Allow for mixed db record definitions

This change is to account for differences in the #db record when a
cluster is operating in a mixed version state (i.e., when running a
rolling reboot to upgrade).

There are only a few operations that are valid on #db records that are
shared between nodes so rather than attempt to map the entire API
between the old and new records we're limiting to just the required API
calls.

COUCHDB-3288

2 files changed, 70 insertions, 5 deletions

diff --git a/src/couch/src/couch_db.erl b/src/couch/src/couch_db.erl
index 26d18c8e7..5e720c284 100644
--- a/src/couch/src/couch_db.erl
+++ b/src/couch/src/couch_db.erl
@@ -219,7 +219,9 @@ is_system_db(#db{options = Options}) ->
 is_clustered(#db{main_pid = nil}) ->
     true;
 is_clustered(#db{}) ->
-    false.
+    false;
+is_clustered(?NEW_PSE_DB = Db) ->
+    ?PSE_DB_MAIN_PID(Db) == undefined.
 
 ensure_full_commit(#db{main_pid=Pid, instance_start_time=StartTime}) ->
     ok = gen_server:call(Pid, full_commit, infinity),
@@ -232,6 +234,8 @@ ensure_full_commit(Db, RequiredSeq) ->
 
 close(#db{fd_monitor=Ref}) ->
     erlang:demonitor(Ref, [flush]),
+    ok;
+close(?NEW_PSE_DB) ->
     ok.
 
 is_idle(#db{compactor_pid=nil, waiting_delayed_commit=nil} = Db) ->
@@ -414,7 +418,9 @@ get_update_seq(#db{update_seq=Seq})->
     Seq.
 
 get_user_ctx(#db{user_ctx = UserCtx}) ->
-    UserCtx.
+    UserCtx;
+get_user_ctx(?NEW_PSE_DB = Db) ->
+    ?PSE_DB_USER_CTX(Db).
 
 get_purge_seq(#db{}=Db) ->
     couch_db_header:purge_seq(Db#db.header).
@@ -632,7 +638,9 @@ get_members(#db{security=SecProps}) ->
         couch_util:get_value(<<"readers">>, SecProps, {[]})).
 
 get_security(#db{security=SecProps}) ->
-    {SecProps}.
+    {SecProps};
+get_security(?NEW_PSE_DB = Db) ->
+    {?PSE_DB_SECURITY(Db)}.
 
 set_security(#db{main_pid=Pid}=Db, {NewSecProps}) when is_list(NewSecProps) ->
     check_is_admin(Db),
@@ -681,7 +689,9 @@ set_revs_limit(_Db, _Limit) ->
     throw(invalid_revs_limit).
 
 name(#db{name=Name}) ->
-    Name.
+    Name;
+name(?NEW_PSE_DB = Db) ->
+    ?PSE_DB_NAME(Db).
 
 compression(#db{compression=Compression}) ->
     Compression.
diff --git a/src/couch/src/couch_db_int.hrl b/src/couch/src/couch_db_int.hrl
index fc739b781..da1e45d75 100644
--- a/src/couch/src/couch_db_int.hrl
+++ b/src/couch/src/couch_db_int.hrl
@@ -35,4 +35,59 @@
     compression,
     before_doc_update = nil, % nil | fun(Doc, Db) -> NewDoc
     after_doc_read = nil    % nil | fun(Doc, Db) -> NewDoc
-}).
\ No newline at end of file
+}).
+
+
+-record(new_pse_db, {
+    vsn,
+    name,
+    filepath,
+
+    engine = {couch_bt_engine, undefined},
+
+    main_pid = nil,
+    compactor_pid = nil,
+
+    committed_update_seq,
+
+    instance_start_time, % number of microsecs since jan 1 1970 as a binary string
+
+    user_ctx = #user_ctx{},
+    security = [],
+    validate_doc_funs = undefined,
+
+    before_doc_update = nil, % nil | fun(Doc, Db) -> NewDoc
+    after_doc_read = nil,    % nil | fun(Doc, Db) -> NewDoc
+
+    waiting_delayed_commit = nil,
+
+    options = [],
+    compression
+}).
+
+
+-define(NEW_PSE_DB, {
+    db,
+    _, % Version
+    _, % Name
+    _, % FilePath
+    _, % Engine
+    _, % MainPid
+    _, % CompactorPid
+    _, % CommittedUpdateSeq
+    _, % InstanceStartTime
+    _, % UserCtx
+    _, % Security
+    _, % ValidateDocFuns
+    _, % BeforeDocUpdate
+    _, % AfterDocRead
+    _, % WaitingDelayedCommit
+    _, % Options
+    _  % Compression
+}).
+
+
+-define(PSE_DB_NAME(Db), element(3, Db)).
+-define(PSE_DB_MAIN_PID(Db), element(6, Db)).
+-define(PSE_DB_USER_CTX(Db), element(10, Db)).
+-define(PSE_DB_SECURITY(Db), element(11, Db)).