Hi hackers,
I noticed an issue in `statext_dependencies_deserialize()`. The sanity
check uses `SizeOfItem` to validate the bytea size, but `SizeOfItem()`
expects the number of attributes in a single dependency, not the number
of dependencies. This means the check is computing the size of one
dependency with ndeps attributes, which is incorrect.
It should use `MinSizeOfItems` instead, which correctly computes the
minimum expected size as the header plus `ndeps` minimally-sized
dependency items.
Notably, the similar function for ndistinct extended statistics
`statext_ndistinct_deserialize()` already uses `MinSizeOfItems`
correctly, which suggests this is a typo rather than an intentional choice.
--
Best regards,
Ilia Evdokimov,
Tantor Labs LLC,
https://tantorlabs.com/
From 5e760b9d63c12ef504a3fd3be75dd2511211165b Mon Sep 17 00:00:00 2001
From: Evdokimov Ilia <[email protected]>
Date: Tue, 19 May 2026 17:17:01 +0300
Subject: [PATCH v1] Fix size check in statext_dependencies_deserialize()
The sanity check was using SizeOfItem(dependencies->ndeps) to validate
the bytea size, but SizeOfItem() expects the number of attributes in a
single dependency, not the number of dependencies. Replace it with
MinSizeOfItems(ndeps), which correctly computes the minimum expected
size as the header plus ndeps minimally-sized dependency items.
---
src/backend/statistics/dependencies.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index e3a2f5817e0..95dcc218978 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -529,7 +529,7 @@ statext_dependencies_deserialize(bytea *data)
elog(ERROR, "invalid zero-length item array in MVDependencies");
/* what minimum bytea size do we expect for those parameters */
- min_expected_size = SizeOfItem(dependencies->ndeps);
+ min_expected_size = MinSizeOfItems(dependencies->ndeps);
if (VARSIZE_ANY_EXHDR(data) < min_expected_size)
elog(ERROR, "invalid dependencies size %zu (expected at least %zu)",
--
2.34.1
