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help / color / mirror / Atom feedFrom: Fujii Masao <fujii@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix integer to_char() overflow with V format
Date: Tue, 01 Sep 2026 02:44:01 +0000
Message-ID: <E1x1ETg-00000002y8B-2jZP@gemulon.postgresql.org> (raw)
Fix integer to_char() overflow with V format
When to_char() formatted an integer value with a V pattern, it could
return an incorrect result instead of reporting an overflow. V shifts
the decimal point by multiplying the input value by a power of ten before
formatting it, so, for example,
to_char(3, '9V999999999')
requires computing 3 * 10^9. This result does not fit in int4, but
the integer variant of to_char() performed the multiplication using a
plain int32 expression. The intermediate result could therefore
overflow, causing the function to output incorrect digits instead of
raising "integer out of range".
Use dtoi4() and int4mul() for this calculation so that both an
out-of-range multiplier and an out-of-range product are detected, as
with ordinary integer arithmetic. This also matches the existing int8
implementation, which uses dtoi8() and int8mul() for the same
operation.
After this change, to_char() with V format either returns the
correctly formatted result when the scaled value fits in int4, or
raises "integer out of range" when it does not.
Backpatch to all supported versions.
Reported-by: Andrey Rachitskiy <pl0h0yp1@gmail.com>
Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
Reviewed-by: Miłosz Bieniek <bieniek.milosz@proton.me>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CAB8bMivEfqZxOVdzc3kZDN++XshmkEz2t7dfGBU8+oUm864EZg@mail.gmail.com
Backpatch-through: 14
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/3b120b1e94dd0387ca40e1e356f6b7eb8793d297
Modified Files
--------------
src/backend/utils/adt/formatting.c | 16 +++++++++-------
src/test/regress/expected/int4.out | 27 +++++++++++++++++++++++++++
src/test/regress/sql/int4.sql | 9 +++++++++
3 files changed, 45 insertions(+), 7 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: fujii@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix integer to_char() overflow with V format
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