (executed the test five times)
(1)PentiumIII
original: 39.789s 36.823s 36.737s 37.752s 37.019s
patched : 18.560s 19.103s 18.830s 18.408s 18.853s
(2)Pentium4
original: 16.349s 14.997s 12.979s 13.169s 12.955s
patched : 7.005s 6.594s 6.770s 6.740s 6.828s
(3)Itanium2
original: 15.392s 15.447s 15.350s 15.370s 15.417s
patched : 7.413s 7.330s 7.334s 7.339s 7.339s
(4)Ultra Sparc
original: 64.435s 59.336s 59.332s 58.455s 59.781s
patched : 28.630s 28.666s 28.983s 28.744s 28.595s
Atsushi Ogawa
---
src/backend/utils/adt/numeric.c | 112 +++++++++++++++++++++-----------
1 file changed, 73 insertions(+), 39 deletions(-)
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index bd1e28d64b9..f3fa9086be8 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -14,7 +14,7 @@
* Copyright (c) 1998-2005, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.90 2006/01/25 18:15:03 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.91 2006/02/07 16:03:50 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -229,6 +229,10 @@ static void dump_var(const char *str, NumericVar *var);
#define init_var(v) MemSetAligned(v, 0, sizeof(NumericVar))
+#define NUMERIC_DIGITS(num) ((NumericDigit *)(num)->n_data)
+#define NUMERIC_NDIGITS(num) \
+ (((num)->varlen - NUMERIC_HDRSZ) / sizeof(NumericDigit))
+
static void alloc_var(NumericVar *var, int ndigits);
static void free_var(NumericVar *var);
static void zero_var(NumericVar *var);
@@ -250,6 +254,10 @@ static double numericvar_to_double_no_overflow(NumericVar *var);
static int cmp_numerics(Numeric num1, Numeric num2);
static int cmp_var(NumericVar *var1, NumericVar *var2);
+static int cmp_var_common(const NumericDigit *var1digits, int var1ndigits,
+ int var1weight, int var1sign,
+ const NumericDigit *var2digits, int var2ndigits,
+ int var2weight, int var2sign);
static void add_var(NumericVar *var1, NumericVar *var2, NumericVar *result);
static void sub_var(NumericVar *var1, NumericVar *var2, NumericVar *result);
static void mul_var(NumericVar *var1, NumericVar *var2, NumericVar *result,
@@ -271,6 +279,10 @@ static void power_var_int(NumericVar *base, int exp, NumericVar *result,
int rscale);
static int cmp_abs(NumericVar *var1, NumericVar *var2);
+static int cmp_abs_common(const NumericDigit *var1digits, int var1ndigits,
+ int var1weight,
+ const NumericDigit *var2digits, int var2ndigits,
+ int var2weight);
static void add_abs(NumericVar *var1, NumericVar *var2, NumericVar *result);
static void sub_abs(NumericVar *var1, NumericVar *var2, NumericVar *result);
static void round_var(NumericVar *var, int rscale);
@@ -1061,19 +1073,10 @@ cmp_numerics(Numeric num1, Numeric num2)
}
else
{
- NumericVar arg1;
- NumericVar arg2;
-
- init_var(&arg1);
- init_var(&arg2);
-
- set_var_from_num(num1, &arg1);
- set_var_from_num(num2, &arg2);
-
- result = cmp_var(&arg1, &arg2);
-
- free_var(&arg1);
- free_var(&arg2);
+ result = cmp_var_common(NUMERIC_DIGITS(num1), NUMERIC_NDIGITS(num1),
+ num1->n_weight, NUMERIC_SIGN(num1),
+ NUMERIC_DIGITS(num2), NUMERIC_NDIGITS(num2),
+ num2->n_weight, NUMERIC_SIGN(num2));
}
return result;
@@ -2591,11 +2594,11 @@ int8_avg(PG_FUNCTION_ARGS)
static void
dump_numeric(const char *str, Numeric num)
{
- NumericDigit *digits = (NumericDigit *) num->n_data;
+ NumericDigit *digits = NUMERIC_DIGITS(num);
int ndigits;
int i;
- ndigits = (num->varlen - NUMERIC_HDRSZ) / sizeof(NumericDigit);
+ ndigits = NUMERIC_NDIGITS(num);
printf("%s: NUMERIC w=%d d=%d ", str, num->n_weight, NUMERIC_DSCALE(num));
switch (NUMERIC_SIGN(num))
@@ -2895,7 +2898,7 @@ set_var_from_num(Numeric num, NumericVar *dest)
{
int ndigits;
- ndigits = (num->varlen - NUMERIC_HDRSZ) / sizeof(NumericDigit);
+ ndigits = NUMERIC_NDIGITS(num);
alloc_var(dest, ndigits);
@@ -3394,32 +3397,52 @@ numericvar_to_double_no_overflow(NumericVar *var)
static int
cmp_var(NumericVar *var1, NumericVar *var2)
{
- if (var1->ndigits == 0)
+ return cmp_var_common(var1->digits, var1->ndigits,
+ var1->weight, var1->sign,
+ var2->digits, var2->ndigits,
+ var2->weight, var2->sign);
+}
+
+/*
+ * cmp_var_common() -
+ *
+ * Main routine of cmp_var(). This function can be used by both
+ * NumericVar and Numeric.
+ */
+static int
+cmp_var_common(const NumericDigit *var1digits, int var1ndigits,
+ int var1weight, int var1sign,
+ const NumericDigit *var2digits, int var2ndigits,
+ int var2weight, int var2sign)
+{
+ if (var1ndigits == 0)
{
- if (var2->ndigits == 0)
+ if (var2ndigits == 0)
return 0;
- if (var2->sign == NUMERIC_NEG)
+ if (var2sign == NUMERIC_NEG)
return 1;
return -1;
}
- if (var2->ndigits == 0)
+ if (var2ndigits == 0)
{
- if (var1->sign == NUMERIC_POS)
+ if (var1sign == NUMERIC_POS)
return 1;
return -1;
}
- if (var1->sign == NUMERIC_POS)
+ if (var1sign == NUMERIC_POS)
{
- if (var2->sign == NUMERIC_NEG)
+ if (var2sign == NUMERIC_NEG)
return 1;
- return cmp_abs(var1, var2);
+ return cmp_abs_common(var1digits, var1ndigits, var1weight,
+ var2digits, var2ndigits, var2weight);
}
- if (var2->sign == NUMERIC_POS)
+ if (var2sign == NUMERIC_POS)
return -1;
- return cmp_abs(var2, var1);
+ return cmp_abs_common(var2digits, var2ndigits, var2weight,
+ var1digits, var1ndigits, var1weight);
}
@@ -4814,33 +4837,44 @@ power_var_int(NumericVar *base, int exp, NumericVar *result, int rscale)
static int
cmp_abs(NumericVar *var1, NumericVar *var2)
{
- NumericDigit *var1digits = var1->digits;
- NumericDigit *var2digits = var2->digits;
+ return cmp_abs_common(var1->digits, var1->ndigits, var1->weight,
+ var2->digits, var2->ndigits, var2->weight);
+}
+
+/* ----------
+ * cmp_abs_common() -
+ *
+ * Main routine of cmp_abs(). This function can be used by both
+ * NumericVar and Numeric.
+ * ----------
+ */
+static int
+cmp_abs_common(const NumericDigit *var1digits, int var1ndigits, int var1weight,
+ const NumericDigit *var2digits, int var2ndigits, int var2weight)
+{
int i1 = 0;
int i2 = 0;
- int w1 = var1->weight;
- int w2 = var2->weight;
/* Check any digits before the first common digit */
- while (w1 > w2 && i1 < var1->ndigits)
+ while (var1weight > var2weight && i1 < var1ndigits)
{
if (var1digits[i1++] != 0)
return 1;
- w1--;
+ var1weight--;
}
- while (w2 > w1 && i2 < var2->ndigits)
+ while (var2weight > var1weight && i2 < var2ndigits)
{
if (var2digits[i2++] != 0)
return -1;
- w2--;
+ var2weight--;
}
/* At this point, either w1 == w2 or we've run out of digits */
- if (w1 == w2)
+ if (var1weight == var2weight)
{
- while (i1 < var1->ndigits && i2 < var2->ndigits)
+ while (i1 < var1ndigits && i2 < var2ndigits)
{
int stat = var1digits[i1++] - var2digits[i2++];
@@ -4857,12 +4891,12 @@ cmp_abs(NumericVar *var1, NumericVar *var2)
* At this point, we've run out of digits on one side or the other; so any
* remaining nonzero digits imply that side is larger
*/
- while (i1 < var1->ndigits)
+ while (i1 < var1ndigits)
{
if (var1digits[i1++] != 0)
return 1;
}
- while (i2 < var2->ndigits)
+ while (i2 < var2ndigits)
{
if (var2digits[i2++] != 0)
return -1;
--
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