Edits for DDL replication/Mixed version prohibition #6851
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Signed-off-by: Dj Walker-Morgan <[email protected]>
djw-m
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Signed-off-by: Dj Walker-Morgan <[email protected]>
| * **Restart Postgres** | ||
| * Proceed to restart the PostgreSQL service: | ||
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| `systemctl start postgres` | ||
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| * **Update the extensions** | ||
| * The upgrade process checks for extension updates and generates a script named `updated_extensions.sql` in the current directory if needed. | ||
| This contains `ALTER EXTENSION` commands for any extensions that need updating after the upgrade. As these are DDL commands, if you have to run the script before all nodes are upgraded, you should turn off DDL replication temporarily to avoid issues with mixed major versions. If you can defer running the script until all nodes are upgraded, you can run it on each node after the upgrade of that node is complete. |
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Note: possible gotcha here, if someone thinks "yay, I'll just SET bdr.ddl_replication=off before \i-ing the update script" - the update script contains a \c / \connection command for each database that pg_upgrade thinks has extensions which need upgrading, which will start a new session, rendering the SET bdr.ddl_replication=off ineffective, like this:
postgres=# SET bdr.ddl_replication = off;
SET
postgres=# SHOW bdr.ddl_replication ;
bdr.ddl_replication
---------------------
off
(1 row)
postgres=# \c postgres
psql (18devel, server 17.4)
You are now connected to database "postgres" as user "postgres".
postgres=# SHOW bdr.ddl_replication ;
bdr.ddl_replication
---------------------
on
(1 row)
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That's a good point. @sumarjee is there an answer to this problem or do we have to tell people they need to edit the script?
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I was not aware of this, we have to cross link to whatever way we recommend customer to turn off ddl_replication. @ibarwick can you please help with the correcting this as you have already explored on this.
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@ibarwick if it makes more sense to even not at all recommend running this script before all upgrades done, we can do that instead of having these problems..
djw-m
changed the title
What Changed?
Added notes on the requirement not to perform DDL replication during mixed major version upgrades.