PostgreSQL Data Connector Deployment Guide

Production operating guide for the PostgreSQL data connector covering authentication, connection pool sizing, TLS, metrics, and observability.

Authentication & Secrets

The connector uses the native PostgreSQL wire protocol with username/password authentication.

Parameter	Description
pg_host	PostgreSQL server hostname.
pg_port	TCP port (default 5432).
pg_db	Database name.
pg_user	Database user.
pg_pass	Password. Use ${secrets:...} to resolve from a configured secret store.
pg_connection_string	Alternative to the individual parameters.
pg_application_name	Application identifier reported in pg_stat_activity. Defaults to the Spice.ai version.

Passwords must be sourced from a secret store in production. See Secret Stores for configuration options (environment variables, file, Kubernetes, AWS Secrets Manager, HashiCorp Vault).

TLS

TLS is controlled via pg_sslmode:

Value	Behavior
disable	No TLS.
prefer	Try TLS, fall back to plaintext. Not recommended for production.
require	Require TLS; no server certificate verification.
verify-ca	Require TLS and verify the CA chain.
verify-full	Require TLS, verify CA chain, and verify server hostname.

For production, use verify-full with pg_sslrootcert pointing to the CA bundle.

Resilience Controls

Connection Pool Sizing

The connector maintains a per-dataset connection pool:

Parameter	Default	Description
pg_connection_pool_min_idle	1	Minimum idle connections held by the pool.
connection_pool_size	5	Maximum connections the pool will open.

pg_connection_pool_min_idle must be less than or equal to connection_pool_size; conflicting values are rejected as configuration errors at startup.

Size the pool to match concurrent query and refresh load for the dataset. The server's max_connections (default 100) is a shared budget across Spice datasets, other clients, and server-side background workers — plan accordingly, or front Postgres with PgBouncer.

Application Name

The connector automatically sets application_name to the Spice.ai version string, which surfaces in pg_stat_activity.application_name. This value is not configurable.

Retry Behavior

Transient query failures are not automatically retried at the connector layer. Dataset refresh retries are controlled by the acceleration refresh policy (see Data Refresh).

Capacity & Sizing

• Network: Postgres traffic is TCP. Sum connection_pool_size across all Spice datasets sharing the server when sizing max_connections.
• Memory: Result sets are streamed in record batches; memory footprint for federated reads is bounded by DataFusion's batch size (8192 rows default).
• Connection setup cost: TLS handshake and authentication add latency to cold connections. connection_pool_min_idle keeps a warm pool to absorb burst traffic.

Metrics

The PostgreSQL connector exposes observable metrics for its connection pool. Enable them in the dataset's metrics section. See Component Metrics for general configuration.

Metric Name	Type	Description
connection_count	ObservableGauge	Active connections to the database server.
connections_in_pool	ObservableGauge	Idle connections sitting in the pool.
active_wait_requests	ObservableGauge	Requests waiting for a connection (saturation signal).
create_failed	Counter	Connections that failed to be created.
discarded_excess_idle_connection	Counter	Connections closed because the pool already had enough idle connections.
discarded_unestablished_connection	Counter	Connections closed because they could not be established.
dirty_connection_return	Counter	Connections returned in a dirty state (open transaction, pending queries).

Metric instruments are exposed with the prefix dataset_postgres_. Each instrument carries a name attribute set to the dataset name.

Task History

PostgreSQL operations participate in Spice task history via the shared SQL data-connector spans. Queries executed against Postgres are captured as child spans of the enclosing sql_query or accelerated_table_refresh task.

Known Limitations

• Only TCP connections are supported. Unix sockets are not exposed through Spice configuration.
• pg_sslmode: prefer silently downgrades to plaintext and is not recommended for production.
• LISTEN/NOTIFY is not exposed; Postgres CDC is handled through Debezium rather than the Postgres connector directly.
• Server-side cursors are used for federated reads; long-running queries hold a backend for their duration.

Troubleshooting

Symptom	Likely cause	Resolution
FATAL: password authentication failed	Incorrect credentials.	Verify credentials via the secret store; test with psql using the same credentials.
FATAL: too many clients already	Pool size + other clients exceeds server max_connections.	Reduce connection_pool_size or raise max_connections / front the server with PgBouncer.
pg_connection_pool_min_idle must be <= connection_pool_size at startup	Misconfiguration.	Correct the values so pg_connection_pool_min_idle <= connection_pool_size.
Sustained active_wait_requests > 0	Pool saturation.	Increase connection_pool_size or reduce concurrent refreshes.
certificate verify failed	pg_sslmode: verify-ca / verify-full with wrong CA or hostname.	Verify pg_sslrootcert matches the server's issuing CA; with verify-full ensure hostname matches SAN.
Sessions lingering with the default app name	Multiple Spice instances share the same version-based name.	The application_name is auto-set to the Spice.ai version and is not currently configurable.