docs: add pg_subscription_rel and lr troubleshooting guides

[dhanushreddy291]

https://neon-next-git-fork-dhanushreddy291-add-docs-247336-neondatabase.vercel.app/docs/guides/logical-replication-pg_subscription_rel

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Project	Deployment	Review	Updated (UTC)
neon-next	Ready	Preview, Comment	Jan 22, 2026 8:50am

[bgrenon]

@dhanushreddy291 the pgcopydb doc is reviewed with some edits, mostly for concision, but with 2 new points:

• When I tested (neon to neon), --resume did not work. I think the source db needs to support traditional postgres snapshots. I've added language to that effect. Can you confirm this?
• The environment variables from Step 1 were not available to the 2nd monitoring terminal session; I added language capture you need to either set new variables, or include --source flag.

[dhanushreddy291]

@dhanushreddy291 the pgcopydb doc is reviewed with some edits, mostly for concision, but with 2 new points:

Sorry, @bgrenon. I tested LR from other providers to Neon but missed Neon-to-Neon and Neon to third-party postgres. I encountered errors today when doing that and added --no-acl for Neon-to-Neon migrations or Neon to any.

The following error is when we do pgcopydb clone --no-owner from Neon to Neon without --no-acl

The following error is when we do pgcopydb clone --no-owner from Neon to a 3rd party Postgres without --no-acl

• When I tested (neon to neon), --resume did not work. I think the source db needs to support traditional postgres snapshots. I've added language to that effect. Can you confirm this?

I also removed the resume flag and stream sentinel since they don't work without functional LR. My apologies for the oversight.

• The environment variables from Step 1 were not available to the 2nd monitoring terminal session; I added language capture you need to either set new variables, or include --source flag.

Sure. Thanks

[philip]

Hi @dhanushreddy291, do you have thoughts on the state of this PR? Looks like pgcopydb was merged into the docs, is the logical-replication-pg_subscription_rel guide still accurate and useful?

[dhanushreddy291]

Hi @dhanushreddy291, do you have thoughts on the state of this PR? Looks like pgcopydb was merged into the docs, is the logical-replication-pg_subscription_rel guide still accurate and useful?

@philip yes it is good to go, i reorganized parts of pg_subscription_rel guide a bit now.