Database Monitoring for PostgreSQL

• Enable Performance Schema and it’s configuration
• Setup Database Access for the Agent
  • Postgres ≥ 15
  • Postgres ≥ 10
  • Postgres 9.6
• Install Atatus Infrastructure Agent

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Before You Begin

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Enable and Configure PostgreSQL Monitoring Settings

shared_preload_libraries = 'pg_stat_statements'
track_activity_query_size = 4096
pg_stat_statements.track = ALL
pg_stat_statements.max = 10000
pg_stat_statements.track_utility = off
track_io_timing = on

​

Setup Database Access for the Agent

• To connect to the database, use a superuser account (or one with the necessary privileges). For example, for the postgres database, connect as the postgres superuser using psql:
  psql -h 127.0.0.1 -d postgres -U postgres
  

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Postgres ≥ 15

1. Create the atatus user and grant basic permissions:
   CREATE USER atatus WITH password '<UNIQUEPASSWORD>';
   
2. Give the atatus user permission to relevant tables:
   ALTER ROLE atatus INHERIT;
   
3. Create the following schema in every database:
   CREATE SCHEMA atatus;
   GRANT USAGE ON SCHEMA atatus TO atatus;
   GRANT USAGE ON SCHEMA public TO atatus;
   GRANT pg_monitor TO atatus;
   CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
   
   To collect data or custom metrics that require querying additional tables, you may need to grant the SELECT permission on those tables to the atatus user. For example: grant SELECT on TABLE_NAME to atatus;. Refer to the PostgreSQL custom metric collection documentation for more details.
4. Create the function in every database to enable the Agent to collect explain plans.
   CREATE OR REPLACE FUNCTION atatus.explain_statement(
      l_query TEXT,
      OUT explain JSON
   )
   RETURNS SETOF JSON AS
   $$
   DECLARE
   curs REFCURSOR;
   plan JSON;
   
   BEGIN
      OPEN curs FOR EXECUTE pg_catalog.concat('EXPLAIN (FORMAT JSON) ', l_query);
      FETCH curs INTO plan;
      CLOSE curs;
      RETURN QUERY SELECT plan;
   END;
   $$
   LANGUAGE 'plpgsql'
   RETURNS NULL ON NULL INPUT
   SECURITY DEFINER;
   

​

Postgres ≥ 10

1. Create the atatus user and grant basic permissions:
   CREATE USER atatus WITH password '<UNIQUEPASSWORD>';
   
2. Create the following schema in every database:
   CREATE SCHEMA atatus;
   GRANT USAGE ON SCHEMA atatus TO atatus;
   GRANT USAGE ON SCHEMA public TO atatus;
   GRANT pg_monitor TO atatus;
   CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
   
   To collect data or custom metrics that require querying additional tables, you may need to grant the SELECT permission on those tables to the atatus user. For example: grant SELECT on TABLE_NAME to atatus;. Refer to the PostgreSQL custom metric collection documentation for more details.
3. Create the function in every database to enable the Agent to collect explain plans.
   CREATE OR REPLACE FUNCTION atatus.explain_statement(
      l_query TEXT,
      OUT explain JSON
   )
   RETURNS SETOF JSON AS
   $$
   DECLARE
   curs REFCURSOR;
   plan JSON;
   
   BEGIN
      OPEN curs FOR EXECUTE pg_catalog.concat('EXPLAIN (FORMAT JSON) ', l_query);
      FETCH curs INTO plan;
      CLOSE curs;
      RETURN QUERY SELECT plan;
   END;
   $$
   LANGUAGE 'plpgsql'
   RETURNS NULL ON NULL INPUT
   SECURITY DEFINER;
   

​

Postgres 9.6

1. Create the atatus user and grant basic permissions:
   CREATE USER atatus WITH password '<UNIQUEPASSWORD>';
   
2. Create the following schema in every database:
   CREATE SCHEMA atatus;
   GRANT USAGE ON SCHEMA atatus TO atatus;
   GRANT USAGE ON SCHEMA public TO atatus;
   GRANT SELECT ON pg_stat_database TO atatus;
   CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
   
3. Create functions in every database to enable the Agent to read the full contents of pg_stat_activity and pg_stat_statements:
   CREATE OR REPLACE FUNCTION atatus.pg_stat_activity() RETURNS SETOF pg_stat_activity AS
     $$ SELECT * FROM pg_catalog.pg_stat_activity; $$
   LANGUAGE sql
   SECURITY DEFINER;
   CREATE OR REPLACE FUNCTION atatus.pg_stat_statements() RETURNS SETOF pg_stat_statements AS
       $$ SELECT * FROM pg_stat_statements; $$
   LANGUAGE sql
   SECURITY DEFINER;
   
   To collect data or custom metrics that require querying additional tables, you may need to grant the SELECT permission on those tables to the atatus user. For example: grant SELECT on TABLE_NAME to atatus;. Refer to the PostgreSQL custom metric collection documentation for more details.
4. Create the function in every database to enable the Agent to collect explain plans.
   CREATE OR REPLACE FUNCTION atatus.explain_statement(
      l_query TEXT,
      OUT explain JSON
   )
   RETURNS SETOF JSON AS
   $$
   DECLARE
   curs REFCURSOR;
   plan JSON;
   
   BEGIN
      OPEN curs FOR EXECUTE pg_catalog.concat('EXPLAIN (FORMAT JSON) ', l_query);
      FETCH curs INTO plan;
      CLOSE curs;
      RETURN QUERY SELECT plan;
   END;
   $$
   LANGUAGE 'plpgsql'
   RETURNS NULL ON NULL INPUT
   SECURITY DEFINER;
   

​

Verify

psql -h localhost -U atatus postgres -A \
  -c "select * from pg_stat_database limit 1;" \
  && echo -e "\e[0;32mPostgres connection - OK\e[0m" \
  || echo -e "\e[0;31mCannot connect to Postgres\e[0m"

psql -h localhost -U atatus postgres -A \
  -c "select * from pg_stat_activity limit 1;" \
  && echo -e "\e[0;32mPostgres pg_stat_activity read OK\e[0m" \
  || echo -e "\e[0;31mCannot read from pg_stat_activity\e[0m"

psql -h localhost -U atatus postgres -A \
  -c "select * from pg_stat_statements limit 1;" \
  && echo -e "\e[0;32mPostgres pg_stat_statements read OK\e[0m" \
  || echo -e "\e[0;31mCannot read from pg_stat_statements\e[0m"

​

Configure Atatus Infrastructure Agent

1. To enable Database Monitoring for your databases, You should install the Atatus Infrastructure agent in your host machine.
2. Copy the PostgreSQL example configuration file.
   cd /etc/atatus-infra-agent/conf.d/postgresql.d/
   sudo cp postgresql.yml.template postgresql.yml
   
3. Update PostgreSQL Configuration File:

metrics:
  - hosts: ["postgres://127.0.0.1:5432"]
    username: atatus
    password: <UNIQUEPASSWORD>
    dbm: true

logs:
 - type: log

4. Restart the atatus infrastructure agent and PostgreSQL service.
   sudo service postgresql restart
   sudo service atatus-infra-agent restart
   

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Collecting Schemas (Optional)

metrics:
    - hosts:
        - "postgres://<POSTGRES_HOST>:5432"
      username: <DB_USERNAME>
      password: <DB_PASSWORD>
      dbm: true
      db_name: <DB_NAME>
      dbm_postgresql_options:
        collect_database_info:
          enabled: true
          auto_discovery: true
# Optional filters
          # include:
          #   - postgres
          # exclude:
          #   - template_001
          max_tables: 200
        collect_settings:
          enabled: true
          ignore_patterns:
            - '^pg_toast'
            - '^pg_stat'
            - '^pg_stat_tmp'
            - '^pg_locks'
            - '^pg_locks_with_detail'
            - '^pg_locks_status'
            - '^pg_replication_slots'

​

Collecting Custom Metrics (Optional)

metrics:
    - hosts:
        - "postgres://<POSTGRES_HOST>:5432"
      username: <DB_USERNAME>
      password: <DB_PASSWORD>
      dbm: true
      db_name: <DB_NAME>
      dbm_postgresql_options:
        additional_metrics_options:
# The following is an example of a custom query configuration.            
          custom_queries:
            enabled: true
            max_custom_queries: 5
            custom_query:
              - query: |
                  SELECT COUNT(*) AS user_count FROM public.users;
                columns:
                  - name: user_count
                    type: gauge
                tags:
                  - source:custom_user_count