XQuery+Cloud

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XQuery+Cloud Daniela Florescu Oracle 

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My personal history, © PhD in object-oriented query processing/optimization © Loved the database theory and practice (relational, object-oriented, semi-structured) © Got really interested in it, and thought it was important... © ,...then | joined Oracle. 

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... after 4 years in Oracle © Applications are the rea//y important issue = How to develop, deploy, maintain, evolve, customize = Databases are a side effect ® Customers are educated to think they need them ® DB are only useful as part of a general application architecture © Customer is the king ® If they don’t make $$$, you don‘t either © Customers are | --)/ building apps right now 

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Agenda © Current pain in building apps © What can XQuery do for customers ? ® What can the Cloud) do for customers ? © How do we put them together ? 0 ۳۱۵۷۷ 00 2۹۵۱۱۳۷۲۵۱۵۱ ۰ 6 problem ? Some open researc! problems 

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Imagine | am ٩ | need to build a new app, 1. How much does it cost * Cost of developing the app (salaries) = Cost of deploying the app * Hardware, software licenses, maintenance * Loss of income because of mis- provisioning = Do! have to pay up front? = Is the cost proportional with the income ? 

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Other questions ? 2. How fast can | deliver the app ® Quicker on the market then my competitors ? 3. How good the application is * More customers for the app. => more income * Acceptable operational characteristics ? 4. Can | adapt if something changes ? ® Operational characteristics © Functionality 5; Can || Customize the Same app in a 3 different vertical / different set of customers ? 6. Is there a risk in the technology ? 

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Customers concerns Cost Time to market (۷ Customizability Sustainability RAIS. © 6 © © © © Often a tradeoff 

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۱211161611۲ 6135565 1 © Entetpriseyeg Bank of America) aay ec ‏16و81‎ ‏سك‎ ‏رو‎ ‎۲1۳۵ ۱0 ۵۵ © Government agency (eg. DoD) ‏ره و۳‎ Cost Time to market (?) ۱ ea) Customizability كنا onsumer (e.g Craiglist) 771۳116 10 ۲ ‏غ665‎ ‎Flexibility ‎Customizability ‎۳ 7 itis 4 CC) Ce ee) 

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Typical enterprise app stack Communication (XML, REST, WS) cielo IBM Application logic SA (java, C#) Microsoft Database SQL), 1 

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Cost ? $$$$! Cost of developing the app Cost of deploying the app ‏ل لك‎ (hardware, software licenses, (XML, REST, WS maintenance) , WS) ) Loss of income because of mis- Application logic provisioning (Java, C# Do | have to pay up front? Is the cost proportional with the income ? SQL) 

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Time to market ? Years! . How fast can | deliver the app Communication (XML, REST, WS) Application logic (Java, C#) Database SQL) 

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Flexibility ? Customizability? Mara ) any,| changes 6 ۱۶ Operational characteristics 5 Communication (XML, REST, WS) 3 Can | customise it to a different vertical? Application logic (Java, €#) Database SQL) ‏ا‎ 12 cle experience: for every $1M Oracle app licenses, customers 2 ‏و ری(‎ P experience even worse :-) 

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۲۷۷۵ ۲۳۵[0۲ 5۷۱۱ ۱5 EMule) layer infrastructure سس 0۳۵-۲۵05 ۶۱ ۳۱۱۹۱۱5 7 Application Logic (Schema-less) © New apps: « Even the Oracle apps ! aes a. ‏یت‎ Ka) (schemia-less) © New platforms; * Salesforce, GoogleApps, ‏كت‎ ‎XQuery a possible solution. 7 

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Another evil point ® Lack of cost elasticity ® Cost proportional with income © Lack of 21951۱ ۱۱ 11١ 052 0 6 = Response time independent of # clients The Cloud is the beginning orecrso)l ution) 

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Agenda © Current pain in building apps © What can XQuery do for customers ? ® What can the Cloud) do for customers ? © How do we put them together ? 0 ۳۱۵۷۷ 00 2۹۵۱۱۳۷۲۵۱۵۱ ۰ 6 problem ? Some open researc! problems 

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Why XML ? © Covers all spectrum from structured 0212 ۱0 ‏قلاع‎ 17 © Schema independent © Platform independent © Continuity with the basic Internet infrastructure (URI, HTML, HTTP) 

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What is XQuery ? A programming language for XML processing Functional in style Turing complete © ® Navigation ® Declarative query and aggregation (FLWOR) = Search (full text) ® Declarative updates 5 ا 5 ® Scripting J ل 5 ۲ Streaming and windowing Error handling and second order expressions Packaging (modules) © Has limitations (further), 17 

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History and status ® Standard of the W3C * Good and bad 10 years old 40 existing implementations Implemented in major databases Best implementations in| open source If you have XMIL data, itis hand! to hve) le @ecee @ 

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Navigation ® fn:doc("catalog.xml") /items/item fn:doc("catalog.xml")/items//item © fn:doc("catalog.xml”)/items//* © fn:doc("catalog.xml”)/items/@item © fn:doc("parts.xml")/parts/part|partno = $i/partno] © $x/items/item 

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FLWOR for $i in fn:doc("catalog.xml")/items/item, م0 م ‎fn:doc("parts.xml")/parts/partipartno‏ ‏,1 << $s in fn:doc("suppliers.xml)/suppliers /supplier[suppno = $i/suppno] order by $p/description, $s/suppname return 5 5 20 

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Creation of new ۹ 0 ۱ { for $i in fn:doc("catalog.xml")/items/item, $p in fn:doc("parts.xml")/parts/part[partno - $s in fn:doc("suppliers.xml")/suppliers /supplier[suppno = $i/suppno] order by $p/description, $s/suppname return - <item> { $p/description, $s/suppname, $i/price } </item> } </descriptive-catalog> 21 

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Textual search ® $doc ftcontains ( ( “mustang” ftand ({("great", "excellent")} any word occurs at least 2 times) ) window 11 words ftand ftnot “rust” ) same paragraph 22 

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Declarative updates for $p in /inventory/part let $deltap := $changes/part[partno eq $p/partno] return replace value of node $p/quantity with $p/quantity + $deltap/quantity 23 

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Transforms let $oldx := /a/b/x return copy $newx := $oldx modify (rename node $newx as "newx", replace value of node $newx by $newx * 2) return ($oldx, $newx) 24 

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Streams and windowing for sliding window $w in (2, 4, 6, 8, 10, 12, 14) start at $s when fn:true() only end at $e when $e - $s eq 2 return <window>{ $w }</window> © Result of the above query: 5د 6 ا ۱ <window>4 6 8</window= <window>6 8 10</window> <window>8 10 12</window> <window>10 12 14</window> ch) 

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5 ۲۱۵۱۱۲۱9 ه 1 declare $a as xs:integer := 0; declare $b as xs:integer := 1; declare $c as xs:integer := $a + $b; declare $fibseq as xs:integer* := ($a, while ($c < 100) 0 set $fibseq := ($fibseq, $c); set $a := $b; set $b := $c; set $c := $a + $b; ¢fihcanq: ah 

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Where can It be used in today’s architectures? © Databases © Middle tiers ® Information dispatch ‏ه‎ 10 ® Data integration © Browsers (see XQ/B 061۱۵, ۷۷۷۷۷ 9 paper) ® a clayicas (XQuery on iPhone anyon 

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28 XQuery’s real potential ® Standalone MIE ‏گر‎ ‎programming language for information intensive applications Application © Can build extremely Logic rich applications (XQuery) 

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1. Cost Why XQuery 7 2. Time to marke 3. Flexibility 4. Customizability © Because of XML 5. Sustainability ® Schema independent 6. Risk ® Continuity with basic Internet infrastructure * Continuity structured data <--> textual (2 0 © XQuery’s own advantages ® Declarative = Single layer code ® Open source friendly © Extra Goodies ® Opportunity to rethink ACID transactions ® Unique opportunities for introspection ® Code and data migration 2 

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د Declarativity © Small number of lines of code = Development cost = Time to market ‏نا‎ # bugs © Easy to optimize automatically © Easy to parallelize automatically ‏و‎ 5۵661۵1۱۷ ۱۳۱۱۵۵۲۱۵۱۱۲ ۱۱ ۲۵ ۵ ® Easier to achieve elasticity in) performance © Easier to generate automatically ® Important for smart/non-developers UIs 

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Declarativity, negative 596 . Less number of developers capable of writing such code 2. Easy to write, harder to read 3. Tools harder to make (e.g. debuggers) 4, Performance can be unstable © Despite that, in the history of €S we evolve in the direction of declarativity s Assembly, C, C++, Java, Haskell Cobol, SQL 

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Rethink transactions and data consistency, XQuery silent as ACID transactions go = On purpose ! Are ACID transactions really needed ? Are they really enforced in Web apps ? No. Open research field ۶ Interaction of programming languages with new transactional models and new data consistency models 32 © S ‏كن‎ ‎© ‎3 

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09 رل بت © Data consistency is something to optimize, 01 an absolute requirement © Data consistency models [Tanembaum] ‏يا‎ 5۱۱2۱60-1151» ۱۱۵۱۷ ۵۵۵ ( ® No concurrency control at all ® Eventual Consistency (Basic Piouoco))) ® Updates become visible any time and will persist ® No lost update on page level ‏لا‎ ‎© All or no updates of a transaction become visible ‎pseicls, Heal your writes, Mongtoriic‏ كال ا ‎Naina‏ ‎® Strong Consistency ® database-style consistency (ACID) via OCC © Data consistency a la carte 35 

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34 Introspection ecoséunwortal LIES © Everything is (or will be) XML s Data, schemas, code, PULs, metadata, configs, runtime information © Unique opportunity to: ۶ introspect at runtime all of them ® reason about them = change them dynamically (not only 919 but schemas, code and configuration) O Oo research field: ‏»ع‎ Consequences on programming 

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Why NOT XQuery XML is complicated XML Schema is hard/impossible to understand XQuery is complicated YOIaViS ‏داز رررن ع زر‎ (maybe research opport.?) ® Missing a standard persistent data modell = Missing DDL functionality (indexes, integrity constraints) ® Missing basic functionalities (e.g. eval, function. overloading) ® Missing basic data modeling functionality (n:m relationships) XQuery lacks a standard environment (e.g) J2EE) (maybe research opport.?) No tools (debuggers, profilers) ~- 55 =). goport.?) ‎clear yee (certainly research‏ تمر دا كر كيز ‎nAnnoary !)‏ ‎35 

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Agenda © Current pain in building apps © What can XQuery do for customers ? ® What can the Cloud) do for customers ? © How do we put them together ? 0 ۳۱۵۷۷ 00 2۹۵۱۱۳۷۲۵۱۵۱ ۰ 6 problem ? Some open researc! problems 

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What is Cloud radigrn for cornputing of (Certain) aspects of ) 0 © Goal 1: Reduction| of Cost * principle: fine-grained renting of resources 8 pay as you go” (elasticity of cost) 3 Boel 2: Simplification of Management ® potentially infinite/unbreakable computing, resources = potentially no administration ® Goal 3: Elasticity of performance: = Same resp time independently of workload a 0 ‏ا‎ 0 a RY 

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Case Study: Amazon AWS EC2 : scalable virtual private servers using Xen. S3 : WS based storage for applications GQG > hosted wessage queue Par we ‏اجرج‎ PAS PA ee SimpleDB ; the core functionality of a database Hadoop based functionality Similar oroviders: Je) Slur ‏ناه‎ ‎Microsoft Azure, (GoogleApp engine) كك ك3 

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39 The limits of the (Amazon) Cloud © Cloud Computing a great starting jee) ial © Unfortunately, only a fraction of the stack 

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Making use of the Cloud ® Solution 1 (conservative) ‏۲و2‎ ۴ * Take an existing application (Java+SQL, etc) and try to make it run on the cloud (e.g. make Oracle run on AWS) ® Solution 2 (reactionary) « 06۵16 20 165 ۷ infrastructure, specially designed for Web apps requirements, to be deployed in the cloud 0 

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Solution 1 (conservative) ® take a traditional DBMS (e.g., Oracle, MySQL, ...) ® install it on an EC2 instance ® use S3 or EBS as a persistent store كنئ ® traditional databases are available ® proven to work well; many tools ® people trained and confident with them O DiseedlVvaintages Se ee ae ROG Ber ok nent arn cre tea (ome mts 2 ‏باه‎ ( ‎ne eacecd‏ ۹ مر ا کرک ررض ذا اسصم رم رم زرط ‎0 

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Solution 2 (reactionary) © Rethink the whole system) anchitecture = do NOT use a traditional DBMS and app server * create new breed of application server (with DB) = run application server on nm E@2 instances * use S3 + distributed consistency protocols ‏ورد ۱۱۱/۰۱۱۱۰۱ ب‎ Disadvantages DO requires new breed of (immature) systerns + tools = Solves the right problern and gets it right © Examples: * GoogleApps (Python in the cloud) * Sausalito (www.28msec.com) (XQuery in the cloud) ‏كت‎ 

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Agenda © Current pain in building apps © What can XQuery do for customers ? ® What can the Cloud) do for customers ? © How do we put them together ? 0 ۳۱۵۷۷ 00 2۹۵۱۱۳۷۲۵۱۵۱ ۰ 6 problem ? Some open researc! problems 43 

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XQuery + AWS Cloud ® Cookbook: ® Take an existing XQuery processor = Partition the XML data on S3 * Map REST calls to XQuery programs * Run the XQuery programs on EG2 * Use SQS for (asyncronous) updates * Voila. O Tne iiegic is in the glue (XQuery proc. + AWS ) © Application 3 ۰ ۱۷ ‏در ركد‎ 2 * integrated XQuery based application stack for Web-based apps * fully SOA enabled 44 

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XQuery in ۲۱۱۶ 1010 (connected 

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Customers concerns Cost Time to market (۷ Customizability Sustainability 46 

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XQuery In the 61000 ۵ Server) 

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pene In ۱۱۶ 0 (offline) 

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۶ (۵۱۲۵ 1 | ® Look at ‏رف‎ ‎use cases ( consumer and enterprise mashups) 49 

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Competitors; Internet ® Web 2.0 Development Frameworks = E.g., Ruby on Rails, PHP. / LAMP, . _® Deployment in the cloud still ‏ارو‎ ‎® Google AppEngine, Facebook Apps: 7 4 ‏لتر‎ programming model (Python- = Limited functionality * Vendor lock-in, privacy issues, © Oracle on AWS, do-it-yourself om AWS = limited functionality and/or scalability د 

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Competitors; Enterprise © Salesforce AppExchange ® proprietary programming model * Limited applications domain (CRM) ® Microsoft Azure ۱ Net programming model ® manual configuration needed -® (recent offering, market adoption unclear) OWinetiellrzeirion Eompeniias (a.y., VMlWelre) = No offerings / expertise for data, management © Oracle (Grid, RAC) ® limited scalability, cost prohibitive 0 

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Web 2.0 Support vs, Cloud Support AWS Google App Engine, Que: ‏عن‎ ۸ ۷/9 Salesforce, Workday . VMWare Cloud, ‏وه‎ ictal Ruby an Rails. 

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Agenda © Current pain in building apps © What can XQuery do for customers ? ® What can the Cloud) do for customers ? © How do we put them together ? 0 ۳۱۵۷۷ 00 2۹۵۱۱۳۷۲۵۱۵۱ ۰ 6 problem ? Some open researc! problems 

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Versions and variations © Human mind does not like agreements ® We like our differences (for a good reason) © Different ways to see; = Data * Schemas * Code © Current stack is imposing agreement * unlike our own nature ‏م‎ ‎© We have to come Up with solutions that allow, welcome and exploit Variations © Darwinian, evolutionary approach to data, schema and code mutations 7 

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Versions and Variations J Raseercn oroolermns: = What is a (data, schema, code) variation ? What does it mean to run an app in the presence of variations ? How do you store (index, etc) variations ? How do you re-integrate them back into mainstream app (e.g. ‏الل لكت‎ voting ?) = What is the correct caves for data, schema, code that allows and maximally exploits variations ? omer 1 a 56۳ ‏را‎ to. think of 55 1 رت مم 2 ‎ca‏ ل الل مر 

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Conclusion © 0۱6۲۷ ۱۳ ۱6 61000 3٩3 5 alternative for some (large # and large $$) customers © Nothing equivalent in the competition: = How “solid” (standard, tested) this is = Richness of applications —— = Potential for optimization and parallelization * Ease of porting to the cloud 

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My advice ‎Keep the eye on the apps, not‏ ه ‎db‏ ‎Keep the customer tin mind‏ كل ‎® Rethink the entire stack ‎۶ Don’t be afraid to shake down existing ideas about how ‎applications are Supposed! to work