Can't get snapshot working following the documentation

[brunotiago]

Describe the bug
I am trying to snapshot and replicate an on prem PG server to a Neon DB instance but I am facing some configuration issues when starting pgstream. I would like to use snapshot_and_replicate but didn't find many documentation about that so I changed to snapshot.

To Reproduce
Steps to reproduce the behavior:

source:
  postgres:
    url: "postgresql://my_user:password@localhost:5432/db?sslmode=disable"
    mode: snapshot
    snapshot:
      mode: full
      tables: ["*"]
      recorder:
        repeatable_snapshots: true
        postgres_url: "postgresql://my_user:password@localhost:5432/db?sslmode=disable"
      snapshot_workers: 4
      data:
        schema_workers: 4
        table_workers: 4
        batch_bytes: 83886080
      schema:
        mode: pgdump_pgrestore
        pgdump_pgrestore:
          clean_target_db: false

target:
  postgres:
    url: "postgresql://neondb_user:neondb_password@neondb_server?sslmode=require&channel_binding=require"
    batch:
      timeout: 5000
      size: 25
    disable_triggers: false
    on_conflict_action: "nothing"

2. Run command
   pgstream run -c /etc/pgstream/pgstream.yaml --init
3. Output
   using config file: /etc/pgstream/pgstream.yaml
4. Error message:
   Error: error setting up postgres replication handler: create postgres replication client: failed to connect to user=root database=: /var/run/postgresql/.s.PGSQL.5432 (/var/run/postgresql): server error: FATAL: role "root" does not exist (SQLSTATE 28000)

Expected behavior
Expected to have pgstream start doing the snapshot of the DB

Setup (please complete the following information):

• pgstream version: v0.8.3
• Postgres version: 16.4
• Postgres environment: self-hosted

Maybe I am missing something on the configuration, but I tried to follow your documentation and doesn't work. Tried snapshot and replicate and had an error Error: no schema snapshot has been configured

[dosubot]

The error about role "root" does not exist usually means pgstream is trying to connect with a user that isn't present in your database. This happens if the connection URL in your YAML config is missing the user, is malformed, or if your environment is overriding the config and defaulting to root (for example, running as root in a container or shell). Double-check that every Postgres URL in your config (especially source.postgres.url and recorder.postgres_url) includes the correct username and password, and that there are no environment variables or system defaults interfering. The code does not default to root—it uses whatever is in the URL, so any fallback comes from outside pgstream itself (source).

The no schema snapshot has been configured error means your YAML is missing or misnests the schema snapshot section. For snapshot or snapshot_and_replication modes, you need a properly structured schema section under source.postgres.snapshot, with either mode: pgdump_pgrestore (and a non-empty pgdump_pgrestore: subsection) or mode: schemalog. YAML indentation and nesting must match the sample configs exactly—subtle mistakes will trigger this error (source). Reference this sample config for the required structure.

_Written by @dosu

To reply, just mention @dosu.

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[eminano]

Hi @brunotiago , thanks for raising this issue!
Apologies for the late reply, we were at a company offsite last week 🙏

The error you are referring to seems to be related to postgres itself. As dosubot mentions (we're trying it out 🤖 ), can you make sure the url and the user you're referencing in the pgstream config align with the source database?

Thanks again!

[gulcin]

Hello @brunotiago have you had a chance to verify what @eminano suggested?

[brunotiago]

I changed my approach, I replicated the database manually using pg dump and pg restore and then enabled replication using pgstream. It works fine after that.

The insights from @eminano were good and probably right, but I changed my approach and forgot to update the thread. Sorry about that