pg_size_pretty(bigint) would return the value in bytes rather than PB
for the smallest-most bigint value. This happened due to an incorrect
assumption that the absolute value of -
9223372036854775808 could be
stored inside a signed 64-bit type.
Here we fix that by instead storing that value in an unsigned 64-bit type.
This bug does exist in versions prior to 15 but the code there is
sufficiently different and the bug seems sufficiently non-critical that
it does not seem worth risking backpatching further.
Author: Joseph Koshakow <koshy44@gmail.com>
Discussion: https://postgr.es/m/CAAvxfHdTsMZPWEHUrZ=h3cky9Ccc3Mtx2whUHygY+ABP-mCmUw@mail.gmail.com
Backpatch-through: 15
for (unit = size_pretty_units; unit->name != NULL; unit++)
{
uint8 bits;
+ uint64 abs_size = size < 0 ? 0 - (uint64) size : (uint64) size;
- /* use this unit if there are no more units or we're below the limit */
- if (unit[1].name == NULL || Abs(size) < unit->limit)
+ /*
+ * Use this unit if there are no more units or the absolute size is
+ * below the limit for the current unit.
+ */
+ if (unit[1].name == NULL || abs_size < unit->limit)
{
if (unit->round)
size = half_rounded(size);
11528652096115048448 | 10240 PB | -10240 PB
(12 rows)
+-- Ensure we get the expected results when passing the extremities of bigint
+SELECT pg_size_pretty('-9223372036854775808'::bigint),
+ pg_size_pretty('9223372036854775807'::bigint);
+ pg_size_pretty | pg_size_pretty
+----------------+----------------
+ -8192 PB | 8192 PB
+(1 row)
+
-- pg_size_bytes() tests
SELECT size, pg_size_bytes(size) FROM
(VALUES ('1'), ('123bytes'), ('1kB'), ('1MB'), (' 1 GB'), ('1.5 GB '),
(11258449312612351::numeric), (11258449312612352::numeric),
(11528652096115048447::numeric), (11528652096115048448::numeric)) x(size);
+-- Ensure we get the expected results when passing the extremities of bigint
+SELECT pg_size_pretty('-9223372036854775808'::bigint),
+ pg_size_pretty('9223372036854775807'::bigint);
+
-- pg_size_bytes() tests
SELECT size, pg_size_bytes(size) FROM
(VALUES ('1'), ('123bytes'), ('1kB'), ('1MB'), (' 1 GB'), ('1.5 GB '),