nickva commented on a change in pull request #2666: soft-deletion for database
URL: https://github.com/apache/couchdb/pull/2666#discussion_r400377646
##########
File path: src/fabric/src/fabric2_fdb.erl
##########
@@ -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(),
+ case DoRecovery of
+ true ->
+ Timestamp = list_to_binary(fabric2_util:iso8601_timestamp()),
+ DeletedDbKey = erlfdb_tuple:pack({?DELETED_DBS, DbName, Timestamp},
+ 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;
+ false ->
+ erlfdb:clear(Tx, DbKey),
+ erlfdb:clear_range_startswith(Tx, DbPrefix)
+ end,
bump_metadata_version(Tx),
ok.
+deleted_dbs_info(#{} = Db0) ->
+ #{
+ name := DbName,
+ tx := Tx,
+ layer_prefix := LayerPrefix
+ } = ensure_current(Db0, false),
+
+ DeletedDbKey = erlfdb_tuple:pack({?DELETED_DBS, DbName}, LayerPrefix),
+ DeletedDbs = erlfdb:wait(erlfdb:get_range_startswith(Tx, DeletedDbKey)),
+ lists:foldl(fun({DbKey, DbPrefix}, Acc) ->
+ DBInfo = get_info_wait(get_info_future(Tx, DbPrefix)),
+ {?DELETED_DBS, DbName, DeletedTS} =
+ erlfdb_tuple:unpack(DbKey, LayerPrefix),
+ [{DeletedTS, DBInfo}| Acc]
+ end, [], DeletedDbs).
+
+
+undelete(#{} = Db0, TgtDbName, TimeStamp) ->
+ #{
+ name := DbName,
+ tx := Tx,
+ layer_prefix := LayerPrefix
+ } = ensure_current(Db0, false),
+ DbKey = erlfdb_tuple:pack({?ALL_DBS, TgtDbName}, LayerPrefix),
+ case erlfdb:wait(erlfdb:get(Tx, DbKey)) of
+ Bin when is_binary(Bin) ->
+ {error, file_exists};
+ not_found ->
+ DeletedDbTupleKey = {
+ ?DELETED_DBS,
+ DbName,
+ TimeStamp
+ },
+ DeleteDbKey = erlfdb_tuple:pack(DeletedDbTupleKey, LayerPrefix),
+ case erlfdb:wait(erlfdb:get(Tx, DeleteDbKey)) of
+ not_found ->
+ erlang:error({not_found, invalid_timestamp});
+ DbPrefix ->
+ erlfdb:set(Tx, DbKey, DbPrefix),
+ erlfdb:clear(Tx, DeleteDbKey),
+ bump_metadata_version(Tx),
+ ok
+ end
+ end.
+
+
+delete_deleted(#{} = Db0, TimeStamp) ->
+ #{
+ name := DbName,
+ tx := Tx,
+ layer_prefix := LayerPrefix
+ } = ensure_current(Db0),
+
+ DeletedDbTupleKey = {
+ ?DELETED_DBS,
+ DbName,
+ TimeStamp
+ },
+ DeleteDbKey = erlfdb_tuple:pack(DeletedDbTupleKey, LayerPrefix),
+ case erlfdb:wait(erlfdb:get(Tx, DeleteDbKey)) of
+ not_found ->
+ erlang:error({not_found});
+ DbPrefix ->
+ erlfdb:clear(Tx, DeleteDbKey),
+ erlfdb:clear_range_startswith(Tx, DbPrefix),
+ bump_metadata_version(Tx)
Review comment:
I think we're ok not bumping it here if we guarantee (let's have a test for
it) that any soft deleted db handle will reopen. For that we need to bump the
db version when we soft-delete and ensure that to hard deletion (snapshot
removal) always goes through the soft-deletion path first.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
