diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 10 | ||||
| -rw-r--r-- | src/test/regress/expected/numeric.out | 6 | ||||
| -rw-r--r-- | src/test/regress/sql/numeric.sql | 2 |
3 files changed, 17 insertions, 1 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index da639be40bf..8ffeb6166e3 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -202,6 +202,7 @@ struct NumericData */ #define NUMERIC_DSCALE_MASK 0x3FFF +#define NUMERIC_DSCALE_MAX NUMERIC_DSCALE_MASK #define NUMERIC_SIGN(n) \ (NUMERIC_IS_SHORT(n) ? \ @@ -2291,7 +2292,11 @@ numeric_mul(PG_FUNCTION_ARGS) * Unlike add_var() and sub_var(), mul_var() will round its result. In the * case of numeric_mul(), which is invoked for the * operator on numerics, * we request exact representation for the product (rscale = sum(dscale of - * arg1, dscale of arg2)). + * arg1, dscale of arg2)). If the exact result has more digits after the + * decimal point than can be stored in a numeric, we round it. Rounding + * after computing the exact result ensures that the final result is + * correctly rounded (rounding in mul_var() using a truncated product + * would not guarantee this). */ init_var_from_num(num1, &arg1); init_var_from_num(num2, &arg2); @@ -2299,6 +2304,9 @@ numeric_mul(PG_FUNCTION_ARGS) init_var(&result); mul_var(&arg1, &arg2, &result, arg1.dscale + arg2.dscale); + if (result.dscale > NUMERIC_DSCALE_MAX) + round_var(&result, NUMERIC_DSCALE_MAX); + res = make_result(&result); free_var(&result); diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out index ae1daa5744e..bbc7f1c0a08 100644 --- a/src/test/regress/expected/numeric.out +++ b/src/test/regress/expected/numeric.out @@ -1381,6 +1381,12 @@ select 4769999999999999999999999999999999999999999999999999999999999999999999999 47699999999999999999999999999999999999999999999999999999999999999999999999999999999999985230000000000000000000000000000000000000000000000000000000000000000000000000000000000001 (1 row) +select (0.1 - 2e-16383) * (0.1 - 3e-16383) = 0.01 as rounds_to_point_zero_one; + rounds_to_point_zero_one +-------------------------- + t +(1 row) + -- -- Test some corner cases for division -- diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql index d6ff9b8a399..d0d05957e61 100644 --- a/src/test/regress/sql/numeric.sql +++ b/src/test/regress/sql/numeric.sql @@ -841,6 +841,8 @@ select 4770999999999999999999999999999999999999999999999999999999999999999999999 select 4769999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999; +select (0.1 - 2e-16383) * (0.1 - 3e-16383) = 0.01 as rounds_to_point_zero_one; + -- -- Test some corner cases for division -- |