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Posted to commits@couchdb.apache.org by da...@apache.org on 2017/06/30 15:53:05 UTC

[couchdb] branch optimize-ddoc-cache updated (747c248 -> 1fa3851)

This is an automated email from the ASF dual-hosted git repository.

davisp pushed a change to branch optimize-ddoc-cache
in repository https://gitbox.apache.org/repos/asf/couchdb.git.


    omit 747c248  TMP: Simple benchmark script
    omit 629d9af  Rewrite ddoc_cache to improve performance
    omit c1e7700  Remove duplicated eviction messages
     add 2269b64  Factor attachment_doc/0
     add d3bae3f  Return 409 to PUT attachment with non-existent rev
     add 4249ab3  Fix race in couchdb_views_tests
     add a00d683  Merge pull request #600 from cloudant/fix-couchdb_views_tests
     add 3f37ec1  Wait for listener's exit during restart test
     add f1a1d7f  Merge pull request #590 from cloudant/fix-couch_log_config_listener_test
     add 4e5e84e  Use efficient set storage for field names
     add 90db262  Merge branch '3358-use-efficient-set'
     add 2f539e0  Add X-Frame-Options (#582)
     add c7f7dcf  Fix "not_mocked" error in compaction tests
     add 7105971  Refactor compaction tests setup and teardown
     add 9ea4ad8  Address a race on compacting process exit
     add d23b26d  Merge pull request #614 from cloudant/fix-compaction_daemon_tests
     add 571a2fc  Ensure replicator _active_tasks entry reports recent pending changes value
     add 67048ab  Add a soak-eunit target to Makefile
     new d7d1f8b  Remove duplicated eviction messages
     new 409e71c  Rewrite ddoc_cache to improve performance
     new 1fa3851  TMP: Simple benchmark script

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Summary of changes:
 Makefile                                           |  6 ++
 rel/overlay/etc/default.ini                        |  9 ++
 src/chttpd/src/chttpd.erl                          |  5 +-
 src/chttpd/src/chttpd_xframe_options.erl           | 99 ++++++++++++++++++++++
 src/chttpd/test/chttpd_db_test.erl                 | 53 +++++++-----
 src/chttpd/test/chttpd_xframe_test.erl             | 84 ++++++++++++++++++
 src/couch/include/couch_db.hrl                     |  1 +
 src/couch/src/couch_httpd.erl                      |  8 +-
 src/couch/test/couchdb_compaction_daemon_tests.erl | 52 +++++++-----
 src/couch/test/couchdb_views_tests.erl             | 15 +++-
 .../test/couch_log_config_listener_test.erl        | 23 ++++-
 .../src/couch_replicator_changes_reader.erl        | 23 +++--
 .../src/couch_replicator_scheduler_job.erl         | 16 +++-
 .../src/couch_replicator_worker.erl                |  4 +
 src/mango/src/mango_native_proc.erl                | 16 ++--
 test/javascript/tests/attachments.js               |  3 +-
 16 files changed, 335 insertions(+), 82 deletions(-)
 create mode 100644 src/chttpd/src/chttpd_xframe_options.erl
 create mode 100644 src/chttpd/test/chttpd_xframe_test.erl

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[couchdb] 03/03: TMP: Simple benchmark script

Posted by da...@apache.org.
This is an automated email from the ASF dual-hosted git repository.

davisp pushed a commit to branch optimize-ddoc-cache
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit 1fa385186039a6eaf6cd9afa52b9b2f6ca399b3d
Author: Paul J. Davis <pa...@gmail.com>
AuthorDate: Wed Jun 28 10:58:34 2017 -0500

    TMP: Simple benchmark script
---
 src/ddoc_cache/src/ddoc_cache_speed.erl | 61 +++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/src/ddoc_cache/src/ddoc_cache_speed.erl b/src/ddoc_cache/src/ddoc_cache_speed.erl
new file mode 100644
index 0000000..38cd0b9
--- /dev/null
+++ b/src/ddoc_cache/src/ddoc_cache_speed.erl
@@ -0,0 +1,61 @@
+-module(ddoc_cache_speed).
+
+-export([
+    go/1,
+    recover/1
+]).
+
+
+-define(RANGE, 1000).
+
+
+go(WorkerCount) when is_integer(WorkerCount), WorkerCount > 0 ->
+    spawn_workers(WorkerCount),
+    report().
+
+
+recover(DbName) ->
+    {ok, {stuff, DbName}}.
+
+
+spawn_workers(0) ->
+    ok;
+
+spawn_workers(WorkerCount) ->
+    Self = self(),
+    WorkerDb = list_to_binary(integer_to_list(WorkerCount)),
+    spawn(fun() ->
+        do_work(Self, WorkerDb, 0)
+    end),
+    spawn_workers(WorkerCount - 1).
+
+
+do_work(Parent, WorkerDb, Count) when Count >= 25 ->
+    Parent ! {done, Count},
+    do_work(Parent, WorkerDb, 0);
+
+do_work(Parent, WorkerDb, Count) ->
+    {ok, _} = ddoc_cache:open_custom(WorkerDb, ?MODULE),
+    do_work(Parent, WorkerDb, Count + 1).
+
+
+report() ->
+    report(os:timestamp(), 0).
+
+
+report(Start, Count) ->
+    Now = os:timestamp(),
+    case timer:now_diff(Now, Start) of
+        N when N > 1000000 ->
+            {_, MQL} = process_info(whereis(ddoc_cache_lru), message_queue_len),
+            io:format("~p ~p~n", [Count, MQL]),
+            report(Now, 0);
+        _ ->
+            receive
+                {done, Done} ->
+                    report(Start, Count + Done)
+            after 100 ->
+                report(Start, Count)
+            end
+    end.
+

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[couchdb] 01/03: Remove duplicated eviction messages

Posted by da...@apache.org.
This is an automated email from the ASF dual-hosted git repository.

davisp pushed a commit to branch optimize-ddoc-cache
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit d7d1f8b932322b28cb9b7a5258f77ae8c3fc209a
Author: Paul J. Davis <pa...@gmail.com>
AuthorDate: Tue Jun 20 10:20:01 2017 -0500

    Remove duplicated eviction messages
    
    This is an old merge artifact that was duplicating the event
    notifications twice per design document update.
---
 src/couch/src/couch_db_updater.erl | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/src/couch/src/couch_db_updater.erl b/src/couch/src/couch_db_updater.erl
index 49061b2..2b448fd 100644
--- a/src/couch/src/couch_db_updater.erl
+++ b/src/couch/src/couch_db_updater.erl
@@ -923,16 +923,7 @@ update_docs_int(Db, DocsList, NonRepDocs, MergeConflicts, FullCommit) ->
         (_) -> []
     end, Ids),
 
-    Db4 = case length(UpdatedDDocIds) > 0 of
-        true ->
-            couch_event:notify(Db3#db.name, ddoc_updated),
-            ddoc_cache:evict(Db3#db.name, UpdatedDDocIds),
-            refresh_validate_doc_funs(Db3);
-        false ->
-            Db3
-    end,
-
-    {ok, commit_data(Db4, not FullCommit), UpdatedDDocIds}.
+    {ok, commit_data(Db3, not FullCommit), UpdatedDDocIds}.
 
 update_local_docs(Db, []) ->
     {ok, Db};

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[couchdb] 02/03: Rewrite ddoc_cache to improve performance

Posted by da...@apache.org.
This is an automated email from the ASF dual-hosted git repository.

davisp pushed a commit to branch optimize-ddoc-cache
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit 409e71c957fa2e0b4202a5d24a1d1f96ae5b87dd
Author: Paul J. Davis <pa...@gmail.com>
AuthorDate: Fri Jun 16 13:29:47 2017 -0500

    Rewrite ddoc_cache to improve performance
    
    There were a couple issues with the previous ddoc_cache implementation
    that made it possible to tip over the ddoc_cache_opener process. First,
    there were a lot of messages flowing through a single gen_server. And
    second, the cache relied on periodically evicting entries to ensure
    proper behavior in not caching an entry forever after it had changed on
    disk.
    
    The new version makes two important changes. First, entries now have an
    associated process that manages the cache entry. This process will
    periodically refresh the entry and if the entry has changed or no longer
    exists the process will remove its entry from cache.
    
    The second major change is that the cache entry process directly mutates
    the related ets table entries so that our performance is not dependent
    on the speed of ets table mutations. Using a custom entry that does no
    work the cache can now sustain roughly one million operations a second
    with a twenty thousand clients fighting over a cache limited to one
    thousand items. In production this means that cache performance will
    likely be rate limited by other factors like loading design documents
    from disk.
---
 src/couch/src/couch_db_updater.erl                 |   2 +-
 src/ddoc_cache/src/ddoc_cache.app.src              |  22 +-
 src/ddoc_cache/src/ddoc_cache.erl                  |  79 ++----
 .../src/{ddoc_cache_util.erl => ddoc_cache.hrl}    |  50 ++--
 src/ddoc_cache/src/ddoc_cache_entry.erl            | 279 ++++++++++++++++++++
 ..._cache_util.erl => ddoc_cache_entry_custom.erl} |  22 +-
 ..._cache_util.erl => ddoc_cache_entry_ddocid.erl} |  25 +-
 ...he_util.erl => ddoc_cache_entry_ddocid_rev.erl} |  27 +-
 ...il.erl => ddoc_cache_entry_validation_funs.erl} |  29 +-
 src/ddoc_cache/src/ddoc_cache_lru.erl              | 293 +++++++++++++++++++++
 src/ddoc_cache/src/ddoc_cache_opener.erl           | 245 +----------------
 src/ddoc_cache/src/ddoc_cache_sup.erl              |  35 +--
 src/ddoc_cache/src/ddoc_cache_tables.erl           |  68 +++++
 src/ddoc_cache/test/ddoc_cache_basic_test.erl      | 122 +++++++++
 src/ddoc_cache/test/ddoc_cache_coverage_test.erl   |  86 ++++++
 src/ddoc_cache/test/ddoc_cache_disabled_test.erl   |  52 ++++
 src/ddoc_cache/test/ddoc_cache_entry_test.erl      | 120 +++++++++
 .../ddoc_cache_util.erl => test/ddoc_cache_ev.erl} |  21 +-
 src/ddoc_cache/test/ddoc_cache_eviction_test.erl   |  93 +++++++
 src/ddoc_cache/test/ddoc_cache_lru_test.erl        | 167 ++++++++++++
 src/ddoc_cache/test/ddoc_cache_no_cache_test.erl   |  78 ++++++
 src/ddoc_cache/test/ddoc_cache_open_error_test.erl |  46 ++++
 src/ddoc_cache/test/ddoc_cache_opener_test.erl     |  33 +++
 src/ddoc_cache/test/ddoc_cache_refresh_test.erl    | 167 ++++++++++++
 src/ddoc_cache/test/ddoc_cache_remove_test.erl     | 206 +++++++++++++++
 .../ddoc_cache_test.hrl}                           |  30 +--
 src/ddoc_cache/test/ddoc_cache_tutil.erl           |  84 ++++++
 27 files changed, 2036 insertions(+), 445 deletions(-)

diff --git a/src/couch/src/couch_db_updater.erl b/src/couch/src/couch_db_updater.erl
index 2b448fd..1c4b561 100644
--- a/src/couch/src/couch_db_updater.erl
+++ b/src/couch/src/couch_db_updater.erl
@@ -319,7 +319,7 @@ handle_info({update_docs, Client, GroupedDocs, NonRepDocs, MergeConflicts,
                     couch_event:notify(Db2#db.name, {ddoc_updated, DDocId})
                 end, UpdatedDDocIds),
                 couch_event:notify(Db2#db.name, ddoc_updated),
-                ddoc_cache:evict(Db2#db.name, UpdatedDDocIds),
+                ddoc_cache:refresh(Db2#db.name, UpdatedDDocIds),
                 refresh_validate_doc_funs(Db2);
             false ->
                 Db2
diff --git a/src/ddoc_cache/src/ddoc_cache.app.src b/src/ddoc_cache/src/ddoc_cache.app.src
index a64b2f5..38fceda 100644
--- a/src/ddoc_cache/src/ddoc_cache.app.src
+++ b/src/ddoc_cache/src/ddoc_cache.app.src
@@ -13,14 +13,8 @@
 {application, ddoc_cache, [
     {description, "Design Document Cache"},
     {vsn, git},
-    {modules, [
-        ddoc_cache,
-        ddoc_cache_app,
-        ddoc_cache_opener,
-        ddoc_cache_sup,
-        ddoc_cache_util
-    ]},
     {registered, [
+        ddoc_cache_tables,
         ddoc_cache_lru,
         ddoc_cache_opener
     ]},
@@ -28,17 +22,11 @@
         kernel,
         stdlib,
         crypto,
+        config,
         couch_event,
-        ets_lru,
-        mem3,
-        fabric,
         couch_log,
-        couch_stats
+        couch_stats,
+        fabric
     ]},
-    {mod, {ddoc_cache_app, []}},
-    {env, [
-        {max_objects, unlimited},
-        {max_size, 104857600}, % 100M
-        {max_lifetime, 60000} % 1m
-    ]}
+    {mod, {ddoc_cache_app, []}}
 ]}.
diff --git a/src/ddoc_cache/src/ddoc_cache.erl b/src/ddoc_cache/src/ddoc_cache.erl
index ed93309..50cac30 100644
--- a/src/ddoc_cache/src/ddoc_cache.erl
+++ b/src/ddoc_cache/src/ddoc_cache.erl
@@ -12,86 +12,43 @@
 
 -module(ddoc_cache).
 
--export([
-    start/0,
-    stop/0
-]).
 
 -export([
     open_doc/2,
     open_doc/3,
     open_validation_funs/1,
-    evict/2,
+    open_custom/2,
+    refresh/2,
 
     %% deprecated
     open/2
 ]).
 
-start() ->
-    application:start(ddoc_cache).
-
-stop() ->
-    application:stop(ddoc_cache).
 
 open_doc(DbName, DocId) ->
-    Key = {DbName, DocId, '_'},
-    case ddoc_cache_opener:match_newest(Key) of
-        {ok, _} = Resp ->
-            couch_stats:increment_counter([ddoc_cache, hit]),
-            Resp;
-        missing ->
-            couch_stats:increment_counter([ddoc_cache, miss]),
-            ddoc_cache_opener:open_doc(DbName, DocId);
-        recover ->
-            couch_stats:increment_counter([ddoc_cache, recovery]),
-            ddoc_cache_opener:recover_doc(DbName, DocId)
-    end.
+    Key = {ddoc_cache_entry_ddocid, {DbName, DocId}},
+    ddoc_cache_lru:open(Key).
+
 
 open_doc(DbName, DocId, RevId) ->
-    Key = {DbName, DocId, RevId},
-    case ddoc_cache_opener:lookup(Key) of
-        {ok, _} = Resp ->
-            couch_stats:increment_counter([ddoc_cache, hit]),
-            Resp;
-        missing ->
-            couch_stats:increment_counter([ddoc_cache, miss]),
-            ddoc_cache_opener:open_doc(DbName, DocId, RevId);
-        recover ->
-            couch_stats:increment_counter([ddoc_cache, recovery]),
-            ddoc_cache_opener:recover_doc(DbName, DocId, RevId)
-    end.
+    Key = {ddoc_cache_entry_ddocid_rev, {DbName, DocId, RevId}},
+    ddoc_cache_lru:open(Key).
+
 
 open_validation_funs(DbName) ->
-    Key = {DbName, validation_funs},
-    case ddoc_cache_opener:lookup(Key) of
-        {ok, _} = Resp ->
-            couch_stats:increment_counter([ddoc_cache, hit]),
-            Resp;
-        missing ->
-            couch_stats:increment_counter([ddoc_cache, miss]),
-            ddoc_cache_opener:open_validation_funs(DbName);
-        recover ->
-            couch_stats:increment_counter([ddoc_cache, recovery]),
-            ddoc_cache_opener:recover_validation_funs(DbName)
-    end.
+    Key = {ddoc_cache_entry_validation_funs, DbName},
+    ddoc_cache_lru:open(Key).
+
 
 open_custom(DbName, Mod) ->
-    Key = {DbName, Mod},
-    case ddoc_cache_opener:lookup(Key) of
-        {ok, _} = Resp ->
-            couch_stats:increment_counter([ddoc_cache, hit]),
-            Resp;
-        missing ->
-            couch_stats:increment_counter([ddoc_cache, miss]),
-            ddoc_cache_opener:open_doc(DbName, Mod);
-        recover ->
-            couch_stats:increment_counter([ddoc_cache, recovery]),
-            Mod:recover(DbName)
-    end.
-
-evict(ShardDbName, DDocIds) ->
+    Key = {ddoc_cache_entry_custom, {DbName, Mod}},
+    ddoc_cache_lru:open(Key).
+
+
+refresh(ShardDbName, DDocIds) when is_list(DDocIds) ->
     DbName = mem3:dbname(ShardDbName),
-    ddoc_cache_opener:evict_docs(DbName, DDocIds).
+    ddoc_cache_lru:refresh(DbName, DDocIds).
+
 
 open(DbName, validation_funs) ->
     open_validation_funs(DbName);
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/src/ddoc_cache.hrl
similarity index 52%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/src/ddoc_cache.hrl
index fb3c0b9..dba0d37 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/src/ddoc_cache.hrl
@@ -10,25 +10,31 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
-
-
--export([
-    new_uuid/0
-]).
-
-
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
-
-
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
-
-
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+-type dbname() :: iodata().
+-type docid() :: iodata().
+-type doc_hash() :: <<_:128>>.
+-type revision() :: {pos_integer(), doc_hash()}.
+
+-define(CACHE, ddoc_cache_entries).
+-define(LRU, ddoc_cache_lru).
+-define(REFRESH_TIMEOUT, 67000).
+-define(SHUTDOWN_TIMEOUT, 1000).
+
+-record(entry, {
+    key,
+    val,
+    pid
+}).
+
+-record(opener, {
+    key,
+    pid,
+    clients
+}).
+
+
+-ifdef(TEST).
+-define(EVENT(Name, Arg), ddoc_cache_ev:event(Name, Arg)).
+-else.
+-define(EVENT(Name, Arg), ignore).
+-endif.
diff --git a/src/ddoc_cache/src/ddoc_cache_entry.erl b/src/ddoc_cache/src/ddoc_cache_entry.erl
new file mode 100644
index 0000000..4dee2a1
--- /dev/null
+++ b/src/ddoc_cache/src/ddoc_cache_entry.erl
@@ -0,0 +1,279 @@
+% 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.
+
+-module(ddoc_cache_entry).
+
+
+-export([
+    dbname/1,
+    ddocid/1,
+    recover/1,
+
+    start_link/1,
+    shutdown/1,
+    open/2,
+    accessed/1,
+    refresh/1
+]).
+
+-export([
+    init/1,
+    terminate/2,
+    handle_call/3,
+    handle_cast/2,
+    handle_info/2,
+    code_change/3
+]).
+
+-export([
+    do_open/1
+]).
+
+
+-include("ddoc_cache.hrl").
+
+
+-record(st, {
+    key,
+    val,
+    opener,
+    waiters,
+    ts
+}).
+
+
+dbname({Mod, Arg}) ->
+    Mod:dbname(Arg).
+
+
+ddocid({Mod, Arg}) ->
+    Mod:ddocid(Arg).
+
+
+recover({Mod, Arg}) ->
+    Mod:recover(Arg).
+
+
+start_link(Key) ->
+    Pid = proc_lib:spawn_link(?MODULE, init, [Key]),
+    {ok, Pid}.
+
+
+shutdown(Pid) ->
+    ok = gen_server:call(Pid, shutdown).
+
+
+open(Pid, Key) ->
+    try
+        Resp = gen_server:call(Pid, open),
+        case Resp of
+            {open_ok, Val} ->
+                Val;
+            {open_error, {T, R, S}} ->
+                erlang:raise(T, R, S)
+        end
+    catch exit:_ ->
+        % Its possible that this process was evicted just
+        % before we tried talking to it. Just fallback
+        % to a standard recovery
+        recover(Key)
+    end.
+
+
+accessed(Pid) ->
+    gen_server:cast(Pid, accessed).
+
+
+refresh(Pid) ->
+    gen_server:cast(Pid, refresh).
+
+
+init(Key) ->
+    true = ets:update_element(?CACHE, Key, {#entry.pid, self()}),
+    St = #st{
+        key = Key,
+        opener = spawn_opener(Key),
+        waiters = []
+    },
+    ?EVENT(started, Key),
+    gen_server:enter_loop(?MODULE, [], St).
+
+
+terminate(_Reason, St) ->
+    #st{
+        key = Key,
+        opener = Pid,
+        ts = Ts
+    } = St,
+    % We may have already deleted our cache entry
+    % during shutdown
+    Pattern = #entry{key = Key, pid = self(), _ = '_'},
+    CacheMSpec = [{Pattern, [], [true]}],
+    true = ets:select_delete(?CACHE, CacheMSpec) < 2,
+    % We may have already deleted our LRU entry
+    % during shutdown
+    if Ts == undefined -> ok; true ->
+        LruMSpec = [{{{Ts, Key, self()}}, [], [true]}],
+        true = ets:select_delete(?LRU, LruMSpec) < 2
+    end,
+    % Blow away any current opener if it exists
+    if not is_pid(Pid) -> ok; true ->
+        catch exit(Pid, kill)
+    end,
+    ok.
+
+
+handle_call(open, From, #st{val = undefined} = St) ->
+    NewSt = St#st{
+        waiters = [From | St#st.waiters]
+    },
+    {noreply, NewSt};
+
+handle_call(open, _From, St) ->
+    {reply, St#st.val, St};
+
+handle_call(shutdown, _From, St) ->
+    remove_from_cache(St),
+    {stop, normal, ok, St};
+
+handle_call(Msg, _From, St) ->
+    {stop, {bad_call, Msg}, {bad_call, Msg}, St}.
+
+
+handle_cast(accessed, St) ->
+    ?EVENT(accessed, St#st.key),
+    drain_accessed(),
+    {noreply, update_lru(St)};
+
+handle_cast(refresh, #st{opener = Ref} = St) when is_reference(Ref) ->
+    #st{
+        key = Key
+    } = St,
+    erlang:cancel_timer(Ref),
+    NewSt = St#st{
+        opener = spawn_opener(Key)
+    },
+    {noreply, NewSt};
+
+handle_cast(refresh, #st{opener = Pid} = St) when is_pid(Pid) ->
+    catch exit(Pid, kill),
+    receive
+        {'DOWN', _, _, Pid, _} -> ok
+    end,
+    NewSt = St#st{
+        opener = spawn_opener(St#st.key)
+    },
+    {noreply, NewSt};
+
+handle_cast(Msg, St) ->
+    {stop, {bad_cast, Msg}, St}.
+
+
+handle_info({'DOWN', _, _, Pid, Resp}, #st{key = Key, opener = Pid} = St) ->
+    case Resp of
+        {open_ok, Key, {ok, Val}} ->
+            if not is_list(St#st.waiters) -> ok; true ->
+                respond(St#st.waiters, {open_ok, {ok, Val}})
+            end,
+            update_cache(St, Val),
+            Msg = {'$gen_cast', refresh},
+            Timer = erlang:send_after(?REFRESH_TIMEOUT, self(), Msg),
+            NewSt = St#st{
+                val = {open_ok, {ok, Val}},
+                opener = Timer
+            },
+            {noreply, update_lru(NewSt)};
+        {Status, Key, Other} ->
+            NewSt = St#st{
+                val = {Status, Other},
+                opener = undefined,
+                waiters = undefined
+            },
+            remove_from_cache(NewSt),
+            if not is_list(St#st.waiters) -> ok; true ->
+                respond(St#st.waiters, {Status, Other})
+            end,
+            {stop, normal, NewSt}
+    end;
+
+handle_info(Msg, St) ->
+    {stop, {bad_info, Msg}, St}.
+
+
+code_change(_, St, _) ->
+    {ok, St}.
+
+
+spawn_opener(Key) ->
+    {Pid, _} = erlang:spawn_monitor(?MODULE, do_open, [Key]),
+    Pid.
+
+
+do_open(Key) ->
+    try recover(Key) of
+        Resp ->
+            erlang:exit({open_ok, Key, Resp})
+    catch T:R ->
+        S = erlang:get_stacktrace(),
+        erlang:exit({open_error, Key, {T, R, S}})
+    end.
+
+
+update_lru(#st{key = Key, ts = Ts} = St) ->
+    if Ts == undefined -> ok; true ->
+        MSpec = [{{{Ts, Key, self()}}, [], [true]}],
+        1 = ets:select_delete(?LRU, MSpec)
+    end,
+    NewTs = os:timestamp(),
+    true = ets:insert(?LRU, {{NewTs, Key, self()}}),
+    St#st{ts = NewTs}.
+
+
+update_cache(#st{val = undefined} = St, Val) ->
+    true = ets:update_element(?CACHE, St#st.key, {#entry.val, Val}),
+    ?EVENT(inserted, St#st.key);
+
+update_cache(#st{val = V1} = _St, V2) when {open_ok, {ok, V2}} == V1 ->
+    ?EVENT(update_noop, _St#st.key);
+
+update_cache(St, Val) ->
+    true = ets:update_element(?CACHE, St#st.key, {#entry.val, Val}),
+    ?EVENT(updated, {St#st.key, Val}).
+
+
+remove_from_cache(St) ->
+    #st{
+        key = Key,
+        ts = Ts
+    } = St,
+    Pattern = #entry{key = Key, pid = self(), _ = '_'},
+    CacheMSpec = [{Pattern, [], [true]}],
+    1 = ets:select_delete(?CACHE, CacheMSpec),
+    if Ts == undefined -> ok; true ->
+        LruMSpec = [{{{Ts, Key, self()}}, [], [true]}],
+        1 = ets:select_delete(?LRU, LruMSpec)
+    end,
+    ?EVENT(removed, St#st.key),
+    ok.
+
+
+drain_accessed() ->
+    receive
+        {'$gen_cast', accessed} ->
+            drain_accessed()
+    after 0 ->
+        ok
+    end.
+
+
+respond(Waiters, Resp) ->
+    [gen_server:reply(W, Resp) || W <- Waiters].
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/src/ddoc_cache_entry_custom.erl
similarity index 62%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/src/ddoc_cache_entry_custom.erl
index fb3c0b9..d858ad6 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/src/ddoc_cache_entry_custom.erl
@@ -10,25 +10,23 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
+-module(ddoc_cache_entry_custom).
 
 
 -export([
-    new_uuid/0
+    dbname/1,
+    ddocid/1,
+    recover/1
 ]).
 
 
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
+dbname({DbName, _}) ->
+    DbName.
 
 
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
+ddocid(_) ->
+    no_ddocid.
 
 
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+recover({DbName, Mod}) ->
+    Mod:recover(DbName).
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/src/ddoc_cache_entry_ddocid.erl
similarity index 62%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/src/ddoc_cache_entry_ddocid.erl
index fb3c0b9..cac9abc 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/src/ddoc_cache_entry_ddocid.erl
@@ -10,25 +10,26 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
+-module(ddoc_cache_entry_ddocid).
 
 
 -export([
-    new_uuid/0
+    dbname/1,
+    ddocid/1,
+    recover/1
 ]).
 
 
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
+-include_lib("couch/include/couch_db.hrl").
 
 
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
+dbname({DbName, _}) ->
+    DbName.
 
 
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+ddocid({_, DDocId}) ->
+    DDocId.
+
+
+recover({DbName, DDocId}) ->
+    fabric:open_doc(DbName, DDocId, [ejson_body, ?ADMIN_CTX]).
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/src/ddoc_cache_entry_ddocid_rev.erl
similarity index 61%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/src/ddoc_cache_entry_ddocid_rev.erl
index fb3c0b9..012abab 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/src/ddoc_cache_entry_ddocid_rev.erl
@@ -10,25 +10,28 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
+-module(ddoc_cache_entry_ddocid_rev).
 
 
 -export([
-    new_uuid/0
+    dbname/1,
+    ddocid/1,
+    recover/1
 ]).
 
 
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
+-include_lib("couch/include/couch_db.hrl").
 
 
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
+dbname({DbName, _, _}) ->
+    DbName.
 
 
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+ddocid({_, DDocId, _}) ->
+    DDocId.
+
+
+recover({DbName, DDocId, Rev}) ->
+    Opts = [ejson_body, ?ADMIN_CTX],
+    {ok, [Resp]} = fabric:open_revs(DbName, DDocId, [Rev], Opts),
+    Resp.
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/src/ddoc_cache_entry_validation_funs.erl
similarity index 58%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/src/ddoc_cache_entry_validation_funs.erl
index fb3c0b9..3d43f7a 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/src/ddoc_cache_entry_validation_funs.erl
@@ -10,25 +10,30 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
+-module(ddoc_cache_entry_validation_funs).
 
 
 -export([
-    new_uuid/0
+    dbname/1,
+    ddocid/1,
+    recover/1
 ]).
 
 
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
+dbname(DbName) ->
+    DbName.
 
 
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
+ddocid(_) ->
+    no_ddocid.
 
 
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+recover(DbName) ->
+    {ok, DDocs} = fabric:design_docs(mem3:dbname(DbName)),
+    Funs = lists:flatmap(fun(DDoc) ->
+        case couch_doc:get_validate_doc_fun(DDoc) of
+            nil -> [];
+            Fun -> [Fun]
+        end
+    end, DDocs),
+    {ok, Funs}.
diff --git a/src/ddoc_cache/src/ddoc_cache_lru.erl b/src/ddoc_cache/src/ddoc_cache_lru.erl
new file mode 100644
index 0000000..5d47639
--- /dev/null
+++ b/src/ddoc_cache/src/ddoc_cache_lru.erl
@@ -0,0 +1,293 @@
+% 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.
+
+-module(ddoc_cache_lru).
+-behaviour(gen_server).
+-vsn(1).
+
+
+-export([
+    start_link/0,
+    open/1,
+    refresh/2
+]).
+
+-export([
+    init/1,
+    terminate/2,
+    handle_call/3,
+    handle_cast/2,
+    handle_info/2,
+    code_change/3
+]).
+
+-export([
+    handle_db_event/3
+]).
+
+
+-include("ddoc_cache.hrl").
+
+
+-record(st, {
+    pids, % pid -> key
+    dbs, % dbname -> docid -> key -> pid
+    size,
+    evictor
+}).
+
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+
+open(Key) ->
+    try ets:lookup(?CACHE, Key) of
+        [] ->
+            lru_start(Key);
+        [#entry{pid = undefined}] ->
+            lru_start(Key);
+        [#entry{val = undefined, pid = Pid}] ->
+            couch_stats:increment_counter([ddoc_cache, miss]),
+            ddoc_cache_entry:open(Pid, Key);
+        [#entry{val = Val, pid = Pid}] ->
+            couch_stats:increment_counter([ddoc_cache, hit]),
+            ddoc_cache_entry:accessed(Pid),
+            {ok, Val}
+    catch _:_ ->
+        couch_stats:increment_counter([ddoc_cache, recovery]),
+        ddoc_cache_entry:recover(Key)
+    end.
+
+
+refresh(DbName, DDocIds) ->
+    gen_server:cast(?MODULE, {refresh, DbName, DDocIds}).
+
+
+init(_) ->
+    process_flag(trap_exit, true),
+    {ok, Pids} = khash:new(),
+    {ok, Dbs} = khash:new(),
+    {ok, Evictor} = couch_event:link_listener(
+            ?MODULE, handle_db_event, nil, [all_dbs]
+        ),
+    {ok, #st{
+        pids = Pids,
+        dbs = Dbs,
+        size = 0,
+        evictor = Evictor
+    }}.
+
+
+terminate(_Reason, St) ->
+    case is_pid(St#st.evictor) of
+        true -> catch exit(St#st.evictor, kill);
+        false -> ok
+    end,
+    ok.
+
+
+handle_call({start, Key}, _From, St) ->
+    #st{
+        pids = Pids,
+        dbs = Dbs,
+        size = CurSize
+    } = St,
+    case ets:lookup(?CACHE, Key) of
+        [] ->
+            MaxSize = config:get_integer("ddoc_cache", "max_size", 1000),
+            case trim(St, CurSize, max(0, MaxSize)) of
+                {ok, N} ->
+                    true = ets:insert_new(?CACHE, #entry{key = Key}),
+                    {ok, Pid} = ddoc_cache_entry:start_link(Key),
+                    true = ets:update_element(?CACHE, Key, {#entry.pid, Pid}),
+                    ok = khash:put(Pids, Pid, Key),
+                    store_key(Dbs, Key, Pid),
+                    {reply, {ok, Pid}, St#st{size = CurSize - N + 1}};
+                full ->
+                    ?EVENT(full, Key),
+                    {reply, full, St}
+            end;
+        [#entry{pid = Pid}] ->
+            {reply, {ok, Pid}, St}
+    end;
+
+handle_call(Msg, _From, St) ->
+    {stop, {invalid_call, Msg}, {invalid_call, Msg}, St}.
+
+
+handle_cast({evict, DbName}, St) ->
+    gen_server:abcast(mem3:nodes(), ?MODULE, {do_evict, DbName}),
+    {noreply, St};
+
+handle_cast({refresh, DbName, DDocIds}, St) ->
+    gen_server:abcast(mem3:nodes(), ?MODULE, {do_refresh, DbName, DDocIds}),
+    {noreply, St};
+
+handle_cast({do_evict, DbName}, St) ->
+    #st{
+        dbs = Dbs
+    } = St,
+    ToRem = case khash:lookup(Dbs, DbName) of
+        {value, DDocIds} ->
+            AccOut = khash:fold(DDocIds, fun(_, Keys, Acc1) ->
+                khash:to_list(Keys) ++ Acc1
+            end, []),
+            ?EVENT(evicted, DbName),
+            AccOut;
+        not_found ->
+            ?EVENT(evict_noop, DbName),
+            []
+    end,
+    lists:foreach(fun({Key, Pid}) ->
+        remove_entry(St, Key, Pid)
+    end, ToRem),
+    khash:del(Dbs, DbName),
+    {noreply, St};
+
+handle_cast({do_refresh, DbName, DDocIdList}, St) ->
+    #st{
+        dbs = Dbs
+    } = St,
+    case khash:lookup(Dbs, DbName) of
+        {value, DDocIds} ->
+            lists:foreach(fun(DDocId) ->
+                case khash:lookup(DDocIds, DDocId) of
+                    {value, Keys} ->
+                        khash:fold(Keys, fun(_, Pid, _) ->
+                            ddoc_cache_entry:refresh(Pid)
+                        end, nil);
+                    not_found ->
+                        ok
+                end
+            end, [no_ddocid | DDocIdList]);
+        not_found ->
+            ok
+    end,
+    {noreply, St};
+
+handle_cast(Msg, St) ->
+    {stop, {invalid_cast, Msg}, St}.
+
+
+handle_info({'EXIT', Pid, _Reason}, #st{evictor = Pid} = St) ->
+    ?EVENT(evictor_died, Pid),
+    {ok, Evictor} = couch_event:link_listener(
+            ?MODULE, handle_db_event, nil, [all_dbs]
+        ),
+    {noreply, St#st{evictor=Evictor}};
+
+handle_info({'EXIT', Pid, normal}, St) ->
+    % This clause handles when an entry starts
+    % up but encounters an error or uncacheable
+    % response from its recover call.
+    #st{
+        pids = Pids
+    } = St,
+    {value, Key} = khash:lookup(Pids, Pid),
+    khash:del(Pids, Pid),
+    remove_key(St, Key),
+    {noreply, St};
+
+handle_info(Msg, St) ->
+    {stop, {invalid_info, Msg}, St}.
+
+
+code_change(_OldVsn, St, _Extra) ->
+    {ok, St}.
+
+
+handle_db_event(ShardDbName, created, St) ->
+    gen_server:cast(?MODULE, {evict, mem3:dbname(ShardDbName)}),
+    {ok, St};
+
+handle_db_event(ShardDbName, deleted, St) ->
+    gen_server:cast(?MODULE, {evict, mem3:dbname(ShardDbName)}),
+    {ok, St};
+
+handle_db_event(_DbName, _Event, St) ->
+    {ok, St}.
+
+
+lru_start(Key) ->
+    case gen_server:call(?MODULE, {start, Key}, infinity) of
+        {ok, Pid} ->
+            couch_stats:increment_counter([ddoc_cache, miss]),
+            ddoc_cache_entry:open(Pid, Key);
+        full ->
+            couch_stats:increment_counter([ddoc_cache, recovery]),
+            ddoc_cache_entry:recover(Key)
+    end.
+
+
+trim(_, _, 0) ->
+    full;
+
+trim(_St, CurSize, MaxSize) when CurSize < MaxSize ->
+    {ok, 0};
+
+trim(St, CurSize, MaxSize) when CurSize >= MaxSize ->
+    case ets:first(?LRU) of
+        '$end_of_table' ->
+            full;
+        {_Ts, Key, Pid} ->
+            remove_entry(St, Key, Pid),
+            {ok, 1}
+    end.
+
+
+remove_entry(St, Key, Pid) ->
+    #st{
+        pids = Pids
+    } = St,
+    unlink(Pid),
+    ddoc_cache_entry:shutdown(Pid),
+    khash:del(Pids, Pid),
+    remove_key(St, Key).
+
+
+store_key(Dbs, Key, Pid) ->
+    DbName = ddoc_cache_entry:dbname(Key),
+    DDocId = ddoc_cache_entry:ddocid(Key),
+    case khash:lookup(Dbs, DbName) of
+        {value, DDocIds} ->
+            case khash:lookup(DDocIds, DDocId) of
+                {value, Keys} ->
+                    khash:put(Keys, Key, Pid);
+                not_found ->
+                    {ok, Keys} = khash:from_list([{Key, Pid}]),
+                    khash:put(DDocIds, DDocId, Keys)
+            end;
+        not_found ->
+            {ok, Keys} = khash:from_list([{Key, Pid}]),
+            {ok, DDocIds} = khash:from_list([{DDocId, Keys}]),
+            khash:put(Dbs, DbName, DDocIds)
+    end.
+
+
+remove_key(St, Key) ->
+    #st{
+        dbs = Dbs
+    } = St,
+    DbName = ddoc_cache_entry:dbname(Key),
+    DDocId = ddoc_cache_entry:ddocid(Key),
+    {value, DDocIds} = khash:lookup(Dbs, DbName),
+    {value, Keys} = khash:lookup(DDocIds, DDocId),
+    khash:del(Keys, Key),
+    case khash:size(Keys) of
+        0 -> khash:del(DDocIds, DDocId);
+        _ -> ok
+    end,
+    case khash:size(DDocIds) of
+        0 -> khash:del(Dbs, DbName);
+        _ -> ok
+    end.
diff --git a/src/ddoc_cache/src/ddoc_cache_opener.erl b/src/ddoc_cache/src/ddoc_cache_opener.erl
index b76a228..7839bcb 100644
--- a/src/ddoc_cache/src/ddoc_cache_opener.erl
+++ b/src/ddoc_cache/src/ddoc_cache_opener.erl
@@ -14,279 +14,52 @@
 -behaviour(gen_server).
 -vsn(1).
 
--include_lib("couch/include/couch_db.hrl").
--include_lib("mem3/include/mem3.hrl").
-
 -export([
     start_link/0
 ]).
+
 -export([
     init/1,
     terminate/2,
-
     handle_call/3,
     handle_cast/2,
     handle_info/2,
-
     code_change/3
 ]).
 
--export([
-    open_doc/2,
-    open_doc/3,
-    open_validation_funs/1,
-    evict_docs/2,
-    lookup/1,
-    match_newest/1,
-    recover_doc/2,
-    recover_doc/3,
-    recover_validation_funs/1
-]).
--export([
-    handle_db_event/3
-]).
--export([
-    fetch_doc_data/1
-]).
-
--define(CACHE, ddoc_cache_lru).
--define(OPENING, ddoc_cache_opening).
-
--type dbname() :: iodata().
--type docid() :: iodata().
--type doc_hash() :: <<_:128>>.
--type revision() :: {pos_integer(), doc_hash()}.
-
--record(opener, {
-    key,
-    pid,
-    clients
-}).
-
--record(st, {
-    db_ddocs,
-    evictor
-}).
 
 start_link() ->
     gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
 
--spec open_doc(dbname(), docid()) -> {ok, #doc{}}.
-open_doc(DbName, DocId) ->
-    Resp = gen_server:call(?MODULE, {open, {DbName, DocId}}, infinity),
-    handle_open_response(Resp).
-
--spec open_doc(dbname(), docid(), revision()) -> {ok, #doc{}}.
-open_doc(DbName, DocId, Rev) ->
-    Resp = gen_server:call(?MODULE, {open, {DbName, DocId, Rev}}, infinity),
-    handle_open_response(Resp).
-
--spec open_validation_funs(dbname()) -> {ok, [fun()]}.
-open_validation_funs(DbName) ->
-    Resp = gen_server:call(?MODULE, {open, {DbName, validation_funs}}, infinity),
-    handle_open_response(Resp).
-
--spec evict_docs(dbname(), [docid()]) -> ok.
-evict_docs(DbName, DocIds) ->
-    gen_server:cast(?MODULE, {evict, DbName, DocIds}).
-
-lookup(Key) ->
-    try ets_lru:lookup_d(?CACHE, Key) of
-        {ok, _} = Resp ->
-            Resp;
-        _ ->
-            missing
-    catch
-        error:badarg ->
-            recover
-    end.
-
-match_newest(Key) ->
-    try ets_lru:match_object(?CACHE, Key, '_') of
-        [] ->
-            missing;
-        Docs ->
-            Sorted = lists:sort(
-                fun (#doc{deleted=DelL, revs=L}, #doc{deleted=DelR, revs=R}) ->
-                    {not DelL, L} > {not DelR, R}
-                end, Docs),
-            {ok, hd(Sorted)}
-    catch
-        error:badarg ->
-            recover
-    end.
-
-recover_doc(DbName, DDocId) ->
-    fabric:open_doc(DbName, DDocId, [ejson_body, ?ADMIN_CTX]).
-
-recover_doc(DbName, DDocId, Rev) ->
-    {ok, [Resp]} = fabric:open_revs(DbName, DDocId, [Rev], [ejson_body, ?ADMIN_CTX]),
-    Resp.
-
-recover_validation_funs(DbName) ->
-    {ok, DDocs} = fabric:design_docs(mem3:dbname(DbName)),
-    Funs = lists:flatmap(fun(DDoc) ->
-        case couch_doc:get_validate_doc_fun(DDoc) of
-            nil -> [];
-            Fun -> [Fun]
-        end
-    end, DDocs),
-    {ok, Funs}.
-
-handle_db_event(ShardDbName, created, St) ->
-    gen_server:cast(?MODULE, {evict, mem3:dbname(ShardDbName)}),
-    {ok, St};
-handle_db_event(ShardDbName, deleted, St) ->
-    gen_server:cast(?MODULE, {evict, mem3:dbname(ShardDbName)}),
-    {ok, St};
-handle_db_event(_DbName, _Event, St) ->
-    {ok, St}.
 
 init(_) ->
-    process_flag(trap_exit, true),
-    _ = ets:new(?OPENING, [set, protected, named_table, {keypos, #opener.key}]),
-    {ok, Evictor} = couch_event:link_listener(
-            ?MODULE, handle_db_event, nil, [all_dbs]
-        ),
-    {ok, #st{
-        evictor = Evictor
-    }}.
+    {ok, nil}.
 
-terminate(_Reason, St) ->
-    case is_pid(St#st.evictor) of
-        true -> exit(St#st.evictor, kill);
-        false -> ok
-    end,
+terminate(_Reason, _St) ->
     ok.
 
-handle_call({open, OpenerKey}, From, St) ->
-    case ets:lookup(?OPENING, OpenerKey) of
-        [#opener{clients=Clients}=O] ->
-            ets:insert(?OPENING, O#opener{clients=[From | Clients]}),
-            {noreply, St};
-        [] ->
-            Pid = spawn_link(?MODULE, fetch_doc_data, [OpenerKey]),
-            ets:insert(?OPENING, #opener{key=OpenerKey, pid=Pid, clients=[From]}),
-            {noreply, St}
-    end;
 
 handle_call(Msg, _From, St) ->
     {stop, {invalid_call, Msg}, {invalid_call, Msg}, St}.
 
 
-handle_cast({evict, DbName}, St) ->
-    gen_server:abcast(mem3:nodes(), ?MODULE, {do_evict, DbName}),
+% The do_evict clauses are upgrades while we're
+% in a rolling reboot.
+handle_cast({do_evict, _} = Msg, St) ->
+    gen_server:cast(ddoc_cache_lru, Msg),
     {noreply, St};
 
-handle_cast({evict, DbName, DDocIds}, St) ->
-    gen_server:abcast(mem3:nodes(), ?MODULE, {do_evict, DbName, DDocIds}),
-    {noreply, St};
-
-handle_cast({do_evict, DbName}, St) ->
-    DDocIds = lists:flatten(ets_lru:match(?CACHE, {DbName, '$1', '_'}, '_')),
-    handle_cast({do_evict, DbName, DDocIds}, St);
-
 handle_cast({do_evict, DbName, DDocIds}, St) ->
-    CustomKeys = lists:flatten(ets_lru:match(?CACHE, {DbName, '$1'}, '_')),
-    lists:foreach(fun(Mod) ->
-        ets_lru:remove(?CACHE, {DbName, Mod})
-    end, CustomKeys),
-    lists:foreach(fun(DDocId) ->
-        Revs = ets_lru:match(?CACHE, {DbName, DDocId, '$1'}, '_'),
-        lists:foreach(fun([Rev]) ->
-            ets_lru:remove(?CACHE, {DbName, DDocId, Rev})
-        end, Revs)
-    end, DDocIds),
+    gen_server:cast(ddoc_cache_lru, {do_refresh, DbName, DDocIds}),
     {noreply, St};
 
 handle_cast(Msg, St) ->
     {stop, {invalid_cast, Msg}, St}.
 
-handle_info({'EXIT', Pid, Reason}, #st{evictor=Pid}=St) ->
-    couch_log:error("ddoc_cache_opener evictor died ~w", [Reason]),
-    {ok, Evictor} = couch_event:link_listener(?MODULE, handle_db_event, nil, [all_dbs]),
-    {noreply, St#st{evictor=Evictor}};
-
-handle_info({'EXIT', _Pid, {open_ok, OpenerKey, Resp}}, St) ->
-    respond(OpenerKey, {open_ok, Resp}),
-    {noreply, St};
-
-handle_info({'EXIT', _Pid, {open_error, OpenerKey, Type, Error}}, St) ->
-    respond(OpenerKey, {open_error, Type, Error}),
-    {noreply, St};
-
-handle_info({'EXIT', Pid, Reason}, St) ->
-    Pattern = #opener{pid=Pid, _='_'},
-    case ets:match_object(?OPENING, Pattern) of
-        [#opener{key=OpenerKey, clients=Clients}] ->
-            _ = [gen_server:reply(C, {error, Reason}) || C <- Clients],
-            ets:delete(?OPENING, OpenerKey),
-            {noreply, St};
-        [] ->
-            {stop, {unknown_pid_died, {Pid, Reason}}, St}
-    end;
 
 handle_info(Msg, St) ->
     {stop, {invalid_info, Msg}, St}.
 
+
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
-
--spec fetch_doc_data({dbname(), validation_funs}) -> no_return();
-                    ({dbname(), atom()}) -> no_return();
-                    ({dbname(), docid()}) -> no_return();
-                    ({dbname(), docid(), revision()}) -> no_return().
-fetch_doc_data({DbName, validation_funs}=OpenerKey) ->
-    {ok, Funs} = recover_validation_funs(DbName),
-    ok = ets_lru:insert(?CACHE, OpenerKey, Funs),
-    exit({open_ok, OpenerKey, {ok, Funs}});
-fetch_doc_data({DbName, Mod}=OpenerKey) when is_atom(Mod) ->
-    % This is not actually a docid but rather a custom cache key.
-    % Treat the argument as a code module and invoke its recover function.
-    try Mod:recover(DbName) of
-        {ok, Result} ->
-            ok = ets_lru:insert(?CACHE, OpenerKey, Result),
-            exit({open_ok, OpenerKey, {ok, Result}});
-        Else ->
-            exit({open_ok, OpenerKey, Else})
-    catch
-        Type:Reason ->
-            exit({open_error, OpenerKey, Type, Reason})
-    end;
-fetch_doc_data({DbName, DocId}=OpenerKey) ->
-    try recover_doc(DbName, DocId) of
-        {ok, Doc} ->
-            {RevDepth, [RevHash| _]} = Doc#doc.revs,
-            Rev = {RevDepth, RevHash},
-            ok = ets_lru:insert(?CACHE, {DbName, DocId, Rev}, Doc),
-            exit({open_ok, OpenerKey, {ok, Doc}});
-        Else ->
-            exit({open_ok, OpenerKey, Else})
-    catch
-        Type:Reason ->
-            exit({open_error, OpenerKey, Type, Reason})
-    end;
-fetch_doc_data({DbName, DocId, Rev}=OpenerKey) ->
-    try recover_doc(DbName, DocId, Rev) of
-        {ok, Doc} ->
-            ok = ets_lru:insert(?CACHE, {DbName, DocId, Rev}, Doc),
-            exit({open_ok, OpenerKey, {ok, Doc}});
-        Else ->
-            exit({open_ok, OpenerKey, Else})
-    catch
-        Type:Reason ->
-            exit({open_error, OpenerKey, Type, Reason})
-    end.
-
-handle_open_response(Resp) ->
-    case Resp of
-        {open_ok, Value} -> Value;
-        {open_error, throw, Error} -> throw(Error);
-        {open_error, error, Error} -> erlang:error(Error);
-        {open_error, exit, Error} -> exit(Error)
-    end.
-
-respond(OpenerKey, Resp) ->
-    [#opener{clients=Clients}] = ets:lookup(?OPENING, OpenerKey),
-    _ = [gen_server:reply(C, Resp) || C <- Clients],
-    ets:delete(?OPENING, OpenerKey).
diff --git a/src/ddoc_cache/src/ddoc_cache_sup.erl b/src/ddoc_cache/src/ddoc_cache_sup.erl
index 85e90b3..35393e1 100644
--- a/src/ddoc_cache/src/ddoc_cache_sup.erl
+++ b/src/ddoc_cache/src/ddoc_cache_sup.erl
@@ -27,12 +27,20 @@ start_link() ->
 init([]) ->
     Children = [
         {
+            ddoc_cache_tables,
+            {ddoc_cache_tables, start_link, []},
+            permanent,
+            5000,
+            worker,
+            [ddoc_cache_tables]
+        },
+        {
             ddoc_cache_lru,
-            {ets_lru, start_link, [ddoc_cache_lru, lru_opts()]},
+            {ddoc_cache_lru, start_link, []},
             permanent,
             5000,
             worker,
-            [ets_lru]
+            [ddoc_cache_lru]
         },
         {
             ddoc_cache_opener,
@@ -43,25 +51,4 @@ init([]) ->
             [ddoc_cache_opener]
         }
     ],
-    {ok, {{one_for_one, 5, 10}, Children}}.
-
-
-lru_opts() ->
-    case application:get_env(ddoc_cache, max_objects) of
-        {ok, MxObjs} when is_integer(MxObjs), MxObjs >= 0 ->
-            [{max_objects, MxObjs}];
-        _ ->
-            []
-    end ++
-    case application:get_env(ddoc_cache, max_size) of
-        {ok, MxSize} when is_integer(MxSize), MxSize >= 0 ->
-            [{max_size, MxSize}];
-        _ ->
-            []
-    end ++
-    case application:get_env(ddoc_cache, max_lifetime) of
-        {ok, MxLT} when is_integer(MxLT), MxLT >= 0 ->
-            [{max_lifetime, MxLT}];
-        _ ->
-            []
-    end.
+    {ok, {{one_for_all, 25, 1}, Children}}.
diff --git a/src/ddoc_cache/src/ddoc_cache_tables.erl b/src/ddoc_cache/src/ddoc_cache_tables.erl
new file mode 100644
index 0000000..5856776
--- /dev/null
+++ b/src/ddoc_cache/src/ddoc_cache_tables.erl
@@ -0,0 +1,68 @@
+% 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.
+
+-module(ddoc_cache_tables).
+-behaviour(gen_server).
+-vsn(1).
+
+
+-export([
+    start_link/0
+]).
+
+-export([
+    init/1,
+    terminate/2,
+    handle_call/3,
+    handle_cast/2,
+    handle_info/2,
+    code_change/3
+]).
+
+
+-include("ddoc_cache.hrl").
+
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+
+init(_) ->
+    BaseOpts = [public, named_table],
+    CacheOpts = [
+        set,
+        {read_concurrency, true},
+        {keypos, #entry.key}
+    ] ++ BaseOpts,
+    ets:new(?CACHE, CacheOpts),
+    ets:new(?LRU, [ordered_set, {write_concurrency, true}] ++ BaseOpts),
+    {ok, nil}.
+
+
+terminate(_Reason, _St) ->
+    ok.
+
+
+handle_call(Msg, _From, St) ->
+    {stop, {invalid_call, Msg}, {invalid_call, Msg}, St}.
+
+
+handle_cast(Msg, St) ->
+    {stop, {invalid_cast, Msg}, St}.
+
+
+handle_info(Msg, St) ->
+    {stop, {invalid_info, Msg}, St}.
+
+
+code_change(_OldVsn, St, _Extra) ->
+    {ok, St}.
diff --git a/src/ddoc_cache/test/ddoc_cache_basic_test.erl b/src/ddoc_cache/test/ddoc_cache_basic_test.erl
new file mode 100644
index 0000000..227ac54
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_basic_test.erl
@@ -0,0 +1,122 @@
+% 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.
+
+-module(ddoc_cache_basic_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(DbName) ->
+    {ok, {DbName, totes_custom}}.
+
+
+check_basic_test_() ->
+    {
+        setup,
+        fun ddoc_cache_tutil:start_couch/0,
+        fun ddoc_cache_tutil:stop_couch/1,
+        {with, [
+            fun cache_ddoc/1,
+            fun cache_ddoc_rev/1,
+            fun cache_vdu/1,
+            fun cache_custom/1,
+            fun cache_ddoc_refresher_unchanged/1,
+            fun dont_cache_not_found/1,
+            fun deprecated_api_works/1
+        ]}
+    }.
+
+
+cache_ddoc({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    Resp1 = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertMatch({ok, #doc{id = ?FOOBAR}}, Resp1),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    Resp2 = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertEqual(Resp1, Resp2),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+cache_ddoc_rev({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?FOOBAR),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    Resp1 = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    ?assertMatch({ok, #doc{id = ?FOOBAR}}, Resp1),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    Resp2 = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    ?assertEqual(Resp1, Resp2),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+
+    % Assert that the non-rev cache entry is separate
+    Resp3 = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertMatch({ok, #doc{id = ?FOOBAR}}, Resp3),
+    ?assertEqual(2, ets:info(?CACHE, size)).
+
+
+cache_vdu({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    Resp1 = ddoc_cache:open_validation_funs(DbName),
+    ?assertMatch({ok, [_]}, Resp1),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    Resp2 = ddoc_cache:open_validation_funs(DbName),
+    ?assertEqual(Resp1, Resp2),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+cache_custom({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    Resp1 = ddoc_cache:open_custom(DbName, ?MODULE),
+    ?assertMatch({ok, {DbName, totes_custom}}, Resp1),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    Resp2 = ddoc_cache:open_custom(DbName, ?MODULE),
+    ?assertEqual(Resp1, Resp2),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+cache_ddoc_refresher_unchanged({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    ddoc_cache:open_doc(DbName, ?FOOBAR),
+    [Entry1] = ets:lookup(?CACHE, ets:first(?CACHE)),
+    ddoc_cache:open_doc(DbName, ?FOOBAR),
+    [Entry2] = ets:lookup(?CACHE, ets:first(?CACHE)),
+    ?assertEqual(Entry1, Entry2).
+
+
+dont_cache_not_found({DbName, _}) ->
+    DDocId = <<"_design/not_found">>,
+    ddoc_cache_tutil:clear(),
+    Resp = ddoc_cache:open_doc(DbName, DDocId),
+    ?assertEqual({not_found, missing}, Resp),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    ?assertEqual(0, ets:info(?LRU, size)).
+
+
+deprecated_api_works({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    {ok, _} = ddoc_cache:open(DbName, ?FOOBAR),
+    {ok, _} = ddoc_cache:open(DbName, <<"foobar">>),
+    {ok, _} = ddoc_cache:open(DbName, ?MODULE),
+    {ok, _} = ddoc_cache:open(DbName, validation_funs).
+
diff --git a/src/ddoc_cache/test/ddoc_cache_coverage_test.erl b/src/ddoc_cache/test/ddoc_cache_coverage_test.erl
new file mode 100644
index 0000000..395f560
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_coverage_test.erl
@@ -0,0 +1,86 @@
+% 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.
+
+-module(ddoc_cache_coverage_test).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+coverage_test_() ->
+    {
+        setup,
+        fun ddoc_cache_tutil:start_couch/0,
+        fun ddoc_cache_tutil:stop_couch/1,
+        [
+            fun restart_lru/0,
+            fun restart_tables/0,
+            fun restart_evictor/0
+        ]
+    }.
+
+
+restart_lru() ->
+    send_bad_messages(ddoc_cache_lru),
+    ?assertEqual(ok, ddoc_cache_lru:terminate(bang, {st, a, b, c, d})),
+    ?assertEqual({ok, foo}, ddoc_cache_lru:code_change(1, foo, [])).
+
+
+restart_tables() ->
+    send_bad_messages(ddoc_cache_tables),
+    ?assertEqual(ok, ddoc_cache_tables:terminate(bang, baz)),
+    ?assertEqual({ok, foo}, ddoc_cache_tables:code_change(1, foo, [])).
+
+
+restart_evictor() ->
+    meck:new(ddoc_cache_ev, [passthrough]),
+    try
+        State = sys:get_state(ddoc_cache_lru),
+        Evictor = element(5, State),
+        Ref = erlang:monitor(process, Evictor),
+        exit(Evictor, shutdown),
+        receive
+            {'DOWN', Ref, _, _, Reason} ->
+                couch_log:error("MONITOR: ~p", [Reason]),
+                ok
+        end,
+        meck:wait(ddoc_cache_ev, event, [evictor_died, '_'], 1000),
+        NewState = sys:get_state(ddoc_cache_lru),
+        NewEvictor = element(5, NewState),
+        ?assertNotEqual(Evictor, NewEvictor)
+    after
+        meck:unload()
+    end.
+
+
+send_bad_messages(Name) ->
+    wait_for_restart(Name, fun() ->
+        ?assertEqual({invalid_call, foo}, gen_server:call(Name, foo))
+    end),
+    wait_for_restart(Name, fun() ->
+        gen_server:cast(Name, foo)
+    end),
+    wait_for_restart(Name, fun() ->
+        whereis(Name) ! foo
+    end).
+
+
+wait_for_restart(Server, Fun) ->
+    Ref = erlang:monitor(process, whereis(Server)),
+    Fun(),
+    receive
+        {'DOWN', Ref, _, _, _} ->
+            ok
+    end,
+    ?assert(is_pid(test_util:wait_process(Server))).
diff --git a/src/ddoc_cache/test/ddoc_cache_disabled_test.erl b/src/ddoc_cache/test/ddoc_cache_disabled_test.erl
new file mode 100644
index 0000000..ef73180
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_disabled_test.erl
@@ -0,0 +1,52 @@
+% 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.
+
+-module(ddoc_cache_disabled_test).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    config:set("ddoc_cache", "max_size", "0", false),
+    Ctx.
+
+
+check_disabled_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun ddoc_cache_tutil:stop_couch/1,
+        {with, [
+            fun resp_ok/1,
+            fun resp_not_found/1
+        ]}
+    }.
+
+
+resp_ok({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    Resp = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertMatch({ok, #doc{id = ?FOOBAR}}, Resp),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    ?assertEqual(0, ets:info(?LRU, size)).
+
+
+resp_not_found({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    Resp = ddoc_cache:open_doc(DbName, <<"_design/not_found">>),
+    ?assertEqual({not_found, missing}, Resp),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    ?assertEqual(0, ets:info(?LRU, size)).
diff --git a/src/ddoc_cache/test/ddoc_cache_entry_test.erl b/src/ddoc_cache/test/ddoc_cache_entry_test.erl
new file mode 100644
index 0000000..62afc72
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_entry_test.erl
@@ -0,0 +1,120 @@
+% 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.
+
+-module(ddoc_cache_entry_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(<<"foo">>) ->
+    timer:sleep(30000);
+
+recover(DbName) ->
+    {ok, {DbName, such_custom}}.
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:new(ddoc_cache_ev, [passthrough]),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_entry_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun cancel_and_replace_opener/1,
+            fun condenses_access_messages/1,
+            fun kill_opener_on_terminate/1,
+            fun open_dead_entry/1,
+            fun handles_bad_messages/1,
+            fun handles_code_change/1
+        ]}
+    }.
+
+
+cancel_and_replace_opener(_) ->
+    Key = {ddoc_cache_entry_custom, {<<"foo">>, ?MODULE}},
+    true = ets:insert_new(?CACHE, #entry{key = Key}),
+    {ok, Entry} = ddoc_cache_entry:start_link(Key),
+    Opener1 = element(4, sys:get_state(Entry)),
+    Ref1 = erlang:monitor(process, Opener1),
+    gen_server:cast(Entry, refresh),
+    receive {'DOWN', Ref1, _, _, _} -> ok end,
+    Opener2 = element(4, sys:get_state(Entry)),
+    ?assert(Opener2 /= Opener1),
+    ?assert(is_process_alive(Opener2)),
+    % Clean up after ourselves
+    unlink(Entry),
+    ddoc_cache_entry:shutdown(Entry).
+
+
+condenses_access_messages({DbName, _}) ->
+    meck:reset(ddoc_cache_ev),
+    Key = {ddoc_cache_entry_custom, {DbName, ?MODULE}},
+    true = ets:insert(?CACHE, #entry{key = Key}),
+    {ok, Entry} = ddoc_cache_entry:start_link(Key),
+    erlang:suspend_process(Entry),
+    lists:foreach(fun(_) ->
+        gen_server:cast(Entry, accessed)
+    end, lists:seq(1, 100)),
+    erlang:resume_process(Entry),
+    meck:wait(1, ddoc_cache_ev, event, [accessed, Key], 1000),
+    ?assertError(
+            timeout,
+            meck:wait(2, ddoc_cache_ev, event, [accessed, Key], 100)
+        ),
+    unlink(Entry),
+    ddoc_cache_entry:shutdown(Entry).
+
+
+kill_opener_on_terminate(_) ->
+    Pid = spawn(fun() -> receive _ -> ok end end),
+    ?assert(is_process_alive(Pid)),
+    St = {st, key, val, Pid, waiters, ts},
+    ?assertEqual(ok, ddoc_cache_entry:terminate(normal, St)),
+    ?assert(not is_process_alive(Pid)).
+
+
+open_dead_entry({DbName, _}) ->
+    Pid = spawn(fun() -> ok end),
+    Key = {ddoc_cache_entry_custom, {DbName, ?MODULE}},
+    ?assertEqual(recover(DbName), ddoc_cache_entry:open(Pid, Key)).
+
+
+handles_bad_messages(_) ->
+    CallExpect = {stop, {bad_call, foo}, {bad_call, foo}, baz},
+    CastExpect = {stop, {bad_cast, foo}, bar},
+    InfoExpect = {stop, {bad_info, foo}, bar},
+    ?assertEqual(CallExpect, ddoc_cache_entry:handle_call(foo, bar, baz)),
+    ?assertEqual(CastExpect, ddoc_cache_entry:handle_cast(foo, bar)),
+    ?assertEqual(InfoExpect, ddoc_cache_entry:handle_info(foo, bar)).
+
+
+handles_code_change(_) ->
+    CCExpect = {ok, bar},
+    ?assertEqual(CCExpect, ddoc_cache_entry:code_change(foo, bar, baz)).
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/test/ddoc_cache_ev.erl
similarity index 61%
copy from src/ddoc_cache/src/ddoc_cache_util.erl
copy to src/ddoc_cache/test/ddoc_cache_ev.erl
index fb3c0b9..a451342 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/test/ddoc_cache_ev.erl
@@ -10,25 +10,12 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
-
+-module(ddoc_cache_ev).
 
 -export([
-    new_uuid/0
+    event/2
 ]).
 
 
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
-
-
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
-
-
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+event(Name, Arg) ->
+    couch_log:error("~s :: ~s :: ~p", [?MODULE, Name, Arg]).
diff --git a/src/ddoc_cache/test/ddoc_cache_eviction_test.erl b/src/ddoc_cache/test/ddoc_cache_eviction_test.erl
new file mode 100644
index 0000000..0b9f57b
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_eviction_test.erl
@@ -0,0 +1,93 @@
+% 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.
+
+-module(ddoc_cache_eviction_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(DbName) ->
+    {ok, {DbName, totes_custom}}.
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:new(ddoc_cache_ev, [passthrough]),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_eviction_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun evict_all/1,
+            fun dont_evict_all_unrelated/1,
+            fun check_upgrade_clause/1
+        ]}
+    }.
+
+
+evict_all({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?FOOBAR),
+    ShardName = element(2, hd(mem3:shards(DbName))),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    {ok, _} = ddoc_cache:open_validation_funs(DbName),
+    {ok, _} = ddoc_cache:open_custom(DbName, ?MODULE),
+    ?assertEqual(4, ets:info(?CACHE, size)),
+    {ok, _} = ddoc_cache_lru:handle_db_event(ShardName, deleted, foo),
+    meck:wait(ddoc_cache_ev, event, [evicted, DbName], 1000),
+    meck:wait(4, ddoc_cache_ev, event, [removed, '_'], 1000),
+    ?assertEqual(0, ets:info(?CACHE, size)).
+
+
+dont_evict_all_unrelated({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?FOOBAR),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    {ok, _} = ddoc_cache:open_validation_funs(DbName),
+    {ok, _} = ddoc_cache:open_custom(DbName, ?MODULE),
+    ?assertEqual(4, ets:info(?CACHE, size)),
+    ShardName = <<"shards/00000000-ffffffff/test.1384769918">>,
+    {ok, _} = ddoc_cache_lru:handle_db_event(ShardName, deleted, foo),
+    meck:wait(ddoc_cache_ev, event, [evict_noop, <<"test">>], 1000),
+    ?assertEqual(4, ets:info(?CACHE, size)).
+
+
+check_upgrade_clause({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    gen_server:cast(ddoc_cache_opener, {do_evict, DbName}),
+    meck:wait(ddoc_cache_ev, event, [evicted, DbName], 1000),
+    meck:wait(ddoc_cache_ev, event, [removed, '_'], 1000),
+    ?assertEqual(0, ets:info(?CACHE, size)).
diff --git a/src/ddoc_cache/test/ddoc_cache_lru_test.erl b/src/ddoc_cache/test/ddoc_cache_lru_test.erl
new file mode 100644
index 0000000..f5cef16
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_lru_test.erl
@@ -0,0 +1,167 @@
+% 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.
+
+-module(ddoc_cache_lru_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(<<"pause", _/binary>>) ->
+    receive go -> ok end,
+    {ok, paused};
+
+recover(DbName) ->
+    {ok, DbName}.
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    config:set("ddoc_cache", "max_size", "5", false),
+    meck:new(ddoc_cache_ev, [passthrough]),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_not_started_test() ->
+    % Starting couch, but not ddoc_cache
+    Ctx = test_util:start_couch(),
+    try
+        Key = {ddoc_cache_entry_custom, {<<"dbname">>, ?MODULE}},
+        ?assertEqual({ok, <<"dbname">>}, ddoc_cache_lru:open(Key))
+    after
+        test_util:stop_couch(Ctx)
+    end.
+
+
+check_lru_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun check_multi_start/1,
+            fun check_multi_open/1,
+            fun check_capped_size/1,
+            fun check_full_cache/1
+        ]}
+    }.
+
+
+check_multi_start(_) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Key = {ddoc_cache_entry_custom, {<<"pause">>, ?MODULE}},
+    % These will all get sent through ddoc_cache_lru
+    Clients = lists:map(fun(_) ->
+        spawn_monitor(fun() ->
+            ddoc_cache_lru:open(Key)
+        end)
+    end, lists:seq(1, 10)),
+    meck:wait(ddoc_cache_ev, event, [started, Key], 1000),
+    lists:foreach(fun({Pid, _Ref}) ->
+        ?assert(is_process_alive(Pid))
+    end, Clients),
+    [#entry{pid = Pid}] = ets:tab2list(?CACHE),
+    Opener = element(4, sys:get_state(Pid)),
+    OpenerRef = erlang:monitor(process, Opener),
+    ?assert(is_process_alive(Opener)),
+    Opener ! go,
+    receive {'DOWN', OpenerRef, _, _, _} -> ok end,
+    lists:foreach(fun({CPid, Ref}) ->
+        receive
+            {'DOWN', Ref, _, _, normal} -> ok;
+            {'DOWN', Ref, _, _, Other} ->
+                io:format(standard_error, "OTHER: ~p~n", [Other]);
+            Other when not is_tuple(Other) orelse element(1, Other) /= 'DOWN' ->
+                io:format(standard_error, "MSG: ~p~n", [Other])
+        after 2000 ->
+            io:format(standard_error, "BLAH?!: ~p ~p", [CPid, process_info(CPid, current_stacktrace)])
+        end
+    end, Clients).
+
+
+check_multi_open(_) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Key = {ddoc_cache_entry_custom, {<<"pause">>, ?MODULE}},
+    % We wait after the first client so that
+    % the rest of the clients go directly to
+    % ddoc_cache_entry bypassing ddoc_cache_lru
+    Client1 = spawn_monitor(fun() ->
+        ddoc_cache_lru:open(Key)
+    end),
+    meck:wait(ddoc_cache_ev, event, [started, Key], 1000),
+    Clients = [Client1] ++ lists:map(fun(_) ->
+        spawn_monitor(fun() ->
+            ddoc_cache_lru:open(Key)
+        end)
+    end, lists:seq(1, 9)),
+    lists:foreach(fun({Pid, _Ref}) ->
+        ?assert(is_process_alive(Pid))
+    end, Clients),
+    [#entry{pid = Pid}] = ets:tab2list(?CACHE),
+    Opener = element(4, sys:get_state(Pid)),
+    OpenerRef = erlang:monitor(process, Opener),
+    ?assert(is_process_alive(Opener)),
+    Opener ! go,
+    receive {'DOWN', OpenerRef, _, _, _} -> ok end,
+    lists:foreach(fun({_, Ref}) ->
+        receive {'DOWN', Ref, _, _, normal} -> ok end
+    end, Clients).
+
+
+check_capped_size(_) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    lists:foreach(fun(I) ->
+        DbName = list_to_binary(integer_to_list(I)),
+        ddoc_cache:open_custom(DbName, ?MODULE),
+        meck:wait(I, ddoc_cache_ev, event, [started, '_'], 1000),
+        ?assertEqual(I, ets:info(?CACHE, size))
+    end, lists:seq(1, 5)),
+    lists:foreach(fun(I) ->
+        DbName = list_to_binary(integer_to_list(I)),
+        ddoc_cache:open_custom(DbName, ?MODULE),
+        meck:wait(I, ddoc_cache_ev, event, [started, '_'], 1000),
+        ?assertEqual(5, ets:info(?CACHE, size))
+    end, lists:seq(6, 20)).
+
+
+check_full_cache(_) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    lists:foreach(fun(I) ->
+        DbSuffix = list_to_binary(integer_to_list(I)),
+        DbName = <<"pause", DbSuffix/binary>>,
+        spawn(fun() -> ddoc_cache:open_custom(DbName, ?MODULE) end),
+        meck:wait(I, ddoc_cache_ev, event, [started, '_'], 1000),
+        ?assertEqual(I, ets:info(?CACHE, size))
+    end, lists:seq(1, 5)),
+    lists:foreach(fun(I) ->
+        DbSuffix = list_to_binary(integer_to_list(I)),
+        DbName = <<"pause", DbSuffix/binary>>,
+        spawn(fun() -> ddoc_cache:open_custom(DbName, ?MODULE) end),
+        meck:wait(I - 5, ddoc_cache_ev, event, [full, '_'], 1000),
+        ?assertEqual(5, ets:info(?CACHE, size))
+    end, lists:seq(6, 20)).
diff --git a/src/ddoc_cache/test/ddoc_cache_no_cache_test.erl b/src/ddoc_cache/test/ddoc_cache_no_cache_test.erl
new file mode 100644
index 0000000..a5a5751
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_no_cache_test.erl
@@ -0,0 +1,78 @@
+% 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.
+
+-module(ddoc_cache_no_cache_test).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+
+ddoc(DDocId) ->
+    {ok, #doc{
+        id = DDocId,
+        body = {[
+            {<<"ohai">>, null}
+        ]}
+    }}.
+
+
+not_found(_DDocId) ->
+    {not_found, missing}.
+
+
+return_error(_DDocId) ->
+    {error, timeout}.
+
+
+start(Resp) ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:new(fabric),
+    meck:expect(fabric, open_doc, fun(_, DDocId, _) ->
+        Resp(DDocId)
+    end),
+    Ctx.
+
+
+stop(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+no_cache_open_ok_test() ->
+    Ctx = start(fun ddoc/1),
+    try
+        Resp = ddoc_cache:open_doc(<<"foo">>, <<"bar">>),
+        ?assertEqual(ddoc(<<"bar">>), Resp)
+    after
+        stop(Ctx)
+    end.
+
+
+no_cache_open_not_found_test() ->
+    Ctx = start(fun not_found/1),
+    try
+        Resp = ddoc_cache:open_doc(<<"foo">>, <<"bar">>),
+        ?assertEqual(not_found(<<"bar">>), Resp)
+    after
+        stop(Ctx)
+    end.
+
+
+no_cache_open_error_test() ->
+    Ctx = start(fun return_error/1),
+    try
+        Resp = ddoc_cache:open_doc(<<"foo">>, <<"bar">>),
+        ?assertEqual(return_error(<<"bar">>), Resp)
+    after
+        stop(Ctx)
+    end.
diff --git a/src/ddoc_cache/test/ddoc_cache_open_error_test.erl b/src/ddoc_cache/test/ddoc_cache_open_error_test.erl
new file mode 100644
index 0000000..0ac2390
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_open_error_test.erl
@@ -0,0 +1,46 @@
+% 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.
+
+-module(ddoc_cache_open_error_test).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:expect(fabric, open_doc, fun(_, ?FOOBAR, _) ->
+        erlang:error(test_kaboom)
+    end),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_basic_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun handle_open_error/1
+        ]}
+    }.
+
+
+handle_open_error({DbName, _}) ->
+    ?assertError(test_kaboom, ddoc_cache:open_doc(DbName, ?FOOBAR)).
diff --git a/src/ddoc_cache/test/ddoc_cache_opener_test.erl b/src/ddoc_cache/test/ddoc_cache_opener_test.erl
new file mode 100644
index 0000000..c384636
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_opener_test.erl
@@ -0,0 +1,33 @@
+% 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.
+
+-module(ddoc_cache_opener_test).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+empty_hull_test() ->
+    InitExpect = {ok, nil},
+    TermExpect = ok,
+    CallExpect = {stop, {invalid_call, foo}, {invalid_call, foo}, baz},
+    CastExpect = {stop, {invalid_cast, foo}, bar},
+    InfoExpect = {stop, {invalid_info, foo}, bar},
+    CCExpect = {ok, bar},
+    ?assertEqual(InitExpect, ddoc_cache_opener:init(foo)),
+    ?assertEqual(TermExpect, ddoc_cache_opener:terminate(foo, bar)),
+    ?assertEqual(CallExpect, ddoc_cache_opener:handle_call(foo, bar, baz)),
+    ?assertEqual(CastExpect, ddoc_cache_opener:handle_cast(foo, bar)),
+    ?assertEqual(InfoExpect, ddoc_cache_opener:handle_info(foo, bar)),
+    ?assertEqual(CCExpect, ddoc_cache_opener:code_change(foo, bar, baz)).
diff --git a/src/ddoc_cache/test/ddoc_cache_refresh_test.erl b/src/ddoc_cache/test/ddoc_cache_refresh_test.erl
new file mode 100644
index 0000000..7bc1704
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_refresh_test.erl
@@ -0,0 +1,167 @@
+% 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.
+
+-module(ddoc_cache_refresh_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(DbName) ->
+    {ok, {DbName, rand_string()}}.
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:new(ddoc_cache_ev, [passthrough]),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_refresh_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun refresh_ddoc/1,
+            fun refresh_ddoc_rev/1,
+            fun refresh_vdu/1,
+            fun refresh_custom/1,
+            fun refresh_multiple/1,
+            fun check_upgrade_clause/1
+        ]}
+    }.
+
+
+refresh_ddoc({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    [#entry{key = Key, val = DDoc}] = ets:tab2list(?CACHE),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"foo">>, <<"baz">>}]}
+    },
+    {ok, {Depth, RevId}} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    Expect = NewDDoc#doc{
+        revs = {Depth, [RevId | element(2, DDoc#doc.revs)]}
+    },
+    meck:wait(ddoc_cache_ev, event, [updated, {Key, Expect}], 1000),
+    ?assertMatch({ok, Expect}, ddoc_cache:open_doc(DbName, ?FOOBAR)),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+refresh_ddoc_rev({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?FOOBAR),
+    {ok, RevDDoc} = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    [#entry{key = Key, val = DDoc}] = ets:tab2list(?CACHE),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"foo">>, <<"kazam">>}]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    % We pass the rev explicitly so we assert that we're
+    % getting the same original response from the cache
+    meck:wait(ddoc_cache_ev, event, [update_noop, Key], 1000),
+    ?assertMatch({ok, RevDDoc}, ddoc_cache:open_doc(DbName, ?FOOBAR, Rev)),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+refresh_vdu({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    {ok, [_]} = ddoc_cache:open_validation_funs(DbName),
+    [#entry{key = Key}] = ets:tab2list(?CACHE),
+    {ok, DDoc} = fabric:open_doc(DbName, ?VDU, [?ADMIN_CTX]),
+    {ok, _} = fabric:update_doc(DbName, DDoc#doc{body = {[]}}, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [updated, {Key, []}], 1000),
+    ?assertMatch({ok, []}, ddoc_cache:open_validation_funs(DbName)),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+refresh_custom({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    {ok, Resp1} = ddoc_cache:open_custom(DbName, ?MODULE),
+    {ok, DDoc} = fabric:open_doc(DbName, ?VDU, [?CUSTOM]),
+    {ok, _} = fabric:update_doc(DbName, DDoc#doc{body = {[]}}, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [updated, '_'], 1000),
+    ?assertNotEqual({ok, Resp1}, ddoc_cache:open_custom(DbName, ?MODULE)),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+
+refresh_multiple({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?FOOBAR),
+    {ok, DDoc} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    {ok, DDoc} = ddoc_cache:open_doc(DbName, ?FOOBAR, Rev),
+    ?assertEqual(2, ets:info(?CACHE, size)),
+    % Relying on the sort order of entry keys to make
+    % sure our entries line up for this test
+    [
+        #entry{key = NoRevKey, val = DDoc},
+        #entry{key = RevKey, val = DDoc}
+    ] = lists:sort(ets:tab2list(?CACHE)),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"foo">>, <<"kalamazoo">>}]}
+    },
+    {ok, {Depth, RevId}} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    Updated = NewDDoc#doc{
+        revs = {Depth, [RevId | element(2, DDoc#doc.revs)]}
+    },
+    meck:wait(ddoc_cache_ev, event, [update_noop, RevKey], 1000),
+    meck:wait(ddoc_cache_ev, event, [updated, {NoRevKey, Updated}], 1000),
+    % We pass the rev explicitly so we assert that we're
+    % getting the same original response from the cache
+    ?assertEqual({ok, Updated}, ddoc_cache:open_doc(DbName, ?FOOBAR)),
+    ?assertEqual({ok, DDoc}, ddoc_cache:open_doc(DbName, ?FOOBAR, Rev)),
+    ?assertEqual(2, ets:info(?CACHE, size)).
+
+
+check_upgrade_clause({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    [#entry{key = Key}] = ets:tab2list(?CACHE),
+    gen_server:cast(ddoc_cache_opener, {do_evict, DbName, [?FOOBAR]}),
+    meck:wait(ddoc_cache_ev, event, [update_noop, Key], 1000).
+
+
+rand_string() ->
+    Bin = crypto:rand_bytes(8),
+    to_hex(Bin, []).
+
+
+to_hex(<<>>, Acc) ->
+    list_to_binary(lists:reverse(Acc));
+to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
+    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
+
+
+hexdig(C) when C >= 0, C =< 9 ->
+    C + $0;
+hexdig(C) when C >= 10, C =< 15 ->
+    C + $A - 10.
\ No newline at end of file
diff --git a/src/ddoc_cache/test/ddoc_cache_remove_test.erl b/src/ddoc_cache/test/ddoc_cache_remove_test.erl
new file mode 100644
index 0000000..7596b99
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_remove_test.erl
@@ -0,0 +1,206 @@
+% 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.
+
+-module(ddoc_cache_remove_test).
+
+
+-export([
+    recover/1
+]).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("mem3/include/mem3.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include("ddoc_cache_test.hrl").
+
+
+recover(DbName) ->
+    {ok, #doc{body = {Body}}} = fabric:open_doc(DbName, ?CUSTOM, [?ADMIN_CTX]),
+    case couch_util:get_value(<<"status">>, Body) of
+        <<"ok">> ->
+            {ok, yay};
+        <<"not_ok">> ->
+            {ruh, roh};
+        <<"error">> ->
+            erlang:error(thpppt)
+    end.
+
+
+start_couch() ->
+    Ctx = ddoc_cache_tutil:start_couch(),
+    meck:new(ddoc_cache_ev, [passthrough]),
+    Ctx.
+
+
+stop_couch(Ctx) ->
+    meck:unload(),
+    ddoc_cache_tutil:stop_couch(Ctx).
+
+
+check_refresh_test_() ->
+    {
+        setup,
+        fun start_couch/0,
+        fun stop_couch/1,
+        {with, [
+            fun remove_ddoc/1,
+            fun remove_ddoc_rev/1,
+            fun remove_ddoc_rev_only/1,
+            fun remove_custom_not_ok/1,
+            fun remove_custom_error/1
+        ]}
+    }.
+
+
+remove_ddoc({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?FOOBAR),
+    ?assertEqual(1, ets:info(?CACHE, size)),
+    [#entry{key = Key, val = DDoc}] = ets:tab2list(?CACHE),
+    NewDDoc = DDoc#doc{
+        deleted = true,
+        body = {[]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [removed, Key], 1000),
+    ?assertMatch({not_found, deleted}, ddoc_cache:open_doc(DbName, ?FOOBAR)),
+    ?assertEqual(0, ets:info(?CACHE, size)).
+
+
+remove_ddoc_rev({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?VDU),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?VDU, Rev),
+    [#entry{key = Key, val = DDoc, pid = Pid}] = ets:tab2list(?CACHE),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"an">>, <<"update">>}]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [update_noop, Key], 1000),
+    % Compact the database so that the old rev is removed
+    lists:foreach(fun(Shard) ->
+        do_compact(Shard#shard.name)
+    end, mem3:local_shards(DbName)),
+    % Trigger a refresh rather than wait for the timeout
+    ddoc_cache_entry:refresh(Pid),
+    meck:wait(ddoc_cache_ev, event, [removed, Key], 1000),
+    ?assertMatch(
+            {{not_found, missing}, _},
+            ddoc_cache:open_doc(DbName, ?VDU, Rev)
+        ),
+    ?assertEqual(0, ets:info(?CACHE, size)).
+
+
+remove_ddoc_rev_only({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    Rev = ddoc_cache_tutil:get_rev(DbName, ?VDU),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?VDU),
+    {ok, _} = ddoc_cache:open_doc(DbName, ?VDU, Rev),
+    % Relying on the sort order of keys to keep
+    % these lined up for testing
+    [
+        #entry{key = NoRevKey, val = DDoc, pid = NoRevPid},
+        #entry{key = RevKey, val = DDoc, pid = RevPid}
+    ] = lists:sort(ets:tab2list(?CACHE)),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"new">>, <<"awesomeness">>}]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [updated, '_'], 1000),
+    meck:wait(ddoc_cache_ev, event, [update_noop, RevKey], 1000),
+    % Compact the database so that the old rev is removed
+    lists:foreach(fun(Shard) ->
+        do_compact(Shard#shard.name)
+    end, mem3:local_shards(DbName)),
+    % Trigger a refresh rather than wait for the timeout
+    ddoc_cache_entry:refresh(NoRevPid),
+    ddoc_cache_entry:refresh(RevPid),
+    meck:wait(ddoc_cache_ev, event, [update_noop, NoRevKey], 1000),
+    meck:wait(ddoc_cache_ev, event, [removed, RevKey], 1000),
+    ?assertMatch({ok, _}, ddoc_cache:open_doc(DbName, ?VDU)),
+    ?assertMatch(
+            {{not_found, missing}, _},
+            ddoc_cache:open_doc(DbName, ?VDU, Rev)
+        ),
+    ?assertEqual(1, ets:info(?CACHE, size)).
+
+remove_custom_not_ok({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    init_custom_ddoc(DbName),
+    {ok, _} = ddoc_cache:open_custom(DbName, ?MODULE),
+    [#entry{key = Key}] = ets:tab2list(?CACHE),
+    {ok, DDoc} = fabric:open_doc(DbName, ?CUSTOM, [?ADMIN_CTX]),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"status">>, <<"not_ok">>}]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [removed, Key], 1000),
+    ?assertEqual({ruh, roh}, ddoc_cache:open_custom(DbName, ?MODULE)),
+    ?assertEqual(0, ets:info(?CACHE, size)).
+
+
+remove_custom_error({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+    init_custom_ddoc(DbName),
+    {ok, _} = ddoc_cache:open_custom(DbName, ?MODULE),
+    [#entry{key = Key}] = ets:tab2list(?CACHE),
+    {ok, DDoc} = fabric:open_doc(DbName, ?CUSTOM, [?ADMIN_CTX]),
+    NewDDoc = DDoc#doc{
+        body = {[{<<"status">>, <<"error">>}]}
+    },
+    {ok, _} = fabric:update_doc(DbName, NewDDoc, [?ADMIN_CTX]),
+    meck:wait(ddoc_cache_ev, event, [removed, Key], 1000),
+    ?assertError(thpppt, ddoc_cache:open_custom(DbName, ?MODULE)),
+    ?assertEqual(0, ets:info(?CACHE, size)).
+
+
+init_custom_ddoc(DbName) ->
+    Body = {[{<<"status">>, <<"ok">>}]},
+    {ok, Doc} = fabric:open_doc(DbName, ?CUSTOM, [?ADMIN_CTX]),
+    NewDoc = Doc#doc{body = Body},
+    {ok, _} = fabric:update_doc(DbName, NewDoc, [?ADMIN_CTX]).
+
+
+do_compact(ShardName) ->
+    {ok, Db} = couch_db:open_int(ShardName, []),
+    try
+        {ok, Pid} = couch_db:start_compact(Db),
+        Ref = erlang:monitor(process, Pid),
+        receive
+            {'DOWN', Ref, _, _, _} ->
+                ok
+        end
+    after
+        couch_db:close(Db)
+    end,
+    wait_for_compaction(ShardName).
+
+
+wait_for_compaction(ShardName) ->
+    {ok, Db} = couch_db:open_int(ShardName, []),
+    CompactRunning = try
+        {ok, Info} = couch_db:get_db_info(Db),
+        couch_util:get_value(compact_running, Info)
+    after
+        couch_db:close(Db)
+    end,
+    if not CompactRunning -> ok; true ->
+        timer:sleep(100),
+        wait_for_compaction(ShardName)
+    end.
\ No newline at end of file
diff --git a/src/ddoc_cache/src/ddoc_cache_util.erl b/src/ddoc_cache/test/ddoc_cache_test.hrl
similarity index 59%
rename from src/ddoc_cache/src/ddoc_cache_util.erl
rename to src/ddoc_cache/test/ddoc_cache_test.hrl
index fb3c0b9..73f7bc2 100644
--- a/src/ddoc_cache/src/ddoc_cache_util.erl
+++ b/src/ddoc_cache/test/ddoc_cache_test.hrl
@@ -10,25 +10,17 @@
 % License for the specific language governing permissions and limitations under
 % the License.
 
--module(ddoc_cache_util).
 
+-define(CACHE, ddoc_cache_entries).
+-define(LRU, ddoc_cache_lru).
+-define(OPENERS, ddoc_cache_openers).
 
--export([
-    new_uuid/0
-]).
+-define(FOOBAR, <<"_design/foobar">>).
+-define(VDU, <<"_design/vdu">>).
+-define(CUSTOM, <<"_design/custom">>).
 
-
-new_uuid() ->
-    to_hex(crypto:rand_bytes(16), []).
-
-
-to_hex(<<>>, Acc) ->
-    list_to_binary(lists:reverse(Acc));
-to_hex(<<C1:4, C2:4, Rest/binary>>, Acc) ->
-    to_hex(Rest, [hexdig(C1), hexdig(C2) | Acc]).
-
-
-hexdig(C) when C >= 0, C =< 9 ->
-    C + $0;
-hexdig(C) when C >= 10, C =< 15 ->
-    C + $A - 10.
+-record(entry, {
+    key,
+    val,
+    pid
+}).
diff --git a/src/ddoc_cache/test/ddoc_cache_tutil.erl b/src/ddoc_cache/test/ddoc_cache_tutil.erl
new file mode 100644
index 0000000..cdd372b
--- /dev/null
+++ b/src/ddoc_cache/test/ddoc_cache_tutil.erl
@@ -0,0 +1,84 @@
+% 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.
+
+-module(ddoc_cache_tutil).
+
+
+-compile(export_all).
+
+
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("couch/include/couch_eunit.hrl").
+
+
+start_couch() ->
+    %purge_modules(),
+    Ctx = test_util:start_couch(?CONFIG_CHAIN, [chttpd, ddoc_cache]),
+    TmpDb = ?tempdb(),
+    ok = fabric:create_db(TmpDb, [{q, "1"}, {n, "1"}]),
+    {ok, _} = fabric:update_docs(TmpDb, ddocs(), [?ADMIN_CTX]),
+    {TmpDb, Ctx}.
+
+
+stop_couch({_TmpDb, Ctx}) ->
+    test_util:stop_couch(Ctx).
+
+
+clear() ->
+    application:stop(ddoc_cache),
+    application:start(ddoc_cache).
+
+
+get_rev(DbName, DDocId) ->
+    {_, Ref} = erlang:spawn_monitor(fun() ->
+        {ok, #doc{revs = Revs}} = fabric:open_doc(DbName, DDocId, [?ADMIN_CTX]),
+        {Depth, [RevId | _]} = Revs,
+        exit({Depth, RevId})
+    end),
+    receive
+        {'DOWN', Ref, _, _, Rev} -> Rev
+    end.
+
+
+ddocs() ->
+    FooBar = #doc{
+        id = <<"_design/foobar">>,
+        body = {[
+            {<<"foo">>, <<"bar">>}
+        ]}
+    },
+    VDU = #doc{
+        id = <<"_design/vdu">>,
+        body = {[
+            {<<"validate_doc_update">>, <<"function(doc) {return;}">>}
+        ]}
+    },
+    Custom = #doc{
+        id = <<"_design/custom">>,
+        body = {[
+            {<<"status">>, <<"ok">>},
+            {<<"custom">>, <<"hotrod">>}
+        ]}
+    },
+    [FooBar, VDU, Custom].
+
+
+purge_modules() ->
+    case application:get_key(ddoc_cache, modules) of
+        {ok, Mods} ->
+            lists:foreach(fun(Mod) ->
+                code:delete(Mod),
+                code:purge(Mod)
+            end, Mods);
+        undefined ->
+            ok
+    end.

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