Hello,
I am currently using PostgreSQL Community version 9.4.9 and then using this instance, I am doing logical replication(using replication slots). I have created the replication slots using the following query:
SELECT xlog_position FROM pg_create_logical_replication_slot('cjkimqvfuvixqyjd_00016389_e6f7c975_a311_4067_bcf1_a6accb57ab37', 'test_decoding')
So the issue that I am facing is because of the updates that are being done to my table. I was able to reproduce the same issue again using the following sample:
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1. Table on the source(which is RDS PostgreSQL):
CREATE TABLE public.toast_test1
(
id SERIAL PRIMARY KEY NOT NULL,
is_not_toast INT,
is_toast VARCHAR(32767)
);
CREATE UNIQUE INDEX toast_test_id_uindex1 ON public.toast_test1 (id);
2. Insert some values:
INSERT INTO public.toast_test1
(is_not_toast, is_toast) VALUES
(0, (SELECT string_agg(series::text, ',')
FROM generate_series(1, 1000) AS series));
So basically, every time you execute the above query, a new row will be inserted. So execute the same for 4-5 times.
3. So now I started my replication.
4. If for example, I am doing an update using the below mentioned query on my source instance:
UPDATE public.toast_test SET is_not_toast = 1;
5. On the target, when I do a select * and see that the column with character varying() datatype has changed to 'unchanged-toast-datum'.
6. So on further checking the replication slot at the time, when I issued an update, I can see this:
postgres2@t1=> SELECT * FROM pg_logical_slot_get_changes('cjkimqvfuvixqyjd_00016389_e6f7c975_a311_4067_bcf1_a6accb57ab37', NULL, NULL);
location | xid | data
-------------+-------+---------------------------------------------------------------------------------------------------------------------------
3D/95003D58 | 17974 | BEGIN 17974
3D/950049D0 | 17974 | table public.toast_test1: UPDATE: id[integer]:1 is_not_toast[integer]:1 is_toast[character varying]:unchanged-toast-datum
3D/95004A78 | 17974 | COMMIT 17974
(3 rows)
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Even after setting the REPLICA IDENTITY to FULL for this table did not help.
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Kindly review and please share your comments on this matter.