Data Warehouse Forces and Threats

Data Warehouse Forces and Threats

Forces and threats in a data warehouse and why architecture are metadata are important.

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Stefan Urbanek

November 25, 2019
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  1. FORCES AND THREATS or Why Architecture and Metadata are Important?

    Štefan Urbánek stefan.urbanek@gmail.com @Stiivi DataNatives, November 2019
  2. OUTLINE ▪︎ Forces and Threats ▪︎ Traditional Suffering ▪︎ Damping

    the Forces and Threats ▪︎ How to start? ▪︎ Conclusions
  3. Data warehouse – a concept, not a technology. X Y

    Z
  4. FORCES AND THREATS

  5. Data Warehouse Forces and Threats: interactions that, when unopposed, will

    change the motion of technical, economical, social, organisational and process structures with high potential of causing suffering
  6. CHANGEforce Data Warehouse Technology * you wish! ? ? ?

    ? ? * *
  7. CHANGEforce Data Warehouse Technology ? ? ? ? ? 1995

    2000 2005 2010 2015
  8. GROWTHforce + + + + + + + + structure

    volume + +
  9. COMPLEXITY force … potential relationship ownership definition production

  10. COMPLEXITY force label/definition consumer, owner n2 potential relationships* *only between

    tables, not even mentioning columns … What is relevant?
  11. THREATS* Mistakes in data might lead not only to wrong

    business decisions, but might also have legal, financial or existential implications. *serious and real
  12. TRADITIONAL SUFFERING usually chronic

  13. SUFFERING ▪︎ Bad consistency and no transparency No definitions, too

    many definitions, obscure definitions. Vague opinions in production. ▪︎ Slow time-to-market Time from a requirement or from observing a change to deployment in the production takes too much time. ▪︎ Low performance … despite having the best hardware, systems, algorithms. (some of it)
  14. How do we know, the data we are looking at

    is the data we think we are looking at?
  15. PERFORMANCE We solved “CPU starvation” problem!!! Why are our [internal]

    clients getting data 48-72 hours later? ! 20-30x " ⨝ ⨝ ∑ ⨝ ⨝ … ⨝ quite big quite a lot ⨝ ⨝ ⨝ ⨝ ⨝ ⨝ ⨝ ⨝ ⨝ ⨝ stand-alone ETL process/script
  16. probably the same, who knows? IS ∑ IS ∑ uncontrolled

    growth
  17. DAMPING THE FORCES AND THREATS

  18. ARCHITECTURE + METADATA separation of concerns and reduction of complexity

    potential reduction and annotation of problem space and facilitation of reasoning ∑ A→B
  19. ARCHITECTURE

  20. Data Warehouse “Agreed-upon Analytical Truth” Metadata Sandbox/Playground Staging ~1:1 “Cleaned

    Augmented Operational Reality” Sources Quality Assurance Humans Cubes, Cuboids and Aggregates Machines External Data Platform Data Regulated Data ∑ ∑ proof-of-concepts, ad-hoc analysis business rules “typed tables” External API decision making automation analytics-augmented application 3rd NF, ̣, ❄, … data scientists decision makers financial datamart(s) quality indicators src tgt ownership data models transformations ∑ A→B ? …
  21. Data Warehouse “Agreed-upon Analytical Truth” Metadata Sandbox/Playground Staging ~1:1 “Cleaned

    Augmented Operational Reality” Sources Quality Assurance Humans Cubes, Cuboids and Aggregates Machines External Data Platform Data Regulated Data ∑ ∑ proof-of-concepts, ad-hoc analysis business rules “typed tables” External API decision making automation analytics-augmented application 3rd NF, ̣, ❄, … data scientists decision makers financial datamart(s) quality indicators src tgt ownership data models transformations ∑ A→B ? …
  22. METADATA

  23. METADATA ▪︎ Data Warehouse Assets concepts, entities, attributes, definitions, business

    rules, quality indicators, concept ownerships, … ▪︎ Many Perspectives conceptual, logical, physical, multi-dimensional, security, … ▪︎ Formalised, stored, shared, used revenue ? ? ? visits customers
  24. logical → physical multidimensional hierarchical → 3rd normal form logical

    3rd normal form logical → physical query → precomputed + computed denormalisation → joins physical → logical … → …
  25. Metadata Processing Metadata data models transformations ∑ A→B Compose Compile

    SQL physical schema dialect reality semantics realisation relational algebra Execute A,B,C parameters .cob .java .py
  26. HOW?

  27. STARTING WITH ARCHITECTURE 1. Pick one: If in doubt –

    any known to work. Any separation of concerns is better than none. 2. Make it formal and documented. Otherwise our effort will be dissolved and the content swampified. 3. Stick with it for a while and observe. 4. Adjust as necessary.
  28. STARTING WITH METADATA 1. Pick a problem 2. Use a

    spreadsheet Software at hand, no installation needed; universal, readable and editable by non-engineers. 3. Suffer through the spreadsheet-exchange drill phase Mirror of our processes – seeing the genuine pain points will be useful later. 4. Use functional approach to metadata composition and application … from those spreadsheets. Example: relational algebra library in the language of our ecosystem. 99.(later) Move spreadsheets into a metadata repository
  29. “HELLO METADATA” PROBLEMS ▪︎ Data quality indicators1 ▪︎ Structural (model

    ® schema) consistency check1 ▪︎ Automation of common patterns denormalisation, aggregation, pivot ▪︎ Automate “relationalization” of freely-structured data JSON → relational ▪︎ Browsability 1non-invasive, non-destructive
  30. Doing Things To Data Doing More Things To Data …

    Doing Things To Data Doing More Things To Data … Pipelines without metadata Pipelines with metadata metadata data
  31. DATA QUALITY INDICATORS Doing Things To Data Doing More Things

    To Data … metadata data quality measurements data quality indicators data metadata definition, computation, warning/error thresholds, ownership, affected business entity, …
  32. COMMON PATTERNS Automatically Generated Artefacts Metadata Manually Crafted Artefacts IS

    ∑ denormalize aggregate pivot patterns ∑ controlled growth probably the same, who knows? IS ∑ IS ∑ uncontrolled growth
  33. VISUALISATION AND EXPLORATION Browse-ability: How can we explore a metric?

    How can we drill down? User Interface Metadata Physical Data Region … name Sales Revenue Visits … … 3 2 1 id Cubes Geography … name Date 2 … id … 1 Dimensions Europe Germany Berlin regions Country City Levels 2 region_code country_name … 2 Country 3 country_iso 1 key Region … name id City 2 dim label 2 region_name city_name city_code … countries cities generated which column? concept-to-user propagation
  34. GET /cube/sales/aggregate? cut=date:2010 & split=status:1 & drilldown=date|region & page=10 page_size=100

    & SQL → Metadata Logical Model Physical Physical Data Store Query Context Input Output Cube all attributes base attributes ⨝ joins database metadata Store Mapper locale parameters create schema collect and sort dependencies map attributes mappings mappings of base attributes fact table naming convention hierarchies Star Schema ̣/❄ compile attributes base attributes dependant attributes columns make star (topological sort) query attributes SQL Query Context create context base columns column expressions for attributes SELECT, GROUP BY “star” join statement FROM conditions WHERE Cubes 1.1 – SQL Query Construction A,B,C? SQL
  35. TRANSPARENT REPRESENTATIONS Physical Data Store(s) Pre-Aggregated 3 rd Normal Form

    source of truth derived and managed artefacts Metadata ∑ ∑ ∑ ∑ Multi-Dimensional Query Server ∑ Aggregator metadata repository past 12 months ? ⨝s are expensive Alternative artefacts: a multi-dimensional data store
  36. CONCLUSIONS

  37. SHIELD AGAINST FORCES AND THREATS ▪︎ Change ▪︎ Growth (structural)

    ▪︎ Complexity ▪︎ Threats financial, legal, existential
  38. Force/Threat Architecture Metadata Change separation of concerns abstraction, generalisation Growth

    (structural) separation of concerns, modularity optimisation through better reasoning Complexity separation of concerns, destroy-ability reduction of problem-space, coping with heterogeneity Threats transparency, separation of quality data accounting, verifiable data quality, provable consistency, source of truth
  39. There is path out of the suffering caused by the

    data warehouse forces and threats: The “shield” of architecture and metadata.
  40. THANK YOU Štefan Urbánek stefan.urbanek@gmail.com @Stiivi