postgres.git / summary / log / commit / refs

commit    cfbfdb963a426c4f2f47584b83e0cc4f2f463b8b
Author:   Masahiko Sawada <msawada@postgresql.org>
Date:     Wed Apr 29 16:10:07 2026 +0000
First released in: 17.10, 18.4

    test_tidstore: Stabilize regression tests by sorting offsets.
    
    TidStoreSetBlockOffsets() requires its offsets array to be strictly
    ascending and asserts this precondition. In test_tidstore, we were
    passing random offset numbers deduplicated by a DISTINCT clause in an
    array_agg() call directly to the do_set_block_offsets() test
    harness. However, DISTINCT without an ORDER BY clause does not
    guarantee sorted results according to the SQL standard.
    
    Fix this by sorting the offsets in-place inside do_set_block_offsets()
    before calling TidStoreSetBlockOffsets().
    
    While this assertion failure is not observed during regular regression
    tests because they use queries simple enough that the optimizer
    consistently chooses plans yielding sorted results, it makes sense to
    stabilize the test. The failure could theoretically occur depending on
    the optimizer's plan choice, and has been reported when experimenting
    with certain third-party extensions.
    
    Backpatch to v17, where test_tidstore was introduced, to ensure
    extension development on stable branches does not hit this assertion.
    
    Reported-by: Andrei Lepikhov <lepihov@gmail.com>
    Author: Andrei Lepikhov <lepihov@gmail.com>
    Discussion: https://postgr.es/m/b97f1850-fc7b-43c4-9b04-4e97bb9e7dc0@gmail.com
    Backpatch-through: 17


 src/test/modules/test_tidstore/test_tidstore.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/test/modules/test_tidstore/test_tidstore.c b/src/test/modules/test_tidstore/test_tidstore.c
index eb16e0fbfa6..d12d54f3677 100644
--- a/src/test/modules/test_tidstore/test_tidstore.c
+++ b/src/test/modules/test_tidstore/test_tidstore.c
@@ -75,6 +75,19 @@ itemptr_cmp(const void *left, const void *right)
 	return 0;
 }
 
+static int
+offsetnumber_cmp(const void *a, const void *b)
+{
+	OffsetNumber l = *(const OffsetNumber *) a;
+	OffsetNumber r = *(const OffsetNumber *) b;
+
+	if (l < r)
+		return -1;
+	else if (l > r)
+		return 1;
+	return 0;
+}
+
 /*
  * Create a TidStore. If shared is false, the tidstore is created
  * on TopMemoryContext, otherwise on DSA. Although the tidstore
@@ -179,6 +192,9 @@ do_set_block_offsets(PG_FUNCTION_ARGS)
 	noffs = ArrayGetNItems(ARR_NDIM(ta), ARR_DIMS(ta));
 	offs = ((OffsetNumber *) ARR_DATA_PTR(ta));
 
+	/* TidStoreSetBlockOffsets() requires offsets to be strictly ascending. */
+	qsort(offs, noffs, sizeof(OffsetNumber), offsetnumber_cmp);
+
 	/* Set TIDs in the store */
 	TidStoreLockExclusive(tidstore);
 	TidStoreSetBlockOffsets(tidstore, blkno, offs, noffs);


[parent: 1e71970d2d2b]