Remove delayed commits optionremove_delayed_commits

This effectively removes a lot couch_db:ensure_full_commit/1,2 calls.

However/ _ensure_full_commit HTTP API was left as is since replicator from
older versions of CouchDB would call that, it just returns the start time as if
ensure_commit function was called.

Issue: https://github.com/apache/couchdb/issues/2165

32 files changed, 26 insertions, 250 deletions

diff --git a/rel/overlay/etc/default.ini b/rel/overlay/etc/default.ini
index dbb0744b9..3a363947b 100644
--- a/rel/overlay/etc/default.ini
+++ b/rel/overlay/etc/default.ini
@@ -10,7 +10,6 @@ view_index_dir = {{view_index_dir}}
 ; plugin_dir =
 os_process_timeout = 5000 ; 5 seconds. for view servers.
 max_dbs_open = 500
-delayed_commits = false
 ; Method used to compress everything that is appended to database and view index files, except
 ; for attachments (see the attachments section). Available methods are:
 ;
diff --git a/src/couch/src/couch_db.erl b/src/couch/src/couch_db.erl
index 6135813ae..1e09b9e74 100644
--- a/src/couch/src/couch_db.erl
+++ b/src/couch/src/couch_db.erl
@@ -65,9 +65,6 @@
     set_security/2,
     set_user_ctx/2,
 
-    ensure_full_commit/1,
-    ensure_full_commit/2,
-
     load_validation_funs/1,
     reload_validation_funs/1,
 
@@ -226,21 +223,12 @@ is_partitioned(#db{options = Options}) ->
     Props = couch_util:get_value(props, Options, []),
     couch_util:get_value(partitioned, Props, false).
 
-ensure_full_commit(#db{main_pid=Pid, instance_start_time=StartTime}) ->
-    ok = gen_server:call(Pid, full_commit, infinity),
-    {ok, StartTime}.
-
-ensure_full_commit(Db, RequiredSeq) ->
-    #db{main_pid=Pid, instance_start_time=StartTime} = Db,
-    ok = gen_server:call(Pid, {full_commit, RequiredSeq}, infinity),
-    {ok, StartTime}.
-
 close(#db{} = Db) ->
     ok = couch_db_engine:decref(Db);
 close(?OLD_DB_REC) ->
     ok.
 
-is_idle(#db{compactor_pid=nil, waiting_delayed_commit=nil} = Db) ->
+is_idle(#db{compactor_pid=nil} = Db) ->
     monitored_by(Db) == [];
 is_idle(_Db) ->
     false.
@@ -753,9 +741,7 @@ get_security(?OLD_DB_REC = Db) ->
 set_security(#db{main_pid=Pid}=Db, {NewSecProps}) when is_list(NewSecProps) ->
     check_is_admin(Db),
     ok = validate_security_object(NewSecProps),
-    ok = gen_server:call(Pid, {set_security, NewSecProps}, infinity),
-    {ok, _} = ensure_full_commit(Db),
-    ok;
+    gen_server:call(Pid, {set_security, NewSecProps}, infinity);
 set_security(_, _) ->
     throw(bad_request).
 
@@ -1256,24 +1242,6 @@ make_first_doc_on_disk(Db, Id, Pos, [{_Rev, #leaf{deleted=IsDel, ptr=Sp}} |_]=Do
     Revs = [Rev || {Rev, _} <- DocPath],
     make_doc(Db, Id, IsDel, Sp, {Pos, Revs}).
 
-set_commit_option(Options) ->
-    CommitSettings = {
-        [true || O <- Options, O==full_commit orelse O==delay_commit],
-        config:get("couchdb", "delayed_commits", "false")
-    },
-    case CommitSettings of
-    {[true], _} ->
-        Options; % user requested explicit commit setting, do not change it
-    {_, "true"} ->
-        Options; % delayed commits are enabled, do nothing
-    {_, "false"} ->
-        [full_commit|Options];
-    {_, Else} ->
-        couch_log:error("[couchdb] delayed_commits setting must be true/false,"
-                        " not ~p", [Else]),
-        [full_commit|Options]
-    end.
-
 collect_results_with_metrics(Pid, MRef, []) ->
     Begin = os:timestamp(),
     try
@@ -1299,14 +1267,12 @@ collect_results(Pid, MRef, ResultsAcc) ->
     end.
 
 write_and_commit(#db{main_pid=Pid, user_ctx=Ctx}=Db, DocBuckets1,
-        NonRepDocs, Options0) ->
+        NonRepDocs, Options) ->
     DocBuckets = prepare_doc_summaries(Db, DocBuckets1),
-    Options = set_commit_option(Options0),
     MergeConflicts = lists:member(merge_conflicts, Options),
-    FullCommit = lists:member(full_commit, Options),
     MRef = erlang:monitor(process, Pid),
     try
-        Pid ! {update_docs, self(), DocBuckets, NonRepDocs, MergeConflicts, FullCommit},
+        Pid ! {update_docs, self(), DocBuckets, NonRepDocs, MergeConflicts},
         case collect_results_with_metrics(Pid, MRef, []) of
         {ok, Results} -> {ok, Results};
         retry ->
@@ -1320,7 +1286,7 @@ write_and_commit(#db{main_pid=Pid, user_ctx=Ctx}=Db, DocBuckets1,
             % We only retry once
             DocBuckets3 = prepare_doc_summaries(Db2, DocBuckets2),
             close(Db2),
-            Pid ! {update_docs, self(), DocBuckets3, NonRepDocs, MergeConflicts, FullCommit},
+            Pid ! {update_docs, self(), DocBuckets3, NonRepDocs, MergeConflicts},
             case collect_results_with_metrics(Pid, MRef, []) of
             {ok, Results} -> {ok, Results};
             retry -> throw({update_error, compaction_retry})
diff --git a/src/couch/src/couch_db_int.hrl b/src/couch/src/couch_db_int.hrl
index a412b338b..35b548d68 100644
--- a/src/couch/src/couch_db_int.hrl
+++ b/src/couch/src/couch_db_int.hrl
@@ -32,6 +32,8 @@
     before_doc_update = nil, % nil | fun(Doc, Db) -> NewDoc
     after_doc_read = nil,    % nil | fun(Doc, Db) -> NewDoc
 
+    % feature removed in 3.x, but field kept to avoid changing db record size
+    % and breaking rolling cluster upgrade
     waiting_delayed_commit = nil,
 
     options = [],
diff --git a/src/couch/src/couch_db_split.erl b/src/couch/src/couch_db_split.erl
index b9c23a998..5bf98b6fd 100644
--- a/src/couch/src/couch_db_split.erl
+++ b/src/couch/src/couch_db_split.erl
@@ -488,7 +488,6 @@ copy_local_docs(#state{source_db = Db, targets = Targets} = State) ->
             [_ | _] ->
                 Docs1 = lists:reverse(Docs),
                 {ok, _} = couch_db:update_docs(TDb, Docs1),
-                {ok, _} = couch_db:ensure_full_commit(TDb),
                 T#target{buffer = []}
         end
     end, Targets1),
diff --git a/src/couch/src/couch_db_updater.erl b/src/couch/src/couch_db_updater.erl
index 4227ff036..6e164e536 100644
--- a/src/couch/src/couch_db_updater.erl
+++ b/src/couch/src/couch_db_updater.erl
@@ -67,15 +67,6 @@ terminate(Reason, Db) ->
 
 handle_call(get_db, _From, Db) ->
     {reply, {ok, Db}, Db, idle_limit()};
-handle_call(full_commit, _From, #db{waiting_delayed_commit=nil}=Db) ->
-    {reply, ok, Db, idle_limit()}; % no data waiting, return ok immediately
-handle_call(full_commit, _From,  Db) ->
-    {reply, ok, commit_data(Db), idle_limit()};
-handle_call({full_commit, RequiredSeq}, _From, Db)
-        when RequiredSeq =< Db#db.committed_update_seq ->
-    {reply, ok, Db, idle_limit()};
-handle_call({full_commit, _}, _, Db) ->
-    {reply, ok, commit_data(Db), idle_limit()}; % commit the data and return ok
 handle_call(start_compact, _From, Db) ->
     {noreply, NewDb, _Timeout} = handle_cast(start_compact, Db),
     {reply, {ok, NewDb#db.compactor_pid}, NewDb, idle_limit()};
@@ -171,20 +162,18 @@ handle_cast(Msg, #db{name = Name} = Db) ->
     {stop, Msg, Db}.
 
 
-handle_info({update_docs, Client, GroupedDocs, NonRepDocs, MergeConflicts,
-        FullCommit}, Db) ->
+handle_info({update_docs, Client, GroupedDocs, NonRepDocs, MergeConflicts},
+        Db) ->
     GroupedDocs2 = sort_and_tag_grouped_docs(Client, GroupedDocs),
     if NonRepDocs == [] ->
-        {GroupedDocs3, Clients, FullCommit2} = collect_updates(GroupedDocs2,
-                [Client], MergeConflicts, FullCommit);
+        {GroupedDocs3, Clients} = collect_updates(GroupedDocs2,
+                [Client], MergeConflicts);
     true ->
         GroupedDocs3 = GroupedDocs2,
-        FullCommit2 = FullCommit,
         Clients = [Client]
     end,
     NonRepDocs2 = [{Client, NRDoc} || NRDoc <- NonRepDocs],
-    try update_docs_int(Db, GroupedDocs3, NonRepDocs2, MergeConflicts,
-                FullCommit2) of
+    try update_docs_int(Db, GroupedDocs3, NonRepDocs2, MergeConflicts) of
     {ok, Db2, UpdatedDDocIds} ->
         ok = gen_server:call(couch_server, {db_updated, Db2}, infinity),
         case {couch_db:get_update_seq(Db), couch_db:get_update_seq(Db2)} of
@@ -217,17 +206,6 @@ handle_info({update_docs, Client, GroupedDocs, NonRepDocs, MergeConflicts,
             [catch(ClientPid ! {retry, self()}) || ClientPid <- Clients],
             {noreply, Db, hibernate_if_no_idle_limit()}
     end;
-handle_info(delayed_commit, #db{waiting_delayed_commit=nil}=Db) ->
-    %no outstanding delayed commits, ignore
-    {noreply, Db, idle_limit()};
-handle_info(delayed_commit, Db) ->
-    case commit_data(Db) of
-        Db ->
-            {noreply, Db, idle_limit()};
-        Db2 ->
-            ok = gen_server:call(couch_server, {db_updated, Db2}, infinity),
-            {noreply, Db2, idle_limit()}
-    end;
 handle_info({'EXIT', _Pid, normal}, Db) ->
     {noreply, Db, idle_limit()};
 handle_info({'EXIT', _Pid, Reason}, Db) ->
@@ -295,20 +273,20 @@ merge_updates([], RestB) ->
 merge_updates(RestA, []) ->
     RestA.
 
-collect_updates(GroupedDocsAcc, ClientsAcc, MergeConflicts, FullCommit) ->
+collect_updates(GroupedDocsAcc, ClientsAcc, MergeConflicts) ->
     receive
         % Only collect updates with the same MergeConflicts flag and without
         % local docs. It's easier to just avoid multiple _local doc
         % updaters than deal with their possible conflicts, and local docs
         % writes are relatively rare. Can be optmized later if really needed.
-        {update_docs, Client, GroupedDocs, [], MergeConflicts, FullCommit2} ->
+        {update_docs, Client, GroupedDocs, [], MergeConflicts} ->
             GroupedDocs2 = sort_and_tag_grouped_docs(Client, GroupedDocs),
             GroupedDocsAcc2 =
                 merge_updates(GroupedDocsAcc, GroupedDocs2),
             collect_updates(GroupedDocsAcc2, [Client | ClientsAcc],
-                    MergeConflicts, (FullCommit or FullCommit2))
+                    MergeConflicts)
     after 0 ->
-        {GroupedDocsAcc, ClientsAcc, FullCommit}
+        {GroupedDocsAcc, ClientsAcc}
     end.
 
 
@@ -633,7 +611,7 @@ maybe_stem_full_doc_info(#full_doc_info{rev_tree = Tree} = Info, Limit) ->
             Info
     end.
 
-update_docs_int(Db, DocsList, LocalDocs, MergeConflicts, FullCommit) ->
+update_docs_int(Db, DocsList, LocalDocs, MergeConflicts) ->
     UpdateSeq = couch_db_engine:get_update_seq(Db),
     RevsLimit = couch_db_engine:get_revs_limit(Db),
 
@@ -705,7 +683,7 @@ update_docs_int(Db, DocsList, LocalDocs, MergeConflicts, FullCommit) ->
         (_) -> []
     end, Ids),
 
-    {ok, commit_data(Db1, not FullCommit), UpdatedDDocIds}.
+    {ok, commit_data(Db1), UpdatedDDocIds}.
 
 
 update_local_doc_revs(Docs) ->
@@ -852,21 +830,8 @@ apply_purge_reqs([Req | RestReqs], IdFDIs, USeq, Replies) ->
 
 
 commit_data(Db) ->
-    commit_data(Db, false).
-
-commit_data(#db{waiting_delayed_commit=nil} = Db, true) ->
-    TRef = erlang:send_after(1000,self(),delayed_commit),
-    Db#db{waiting_delayed_commit=TRef};
-commit_data(Db, true) ->
-    Db;
-commit_data(Db, _) ->
-    #db{
-        waiting_delayed_commit = Timer
-    } = Db,
-    if is_reference(Timer) -> erlang:cancel_timer(Timer); true -> ok end,
     {ok, Db1} = couch_db_engine:commit_data(Db),
     Db1#db{
-        waiting_delayed_commit = nil,
         committed_update_seq = couch_db_engine:get_update_seq(Db)
     }.
 
diff --git a/src/couch/src/couch_httpd_db.erl b/src/couch/src/couch_httpd_db.erl
index 6cfae9610..1a07b202c 100644
--- a/src/couch/src/couch_httpd_db.erl
+++ b/src/couch/src/couch_httpd_db.erl
@@ -283,23 +283,7 @@ db_req(#httpd{path_parts=[_DbName]}=Req, _Db) ->
 db_req(#httpd{method='POST',path_parts=[_,<<"_ensure_full_commit">>]}=Req, Db) ->
     couch_httpd:validate_ctype(Req, "application/json"),
     _ = couch_httpd:body(Req),
-    UpdateSeq = couch_db:get_update_seq(Db),
-    CommittedSeq = couch_db:get_committed_update_seq(Db),
-    {ok, StartTime} =
-    case couch_httpd:qs_value(Req, "seq") of
-    undefined ->
-        couch_db:ensure_full_commit(Db);
-    RequiredStr ->
-        RequiredSeq = list_to_integer(RequiredStr),
-        if RequiredSeq > UpdateSeq ->
-            throw({bad_request,
-                "can't do a full commit ahead of current update_seq"});
-        RequiredSeq > CommittedSeq ->
-            couch_db:ensure_full_commit(Db);
-        true ->
-            {ok, couch_db:get_instance_start_time(Db)}
-        end
-    end,
+    StartTime = couch_db:get_instance_start_time(Db),
     send_json(Req, 201, {[
         {ok, true},
         {instance_start_time, StartTime}
diff --git a/src/couch/test/eunit/couch_auth_cache_tests.erl b/src/couch/test/eunit/couch_auth_cache_tests.erl
index 706c0cee9..5439dd7b9 100644
--- a/src/couch/test/eunit/couch_auth_cache_tests.erl
+++ b/src/couch/test/eunit/couch_auth_cache_tests.erl
@@ -191,7 +191,6 @@ should_restore_cache_after_userdoc_recreation(DbName) ->
 should_drop_cache_on_auth_db_change(DbName) ->
     ?_test(begin
         {ok, _} = update_user_doc(DbName, "joe", "pass1"),
-        full_commit(DbName),
         config:set("couch_httpd_auth", "authentication_db",
                          ?b2l(?tempdb()), false),
         ?assertEqual(nil, couch_auth_cache:get_user_creds("joe"))
@@ -202,14 +201,12 @@ should_restore_cache_on_auth_db_change(DbName) ->
         PasswordHash = hash_password("pass1"),
         {ok, _} = update_user_doc(DbName, "joe", "pass1"),
         {ok, Creds, _} = couch_auth_cache:get_user_creds("joe"),
-        full_commit(DbName),
 
         DbName1 = ?tempdb(),
         config:set("couch_httpd_auth", "authentication_db",
                          ?b2l(DbName1), false),
 
         {ok, _} = update_user_doc(DbName1, "joe", "pass5"),
-        full_commit(DbName1),
 
         config:set("couch_httpd_auth", "authentication_db",
                          ?b2l(DbName), false),
@@ -224,7 +221,6 @@ should_recover_cache_after_shutdown(DbName) ->
         PasswordHash = hash_password("pass2"),
         {ok, Rev0} = update_user_doc(DbName, "joe", "pass1"),
         {ok, Rev1} = update_user_doc(DbName, "joe", "pass2", Rev0),
-        full_commit(DbName),
         shutdown_db(DbName),
         {ok, Rev1} = get_doc_rev(DbName, "joe"),
         ?assertEqual(PasswordHash, get_user_doc_password_sha(DbName, "joe"))
@@ -328,11 +324,6 @@ delete_user_doc(DbName, UserName) ->
     {ok, _} = couch_db:update_doc(AuthDb, DeletedDoc, []),
     ok = couch_db:close(AuthDb).
 
-full_commit(DbName) ->
-    {ok, AuthDb} = couch_db:open_int(DbName, [?ADMIN_CTX]),
-    {ok, _} = couch_db:ensure_full_commit(AuthDb),
-    ok = couch_db:close(AuthDb).
-
 is_opened(DbName) ->
     {ok, AuthDb} = couch_db:open_int(DbName, [?ADMIN_CTX]),
     Monitors = couch_db:monitored_by(AuthDb) -- [self()],
diff --git a/src/couch/test/eunit/couch_bt_engine_compactor_tests.erl b/src/couch/test/eunit/couch_bt_engine_compactor_tests.erl
index 6c99ceb73..4c4c43958 100644
--- a/src/couch/test/eunit/couch_bt_engine_compactor_tests.erl
+++ b/src/couch/test/eunit/couch_bt_engine_compactor_tests.erl
@@ -101,8 +101,7 @@ create_docs(DbName) ->
             {<<"value">>, 3}
 
         ]}),
-        {ok, _} = couch_db:update_docs(Db, [Doc1, Doc2, Doc3]),
-        couch_db:ensure_full_commit(Db)
+        {ok, _} = couch_db:update_docs(Db, [Doc1, Doc2, Doc3])
     end).
 
 
diff --git a/src/couch/test/eunit/couch_changes_tests.erl b/src/couch/test/eunit/couch_changes_tests.erl
index 0c2f5f91f..10cd56cee 100644
--- a/src/couch/test/eunit/couch_changes_tests.erl
+++ b/src/couch/test/eunit/couch_changes_tests.erl
@@ -36,7 +36,6 @@ setup() ->
         save_doc(Db, {[{<<"_id">>, <<"doc5">>}]})
     ]],
     Rev = lists:nth(3, Revs),
-    couch_db:ensure_full_commit(Db),
     {ok, Db1} = couch_db:reopen(Db),
 
     {ok, Rev1} = save_doc(Db1, {[{<<"_id">>, <<"doc3">>}, {<<"_rev">>, Rev}]}),
diff --git a/src/couch/test/eunit/couch_db_doc_tests.erl b/src/couch/test/eunit/couch_db_doc_tests.erl
index cdcf81d15..1de26c768 100644
--- a/src/couch/test/eunit/couch_db_doc_tests.erl
+++ b/src/couch/test/eunit/couch_db_doc_tests.erl
@@ -103,7 +103,6 @@ add_revision(Db0, DocId, Rev) ->
         {<<"value">>, DocId}
     ] ++ Rev}),
     {ok, NewRev} = couch_db:update_doc(Db, Doc, []),
-    {ok, _} = couch_db:ensure_full_commit(Db),
     couch_doc:rev_to_str(NewRev).
 
 
diff --git a/src/couch/test/eunit/couch_db_split_tests.erl b/src/couch/test/eunit/couch_db_split_tests.erl
index 312b5f84d..8e64c39ee 100644
--- a/src/couch/test/eunit/couch_db_split_tests.erl
+++ b/src/couch/test/eunit/couch_db_split_tests.erl
@@ -277,7 +277,6 @@ create_docs(DbName, DocNum) ->
     end, [], lists:seq(DocNum, 1, -1)),
     couch_util:with_db(DbName, fun(Db) ->
         {ok, _Result} = couch_db:update_docs(Db, Docs),
-        {ok, _StartTime} = couch_db:ensure_full_commit(Db),
         {ok, Db1} = couch_db:reopen(Db),
         UpdateSeq = couch_db:get_update_seq(Db1),
         {ok, UpdateSeq}
diff --git a/src/couch/test/eunit/couch_index_tests.erl b/src/couch/test/eunit/couch_index_tests.erl
index fab3806d0..23c857d6c 100644
--- a/src/couch/test/eunit/couch_index_tests.erl
+++ b/src/couch/test/eunit/couch_index_tests.erl
@@ -113,7 +113,6 @@ create_docs(DbName) ->
 
     ]}),
     {ok, _} = couch_db:update_docs(Db, [Doc1, Doc2, Doc3]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 create_design_doc(DbName, DDName, ViewName) ->
@@ -128,7 +127,6 @@ create_design_doc(DbName, DDName, ViewName) ->
         ]}}
     ]}),
     {ok, Rev} = couch_db:update_doc(Db, DDoc, []),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db),
     Rev.
 
diff --git a/src/couch/test/eunit/couchdb_design_doc_tests.erl b/src/couch/test/eunit/couchdb_design_doc_tests.erl
index eef12e039..653a6cb17 100644
--- a/src/couch/test/eunit/couchdb_design_doc_tests.erl
+++ b/src/couch/test/eunit/couchdb_design_doc_tests.erl
@@ -77,7 +77,6 @@ create_design_doc(DbName, DDName) ->
         ]}}
     ]}),
     {ok, Rev} = couch_db:update_doc(Db, DDoc, []),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db),
     Rev.
 
diff --git a/src/couch/test/eunit/couchdb_mrview_tests.erl b/src/couch/test/eunit/couchdb_mrview_tests.erl
index 1c96a0ae0..f5bad7321 100644
--- a/src/couch/test/eunit/couchdb_mrview_tests.erl
+++ b/src/couch/test/eunit/couchdb_mrview_tests.erl
@@ -187,7 +187,6 @@ create_doc(backdoor, DbName, Id, Body) ->
     Doc = couch_doc:from_json_obj(JsonDoc),
     {ok, Db} = couch_db:open(DbName, [?ADMIN_CTX]),
     {ok, _} = couch_db:update_docs(Db, [Doc]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db);
 create_doc(clustered, DbName, Id, Body) ->
     JsonDoc = couch_util:json_apply_field({<<"_id">>, Id}, Body),
diff --git a/src/couch/test/eunit/couchdb_update_conflicts_tests.erl b/src/couch/test/eunit/couchdb_update_conflicts_tests.erl
index e92c73856..1329aba27 100644
--- a/src/couch/test/eunit/couchdb_update_conflicts_tests.erl
+++ b/src/couch/test/eunit/couchdb_update_conflicts_tests.erl
@@ -22,9 +22,8 @@
 -define(TIMEOUT, 20000).
 
 start() ->
-    Ctx = test_util:start_couch(),
-    config:set("couchdb", "delayed_commits", "true", false),
-    Ctx.
+    test_util:start_couch().
+
 
 setup() ->
     DbName = ?tempdb(),
diff --git a/src/couch/test/eunit/couchdb_vhosts_tests.erl b/src/couch/test/eunit/couchdb_vhosts_tests.erl
index 1c4117215..fbe5579cd 100644
--- a/src/couch/test/eunit/couchdb_vhosts_tests.erl
+++ b/src/couch/test/eunit/couchdb_vhosts_tests.erl
@@ -43,7 +43,6 @@ setup() ->
         ]}
     ]}),
     {ok, _} = couch_db:update_docs(Db, [Doc, Doc1]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db),
 
     Addr = config:get("httpd", "bind_address", "127.0.0.1"),
diff --git a/src/couch/test/eunit/couchdb_views_tests.erl b/src/couch/test/eunit/couchdb_views_tests.erl
index 60bb5c975..d1aba8fd5 100644
--- a/src/couch/test/eunit/couchdb_views_tests.erl
+++ b/src/couch/test/eunit/couchdb_views_tests.erl
@@ -322,7 +322,6 @@ couchdb_1309(DbName) ->
 couchdb_1283() ->
     ?_test(begin
         ok = config:set("couchdb", "max_dbs_open", "3", false),
-        ok = config:set("couchdb", "delayed_commits", "false", false),
 
         {ok, MDb1} = couch_db:create(?tempdb(), [?ADMIN_CTX]),
         DDoc = couch_doc:from_json_obj({[
@@ -406,7 +405,6 @@ create_doc(DbName, DocId) when is_binary(DocId) ->
         {<<"value">>, 999}
     ]}),
     {ok, _} = couch_db:update_docs(Db, [Doc666]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 create_docs(DbName) ->
@@ -427,7 +425,6 @@ create_docs(DbName) ->
 
     ]}),
     {ok, _} = couch_db:update_docs(Db, [Doc1, Doc2, Doc3]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 populate_db(Db, BatchSize, N) when N > 0 ->
@@ -456,7 +453,6 @@ create_design_doc(DbName, DDName, ViewName) ->
         ]}}
     ]}),
     {ok, Rev} = couch_db:update_doc(Db, DDoc, []),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db),
     Rev.
 
@@ -476,7 +472,6 @@ update_design_doc(DbName, DDName, ViewName) ->
         ]}}
     ]}),
     {ok, NewRev} = couch_db:update_doc(Db, DDoc, [?ADMIN_CTX]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db),
     NewRev.
 
diff --git a/src/couch_index/src/couch_index.erl b/src/couch_index/src/couch_index.erl
index cae95779e..ab6deae59 100644
--- a/src/couch_index/src/couch_index.erl
+++ b/src/couch_index/src/couch_index.erl
@@ -377,17 +377,7 @@ code_change(_OldVsn, State, _Extra) ->
 
 maybe_restart_updater(#st{waiters=[]}) ->
     ok;
-maybe_restart_updater(#st{mod=Mod, idx_state=IdxState}=State) ->
-    couch_util:with_db(Mod:get(db_name, IdxState), fun(Db) ->
-        UpdateSeq = couch_db:get_update_seq(Db),
-        CommittedSeq = couch_db:get_committed_update_seq(Db),
-        CanUpdate = UpdateSeq > CommittedSeq,
-        UOpts = Mod:get(update_options, IdxState),
-        case CanUpdate and lists:member(committed_only, UOpts) of
-            true -> couch_db:ensure_full_commit(Db);
-            false -> ok
-        end
-    end),
+maybe_restart_updater(#st{idx_state=IdxState}=State) ->
     couch_index_updater:run(State#st.updater, IdxState).
 
 
diff --git a/src/couch_mrview/test/eunit/couch_mrview_changes_since_tests.erl b/src/couch_mrview/test/eunit/couch_mrview_changes_since_tests.erl
index d670e109b..67106419f 100644
--- a/src/couch_mrview/test/eunit/couch_mrview_changes_since_tests.erl
+++ b/src/couch_mrview/test/eunit/couch_mrview_changes_since_tests.erl
@@ -168,7 +168,6 @@ test_remove_key(Db) ->
     Doc = couch_mrview_test_util:doc(11),
     {ok, Rev} = couch_db:update_doc(Db, Doc, []),
     RevStr = couch_doc:rev_to_str(Rev),
-    {ok, _} =  couch_db:ensure_full_commit(Db),
     {ok, Db1} = couch_db:reopen(Db),
     Result = run_count_query(Db1, 0, []),
     %% check new view key
diff --git a/src/couch_mrview/test/eunit/couch_mrview_index_changes_tests.erl b/src/couch_mrview/test/eunit/couch_mrview_index_changes_tests.erl
index f0be1b9b1..d8dd28773 100644
--- a/src/couch_mrview/test/eunit/couch_mrview_index_changes_tests.erl
+++ b/src/couch_mrview/test/eunit/couch_mrview_index_changes_tests.erl
@@ -198,7 +198,6 @@ test_indexer(Db) ->
 save_doc(Db, Id) ->
     Doc = couch_mrview_test_util:doc(Id),
     {ok, _Rev} = couch_db:update_doc(Db, Doc, []),
-    {ok, _} =  couch_db:ensure_full_commit(Db),
     couch_db:reopen(Db).
 
 run_query(Db, Opts) ->
diff --git a/src/couch_pse_tests/src/cpse_test_attachments.erl b/src/couch_pse_tests/src/cpse_test_attachments.erl
index 8c454ecb6..ddd1077d1 100644
--- a/src/couch_pse_tests/src/cpse_test_attachments.erl
+++ b/src/couch_pse_tests/src/cpse_test_attachments.erl
@@ -41,7 +41,6 @@ cpse_write_attachment(Db1) ->
 
         Actions = [{create, {<<"first">>, {[]}, [Att0]}}],
         {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-        {ok, _} = couch_db:ensure_full_commit(Db2),
         cpse_util:shutdown_db(Db2),
 
         {ok, Db3} = couch_db:reopen(Db2),
diff --git a/src/couch_pse_tests/src/cpse_test_compaction.erl b/src/couch_pse_tests/src/cpse_test_compaction.erl
index c8a2c1a7d..6bc470b2f 100644
--- a/src/couch_pse_tests/src/cpse_test_compaction.erl
+++ b/src/couch_pse_tests/src/cpse_test_compaction.erl
@@ -131,7 +131,6 @@ cpse_compact_with_everything(Db1) ->
     catch throw:not_supported ->
         {ok, Db4}
     end,
-    {ok, _} = couch_db:ensure_full_commit(Db5),
     {ok, Db6} = couch_db:reopen(Db5),
 
     Term1 = cpse_util:db_as_term(Db6),
diff --git a/src/couch_pse_tests/src/cpse_test_get_set_props.erl b/src/couch_pse_tests/src/cpse_test_get_set_props.erl
index 02f0eb531..d49f67f49 100644
--- a/src/couch_pse_tests/src/cpse_test_get_set_props.erl
+++ b/src/couch_pse_tests/src/cpse_test_get_set_props.erl
@@ -89,7 +89,6 @@ check_prop_set(DbName, GetFun, SetFun, Default, Value) ->
     {ok, Db1} = couch_db:reopen(Db0),
     ?assertEqual(Value, couch_db:GetFun(Db1)),
 
-    ?assertMatch({ok, _}, couch_db:ensure_full_commit(Db1)),
     cpse_util:shutdown_db(Db1),
 
     {ok, Db2} = couch_db:reopen(Db1),
diff --git a/src/couch_pse_tests/src/cpse_test_read_write_docs.erl b/src/couch_pse_tests/src/cpse_test_read_write_docs.erl
index fd830d812..a2151340a 100644
--- a/src/couch_pse_tests/src/cpse_test_read_write_docs.erl
+++ b/src/couch_pse_tests/src/cpse_test_read_write_docs.erl
@@ -56,7 +56,6 @@ cpse_write_one_doc(Db1) ->
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
     ?assertEqual(1, couch_db_engine:get_doc_count(Db2)),
 
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -96,7 +95,6 @@ cpse_write_two_docs(Db1) ->
         {create, {<<"bar">>, {[{<<"stuff">>, true}]}}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -122,7 +120,6 @@ cpse_write_three_doc_batch(Db1) ->
         ]}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -145,7 +142,7 @@ cpse_update_doc(Db1) ->
         {update, {<<"foo">>, {[{<<"vsn">>, 2}]}}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
+
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -187,7 +184,6 @@ cpse_delete_doc(Db1) ->
         {delete, {<<"foo">>, {[]}}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -227,7 +223,6 @@ cpse_write_local_doc(Db1) ->
         {create, {<<"_local/foo">>, {[{<<"yay">>, false}]}}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -253,7 +248,6 @@ cpse_write_mixed_batch(Db1) ->
         ]}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -279,7 +273,6 @@ cpse_update_local_doc(Db1) ->
         {update, {<<"_local/foo">>, {[{<<"stuff">>, null}]}}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db1),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
@@ -303,7 +296,6 @@ cpse_delete_local_doc(Db1) ->
         {delete, {<<"_local/foo">>, []}}
     ],
     {ok, Db2} = cpse_util:apply_actions(Db1, Actions),
-    {ok, _} = couch_db:ensure_full_commit(Db2),
     cpse_util:shutdown_db(Db2),
 
     {ok, Db3} = couch_db:reopen(Db2),
diff --git a/src/couch_replicator/src/couch_replicator_docs.erl b/src/couch_replicator/src/couch_replicator_docs.erl
index 81685cd48..e23344122 100644
--- a/src/couch_replicator/src/couch_replicator_docs.erl
+++ b/src/couch_replicator/src/couch_replicator_docs.erl
@@ -805,8 +805,7 @@ create_vdu(DbName) ->
             id = <<"_design/vdu">>,
             body = {[{<<"validate_doc_update">>, VduFun}]}
         },
-        {ok, _} = couch_db:update_docs(Db, [Doc]),
-        couch_db:ensure_full_commit(Db)
+        {ok, _} = couch_db:update_docs(Db, [Doc])
     end).
 
 
diff --git a/src/couch_replicator/test/eunit/couch_replicator_filtered_tests.erl b/src/couch_replicator/test/eunit/couch_replicator_filtered_tests.erl
index 70b25a31b..7ac9a4d71 100644
--- a/src/couch_replicator/test/eunit/couch_replicator_filtered_tests.erl
+++ b/src/couch_replicator/test/eunit/couch_replicator_filtered_tests.erl
@@ -228,7 +228,6 @@ create_docs(DbName) ->
 
     ]}),
     {ok, _} = couch_db:update_docs(Db, [DDoc, Doc1, Doc2, Doc3, Doc4]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 delete_db(DbName) ->
diff --git a/src/couch_replicator/test/eunit/couch_replicator_id_too_long_tests.erl b/src/couch_replicator/test/eunit/couch_replicator_id_too_long_tests.erl
index 1447acfa7..a4696c4b8 100644
--- a/src/couch_replicator/test/eunit/couch_replicator_id_too_long_tests.erl
+++ b/src/couch_replicator/test/eunit/couch_replicator_id_too_long_tests.erl
@@ -77,7 +77,6 @@ create_doc(DbName) ->
     {ok, Db} = couch_db:open(DbName, [?ADMIN_CTX]),
     Doc = couch_doc:from_json_obj({[{<<"_id">>, <<"12345">>}]}),
     {ok, _} = couch_db:update_doc(Db, Doc, []),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 
diff --git a/src/couch_replicator/test/eunit/couch_replicator_selector_tests.erl b/src/couch_replicator/test/eunit/couch_replicator_selector_tests.erl
index 7d92bdcb1..5026c1435 100644
--- a/src/couch_replicator/test/eunit/couch_replicator_selector_tests.erl
+++ b/src/couch_replicator/test/eunit/couch_replicator_selector_tests.erl
@@ -106,7 +106,6 @@ create_docs(DbName) ->
         {<<"_id">>, <<"doc2">>}
     ]}),
     {ok, _} = couch_db:update_docs(Db, [Doc1, Doc2]),
-    couch_db:ensure_full_commit(Db),
     couch_db:close(Db).
 
 delete_db(DbName) ->
diff --git a/src/mem3/src/mem3_reshard_store.erl b/src/mem3/src/mem3_reshard_store.erl
index a1e00544a..c3534b374 100644
--- a/src/mem3/src/mem3_reshard_store.erl
+++ b/src/mem3/src/mem3_reshard_store.erl
@@ -169,7 +169,6 @@ delete_doc(Db, DocId) ->
     case couch_db:open_doc(Db, DocId, []) of
         {ok, #doc{revs = {_, Revs}}} ->
             {ok, _} = couch_db:delete_doc(Db, DocId, Revs),
-            {ok, _} = couch_db:ensure_full_commit(Db),
             ok;
         {not_found, _} ->
             ok
@@ -190,7 +189,6 @@ update_doc(Db, DocId, Body) ->
         true ->
             {ok, _} = couch_db:update_doc(Db, Doc, []),
             couch_log:debug("~p updated doc ~p ~p", [?MODULE, DocId, Body]),
-            {ok, _} = couch_db:ensure_full_commit(Db),
             ok;
         false ->
             couch_log:debug("~p not storing state in ~p", [?MODULE, DocId]),
diff --git a/test/elixir/README.md b/test/elixir/README.md
index f7691ad3c..7c6b10e5a 100644
--- a/test/elixir/README.md
+++ b/test/elixir/README.md
@@ -42,7 +42,6 @@ X means done, - means partially
   - [X] Port conflicts.js
   - [ ] Port cookie_auth.js
   - [X] Port copy_doc.js
-  - [X] Port delayed_commits.js
   - [ ] Port design_docs.js
   - [ ] Port design_options.js
   - [ ] Port design_paths.js
@@ -253,4 +252,4 @@ defmodule Couch.Test.CRUD do
     end
   end
 end
-```
\ No newline at end of file
+```
diff --git a/test/elixir/test/delayed_commits_test.exs b/test/elixir/test/delayed_commits_test.exs
deleted file mode 100644
index 9b00a5916..000000000
--- a/test/elixir/test/delayed_commits_test.exs
+++ /dev/null
@@ -1,35 +0,0 @@
-defmodule DelayedCommitsTest do
-  use CouchTestCase
-
-  @moduledoc """
-  Test CouchDB delayed commits
-  This is a port of the delayed_commits.js suite
-
-  Note that delayed_commits is deprecated in 2.0, so this is a minimal
-  test to show it still works. delayed_commits will be removed in 3.0.
-
-  This test is now skipped. Its a bit of a flaky test so no point running it
-  since we are removing this feature.
-  """
-
-  @tag :pending
-  @tag config: [
-         {"couchdb", "delayed_commits", "true"}
-       ]
-  @tag :with_db
-  test "delayed commit", context do
-    db_name = context[:db_name]
-    doc_id = "doc-1"
-    resp = Couch.put("/#{db_name}/#{doc_id}", body: %{a: 2, b: 4})
-    assert resp.status_code in 201..204
-    assert resp.body["ok"]
-
-    resp = Couch.get("/#{db_name}/#{doc_id}")
-    assert resp.status_code == 200, "The new doc should be in the database"
-
-    restart_cluster()
-
-    resp = Couch.get("/#{db_name}/#{doc_id}")
-    assert resp.status_code == 404, "The new doc should be missing"
-  end
-end
diff --git a/test/javascript/tests/delayed_commits.js b/test/javascript/tests/delayed_commits.js
deleted file mode 100644
index cfb59d11e..000000000
--- a/test/javascript/tests/delayed_commits.js
+++ /dev/null
@@ -1,50 +0,0 @@
-// Licensed under the Apache License, Version 2.0 (the "License"); you may not
-// use this file except in compliance with the License. You may obtain a copy of
-// the License at
-//
-//   http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-// License for the specific language governing permissions and limitations under
-// the License.
-
-couchTests.delayed_commits = function(debug) {
-
-  // Note that delayed_commits is deprecated in 2.0, so this is a minimal
-  // test to show it still works. delayed_commits will be removed in 3.0.
-
-  db_name = get_random_db_name();
-  var db = new CouchDB(db_name, {"X-Couch-Full-Commit":"false"});
-  db.deleteDb();
-  db.createDb();
-  if (debug) debugger;
-
-  run_on_modified_server(
-    [{section: "couchdb",
-      key: "delayed_commits",
-      value: "true"}],
-
-    function () {
-      // By default, couchdb doesn't fully commit documents to disk right away,
-      // it waits about a second to batch the full commit flush along with any
-      // other updates. If it crashes or is restarted you may lose the most
-      // recent commits.
-
-      // restartServer() requires a server to be up 15s before it restarts
-      sleep(15000);
-
-      T(db.save({_id:"1",a:2,b:4}).ok);
-      T(db.open("1") != null);
-
-      restartServer();
-
-      T(db.open("1") == null); // lost the update.
-      // note if we waited > 1 sec before the restart, the doc would likely
-      // commit.
-    });
-
-  // cleanup
-  db.deleteDb();
-};