360 likes | 461 Views
In this presentation by Nick Roussopoulos from September 2009, the evolution of data management from structured to unstructured formats is explored. The session dives into how new computing paradigms, defined by Bell's Law, have introduced challenges and opportunities in data integration and usability. Roussopoulos stresses the importance of understanding data structure to enable innovative applications, addressing the growing needs of continuous, interconnected, and complex data management. He proposes the concept of Sibdata as a flexible solution for integrating disparate data sources efficiently.
E N D
The Sibdata Revolution Nick Roussopoulos DCS & UMIACS & Univ. of Maryland September 2009
Data Management: Past to Current • Structured Data • Structured architectures Nick Roussopoulos
Data Management: Huh??? Nick Roussopoulos
The Landscape Bell’s Law:Every decade, a new, lower cost, class of computers emerges, defined by platform, interface, and interconnect • Mainframes 1960s • Minicomputers 1970s • Microcomputers/PCs 1980s • Web-based computing 1990s • Devices (Smart phones, PDAs, wireless sensors, RFID) 2000’s Enabling a new generation of applications that Mandate new data management methods & tools. Nick Roussopoulos
Data Then and Now • The “Data Industrial Revolution”: Data used to be “hand-crafted”, now it’s generated by computers!!! • The Data Integration quagmire: 40 years of continuous successes (sic) and still a long way to the end. • Structure provides crucial understanding for making data usable and leads to discovery/innovation. Nick Roussopoulos
Data Streaming Data Explosion PoS System Barcodes Phones Sensors RFID • Exponential data growth • New challenges: continuous, inter-connected, distributed, physical • Shrinking business cycles • More complex decisions Inventory Transactional Systems Telematics Clickstream Nick Roussopoulos
The Structure Spectrum • Structured data (schema-first) • regular, known, conforming, … • e.g., Relational database • Unstructured data (schema-never) freeform, irregular, • e.g., plain text, images, audio, … • Semi-structured data (schema-later) • Provides structural information, but less constrained. e.g., XML, tagged text/media Nick Roussopoulos
Data Integration • Integration is the ultimate schema-first problem. • Requires complete understanding & disambiguation • Structure (semantics) is both a key enabler and a key impediment here. Nick Roussopoulos
Structured Data: How much • Conventional Wisdom: ~20% of data is structured currently. • Consumer apps, enterprise search, multimedia apps are placing downward pressure on this. Nick Roussopoulos
State of the Art: Integration-in-the-large • Team work, huge & expensive effort, excruciating pain • Extremely long time lag between data generation and availability • Custom-coded implementations that are often unsuccessful • Clearing house of already discovered knowledge (the high overhead is for disambiguating the semantics of the heterogeneous data) Nick Roussopoulos
Future: Integration-in-the-small • End-user, limited in scope, requires training • Continuous as the data sources and equipment evolve • End-user tools are needed • Small cost, enormous opportunity for discovery and innovation Nick Roussopoulos
Sibling Data • Aggregation and naming of disparate data regardless location • Includes actual data, references to external data, queries that generate data, & programs to process data • May include other sibdata • Open vs Closed • Open: continuous accumulation • Closed: fixed snapshot (archival) • Location Independent semantics Nick Roussopoulos
Web search results Nick Roussopoulos
Content vs URL • Content • http://www.michaelmoore.com/ Nick Roussopoulos
Deep-Web Queries SELECT y.title FROM Yahoo_Movies m WHERE m.title like Moore; Nick Roussopoulos
Result vs. Query • Results are associated with the time the query was run • Queries can be captured in sibdata and executed at will; thus the sibdata would be open and captures a different result each time it executes Nick Roussopoulos
Queries to Relational Databases Yahoo_Actors Nick Roussopoulos
Sibdata • Deal with all the data from everywhere & in whatever form they come • Data co-existence no integrated schema, no single warehouse • Expand-as-you-go • Integrate little by little as you need • ETL Data mapping-integrating as you add more data Nick Roussopoulos
Sibdata Properties • Lightweight • Metadata captures the encapsulation, name, and provenance data • Location-independent • Accessible from anywhere • Isolated • Generated with no interference • Durable • Persist until dropped • Secure • Guarantee security defined by the creators and sources • Compose multiple levels of security to its components Nick Roussopoulos
Comparison to Transactions • Transactions • grouping of many actions into an atomic transaction- ACID properties • Substrate: database • Sibdata • Grouping of data into an atomic sibdata – LLADS • Substrate: actions/transactions/data generators Nick Roussopoulos
Sibdata Infrastructure Nick Roussopoulos
Sibdata Servers • Establish a global sibdata ID and name • Creates and maintains metadata with provenance, users, security, etc. • Provides searchable catalog • Provides storage for non-sib compliant data sources • Fault tolerance (replication) Nick Roussopoulos
Sib Protocols • Establish Sibdata protocol • Concurrency-Consistency issues (?) • Sharing of data • Name conventions • Dispute resolution • Distributed Logging • Security Using chits • Group and multi-valued ownership and visibility Nick Roussopoulos
User Interface • Simple OS support • Query Languages • Graphical Languages • ETL tools • Extra functionality • High dimensional indexing • Mining Nick Roussopoulos
Conclusions • Need to build Sib Infrastructure • Refine the sibdata semantics • Refine the security protocols • For data aggregates • User groups • Great opportunities for innovation Nick Roussopoulos
Presentations & Project • 3 X 7 students = 21 presentations ~2 per lecture • Lecture dates • Sep: 15, 22, 29 • Oct: 6, 13, 20, 27 • Nov: 3, 10, 17, 24 • Dec: 1, 8 • Project: Proposal due Sep 29 • Discussion: Every lecture be prepared to give a 2-3 min progress report, papers found, etc. Nick Roussopoulos
Network Data IndependenceHellerstein Berkeley • Physical Data Independence • Decoupling data from layout (not hard coded applications) • Permits reorganization of data w/o affecting the apps • Declarative query languages • Using the schema • Distributed Databases • Transparency hides location from the user who acts as if he is accessing a centralized database • Limited sites- not capable to expand to the mobility of and constant change of the configuration Nick Roussopoulos
table R 1 4 5 6 9 11 3 1 occurrence file Pilars of Data independence • Indexes- offer indirection allowing modification of the underlying structure • Schema based and declarative query languages & optimization Nick Roussopoulos
Sibdata Independence • Encapsulation of dissimilar data • Data can be moved, rearranged, altered • Additional indices on top of Sibdata becomes part of the sibdata • Naming and provenance data are fixed • Do not change to the outside world • Containment information (sibdata encapsulation within other sibdata) is guaranteed Nick Roussopoulos
DHT (Chord) • Data centric distribution • according to content- total data independence • very large number of distributed servers • Configuration changes rapidly (although this may not be really that important) • Fault-tolerance (extra machines) • Limited to single key searches (not range or join queries Nick Roussopoulos
Network Names & Services • Internet Indirection Infrastructure (i3) • Triggers (id,r) where id = global ID and r is an address to forward packets • When a mobile user moves to r’, he modifies his trigger to (id,r’) • It also supports 1-to-n mappings (anycast) • Content Distribution Networks (Akamai) • Replicates heavy data (images, videos) to multiple sites and redirects user accesses to those that are closer (indirection via location independence) Nick Roussopoulos
Relevant DB Technologies • Distributed Aggregation • Monitor networks (collecting stats) • Computing synopses and pass it along • Adaptive execution plans • Feedback to the execution • Commutative tasks to avoid extended delays • Range search over DHT • Trie hashing • Still limited • P2P & Mobile Databases Nick Roussopoulos
Pier: A P2P in situ Query Engine Goals • Massively distributed processing • Scallability • Relaxed consistency (best effort) Architecture • P2P Built on top of DHT • Multicast to all related nodes (lscan) • Pipelining the intermediate results Nick Roussopoulos
Pier Joins • Stored in DHT • Namespace=relation NR, NS • resourceID =Primary Key (PK) • instanceID =tuple # if not a PK • Assume R and S are already DHT hashed using <NR,PKR,1> and <NS,PKS,1> • Symmetric Join building phase • lscan NR and NS eliminate unqualified tuples and not needed attributes • Rehash all above tuples using • namespace NQ • resourceID=R.pkey*S.pkey • Tuples are tagged with relation name • SymmetricJoin Probing phase • Probing in parallel with building (with callbacks) locally • Satisfying tuples are either sent to the Qsite or DHT-ed for the pipelined op • Consumes a lot of bandwidth Nick Roussopoulos
Better Joins • Fetch Matches • Hash only S • lscan R and fetch NS tuples • Rewriting Join using 2-way semijoin • Project R & R on their PK and joining attribute • Do symmetric join on these projections • Rewriting Join using Bloom filters • Create and DHT the Bloom filters • Do lscan and access the Bloom filter to eliminate not joinable tuples Nick Roussopoulos
Conclusions for Pier • P2P bring massive parallelism • Repetitive data comparison over DHT brings along massive waste of bandwidth • Smarter in situ distillation (2-way semijoins, Bloom filters) work better Nick Roussopoulos