WP9 iMarine Data Management Software Consolidated Specifications

Overview

gCube is a software suite equipped with a rich array of services capable to interface with data sources having different characteristics both in terms of data types these sources offers (e.g. from document data, to statistical, biodiversity, and semantic data - see Data Access and Storage Facilities) and the heterogeneity of data belonging to the same type.

The goal of these specifications is to deal with the above heterogeneity and provide unified views over diverse data items through a number of dedicated services. To meet this goal a number of components have been designed.

This page outlines the design rationale and high-level architecture of such components.

Key Features

The WP9 facilities provide the following key features:

Data Access and Storage

Uniform model and access API over structured data: dynamically pluggable architecture of model and API transformations to and from internal and external data sources;; plugins for document, biodiversity, statistical, and semantic data sources, including sources with custom APIs and standards-based APIs;

Fine-grained access to structured data: horizontal and vertical filtering based on pattern matching;; URI-based resolution;; in-place remote updates;

Scalable access to structured data: autonomic service replication with infrastructure-wide load balancing;

Efficient and scalable storage of structured data: based on graph database technology;

Rich tooling for client and plugin development: high-level Java APIs for service access;; DSLs for pattern construction and stream manipulations;

Remote viewing mechanisms over structured data: “passive” views based on arbitrary access filters;; dynamically pluggable architecture of custom view management schemes;

Uniform modelling and access API over document data: rich descriptions of document content, metadata, annotations, parts, and alternatives; transformations from model and API of key document sources, including OAI providers;; high-level client APIs for model construction and remote access;

Uniform modelling and access API over semantic data: tree-views over RDF graph data;; transformations from model and API of key document sources, including SPARQL endpoints;

Uniform modelling and access over biodiversity data: access API tailored to biodiversity data sources;; dynamically pluggable architecture of transformations from external sources of biodiversity data;; plugins for key biodiversity data sources, including OBIS, GBIF and Catalogue of Life;

Efficient and scalable storage of files: unstructured storage back-end based on MongoDB for replication and high availability, automatic balancing for changes in load and data distribution, no single points of failure, data sharding;; no intrinsic upper bound on file size;

Standards-based and structured storage of files: POSIX-like client API;; support for hierarchical folder structures;

Data Transfer

Point to Point transfer: one writer-one reader as core functionality

Produce only what is requested: a producer-consumer model that blocks when needed and reduces the unnecessary data transfers

Intuitive stream and iterator based interface: simplified usage with reasonable default behavior for common use cases and a variety of features for increased usability and flexibility

Multiple protocols support: data transfer currently supports the following protocols: tcp and http

HTTP Broker Servlet: transfer results are exposed as an http endpoint

Reliable data transfer between Infrastructure Data Sources and Data Storages: by exploiting the uniform access interfaces provided by gCube

Structured and unstructured Data Transfer: both Tree based and File based transfer to cover all possible use-cases

Transfers to local nodes for data staging: data staging for particular use cases can be enabled on each node of the infrastructure

Advanced transfer scheduling and transfer optimization: a dedicated gCube service responsible for data transfer scheduling and transfer optimization

Transfer statistics availability: transfers are logged by the system and made available to interested consumers.

Data enrichment support: species occurrence data enrichment with environmental data dynamically acquired by data providers; data provenance recording

Standard-based data presentation: OGC standard-based Geospatial data presentation

Data Assessment, Harmonisation and Certification Facilities

Workflow-oriented tabular data manipulation: user-defined definition and execution of workflows of data manipulation steps; rich array of data manipulation facilities offered 'as-a-Service'; rich array of data mining facilities offered 'as-a-Service'; rich array of data visualisation facilities offered 'as-a-Service'

Reference-data management support: uniform model for reference-data representation including versioning and provenance

Components

Data Access and Storage

Tree-Based Access: groups components that implement access and storage facilities for structured data of arbitrary semantics, origin, and size; The subsystem focuses on uniform access to structured data for cross-domain processes, including but not limited to system processes; A subset of the components build on the generic interface and specialise it to data with domain-specific semantics, including document data and semantic data

Biodiversity Access: groups components that implement access and storage facilities for structured data with biodiversity semantics and arbitrary origin and size; The subsystem focuses on uniform access to biodiversity data for domain-specific processes and feeds into the Tree-Based Access subsystem

File-Based Access: groups components that implement access and storage facilities for unstructured data with arbitrary semantics and size; The subsystem focuses on storage and retrieval of bytestreams for arbitrary processes, including but not limited to system processes

Data Transfer

Result Set components: this family of components provide a common data transfer mechanism that aims to establish high throughput point to point on demand communication. It has been designed as a core functionality of the overall system and it can be considered as well the building block for the Data Transfer Scheduler & Agent components

Data Transfer Scheduler & Agent components: this family of components guarantees VO/VRE Administrators the possibility to transfer data among Data Sources and Data Storages. It can be exploited as well by any client or web services to implements data movement between infrastructure nodes