wal2mongo

pig build pkg wal2mongo;		# build deb

pig repo add pgsql -u   # add both repo and update cache

pig install wal2mongo;		# install via package name, for the active PG version

pig install wal2mongo -v 18;   # install for PG 18
pig install wal2mongo -v 17;   # install for PG 17
pig install wal2mongo -v 16;   # install for PG 16
pig install wal2mongo -v 15;   # install for PG 15
pig install wal2mongo -v 14;   # install for PG 14

wal_level = logical
max_replication_slots = 10

-- Create a logical replication slot
SELECT * FROM pg_create_logical_replication_slot('w2m_slot', 'wal2mongo');

-- Perform DML operations
CREATE TABLE books (id SERIAL PRIMARY KEY, title VARCHAR(100), author VARCHAR(100));
INSERT INTO books (id, title, author) VALUES (123, 'My Book', 'Author');

-- Peek at changes (MongoDB format)
SELECT * FROM pg_logical_slot_peek_changes('w2m_slot', NULL, NULL);
-- Output: db.books.insertOne( { id:123, title:"My Book", author:"Author" } )

-- Consume changes
SELECT * FROM pg_logical_slot_get_changes('w2m_slot', NULL, NULL);

-- Drop the slot
SELECT pg_drop_replication_slot('w2m_slot');

pg_recvlogical -d postgres --slot w2m_slot --create-slot -P wal2mongo
pg_recvlogical -d postgres --slot w2m_slot --start -f -

// Copy the output from pg_logical_slot_get_changes
db.books.insertOne( { id:123, title:"My Book", author:"Author" } )

mongo < changes.js