davisp commented on a change in pull request #2666: [WIP] soft-deletion for
database
URL: https://github.com/apache/couchdb/pull/2666#discussion_r396598481
##########
File path: src/fabric/src/fabric2_fdb.erl
##########
@@ -346,12 +353,64 @@ 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),
+ erlfdb:set(Tx, DeletedDbKey, DbPrefix),
+ erlfdb:clear(Tx, DbKey);
+ 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).
+
+
+restore(#{} = Db0, DesDbName, Timestamp) ->
+ #{
+ name := DbName,
+ tx := Tx,
+ layer_prefix := LayerPrefix
+ } = ensure_current(Db0, false),
+ DbKey = erlfdb_tuple:pack({?ALL_DBS, DesDbName}, LayerPrefix),
+ case erlfdb:wait(erlfdb:get(Tx, DbKey)) of
+ Bin when is_binary(Bin) ->
+ {error, file_exists};
+ not_found ->
+ DeleteDbKey = erlfdb_tuple:pack({?DELETED_DBS, DbName,
Review comment:
Slight style nit. And this is personal preference, but I find that FDB keys
that span multiple lines its easier to read if we break them out to one line
per. So I'd normal do something like:
```erlang
DeletedDbTupleKey = {
?DELETED_DBS,
DbName,
TimeStamp
},
DeletedDbKey = erlfdb_tuple:pack(DeletedDbTuple, LayerPrefix),
```
----------------------------------------------------------------
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
