Merge branch 'devel' of ssh://github.com/triAGENS/ArangoDB into devel

CHANGELOG

@@ -1,6 +1,9 @@
 v2.2.1 (XXXX-XX-XX)
 -------------------
 
+* fixed hanging write-ahead log recovery for certain cases that involved dropping
+  databases
+
 * fixed issue with --check-version: when creating a new database the check failed
 
 * added startup option `--wal.suppress-shape-information`

UnitTests/HttpInterface/api-cursor-spec.rb

@@ -346,14 +346,18 @@ describe ArangoDB do
         doc.parsed_response['count'].should eq(5)
         doc.parsed_response['result'].length.should eq(1)
 
-        sleep 24 # this should delete the cursor on the server
+        # after this, the cursor might expire eventually
-        doc = ArangoDB.log_put("#{prefix}-create-ttl", cmd)
+        # the problem is that we cannot exactly determine the point in time
-        
+        # when it really vanishes, as this depends on thread scheduling, state     
-        doc.code.should eq(404)
+        # of the cleanup thread etc.
-        doc.headers['content-type'].should eq("application/json; charset=utf-8")
+
-        doc.parsed_response['error'].should eq(true)
+        # sleep 10 # this should delete the cursor on the server
-        doc.parsed_response['errorNum'].should eq(1600)
+        # doc = ArangoDB.log_put("#{prefix}-create-ttl", cmd)
-        doc.parsed_response['code'].should eq(404)
+        # doc.code.should eq(404)
+        # doc.headers['content-type'].should eq("application/json; charset=utf-8")
+        # doc.parsed_response['error'].should eq(true)
+        # doc.parsed_response['errorNum'].should eq(1600)
+        # doc.parsed_response['code'].should eq(404)
       end
       
       it "creates a cursor that will not expire" do

arangod/Wal/LogfileManager.h

@@ -1002,11 +1002,16 @@ namespace triagens {
 /// Setting this variable to *true* will lead to no shape information being 
 /// written into the write-ahead logfiles for documents or edges. While this is 
 /// a good optimization for a single server to save memory (and disk space), it
-/// it will effectively disable using the write-ahead log as a source for 
+/// it will effectively disable using the write-ahead log as a reliable source 
-/// replicating changes to other servers. 
+/// for replicating changes to other servers. A master server with this option
+/// set to *true* will not be able to fully reproduce the structure of saved
+/// documents after a collection has been deleted. In case a replication client
+/// requests a document for which the collection is already deleted, the master
+/// will return an empty document. Note that this only affects replication and
+/// not normal operation on the master.
 ///
 /// **Do not set this variable to *true* on a server that you plan to use as a 
-/// replication master!**
+/// replication master** 
 /// @endDocuBlock
 ////////////////////////////////////////////////////////////////////////////////