Currently they are upgraded during learn on a replica. The are two
problems with this. First the column mapping may not exist on a replica
if it missed this particular schema (because it was down for instance)
and the mapping history is not part of the schema. In this case "Failed
to look up column mapping for schema version" will be thrown. Second lwt
request coordinator may not have the schema for the mutation as well
(because it was freed from the registry already) and when a replica
tries to retrieve the schema from the coordinator the retrieval will fail
causing the whole request to fail with "Schema version XXXX not found"
Both of those problems can be fixed by upgrading stored mutations
during prepare on a node it is stored at. To upgrade the mutation its
column mapping is needed and it is guarantied that it will be present
at the node the mutation is stored at since it is pre-request to store
it that the corresponded schema is available. After that the mutation
is processed using latest schema that will be available on all nodes.
Fixes#10770
Message-Id: <Y7/ifraPJghCWTsq@scylladb.com>
(cherry picked from commit 15ebd59071)
ca7a13cad2