This is a Go-based daemon which collects various information about Postgres databases as well as queries run on it.
All data is converted to a protocol buffers structure which can then be used as data source for monitoring & graphing systems. Or just as reference on how to pull information out of PostgreSQL.
It currently collects information about
- Tables (including column, constraint and trigger definitions)
The collector is available in multiple convenient options:
- APT/YUM packages: https://packages.pganalyze.com/
- Docker sidekick service, see details further down in this file
Configuration (APT/YUM Packages)
After the package was installed, you can find the configuration in /etc/pganalyze-collector.conf
Adjust the values in that file by adding your API key (found in the pganalyze dashboard, use one per database server), and database connection credentials.
You can repeat the configuration block with a different
[name] if you have multiple servers to monitor.
See https://pganalyze.com/docs for further details.
Setting up a Restricted Monitoring User
By default pg_stat_statements does not allow viewing queries run by other users, unless you are a database superuser. Since you probably don't want monitoring to run as a superuser, you can setup a separate monitoring user like this:
CREATE SCHEMA pganalyze; CREATE EXTENSION IF NOT EXISTS pg_stat_statements WITH SCHEMA public; CREATE OR REPLACE FUNCTION pganalyze.get_stat_statements(showtext boolean = true) RETURNS SETOF pg_stat_statements AS $$ /* pganalyze-collector */ SELECT * FROM public.pg_stat_statements(showtext); $$ LANGUAGE sql VOLATILE SECURITY DEFINER; CREATE OR REPLACE FUNCTION pganalyze.get_stat_activity() RETURNS SETOF pg_stat_activity AS $$ /* pganalyze-collector */ SELECT * FROM pg_catalog.pg_stat_activity; $$ LANGUAGE sql VOLATILE SECURITY DEFINER; CREATE OR REPLACE FUNCTION pganalyze.get_column_stats() RETURNS SETOF pg_stats AS $$ /* pganalyze-collector */ SELECT schemaname, tablename, attname, inherited, null_frac, avg_width, n_distinct, NULL::anyarray, most_common_freqs, NULL::anyarray, correlation, NULL::anyarray, most_common_elem_freqs, elem_count_histogram FROM pg_catalog.pg_stats; $$ LANGUAGE sql VOLATILE SECURITY DEFINER; CREATE OR REPLACE FUNCTION pganalyze.get_stat_replication() RETURNS SETOF pg_stat_replication AS $$ /* pganalyze-collector */ SELECT * FROM pg_catalog.pg_stat_replication; $$ LANGUAGE sql VOLATILE SECURITY DEFINER; CREATE USER pganalyze WITH PASSWORD 'mypassword' CONNECTION LIMIT 5; REVOKE ALL ON SCHEMA public FROM pganalyze; GRANT USAGE ON SCHEMA pganalyze TO pganalyze;
If you are using PostgreSQL 9.3 or older, replace
public.pg_stat_statements() in the
pganalyze.get_stat_statements helper method.
Note that these statements must be run as a superuser (to create the
SECURITY DEFINER function),
but from here onwards you can use the
pganalyze user instead.
The collector will automatically use the helper methods
if they exist in the
pganalyze schema - otherwise data will be fetched directly.
If you are on Postgres 9.6 and use activity snapshots:
CREATE OR REPLACE FUNCTION pganalyze.get_stat_progress_vacuum() RETURNS SETOF pg_stat_progress_vacuum AS $$ /* pganalyze-collector */ SELECT * FROM pg_catalog.pg_stat_progress_vacuum; $$ LANGUAGE sql VOLATILE SECURITY DEFINER;
If you are using the Buffer Cache report in pganalyze, you will also need to create this additional helper method:
CREATE EXTENSION IF NOT EXISTS pg_buffercache WITH SCHEMA public; CREATE OR REPLACE FUNCTION pganalyze.get_buffercache() RETURNS SETOF public.pg_buffercache AS $$ /* pganalyze-collector */ SELECT * FROM public.pg_buffercache; $$ LANGUAGE sql VOLATILE SECURITY DEFINER;
If you are using the Sequence report in pganalyze, you will also need these helper methods:
CREATE OR REPLACE FUNCTION pganalyze.get_sequence_oid_for_column(table_name text, column_name text) RETURNS oid AS $$ /* pganalyze-collector */ SELECT pg_get_serial_sequence(table_name, column_name)::regclass::oid; $$ LANGUAGE sql VOLATILE SECURITY DEFINER; --- The following is needed for Postgres 10+: CREATE OR REPLACE FUNCTION pganalyze.get_sequence_state(schema_name text, sequence_name text) RETURNS TABLE( last_value bigint, start_value bigint, increment_by bigint, max_value bigint, min_value bigint, cache_size bigint, cycle boolean ) AS $$ /* pganalyze-collector */ SELECT last_value, start_value, increment_by, max_value, min_value, cache_size, cycle FROM pg_sequences WHERE schemaname = schema_name AND sequencename = sequence_name; $$ LANGUAGE sql VOLATILE SECURITY DEFINER; --- For Postgres 9.6 and older, use this: CREATE OR REPLACE FUNCTION pganalyze.get_sequence_state(schema_name text, sequence_name text) RETURNS TABLE( last_value bigint, start_value bigint, increment_by bigint, max_value bigint, min_value bigint, cache_size bigint, cycle boolean ) AS $$ BEGIN IF NOT EXISTS(SELECT 1 FROM pg_class c JOIN pg_namespace n ON (c.relnamespace = n.oid) WHERE n.nspname = schema_name AND c.relname = sequence_name AND relkind = 'S') THEN RETURN; END IF; RETURN QUERY EXECUTE 'SELECT last_value, start_value, increment_by, max_value, min_value, ' || 'cache_value AS cache_size, is_cycled AS cycle FROM ' || quote_ident(schema_name) || '.' || quote_ident(sequence_name); END $$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER;
If you enabled the optional reset mode (usually not required), you will also need this helper method:
CREATE OR REPLACE FUNCTION pganalyze.reset_stat_statements() RETURNS SETOF void AS $$ /* pganalyze-collector */ SELECT * FROM public.pg_stat_statements_reset(); $$ LANGUAGE sql VOLATILE SECURITY DEFINER;
Setting up Log EXPLAIN helper
This section is relevant only if you use the
setting; if you use the recommended autoexplain extension, or if you
do not plan to use EXPLAIN plan collection, you can skip it.
If you use
enable_log_explain, use a superuser connection to create
the pganalyze schema and this function on each database where EXPLAIN
CREATE OR REPLACE FUNCTION pganalyze.explain(query text, params text) RETURNS text AS $$ DECLARE prepared_query text; prepared_params text; result text; BEGIN SELECT regexp_replace(query, ';+\s*\Z', '') INTO prepared_query; IF prepared_query LIKE '%;%' THEN RAISE EXCEPTION 'cannot run EXPLAIN when query contains semicolon'; END IF; IF array_length(params, 1) > 0 THEN SELECT string_agg(quote_literal(param) || '::unknown', ',') FROM unnest(params) p(param) INTO prepared_params; EXECUTE 'PREPARE pganalyze_explain AS ' || prepared_query; BEGIN EXECUTE 'EXPLAIN (VERBOSE, FORMAT JSON) EXECUTE pganalyze_explain(' || prepared_params || ')' INTO STRICT result; EXCEPTION WHEN OTHERS THEN DEALLOCATE pganalyze_explain; RAISE; END; DEALLOCATE pganalyze_explain; ELSE EXECUTE 'EXPLAIN (VERBOSE, FORMAT JSON) ' || prepared_query INTO STRICT result; END IF; RETURN result; END $$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER;
Note that this function contains a check for semicolons in the query text. This is to minimize collector access to your data: it ensures that the collector cannot piggyback other queries that could exfiltrate data.
To get a feel for the data that is collected you can run the following command. This will show the data that would be sent (in JSON format), without sending it:
Don't hesitate to reach out to firstname.lastname@example.org if you have any questions about what gets sent, or how to adjust the collector data collection.
Docker Container (RDS)
If you are monitoring an RDS database and want to run the collector inside Docker, we recommend the following:
docker pull quay.io/pganalyze/collector:stable docker run \ --rm \ --name pganalyze-mydb \ -e DB_URL=postgres://username:email@example.com/mydb \ -e PGA_API_KEY=YOUR_PGANALYZE_API_KEY \ -e AWS_INSTANCE_ID=YOUR_RDS_DB_IDENTIFIER \ quay.io/pganalyze/collector:stable
You'll need to set PGA_API_KEY, DB_URL, and AWS_INSTANCE_ID with the correct values.
Please also note that the EC2 instance running your Docker setup needs to have an IAM role that allows Cloudwatch access: https://pganalyze.com/docs/install/amazon_rds/03_setup_iam_policy
To get better data quality for server metrics, enable "Enhanced Monitoring" in your RDS dashboard. The pganalyze collector will automatically pick this up and get all the metrics.
We currently require one Docker container per RDS instance monitored.
If you have multiple databases on the same RDS instance, you can monitor them all by specifying DB_ALL_NAMES=1 as an environment variable.
Docker Container (non-RDS)
If the database you want to monitor is running inside a Docker environment you can use the Docker image:
docker pull quay.io/pganalyze/collector:stable docker run \ --name my-app-pga-collector \ --link my-app-db:db \ --env-file collector_config.env \ quay.io/pganalyze/collector:stable
collector_config.env needs to look like this:
PGA_API_KEY=$YOUR_API_KEY PGA_ALWAYS_COLLECT_SYSTEM_DATA=1 DB_NAME=your_database_name DB_USERNAME=your_database_user DB_PASSWORD=your_database_password
The only required arguments are PGA_API_KEY (found in the pganalyze dashboard) and DB_NAME. Only specify
PGA_ALWAYS_COLLECT_SYSTEM_DATA if the database is running on the same host and you'd like the collector to gather system metrics (from inside the container).
Note: You can add
-v /path/to/database/volume/on/host:/var/lib/postgresql/data in order to collect I/O statistics from your database (this requires that it runs on the same machine).
When monitoring a Heroku Postgres database, it is recommended you deploy the collector as its own app inside your Heroku account.
Follow the instructions in the pganalyze documentation to add your databases to the collector.
In case you want to run a script based on data collection running successfully
and/or failing, you can set the
[pganalyze] ... error_callback=/usr/local/bin/my_error_script.sh [mydb] ...
Note that the callback is executed in a shell, so you can use shell expressions as well.
The script will also have the following environment variables set:
- PGA_CALLBACK_TYPE (type of callback,
- PGA_CONFIG_SECTION (server that was processed,
mydbin this example)
- PGA_SNAPSHOT_TYPE (type of data that was processed, currently there are
fullsnapshots, as well as
logssnapshots which contain only log data)
- PGA_ERROR_MESSAGE (error message, in the case of the error callback)
pganalyze-collector is licensed under the 3-clause BSD license, see LICENSE file for details.