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

Documentation/Books/Users/ReleaseNotes/NewFeatures30.mdpp

@@ -238,6 +238,25 @@ more efficiently carry out operations with multiple documents than their single-
 equivalents, which required one HTTP request per operation. With the batch operations,
 the HTTP request/response overhead can be amortized across multiple operations.
 
+!SECTION Persistent indexes
+
+ArangoDB 3.0 provides an experimental persistent index feature. Persistent indexes store
+the index values on disk instead of in-memory only. This means the indexes do not need
+to be rebuilt in-memory when a collection is loaded or reloaded, which should improve
+collection loading times. 
+
+The persistent indexes in ArangoDB are based on the RocksDB engine.
+To create a persistent index for a collection, create an index of type "rocksdb" as
+follows:
+
+```js
+db.mycollection.ensureIndex({ type: "rocksdb", fields: [ "fieldname" ]});
+```
+
+The persistent indexes are sorted, so they allow equality lookups and range queries.
+Note that the feature is still highly experimental and has some known deficiencies. It 
+will be finalized until the release of the 3.0 stable version.
+
 !SECTION Upgraded V8 version
 
 The V8 engine that is used inside ArangoDB to execute JavaScript code has been upgraded from

arangod/Aql/ClusterBlocks.cpp

@@ -930,7 +930,7 @@ bool DistributeBlock::getBlockForClient(size_t atLeast, size_t atMost,
 
     AqlItemBlock* cur = _buffer.at(_index);
 
-    while (_pos < cur->size() && buf.at(clientId).size() < atLeast) {
+    while (_pos < cur->size() && buf.at(clientId).size() < atMost) {
       // this may modify the input item buffer in place
       size_t id = sendToClient(cur);
 

arangod/Cluster/ClusterInfo.cpp

@@ -1547,7 +1547,6 @@ int ClusterInfo::ensureIndexCoordinator(
       "Plan/Collections/" + databaseName + "/" + collectionID;
 
   AgencyCommResult previous = ac.getValues2(key);
-  bool usePrevious = true;
 
   velocypack::Slice collection =
     previous.slice()[0].get(std::vector<std::string>(
@@ -1676,11 +1675,7 @@ int ClusterInfo::ensureIndexCoordinator(
     }
 
     AgencyCommResult result;
-    if (usePrevious) {
-      result = ac.casValue(key, collection, newBuilder.slice(), 0.0, 0.0);
-    } else {  // only when there is no previous value
-      result = ac.setValue(key, newBuilder.slice(), 0.0);
-    }
+    result = ac.casValue(key, collection, newBuilder.slice(), 0.0, 0.0);
 
     if (!result.successful()) {
       return setErrormsg(TRI_ERROR_CLUSTER_COULD_NOT_CREATE_COLLECTION_IN_PLAN,

arangod/Cluster/ClusterInfo.h

@@ -329,7 +329,7 @@ class CollectionInfo {
           for (auto const& serverSlice: VPackArrayIterator(shardSlice.value)) {
             servers.push_back(serverSlice.copyString());
           }
-          (*res).insert(make_pair(shardSlice.key.copyString(), servers));
+          (*res).insert(make_pair(shard, servers));
         }
       }
     }