Add Troubleshooting guide

Author: szarnyasg

_data/menu_docs_preview.json

@@ -219,13 +219,17 @@
                   "page": "Backups and Recovery",
                   "url": "backups_and_recovery"
                 },
+                {
+                  "page": "Public DuckLake on Object Storage",
+                  "url": "public_ducklake_on_object_storage"
+                },
                 {
                   "page": "Using a Remote Data Path",
                   "url": "using_a_remote_data_path"
                 },
                 {
-                  "page": "Public DuckLake on Object Storage",
-                  "url": "public_ducklake_on_object_storage"
+                  "page": "Troubleshooting",
+                  "url": "troubleshooting"
                 }
               ]
             },

docs/preview/duckdb/guides/troubleshooting.md

@@ -0,0 +1,37 @@
+---
+layout: docu
+title: Troubleshooting
+---
+
+This guide explains how to troubleshoot certain issues with DuckLake.
+Besides the issues described on this page, see also the [“Unsupported Features” page]({% link docs/preview/duckdb/unsupported_features.md %}).
+
+## Connecting to an Older DuckLake
+
+If you try to connect to a DuckLake created by an older version of the `ducklake` extension, you get the following error message:
+
+```console
+Invalid Input Error:
+DuckLake catalog version mismatch: catalog version is 0.3, but the extension requires version 0.4-dev1.
+To automatically migrate, set AUTOMATIC_MIGRATION to TRUE when attaching.
+```
+
+To work around this, add the `AUTOMATIC_MIGRATION` flag to the `ATTACH` command:
+
+```sql
+ATTACH '...' (AUTOMATIC_MIGRATION);
+```
+
+## Connecting to a Read-Only DuckLake
+
+If you try to connect to a read-only DuckLake, you get the following error message:
+
+```console
+Invalid Input Error:
+Failed to migrate DuckLake from v0.2 to v0.3:
+Cannot execute statement of type "CREATE" on database "__ducklake_metadata_sf1" which is attached in read-only mode!
+```
+
+It is not possible to connect to a read-only DuckLake with a pre-release version (v0.x).
+To migrate from such a DuckLake, use an older version of the `ducklake` extension and migrate into an intermediate format.
+For example, copy the data into a DuckLake that you have write access to, then connect to that DuckLake using the newer `ducklake` extension.