diff options
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 80e703b1906..3401bc5bdb2 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -433,6 +433,16 @@ btrescan(PG_FUNCTION_ARGS) * not already done in a previous rescan call. To save on palloc * overhead, both workspaces are allocated as one palloc block; only this * function and btendscan know that. + * + * NOTE: this data structure also makes it safe to return data from a + * "name" column, even though btree name_ops uses an underlying storage + * datatype of cstring. The risk there is that "name" is supposed to be + * padded to NAMEDATALEN, but the actual index tuple is probably shorter. + * However, since we only return data out of tuples sitting in the + * currTuples array, a fetch of NAMEDATALEN bytes can at worst pull some + * data out of the markTuples array --- running off the end of memory for + * a SIGSEGV is not possible. Yeah, this is ugly as sin, but it beats + * adding special-case treatment for name_ops elsewhere. */ if (scan->xs_want_itup && so->currTuples == NULL) { |