353 lines
8.9 KiB
Plaintext
353 lines
8.9 KiB
Plaintext
Let's make a logger.
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CREATE TABLE ddl_history (
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id BIGSERIAL PRIMARY KEY,
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event_time TIMESTAMPTZ DEFAULT now(),
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command TEXT,
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object_type TEXT,
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object_name TEXT
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);
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Create the function:
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CREATE OR REPLACE FUNCTION capture_ddl()
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RETURNS event_trigger
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LANGUAGE plpgsql
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AS $$
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BEGIN
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INSERT INTO ddl_history (
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command,
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object_type,
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object_name
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)
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SELECT
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TG_TAG,
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object_type,
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object_identity
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FROM pg_event_trigger_ddl_commands();
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END;
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$$;
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DROP TABLE
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CREATE OR REPLACE FUNCTION capture_drop()
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RETURNS event_trigger
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LANGUAGE plpgsql
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AS $$
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BEGIN
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INSERT INTO ddl_log (
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event_time,
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command,
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object_type,
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object_name
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)
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SELECT
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now(),
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TG_TAG,
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object_type,
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object_identity
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FROM pg_event_trigger_dropped_objects();
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END;
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$$;
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Create the trigger:
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CREATE EVENT TRIGGER capture_ddl_trigger
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ON ddl_command_end
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EXECUTE FUNCTION capture_ddl();
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Now test:
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CREATE TABLE products (
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id INT PRIMARY KEY,
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name TEXT
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);
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Check:
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SELECT * FROM ddl_history;
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docker-compose.yml for LOGICAL REPLICATION MODE
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services:
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postgres:
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image: postgres:15
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container_name: cluster1Node1
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restart: unless-stopped
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environment:
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POSTGRES_USER: postgres
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POSTGRES_PASSWORD: postgres
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POSTGRES_DB: postgres
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ports:
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- "5444:5432"
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volumes:
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- ./postgres_data:/var/lib/postgresql/data
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command:
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- postgres
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- -c
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- wal_level=logical
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- -c
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- max_replication_slots=10
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- -c
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- max_wal_senders=10
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sudo docker compose down
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sudo docker compose up -d
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SHOW wal_level;
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psql -h 172.16.10.123 -p 5444 -U postgres
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SHOW max_replication_slots;
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SHOW max_wal_senders;
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CREATE TABLE users (
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id INT PRIMARY KEY,
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name TEXT
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);
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SELECT *
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FROM pg_create_logical_replication_slot(
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'myslot',
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'test_decoding'
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);
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INSERT INTO users VALUES (1, 'Alice');
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SELECT *
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FROM pg_logical_slot_peek_changes(
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'myslot',
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NULL,
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NULL
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);
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|===================================================|
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| psql -h 127.0.0.1 -p 5444 -U postgres -d postgres |
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|===================================================|
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command:
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- postgres
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- -c
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- wal_level=logical
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- -c
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- shared_preload_libraries=spock
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- -c
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- max_replication_slots=10
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- -c
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- max_wal_senders=10
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- -c
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- track_commit_timestamp=on
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psql -h 127.0.0.1 -p 5444 -U postgres -d postgres
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sudo nano postgres_data/pg_hba.conf
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host all all 172.19.0.0/16 scram-sha-256
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host all all 172.16.10.0/24 scram-sha-256
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sudo docker exec -it cluster1Node1 psql -U postgres -d postgres
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ALTER USER postgres WITH PASSWORD 'postgres';
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sudo docker exec -it cluster1Node3 bash
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psql -U postgres -c "SHOW hba_file;"
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psql -U postgres -c "SELECT pg_reload_conf();"
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|==========|
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|LINK Nodes|
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|==========|
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SELECT spock.sub_create(
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subscription_name := 'node2_from_node1',
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provider_dsn := 'host=172.16.10.123 port=5444 dbname=postgres user=postgres password=postgres'
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);
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|=============|
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|Register Node|
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|=============|
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psql -h localhost -p 5444 -U postgres -d postgres
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CREATE EXTENSION IF NOT EXISTS spock;
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SELECT extname, extversion
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FROM pg_extension
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WHERE extname = 'spock';
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SELECT spock.node_create(
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node_name := 'node1',
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dsn := 'host=172.16.10.123 port=5444 dbname=postgres user=postgres password=postgres'
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);
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SELECT * FROM spock.node;
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|================|
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| CREATE A table |
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|================|
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CREATE TABLE test_replication (
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id bigint PRIMARY KEY,
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source_node text,
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message text
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);
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SELECT spock.repset_add_table(
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'default',
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'test_replication'
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);
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|===========|
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|Turn On DDL|
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|===========|
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CREATE TABLE customers (
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id bigint PRIMARY KEY,
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name text
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);
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ALTER SYSTEM SET spock.enable_ddl_replication = on;
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ALTER SYSTEM SET spock.include_ddl_repset = on;
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SELECT pg_reload_conf();
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SHOW spock.enable_ddl_replication;
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SHOW spock.include_ddl_repset;
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|======================================================|
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| HOW TO INSERT OR PUT AUTO GEN OF ID IN EXISTING TABLE|
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|======================================================|
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ALTER TABLE test_replication
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ALTER COLUMN id ADD GENERATED BY DEFAULT AS IDENTITY;
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HOW TO UPADE A NODE CONFIG
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UPDATE spock.local_node
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SET node_local_interface = (
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SELECT if_id
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FROM spock.node_interface
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WHERE if_name = 'node2_local'
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AND if_nodeid = 13534
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);
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|========================|
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|WAY TO ENTER PSQL SHELL |
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|========================|
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psql "postgresql://postgres_exporter:postgres@172.16.10.178:5444/postgres"
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|=============================|
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|ENDPONT TO DETECT A DEAD LOCK|
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|=============================|
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http://172.16.10.178:9188/metrics | grep -i deadlock
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|========================|
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|FEATURES COMPLETED TODAY|
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|========================|
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| Requirement | `postgres_exporter` | What you need |
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| ----------------------- | ------------------: | --------------------------------- |
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| Connections | ✅ | postgres_exporter |
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| Transactions | ✅ | postgres_exporter |
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| Locks | ✅/⚠️ | PostgreSQL metrics/custom query |
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| Blocking sessions | ⚠️ | Custom PostgreSQL query |
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| Deadlocks | ✅ | postgres_exporter |
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| Long-running queries | ⚠️ | `pg_stat_activity` / custom query |
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| WAL | ✅ | postgres_exporter |
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| Database health | ✅ | postgres_exporter + Prometheus |
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| PostgreSQL CPU usage | ❌ | cAdvisor / process monitoring |
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| PostgreSQL memory usage | ❌ | cAdvisor / process monitoring |
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| Storage/disk usage | ❌ | node_exporter / cAdvisor |
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| Network usage | ❌ | node_exporter / cAdvisor |
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|==================|
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| Whats This for? |
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|==================|
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postgres=# SELECT *
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FROM spock.replication_set_table;
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set_id | set_reloid | set_att_list | set_row_filter
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-----------+------------------+--------------+----------------
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590430464 | ddl_test | |
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590430464 | test_replication | |
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590430464 | lock_test | |
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(3 rows)
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postgres=#
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!!!!!!!!!WHEN TESTING NEW NODES OR REFRESHING THE NODES!!!!!!!!!
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SET spock.enable_ddl_replication = off;
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|=============================|
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|ADD UUID IN AN EXISTING TABLE|
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|=============================|
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CREATE EXTENSION IF NOT EXISTS pgcrypto;
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ALTER TABLE public.test_replication
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ADD COLUMN uuid_id uuid DEFAULT gen_random_uuid();
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Populate any existing rows that somehow got NULL:
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UPDATE public.test_replication
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SET uuid_id = gen_random_uuid()
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WHERE uuid_id IS NULL;
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Make it not null:
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ALTER TABLE public.test_replication
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ALTER COLUMN uuid_id SET NOT NULL;
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Now remove the old primary key:
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ALTER TABLE public.test_replication
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DROP CONSTRAINT test_replication_pkey;
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Make the UUID the new primary key:
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ALTER TABLE public.test_replication
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ADD PRIMARY KEY (uuid_id);
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|===========================|
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|!!!CAUTION AFTER LINKING!!!|
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|===========================|
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CHECK THIS
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SELECT * FROM spock.replication_set_table;
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SELECT
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slot_name,
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active,
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active_pid,
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restart_lsn,
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confirmed_flush_lsn
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FROM pg_replication_slots;
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postgres=# SELECT *
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FROM spock.replication_set;
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|===============================|
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|CREATE A TABLE NOT USING SPROKE|
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|===============================|
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SELECT spock.replicate_ddl(
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$$
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CREATE TABLE public.vm2_ddl_test (
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uuid_id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
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source_node TEXT NOT NULL,
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message TEXT,
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created_at TIMESTAMPTZ DEFAULT now()
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);
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$$
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);
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WTF IS THIS!!!
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To check if provider is sending data
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postgres=# SELECT
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slot_name,
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active,
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active_pid,
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restart_lsn,
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confirmed_flush_lsn
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FROM pg_replication_slots;
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