Database Connectors¶

HolmesGPT can connect directly to databases to run read-only SQL queries, list tables, and describe schemas. This lets Holmes investigate slow queries, check index usage, examine table structures, and read data for troubleshooting.

All database connectors use type: database and share the same configuration pattern. You can configure multiple database instances side by side, each with a different name.

Supported Databases¶

Database	Connection URL Prefix	Details Page
PostgreSQL	`postgresql://`	PostgreSQL
MySQL	`mysql://`	MySQL
MariaDB	`mariadb://` or `mysql://`	MariaDB
ClickHouse	`clickhouse://` or `clickhouse+http://`	ClickHouse
SQL Server	`mssql://`	SQL Server
SQLite	`sqlite:///`	SQLite
MongoDB Atlas	Specialized toolset	MongoDB Atlas

Quick Start¶

Holmes CLIHolmes Helm ChartRobusta Helm Chart

~/.holmes/config.yaml:

toolsets:
  prod-postgres:
    type: database
    config:
      connection_url: "postgresql://holmes:password@db.example.com:5432/mydb"
    llm_instructions: "Production PostgreSQL with customer and order data"

  analytics-clickhouse:
    type: database
    config:
      connection_url: "clickhouse://analyst:pass@clickhouse.internal:8123/analytics"
    llm_instructions: "ClickHouse analytics warehouse"

Create a Kubernetes secret in the namespace Holmes runs in:

kubectl create secret generic holmes-database-connectors \
  --from-literal=POSTGRES_URL='postgresql://holmes:password@db.example.com:5432/mydb' \
  -n <namespace>

When using the standalone Holmes Helm Chart, update your values.yaml:

extraEnvVarsSecrets:
  - holmes-database-connectors

toolsets:
  prod-postgres:
    type: database
    config:
      connection_url: "{{ env.POSTGRES_URL }}"
    llm_instructions: "Production PostgreSQL database"

Apply the configuration:

helm upgrade holmes robusta/holmes -f values.yaml

Create a Kubernetes secret in the namespace Holmes runs in:

kubectl create secret generic holmes-database-connectors \
  --from-literal=POSTGRES_URL='postgresql://holmes:password@db.example.com:5432/mydb' \
  -n <namespace>

When using the Robusta Helm Chart (which includes HolmesGPT), update your generated_values.yaml:

holmes:
  extraEnvVarsSecrets:
    - holmes-database-connectors

  toolsets:
    prod-postgres:
      type: database
      config:
        connection_url: "{{ env.POSTGRES_URL }}"
      llm_instructions: "Production PostgreSQL database"

Apply the configuration:

helm upgrade robusta robusta/robusta -f generated_values.yaml --set clusterName=<YOUR_CLUSTER_NAME>

Configuration Options¶

connection_url (required): Database connection URL (see each database's page for the exact format)
read_only (default: true): Only allow SELECT, SHOW, DESCRIBE, EXPLAIN, and WITH statements
verify_ssl (default: true): Verify SSL certificates
max_rows (default: 200): Maximum rows returned per query (1-10000)
llm_instructions: Context about this database instance for the LLM

Tools Provided¶

Each configured database instance provides three tools:

query: Execute read-only SQL queries
list_tables: List all tables and views in the database
describe_table: Show column definitions, constraints, and indexes for a table

Connection URL Formats¶

# PostgreSQL
postgresql://user:password@host:5432/dbname

# MySQL
mysql://user:password@host:3306/dbname

# MariaDB
mariadb://user:password@host:3306/dbname

# ClickHouse (native)
clickhouse://user:password@host:9000/dbname

# ClickHouse (HTTP)
clickhouse+http://user:password@host:8123/dbname

# SQL Server
mssql://user:password@host:1433/dbname

# SQLite (local file)
sqlite:///path/to/database.db

Specialized Database Toolsets¶

Some databases have dedicated toolsets with features beyond SQL queries:

MongoDB Atlas -- Connects to the Atlas Admin API to analyze logs, alerts, events, slow queries, and cluster metrics. This is a separate toolset (not type: database) since MongoDB uses a different query model.

Common Use Cases¶

"Why is this query slow on prod-postgres: SELECT * FROM orders WHERE status = 'pending'"

"Show me the schema for the users table in analytics-clickhouse"

"List all tables and their sizes in prod-postgres"

"Check for missing indexes on the orders table"