diff options
| author | Tom Lane | 2025-08-05 20:51:10 +0000 |
|---|---|---|
| committer | Tom Lane | 2025-08-05 20:51:10 +0000 |
| commit | 80c758a2e1d720a942610f2f889448d69ce2ce95 (patch) | |
| tree | 94c1a856dffac6c51c07c26fad49844bc00d8c0c | |
| parent | 455a040d966897edd3901f044945398450da338a (diff) | |
Fix incorrect return value in brin_minmax_multi_distance_numeric().
The result of "DirectFunctionCall1(numeric_float8, d)" is already in
Datum form, but the code was incorrectly applying PG_RETURN_FLOAT8()
to it. On machines where float8 is pass-by-reference, this would
result in complete garbage, since an unpredictable pointer value
would be treated as an integer and then converted to float. It's not
entirely clear how much of a problem would ensue on 64-bit hardware,
but certainly interpreting a float8 bitpattern as uint64 and then
converting that to float isn't the intended behavior.
As luck would have it, even the complete-garbage case doesn't break
BRIN indexes, since the results are only used to make choices about
how to merge values into ranges: at worst, we'd make poor choices
resulting in an inefficient index. Doubtless that explains the lack
of field complaints. However, users with BRIN indexes that use the
numeric_minmax_multi_ops opclass may wish to reindex in hopes of
making their indexes more efficient.
Author: Peter Eisentraut <peter@eisentraut.org>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2093712.1753983215@sss.pgh.pa.us
Backpatch-through: 14
| -rw-r--r-- | src/backend/access/brin/brin_minmax_multi.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c index b85a70a0db2..a5a414182ca 100644 --- a/src/backend/access/brin/brin_minmax_multi.c +++ b/src/backend/access/brin/brin_minmax_multi.c @@ -2032,7 +2032,7 @@ brin_minmax_multi_distance_numeric(PG_FUNCTION_ARGS) d = DirectFunctionCall2(numeric_sub, a2, a1); /* a2 - a1 */ - PG_RETURN_FLOAT8(DirectFunctionCall1(numeric_float8, d)); + PG_RETURN_DATUM(DirectFunctionCall1(numeric_float8, d)); } /* |