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| author | Dean Rasheed <dean.a.rasheed@gmail.com> | 2021-01-05 11:04:41 +0000 |
|---|---|---|
| committer | Dean Rasheed <dean.a.rasheed@gmail.com> | 2021-01-05 11:04:41 +0000 |
| commit | 275b190b3ee51e811604e2836f199c080bf1ae37 (patch) | |
| tree | 248af9f1c9e5c7da423d6f8aa02373e68f78f6ae | |
| parent | b847ec7cd878096b22cd6c900d5d33eeaf2fa08f (diff) | |
Fix numeric_power() when the exponent is INT_MIN.
In power_var_int(), the computation of the number of significant
digits to use in the computation used log(Abs(exp)), which isn't safe
because Abs(exp) returns INT_MIN when exp is INT_MIN. Use fabs()
instead of Abs(), so that the exponent is cast to a double before the
absolute value is taken.
Back-patch to 9.6, where this was introduced (by 7d9a4737c2).
Discussion: https://postgr.es/m/CAEZATCVd6pMkz=BrZEgBKyqqJrt2xghr=fNc8+Z=5xC6cgWrWA@mail.gmail.com
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 2 | ||||
| -rw-r--r-- | src/test/regress/expected/numeric.out | 6 | ||||
| -rw-r--r-- | src/test/regress/sql/numeric.sql | 1 |
3 files changed, 8 insertions, 1 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 1463ae66b71..0bb2a7a9a3d 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -8265,7 +8265,7 @@ power_var_int(NumericVar *base, int exp, NumericVar *result, int rscale) * to around log10(abs(exp)) digits, so work with this many extra digits * of precision (plus a few more for good measure). */ - sig_digits += (int) log(Abs(exp)) + 8; + sig_digits += (int) log(fabs(exp)) + 8; /* * Now we can proceed with the multiplications. diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out index 7e55b0e2931..b4c78a2b722 100644 --- a/src/test/regress/expected/numeric.out +++ b/src/test/regress/expected/numeric.out @@ -1506,6 +1506,12 @@ select 0.12 ^ (-20); 2608405330458882702.5529619561355838 (1 row) +select 1.000000000123 ^ (-2147483648); + ?column? +-------------------- + 0.7678656556403084 +(1 row) + -- cases that used to error out select 0.12 ^ (-25); ?column? diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql index 9675b6eabf3..7b3e818e928 100644 --- a/src/test/regress/sql/numeric.sql +++ b/src/test/regress/sql/numeric.sql @@ -873,6 +873,7 @@ select 3.789 ^ 21; select 3.789 ^ 35; select 1.2 ^ 345; select 0.12 ^ (-20); +select 1.000000000123 ^ (-2147483648); -- cases that used to error out select 0.12 ^ (-25); |