kocolosk commented on a change in pull request #1370: [5/5] Clustered Purge
Implementation
URL: https://github.com/apache/couchdb/pull/1370#discussion_r194849338
##########
File path: src/couch/src/couch_db.erl
##########
@@ -369,8 +379,145 @@ get_full_doc_info(Db, Id) ->
get_full_doc_infos(Db, Ids) ->
couch_db_engine:open_docs(Db, Ids).
-purge_docs(#db{main_pid=Pid}, IdsRevs) ->
- gen_server:call(Pid, {purge_docs, IdsRevs}).
+purge_docs(Db, IdRevs) ->
+ purge_docs(Db, IdRevs, []).
+
+-spec purge_docs(#db{}, [{UUId, Id, [Rev]}], [PurgeOption]) ->
+ {ok, [Reply]} when
+ UUId :: binary(),
+ Id :: binary(),
+ Rev :: {non_neg_integer(), binary()},
+ PurgeOption :: interactive_edit | replicated_changes,
+ Reply :: {ok, []} | {ok, [Rev]}.
+purge_docs(#db{main_pid = Pid} = Db, UUIDsIdsRevs, Options) ->
+ % Check here if any UUIDs already exist when
+ % we're not replicating purge infos
+ IsRepl = lists:member(replicated_changes, Options),
+ if IsRepl -> ok; true ->
+ UUIDs = [UUID || {UUID, _, _} <- UUIDsIdsRevs],
+ lists:foreach(fun(Resp) ->
+ if Resp == not_found -> ok; true ->
+ Fmt = "Duplicate purge info UIUD: ~s",
+ Reason = io_lib:format(Fmt, [element(2, Resp)]),
+ throw({badreq, Reason})
+ end
+ end, get_purge_infos(Db, UUIDs))
+ end,
+ increment_stat(Db, [couchdb, database_purges]),
+ gen_server:call(Pid, {purge_docs, UUIDsIdsRevs, Options}).
+
+-spec get_purge_infos(#db{}, [UUId]) -> [PurgeInfo] when
+ UUId :: binary(),
+ PurgeInfo :: {PurgeSeq, UUId, Id, [Rev]} | not_found,
+ PurgeSeq :: non_neg_integer(),
+ Id :: binary(),
+ Rev :: {non_neg_integer(), binary()}.
+get_purge_infos(Db, UUIDs) ->
+ couch_db_engine:load_purge_infos(Db, UUIDs).
+
+
+get_minimum_purge_seq(#db{} = Db) ->
+ PurgeSeq = couch_db_engine:get_purge_seq(Db),
+ OldestPurgeSeq = couch_db_engine:get_oldest_purge_seq(Db),
+ PurgeInfosLimit = couch_db_engine:get_purge_infos_limit(Db),
+
+ FoldFun = fun(#doc{id = DocId, body = {Props}}, SeqAcc) ->
+ case DocId of
+ <<"_local/purge-", _/binary>> ->
+ ClientSeq = couch_util:get_value(<<"purge_seq">>, Props),
+ case ClientSeq of
+ CS when is_integer(CS), CS >= PurgeSeq - PurgeInfosLimit ->
+ {ok, SeqAcc};
+ CS when is_integer(CS) ->
+ case purge_client_exists(Db, DocId, Props) of
+ true -> {ok, erlang:min(CS, SeqAcc)};
+ false -> {ok, SeqAcc}
+ end;
+ _ ->
+ % If there's a broken doc we have to keep every
+ % purge info until the doc is fixed or removed.
+ Fmt = "Invalid purge doc '~s' with purge_seq '~w'",
+ couch_log:error(Fmt, [DocId, ClientSeq]),
+ {ok, erlang:min(OldestPurgeSeq, SeqAcc)}
+ end;
+ _ ->
+ {stop, SeqAcc}
+ end
+ end,
+ InitMinSeq = PurgeSeq - PurgeInfosLimit,
+ Opts = [
+ {start_key, list_to_binary(?LOCAL_DOC_PREFIX ++ "purge-")}
+ ],
+ {ok, MinIdxSeq} = couch_db:fold_local_docs(Db, FoldFun, InitMinSeq, Opts),
+ FinalSeq = case MinIdxSeq < PurgeSeq - PurgeInfosLimit of
+ true -> MinIdxSeq;
+ false -> erlang:max(0, PurgeSeq - PurgeInfosLimit)
+ end,
+ % Log a warning if we've got a purge sequence exceeding the
+ % configured threshold.
+ if FinalSeq >= (PurgeSeq - PurgeInfosLimit) -> ok; true ->
+ Fmt = "The purge sequence for '~s' exceeds configured threshold",
+ couch_log:warning(Fmt, [couch_db:name(Db)])
+ end,
+ FinalSeq.
+
+
+purge_client_exists(DbName, DocId, Props) ->
+ % Warn about clients that have not updated their purge
+ % checkpoints in the last "index_lag_warn_seconds"
+ LagWindow = config:get_integer(
+ "purge", "index_lag_warn_seconds", 86400), % Default 24 hours
+
+ {Mega, Secs, _} = os:timestamp(),
+ NowSecs = Mega * 1000000 + Secs,
+ LagThreshold = NowSecs - LagWindow,
+
+ try
+ CheckFun = get_purge_client_fun(DocId, Props),
+ Exists = CheckFun(DbName, DocId, Props),
+ if not Exists -> ok; true ->
+ Updated = couch_util:get_value(<<"updated_on">>, Props),
+ if is_integer(Updated) and Updated > LagThreshold -> ok; true ->
+ Diff = NowSecs - Updated,
+ Fmt = "Purge checkpoint '~s' not updated in ~p seconds",
+ couch_log:error(Fmt, [DocId, Diff])
+ end
+ end,
+ Exists
+ catch _:_ ->
+ % If we fail to check for a client we have to assume that
+ % it exists.
+ true
+ end.
+
+
+get_purge_client_fun(DocId, Props) ->
+ M0 = couch_util:get_value(<<"verify_module">>, Props),
+ M = try
+ binary_to_existing_atom(M0, latin1)
+ catch error:badarg ->
+ Fmt1 = "Missing index module '~p' for purge checkpoint '~s'",
+ couch_log:error(Fmt1, [M0, DocId]),
+ throw(failed)
+ end,
+
+ F0 = couch_util:get_value(<<"verify_function">>, Props),
+ try
+ F = binary_to_existing_atom(F0, latin1),
+ fun M:F/2
Review comment:
Is it worth checking `erlang:function_exported/3` here?
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