postgres.git / summary / log / commit / refs
commit fea5960fafb0002ea2a80bed1dc03e3a4f85fa1d
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon Nov 16 21:39:59 2020 +0000
First released in: 14.0, 11.11, 12.6, 13.2
Do not return NULL for error cases in satisfies_hash_partition().
Since this function is used as a CHECK constraint condition,
returning NULL is tantamount to returning TRUE, which would have the
effect of letting in a row that doesn't satisfy the hash condition.
Admittedly, the cases for which this is done should be unreachable
in practice, but that doesn't make it any less a bad idea. It also
seems like a dartboard was used to decide which error cases should
throw errors as opposed to returning NULL.
For the checks for NULL input values, I just switched it to returning
false. There's some argument that an error would be better; but the
case really should be can't-happen in a generated hash constraint,
so it's likely not worth more code for.
For the parent-relation-open-failure case, it seems like we might
as well let relation_open throw an error, instead of having an
impossible-to-diagnose constraint failure.
Back-patch to v11 where this code came in.
Discussion: https://postgr.es/m/24067.1605134819@sss.pgh.pa.us
src/backend/partitioning/partbounds.c | 13 ++++++-------
src/test/regress/expected/hash_part.out | 10 +++-------
2 files changed, 9 insertions(+), 14 deletions(-)
diff --git a/src/backend/partitioning/partbounds.c b/src/backend/partitioning/partbounds.c
index 3d2d3f4c3da..19d055493ed 100644
--- a/src/backend/partitioning/partbounds.c
+++ b/src/backend/partitioning/partbounds.c
@@ -4653,6 +4653,8 @@ compute_partition_hash_value(int partnatts, FmgrInfo *partsupfunc, Oid *partcoll
*
* Returns true if remainder produced when this computed single hash value is
* divided by the given modulus is equal to given remainder, otherwise false.
+ * NB: it's important that this never return null, as the constraint machinery
+ * would consider that to be a "pass".
*
* See get_qual_for_hash() for usage.
*/
@@ -4677,9 +4679,9 @@ satisfies_hash_partition(PG_FUNCTION_ARGS)
ColumnsHashData *my_extra;
uint64 rowHash = 0;
- /* Return null if the parent OID, modulus, or remainder is NULL. */
+ /* Return false if the parent OID, modulus, or remainder is NULL. */
if (PG_ARGISNULL(0) || PG_ARGISNULL(1) || PG_ARGISNULL(2))
- PG_RETURN_NULL();
+ PG_RETURN_BOOL(false);
parentId = PG_GETARG_OID(0);
modulus = PG_GETARG_INT32(1);
remainder = PG_GETARG_INT32(2);
@@ -4709,14 +4711,11 @@ satisfies_hash_partition(PG_FUNCTION_ARGS)
int j;
/* Open parent relation and fetch partition key info */
- parent = try_relation_open(parentId, AccessShareLock);
- if (parent == NULL)
- PG_RETURN_NULL();
+ parent = relation_open(parentId, AccessShareLock);
key = RelationGetPartitionKey(parent);
/* Reject parent table that is not hash-partitioned. */
- if (parent->rd_rel->relkind != RELKIND_PARTITIONED_TABLE ||
- key->strategy != PARTITION_STRATEGY_HASH)
+ if (key == NULL || key->strategy != PARTITION_STRATEGY_HASH)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("\"%s\" is not a hash partitioned table",
diff --git a/src/test/regress/expected/hash_part.out b/src/test/regress/expected/hash_part.out
index 91ec7c6f589..4c74e4b7069 100644
--- a/src/test/regress/expected/hash_part.out
+++ b/src/test/regress/expected/hash_part.out
@@ -10,11 +10,7 @@ CREATE TABLE mchash1
PARTITION OF mchash FOR VALUES WITH (MODULUS 4, REMAINDER 0);
-- invalid OID, no such table
SELECT satisfies_hash_partition(0, 4, 0, NULL);
- satisfies_hash_partition
---------------------------
-
-(1 row)
-
+ERROR: could not open relation with OID 0
-- not partitioned
SELECT satisfies_hash_partition('tenk1'::regclass, 4, 0, NULL);
ERROR: "tenk1" is not a hash partitioned table
@@ -34,14 +30,14 @@ ERROR: remainder for hash partition must be less than modulus
SELECT satisfies_hash_partition('mchash'::regclass, NULL, 0, NULL);
satisfies_hash_partition
--------------------------
-
+ f
(1 row)
-- remainder is null
SELECT satisfies_hash_partition('mchash'::regclass, 4, NULL, NULL);
satisfies_hash_partition
--------------------------
-
+ f
(1 row)
-- too many arguments
[parent: 53c7b4f6221b]