davisp commented on a change in pull request #2666: soft-deletion for database
URL: https://github.com/apache/couchdb/pull/2666#discussion_r400287360
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File path: src/fabric/src/fabric2_fdb.erl
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@@ -346,12 +351,97 @@ delete(#{} = Db) ->
} = ensure_current(Db),
DbKey = erlfdb_tuple:pack({?ALL_DBS, DbName}, LayerPrefix),
- erlfdb:clear(Tx, DbKey),
- erlfdb:clear_range_startswith(Tx, DbPrefix),
+ DoRecovery = fabric2_util:do_recovery(),
Review comment:
I think splitting this up into three helpers would be the cleanest API.
Something like this:
```erlang
delete(Db, Options) ->
DoRecovery = fabric2_util:do_recovery(),
DeletedAt = fabric2_util:get_value(deleted_at, Options),
case {DoRecovery, DeletedAt} of
{true, undefined} -> soft_delete_db(Db);
{false, undefined} -> hard_delete_db(Db);
{_, TimeStamp} -> remove_deleted_db(Db, Timestamp)
end.
soft_delete_db(Db) ->
#{
name := DbName,
tx := Tx,
layer_prefix := LayerPrefix
} = ensure_current(Db),
DbKey = erlfdb_tuple:pack({?ALL_DBS, DbName}, LayerPrefix)
Timestamp = list_to_binary(fabric2_util:iso8601_timestamp()),
DeletedDbKeyTuple = {?DELETED_DBS, DbName, Timestamp},
DeletedDbKey = erlfdb_tuple:pack(DeletedDbKeyTuple, LayerPrefix),
case erlfdb:wait(erlfdb:get(Tx, DeletedDbKey)) of
not_found ->
erlfdb:set(Tx, DeletedDbKey, DbPrefix),
erlfdb:clear(Tx, DbKey);
_Val ->
erlang:error({deleted_database_exists, DbName})
end,
bump_metadata_version(Tx),
ok.
hard_delete_db(Db) ->
#{
name := DbName,
tx := Tx,
layer_prefix := LayerPrefix,
db_prefix := DbPrefix
} = ensure_current(Db),
DbKey = erlfdb_tuple:pack({?ALL_DBS, DbName}, LayerPrefix)
erlfdb:clear(Tx, DbKey),
erlfdb:clear_range_startswith(Tx, DbPrefix),
bump_metadata_version(Tx),
ok.
remove_deleted_db(Db, Timestamp) ->
#{
name := DbName,
tx := Tx,
layer_prefix := LayerPrefix
} = ensure_current(Db0, false),
DeletedDbTupleKey = {?DELETED_DBS, DbName, TimeStamp},
DeletedDbKey = erlfdb_tuple:pack(DeletedDbTupleKey, LayerPrefix),
case erlfdb:wait(erlfdb:get(Tx, DeletedDbKey)) of
not_found ->
erlang:error({not_found, missing_timestamp});
DbPrefix ->
erlfdb:clear(Tx, DeleteDbKey),
erlfdb:clear_range_startswith(Tx, DbPrefix)
end,
ok.
```
Though the three helpers get moved down into the helper function section.
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