## Troubleshooting PostgreSQL connectivity

URL: https://docs.atlan.com/apps/connectors/database/postgresql/troubleshooting/troubleshooting-postgresql-connectivity

> Symptom-first troubleshooting for PostgreSQL connectivity - SSL and pg_hba rejections, timeouts, IAM authentication, wrong PrivateLink hostname, misleading error wrappers, and miner preflight failures.

Resolve common PostgreSQL connectivity issues when integrating PostgreSQL with Atlan. Symptom-first, ordered by how often each issue actually occurs in support. Each entry includes the check you can run yourself before opening a ticket.

## Quick index

| You see | Most likely cause | Jump to |
|---|---|---|
| `FATAL: pg_hba.conf rejects connection ... SSL off` (often with `PAM authentication failed`) | Server requires SSL; connection sent none | [SSL rejections](#ssl-rejections---pg_hbaconf--ssl-off-family) |
| "SQL client authentication failed" / "Not able to authenticate your credentials" - but credentials are right | It's usually not auth: read the inner error | [Misleading wrappers](#misleading-error-wrappers---read-the-inner-error) |
| `connection timeout expired` | Firewall, wrong hostname, stale IP, or unopened port | [Timeouts](#timeouts---connection-timeout-expired) |
| IAM auth fails as a password error; PrivateLink itself is healthy | `rds_iam` grant, `rds-db:connect`, or the AWS Region field | [IAM authentication](#iam-authentication-failures-rdsaurora) |
| Timeout right after a PrivateLink setup "completed" | RDS hostname in the Host field instead of the VPCE DNS name, or connection still pending acceptance | [Wrong hostname](#wrong-hostname-after-privatelink-setup) |
| Worked for months, broke overnight, nothing changed on your side | Database restart changed its IP; egress/policy drift; or an Atlan-side change | [Sudden breakage](#it-worked-for-months-then-broke-overnight) |
| Crawler fine, miner fails at preflight | `pg_stat_statements` missing or ungranted | [Miner preflight](#miner-preflight-failures) |

## SSL rejections - "pg_hba.conf ... SSL off" family

**Symptom.** Test connection or preflight fails with errors like (hostnames anonymized):

```
(psycopg.OperationalError) connection failed:
FATAL: PAM authentication failed for user "atlan_user"
FATAL: pg_hba.conf rejects connection for host "10.x.x.x",
 user "atlan_user", database "analytics", SSL off
-- variant: "... no encryption"
```

**Why.** Two-layer rejection. The connection arrived without SSL; the server's `pg_hba.conf` has a `hostssl` (SSL-only) rule for this user/database, so it's rejected before authentication completes - which then also surfaces as a PAM/password failure. No credential change will ever fix it. This is the most common single PostgreSQL connectivity failure.

**Fix.**

1. Set the Atlan connection's SSL mode to `require` (or `verify-ca`/`verify-full` if you have the CA bundle). If you can't find the field, ask support to set the connection's `sslmode`.
2. Have your Postgres admin confirm a `hostssl` rule for the Atlan user and database exists before any broader PAM catch-all (self-managed), or review `rds.force_ssl` and the user's auth method (RDS/Aurora). See [Firewalls, pg_hba.conf, and SSL](https://docs.atlan.com/llms/connectors/postgresql/firewalls-pg-hba-conf-and-ssl/llms.txt).
3. If PAM/LDAP auth is intentional for this account, verify that stack accepts non-interactive logins; otherwise `scram-sha-256` is cleaner for service users.

## Misleading error wrappers - read the inner error

**Symptom.** The UI says `SQL client authentication failed` (e.g. `ATLAN-CLIENT-401-02`), `Not able to authenticate your credentials`, or a generic `HEKA-500-00-009` - but your credentials are verified correct.

**Why.** These are generic wrappers around whatever went wrong underneath. In support history they have wrapped: TCP timeouts (firewall), pg_hba rejections (SSL), stale IPs, missing table grants, and Atlan-internal deployment issues. The word "authentication" in the wrapper is not evidence of an authentication problem.

**Fix.** Expand the workflow logs and find the innermost error line - the ones that matter look like `psycopg.errors.ConnectionTimeout: connection timeout expired` (→ [Timeouts](#timeouts---connection-timeout-expired)), `FATAL: pg_hba.conf rejects ...` (→ [SSL rejections](#ssl-rejections---pg_hbaconf--ssl-off-family)), or `permission denied for table ...` (grants, not connectivity). Then follow that section. If the log shows no inner error at all, paste the wrapper + workflow run link in a ticket - the cause has more than once been on Atlan's side (a connector service blip; a worker/workflow version mismatch), and support can confirm quickly.

## Timeouts - connection timeout expired

**Symptom.** Preflight or test connection hangs, then fails with `psycopg.errors.ConnectionTimeout: connection timeout expired` (sometimes listing several `hostaddr` attempts).

**Why.** TCP never connected. This is gate 1 - nothing to do with users, passwords, or SSL. The usual causes, in observed order of frequency:

1. Atlan's egress IPs aren't allowlisted at your firewall - including the QA-tenant-has-different-IPs trap ([each tenant has its own IPs](https://docs.atlan.com/llms/governance/administration/atlan-network-details/llms.txt)).
2. The database's underlying IP changed (restart/failover) and something pinned to the old IP - NLB target group, peering rule, firewall entry.
3. PrivateLink: the Host field has your RDS hostname instead of the VPCE DNS name (→ [next section](#wrong-hostname-after-privatelink-setup)), the endpoint is still pending acceptance, or a non-default port was never opened on Atlan's side.

**Check yourself.** From outside your network: `nc -vz <host> <port>`. An instant connect means the path is open (look elsewhere); a long hang confirms a network drop. Then compare the IP the hostname resolves to now (`nslookup <host>`) against what your firewall/NLB has configured.

## IAM authentication failures (RDS/Aurora)

**Symptom.** The connection reaches the database (no timeout) but IAM Role/User auth fails with password- or PAM-style errors.

**Check, in order:**

1. IAM Database Authentication enabled on the cluster/instance?
2. `GRANT rds_iam TO atlan_user;` run on the database?
3. IAM role/user has `rds-db:connect` for this DB user and instance? Trust policy allows Atlan's principal (confirm the exact principal with support)?
4. **AWS Region** field set to the database's region? Cross-region tenants hit token-signing mismatches that present as password failures - see [Special cases](https://docs.atlan.com/llms/connectors/postgresql/special-cases/llms.txt).
5. Using Azure? Service Principal auth is not supported - use Basic auth.

## Wrong hostname after PrivateLink setup

**Symptom.** PrivateLink shows **Available** in AWS, connectivity "should" work, but Atlan times out. Meanwhile your own tools connect fine using the RDS hostname.

**Why.** Your tools are inside your network; the RDS hostname resolves for them. Atlan is not - it can only reach your database through the plug it built, whose name looks like `vpce-...-....vpce-svc-....<region>.vpce.amazonaws.com`.

**Fix.** Put the VPCE DNS name from your support ticket in the Host field, character for character, with the correct listener port. If you never received it, ask on the ticket. Also verify the endpoint connection shows **Available**, not **Pending** - nothing accepts itself. See [Phase 4 of the PrivateLink guide](https://docs.atlan.com/llms/connectors/postgresql/set-up-a-private-network-link-to-postgresql/llms.txt).

## It worked for months, then broke overnight

1. **Did the database restart, fail over, or get maintained?** Its IP likely changed. Check every place an IP is pinned: NLB target groups, peering configs, firewall rules. (Self-healing can take days if you wait for DNS caches; fix the pinned value instead.)
2. **Did a firewall or network policy change on your side?** Diff current rules against Atlan's egress IPs from your ticket. Remember QA vs prod tenants have different IPs.
3. **Did the failure start when nothing changed anywhere?** Atlan-side incidents (a connector service blip during a nightly cron; a worker version mismatch after an upgrade) have caused exactly this - both resolved by support without customer changes. If steps 1-2 are clean, open a ticket with the run link and say so.
4. **Port-translated PrivateLink connections only failing?** Mention that pattern explicitly - it has recurred after connector upgrades. See [Special cases](https://docs.atlan.com/llms/connectors/postgresql/special-cases/llms.txt).

## Miner preflight failures

**Symptom.** Crawler works; the miner fails at preflight with messages about `pg_stat_statements` or `permission denied`.

**Fix** (needs a DBA/superuser; on RDS/Cloud SQL, via the parameter group / flags plus a reboot):

```sql
-- 1. shared_preload_libraries must include pg_stat_statements
-- (server/parameter-group setting + restart)
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
GRANT pg_read_all_stats TO atlan_user;
```

The Atlan user itself does not need superuser - the extension just has to be installed by someone who has it.

## Opening ticket that gets solved fast

Include these six things - they usually turn a multi-day exchange into one reply:

- Your Atlan tenant URL and the failing workflow run link
- Connectivity method (internet / PrivateLink / agent) and, for PrivateLink, the VPCE DNS name and listener port in use - flag any port translation
- The innermost error text from the workflow logs (not just the wrapper)
- Where PostgreSQL runs (RDS/Aurora/Azure/Cloud SQL/self-managed) and its SSL requirement (`rds.force_ssl`, `hostssl` rules)
- Result of your own [nc/psql reachability check](https://docs.atlan.com/llms/connectors/postgresql/firewalls-pg-hba-conf-and-ssl/llms.txt)
- Whether it ever worked, and if so when it stopped - plus any restarts/failovers around that time

## Frequently asked questions

### Can Atlan crawl future tables created by any user?

PostgreSQL does not provide a single command to grant access to future tables created by any user on a global level.

You will have to alter the default privileges of every current and future user that creates tables. This is to ensure that the [database role you created for integrating with Atlan](https://docs.atlan.com/llms/connectors/postgresql/set-up-postgresql/llms.txt) has access to the tables created by those users by default. For example:

```sql
ALTER DEFAULT PRIVILEGES FOR USER IN SCHEMA GRANT SELECT, REFERENCES ON TABLES TO atlan_user_role;
```

However, altering the default privileges of every current and future user may not be sustainable or controlled from a single place. To automate the granting of permissions, you can:

**Grant function**

You can automate the granting of privileges to the [database role you created](https://docs.atlan.com/llms/connectors/postgresql/set-up-postgresql/llms.txt) for integrating with Atlan. Note that the function below is located in the public schema. You can use any schema you want to store this function:

- Set custom conditions using PL/pgSQL to skip or allow only certain schemas or tables:

 ```sql
 CREATE OR REPLACE FUNCTION public.grant_permissions_on_all_schemas()
 RETURNS void AS $$
 DECLARE
 schema_name text;
 BEGIN
 FOR schema_name IN (SELECT nspname FROM pg_namespace WHERE nspname NOT LIKE 'pg_%' AND nspname != 'information_schema')
 LOOP
 EXECUTE format('GRANT USAGE ON SCHEMA %I TO atlan_user_role', schema_name);
 -- grant access to all tables, including views, materialized views
 EXECUTE format('GRANT SELECT, REFERENCES ON ALL TABLES IN SCHEMA %I TO atlan_user_role', schema_name);
 END LOOP;
 END;
 $$ LANGUAGE plpgsql;
 ```

- Next, set up a periodic schedule and execute this function on a daily or hourly basis to ensure that the [database role](https://docs.atlan.com/llms/connectors/postgresql/set-up-postgresql/llms.txt) has access to all new schemas or tables:

 ```sql
 select public.grant_permissions_on_all_schemas();
 ```

**Event triggers**

You can create an event trigger on any `CREATE SCHEMA` or `CREATE TABLE` command. This automation will ensure minimal lag, and you will not have to set up a schedule to run the above grant function.

Note that the event trigger only listens to new create event triggers. You will still need to run the grant function above to ensure that the database role has access to all current schemas or tables.

```sql
-- Function to grant permissions on a specific schema
CREATE OR REPLACE FUNCTION public.grant_permissions_on_schema()
RETURNS event_trigger AS $$
DECLARE
 obj record;
BEGIN
 FOR obj IN SELECT * FROM pg_event_trigger_ddl_commands() WHERE command_tag = 'CREATE SCHEMA'
 LOOP
 EXECUTE format('GRANT USAGE ON SCHEMA %I TO atlan_user_role', obj.object_identity);
 RAISE NOTICE 'Granted USAGE on schema % to atlan_user_role', obj.object_identity;
 END LOOP;
END;
$$ LANGUAGE plpgsql;

-- Event trigger for new schemas
CREATE EVENT TRIGGER grant_permissions_on_new_schema ON ddl_command_end
WHEN TAG IN ('CREATE SCHEMA')
EXECUTE FUNCTION public.grant_permissions_on_schema();

-- Function to grant permissions on a specific table
CREATE OR REPLACE FUNCTION public.grant_permissions_on_table()
RETURNS event_trigger AS $$
DECLARE
 obj record;
BEGIN
 FOR obj IN SELECT * FROM pg_event_trigger_ddl_commands() WHERE command_tag = 'CREATE TABLE'
 or command_tag = 'CREATE VIEW'
 or command_tag = 'CREATE TABLE AS'
 or command_tag = 'CREATE MATERIALIZED VIEW'
 LOOP
 EXECUTE format('GRANT SELECT, REFERENCES ON TABLE %s TO atlan_user_role', obj.object_identity);
 RAISE NOTICE 'Granted SELECT, REFERENCES on table % to atlan_user_role', obj.object_identity;
 END LOOP;
END;
$$ LANGUAGE plpgsql;

-- Event trigger for new tables, views, mat views
CREATE EVENT TRIGGER grant_permissions_on_new_table ON ddl_command_end
WHEN TAG IN ('CREATE TABLE', 'CREATE VIEW', 'CREATE TABLE AS', 'CREATE MATERIALIZED VIEW')
EXECUTE FUNCTION public.grant_permissions_on_table();
```

### What databases and schemas does Atlan access?

The connector queries only metadata catalog views—it doesn't read, write, or access data in your actual tables. The connector reads from the following sources during a crawl:

| Source | Type | Purpose |
| --- | --- | --- |
| `information_schema.schemata` | Standard SQL view | Fetch schema names |
| `information_schema.tables` | Standard SQL view | Fetch table and view metadata |
| `information_schema.columns` | Standard SQL view | Fetch column metadata (names, data types, nullability) |
| `pg_database` | System catalog (`pg_catalog`) | Identify the connected database name |

### Does Atlan connect to your actual database or only to system catalogs?

The connector connects to the target database you specify in your connection configuration. Once connected, it reads only from `information_schema` views and the `pg_database` system catalog—it doesn't access your user-created tables or data.

_Last updated: 27 August 2026._

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