Document the behaviour of import/export database with indexes (#340)

Author: acquamarin

src/content/docs/migrate/index.md

@@ -34,6 +34,10 @@ For more compact storage, you can export the data files in Parquet format as fol
 EXPORT DATABASE '/path/to/export' (format="parquet");
 ```
 
+:::note[Note]
+The EXPORT DATABASE command also exports all indexes, regardless of whether their dependent extensions have been loaded or not.
+:::
+
 ## Import database
 
 The `IMPORT DATABASE` command imports the contents of the database from a specific directory to which
@@ -48,8 +52,9 @@ IMPORT DATABASE '/path/to/export';
 ```
 
 :::note[Note]
-The `IMPORT DATABASE` command can only be executed on an empty database.
+1. The `IMPORT DATABASE` command can only be executed on an empty database.
 Currently, in case of a failure during the execution of the `IMPORT DATABASE` command,
 automatic rollback is not supported. Therefore, if the `IMPORT DATABASE` command fails, you will need to delete the 
 database directory you are connected to and reload it again.
+2. The `IMPORT DATABASE` command also imports all indexes, regardless of whether their dependent extensions were loaded during export. If an index's dependent extension was loaded at the time of export, it will be automatically loaded during import. However, if the dependent extension was not loaded during export, it will not be automatically loaded during import. In such cases, users must manually load the dependent extensions before querying the index.
 :::