Add a toast table reference to README.tuples
[ci-skip]
@@ -124,3 +124,10 @@ There are many functions to convert the tuple stored in a TupleTableSlot from
one representation to another. Refer to access/memtup.h and
executor/tuptable.h for more details.
+Toasted attributes
+------------------
+
+Values that are too large to fit into a heap tuple in-line are stored
+externally in a toast table. A large value is broken down into smaller fixed
+sized chunks. Each chunk is stored as a tuple in the toast table. More
+details can be found in access/tuptoaster.c.
\ No newline at end of file
