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From dav...@apache.org
Subject [1/5] couch commit: updated refs/heads/COUCHDB-3287-pluggable-storage-engines to 0f4e1a7 [Forced Update!]
Date Thu, 02 Mar 2017 17:04:07 GMT
Repository: couchdb-couch
Updated Branches:
  refs/heads/COUCHDB-3287-pluggable-storage-engines 09a4de61e -> 0f4e1a7fd (forced update)


Ensure deterministic revisions for attachments

This re-fixes a corner case when recreating a document with an
attachment in a single multipart request. Since we don't detect that we
need a new revision until after the document has been serialized we need
to be able to deserialize the body so that we can generate the same
revisions regardless of the contents of the database. If we don't do
this then we end up including information from the position of the
attachment on disk in the revision calculation which can introduce
branches in the revision tree.

I've left this as a separate commit from the pluggable storage engine
work so that its called out clearly for us to revisit.

COUCHDB-3255


Project: http://git-wip-us.apache.org/repos/asf/couchdb-couch/repo
Commit: http://git-wip-us.apache.org/repos/asf/couchdb-couch/commit/0f4e1a7f
Tree: http://git-wip-us.apache.org/repos/asf/couchdb-couch/tree/0f4e1a7f
Diff: http://git-wip-us.apache.org/repos/asf/couchdb-couch/diff/0f4e1a7f

Branch: refs/heads/COUCHDB-3287-pluggable-storage-engines
Commit: 0f4e1a7fdb3a3816185d2c1cebf4439a4c359872
Parents: 414880e
Author: Paul J. Davis <paul.joseph.davis@gmail.com>
Authored: Wed Feb 8 07:25:37 2017 -0600
Committer: Paul J. Davis <paul.joseph.davis@gmail.com>
Committed: Thu Mar 2 11:03:55 2017 -0600

----------------------------------------------------------------------
 src/couch_bt_engine.erl  | 10 +++++++++-
 src/couch_db.erl         | 12 +-----------
 src/couch_db_updater.erl | 12 +++++++++++-
 3 files changed, 21 insertions(+), 13 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/couchdb-couch/blob/0f4e1a7f/src/couch_bt_engine.erl
----------------------------------------------------------------------
diff --git a/src/couch_bt_engine.erl b/src/couch_bt_engine.erl
index cf31b09..3b31341 100644
--- a/src/couch_bt_engine.erl
+++ b/src/couch_bt_engine.erl
@@ -324,7 +324,15 @@ serialize_doc(#st{} = St, #doc{} = Doc) ->
     SummaryBin = ?term_to_bin({Body, Atts}),
     Md5 = couch_crypto:hash(md5, SummaryBin),
     Data = couch_file:assemble_file_chunk(SummaryBin, Md5),
-    Doc#doc{body = Data}.
+    % TODO: This is a terrible hack to get around the issues
+    %       in COUCHDB-3255. We'll need to come back and figure
+    %       out a better approach to handling the case when we
+    %       need to generate a new revision id after the doc
+    %       has been serialized.
+    Doc#doc{
+        body = Data,
+        meta = [{comp_body, Body} | Doc#doc.meta]
+    }.
 
 
 write_doc_body(St, #doc{} = Doc) ->

http://git-wip-us.apache.org/repos/asf/couchdb-couch/blob/0f4e1a7f/src/couch_db.erl
----------------------------------------------------------------------
diff --git a/src/couch_db.erl b/src/couch_db.erl
index f5281a3..ca63a40 100644
--- a/src/couch_db.erl
+++ b/src/couch_db.erl
@@ -945,7 +945,7 @@ prep_and_validate_replicated_updates(Db, [Bucket|RestBuckets], [OldInfo|RestOldI
 
 
 
-new_revid(#doc{body=Body0, revs={OldStart,OldRevs}, atts=Atts, deleted=Deleted}) ->
+new_revid(#doc{body=Body, revs={OldStart,OldRevs}, atts=Atts, deleted=Deleted}) ->
     DigestedAtts = lists:foldl(fun(Att, Acc) ->
         [N, T, M] = couch_att:fetch([name, type, md5], Att),
         case M == <<>> of
@@ -953,16 +953,6 @@ new_revid(#doc{body=Body0, revs={OldStart,OldRevs}, atts=Atts, deleted=Deleted})
             false -> [{N, T, M} | Acc]
         end
     end, [], Atts),
-    Body = case Body0 of
-        {summary, [_Len, _Md5, BodyAtts], _SizeInfo, _AttsFd} ->
-            {CompBody, _CompAtts} = binary_to_term(BodyAtts),
-            couch_compress:decompress(CompBody);
-        {summary, [_Len, BodyAtts], _SizeInfo, _AttsFd} ->
-            {CompBody, _CompAtts} = binary_to_term(BodyAtts),
-            couch_compress:decompress(CompBody);
-        Else ->
-            Else
-    end,
     case DigestedAtts of
         Atts2 when length(Atts) =/= length(Atts2) ->
             % We must have old style non-md5 attachments

http://git-wip-us.apache.org/repos/asf/couchdb-couch/blob/0f4e1a7f/src/couch_db_updater.erl
----------------------------------------------------------------------
diff --git a/src/couch_db_updater.erl b/src/couch_db_updater.erl
index cbd2e79..86a0300 100644
--- a/src/couch_db_updater.erl
+++ b/src/couch_db_updater.erl
@@ -520,7 +520,17 @@ merge_rev_tree(OldInfo, NewDoc, Client, Limit, false)
             % Update the new doc based on revisions in OldInfo
             #doc_info{revs=[WinningRev | _]} = couch_doc:to_doc_info(OldInfo),
             #rev_info{rev={OldPos, OldRev}} = WinningRev,
-            NewRevId = couch_db:new_revid(NewDoc#doc{revs={OldPos, [OldRev]}}),
+            Body = case couch_util:get_value(comp_body, NewDoc#doc.meta) of
+                CompBody when is_binary(CompBody) ->
+                    couch_compress:decompress(CompBody);
+                _ ->
+                    NewDoc#doc.body
+            end,
+            RevIdDoc = NewDoc#doc{
+                revs = {OldPos, [OldRev]},
+                body = Body
+            },
+            NewRevId = couch_db:new_revid(RevIdDoc),
             NewDoc2 = NewDoc#doc{revs={OldPos + 1, [NewRevId, OldRev]}},
 
             % Merge our modified new doc into the tree


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