[/map {"- map/map "}) [/map/topicref {"- map/topicref "}) [/map/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicmeta/navtitle {"- topic/navtitle "}) Introduction (navtitle][/map/topicref/topicmeta/linktext {"- map/linktext "}) Introduction (linktext][/map/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This section lists administrative tasks and tools that you can use to do these tasks. (shortdesc] (topicmeta][/map/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) List of administrative tasks (navtitle][/map/topicref/topicref/topicmeta/linktext {"- map/linktext "}) List of administrative tasks (linktext][/map/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This topic lists top-level administrator tasks for Studio, the Dgraph, the Dgraph HDFS Agent, and the Dgraph Gateway. (shortdesc] (topicmeta] (topicref] (topicref] [/map/topicref {"- map/topicref "}) [/map/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicmeta/navtitle {"- topic/navtitle "}) Cluster Architecture (navtitle][/map/topicref/topicmeta/linktext {"- map/linktext "}) Cluster Architecture (linktext][/map/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This section describes the architecture of a Big Data Discovery cluster. (shortdesc] (topicmeta][/map/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Cluster components (navtitle][/map/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Cluster components (linktext][/map/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) A Big Data Discovery cluster is a deployment of Big Data Discovery on multiple machines. Such a deployment can be made up of any number of nodes. (shortdesc] (topicmeta][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Overview (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Overview (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This topic provides an overview of the components in a Big Data Discovery cluster. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Diagram of a Big Data Discovery Cluster (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Diagram of a Big Data Discovery Cluster (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This diagram illustrates a cluster of Big Data Discovery nodes deployed on top of an existing Hadoop cluster. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Cluster of Dgraph nodes (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Cluster of Dgraph nodes (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) A typical BDD cluster deployment includes a set of Dgraph nodes. Together, these nodes form a Dgraph cluster within the BDD cluster. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Leader and follower Dgraph nodes (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Leader and follower Dgraph nodes (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) Dgraph nodes can have two roles within the Dgraph cluster: leader and follower. (shortdesc] (topicmeta] (topicref] (topicref][/map/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Cluster behavior (navtitle][/map/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Cluster behavior (linktext][/map/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) There are many possible scenarios of Big Data Discovery deployment clusters. This section describes how the BDD cluster behaves and maintains enhanced availability in various scenarios, such as during node startup, updates to the Dgraph databases, or to individual node failures. (shortdesc] (topicmeta][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Load balancing and routing requests (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Load balancing and routing requests (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This topic discusses the load balancing and routing requests from Studio nodes to the Dgraph nodes in Oracle Big Data Discovery. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) How session affinity is used (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) How session affinity is used (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) When a WebLogic Server node hosting Studio and Dgraph Gateway receives a client request, it routes the request to a Dgraph node using session affinity, based on the session ID specified in the header of the request. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Startup of Dgraph nodes (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Startup of Dgraph nodes (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) Once the Big Data Discovery cluster is started, it activates the Dgraph processes on a subset of the nodes that are hosting the Dgraph instances. This topic discusses the behavior of the Dgraph nodes at startup. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) How updates are processed (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) How updates are processed (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) In a Dgraph cluster, updates to the records or configuration in a specific Dgraph database are routed to that database's leader Dgraph node. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) Role of ZooKeeper (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) Role of ZooKeeper (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) The ZooKeeper utility provides configuration and state management and distributed coordination services to Dgraph nodes of the Big Data Discovery cluster. It ensures high availability of the query processing by the Dgraph nodes in the cluster. (shortdesc] (topicmeta] (topicref][/map/topicref/topicref/topicref {"- map/topicref "}) [/map/topicref/topicref/topicref/topicmeta {"- map/topicmeta "}) [/map/topicref/topicref/topicref/topicmeta/navtitle {"- topic/navtitle "}) How high availability is achieved (navtitle][/map/topicref/topicref/topicref/topicmeta/linktext {"- map/linktext "}) How high availability is achieved (linktext][/map/topicref/topicref/topicref/topicmeta/shortdesc {"- map/shortdesc "}) This topic discusses how the BDD cluster deployment ensures high availability of query-processing. (shortdesc] (topicmeta] (topicref] (topicref] (topicref] (map]