Re: Long text values destroys logical replication slots

On Wed, Oct 28, 2015 at 10:17 PM, Andres Freund <andres@anarazel.de> wrote:
> Can you reproduce it with test_decoding as the output plugin?

You can just use that for example to get an assertion failure:
CREATE TABLE a (b text);
ALTER TABLE ONLY a REPLICA IDENTITY FULL;
SELECT * FROM pg_create_logical_replication_slot('new', 'test_decoding');
INSERT INTO a (b) VALUES (repeat('k', 2000000));
UPDATE a SET b = 'c';
select * from pg_logical_slot_peek_changes('new', NULL, NULL); -- boom

frame #3: 0x0000000100458ca9
postgres`DecodeXLogTuple(data=0x00007fb7e2126046, len=22910,
tuple=0x000000010a32e038) + 137 at decode.c:856
   853         int            datalen = len - SizeOfHeapHeader;
   854
   855         Assert(datalen >= 0);
-> 856         Assert(datalen <= MaxHeapTupleSize);
(lldb) p datalen
(int) $0 = 22905
--
Michael