diff options
Diffstat (limited to 'src/backend/nodes/list.c')
| -rw-r--r-- | src/backend/nodes/list.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/nodes/list.c b/src/backend/nodes/list.c index f3e18007086..55fd4c359b1 100644 --- a/src/backend/nodes/list.c +++ b/src/backend/nodes/list.c @@ -1011,8 +1011,11 @@ list_append_unique_oid(List *list, Oid datum) * via equal(). * * This is almost the same functionality as list_union(), but list1 is - * modified in-place rather than being copied. Note also that list2's cells - * are not inserted in list1, so the analogy to list_concat() isn't perfect. + * modified in-place rather than being copied. However, callers of this + * function may have strict ordering expectations -- i.e. that the relative + * order of those list2 elements that are not duplicates is preserved. Note + * also that list2's cells are not inserted in list1, so the analogy to + * list_concat() isn't perfect. */ List * list_concat_unique(List *list1, List *list2) |