A Survey of HBase Application Archetypes

1. Headline Goes Here Speaker Name or Subhead Goes Here DO NOT USE PUBLICLY PRIOR TO 10/23/12 Apache HBase Application Archetypes Lars George | @larsgeorge | Cloudera EMEA Chief Architect | HBase PMC Jonathan Hsieh | @jmhsieh | Cloudera HBase Tech lead | HBase PMC HBaseCon 2014 May 5th , 2014 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 1

2. About Lars and Jon Lars George • EMEA Chief Architect @Cloudera • Apache HBase PMC • O’Reilly Author of HBase – The Definitive Guide • Contact • lars@cloudera.com • @larsgeorge Jon Hsieh • Tech Lead HBase Team @Cloudera • Apache HBase PMC • Apache Flume founder • Contact: • jon@cloudera.com • @jmhsieh 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 2

3. About Supporting HBase at Cloudera • Supporting Customers using HBase since 2011 • HBase Training • Professional Services • Team has experience supporting and running HBase since 2009 • 8 committers on staff • 2 HBase book authors • As of Jan 2014, ~20,000 HBase nodes (in aggregate) under management • Information in this presentation is either aggregated customer data or from public sources. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 3

4. An Apache HBase Timeline 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 20142008 2009 2010 2011 20132012 Apr’11: CDH3 GA with HBase 0.90.1 May ‘12: HBaseCon 2012 Jun ‘13: HBaseCon 2013 Summer‘11: Messages on HBaseSummer ‘09 StumbleUpon goes production on HBase ~0.20 Nov ‘11: Cassini on HBase Jan ‘13 Phoenix on HBase Summer‘11: Web Crawl Cache 4 Sept’11: HBase TDG published Nov’12: HBase in Action published 2015 May ‘14: HBaseCon 2014 Aug ‘13 Flurry 1k-1k node cluster replication Summer ‘14 HBase v1.0.0 released Jan’14: Cloudera has ~20k Hbase nodes under management

5. Apache HBase “Nascar” Slide 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 5

6. Outline • Definitions • Archetypes • The Good • The Bad • The Maybe • Conclusion 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 6

7. A vocabulary for HBase Archetypes Definitions 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 7

8. Defining HBase Archetypes • There are a lot of HBase applications • Some successful, some less so • They have common architecture patterns • They have common tradeoffs • Archetypes are common architecture patterns • Common across multiple use-cases • Extracted to be repeatable • Our Goal: Define patterns à la “Gang of Four” (Gamma, Helm, Johnson, Vlissides) 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 8

9. So you want to use HBase? • What data is being stored? • Entity data • Event data • Why is the data being stored? • Operational use cases • Analytical use cases • How does the data get in and out? • Real time vs. Batch • Random vs. Sequential 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 9

10. What is being stored? There are primarly two kinds of big data workloads. They have different storage requirements. Entities Events 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 10

11. Entity Centric Data • Entity data is information about current state • Generally real time reads and writes • Examples: • Accounts • Users • Geolocation points • Click Counts and Metrics • Current Sensors Reading • Scales up with # of Humans and # of Machines/Sensors • Billions of distinct entities 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 11

12. Event Centric Data • Event centric data are time-series data points recording successive points spaced over time intervals. • Generally real time write, some combination of real time read or batch read • Examples: • Sensor data over time • Historical Stock Ticker data • Historical Metrics • Clicks time-series • Scales up due to finer grained intervals, retention policies, and the passage of time 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 12

13. Events about Entities • Majority Big Data use cases are dealing with event-based data • |Entities| * |Events| = Big data • When you ask questions, do you hone in on entity first? • When you ask questions, do you hone in on time ranges first? • Your answer will help you determine where and how to store your data. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 13

14. Why are you storing the data? • So what kind of questions are you asking the data? • Entity-centric questions • Give me everything about entity e • Give me the most recent event v about entity e • Give me the n most recent events V about entity e • Give me all events V about e between time [t1,t2] • Event and Time-centric questions • Give me an aggregates on each entity between time [t1,t2] • Give me an aggregate on each time interval for entity e • Find events V that match some other given criteria 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 14

15. How does data get in and out of HBase? HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Gets Short scan Full Scan, MapReduce HBase Scanner Bulk Import HBase Client 15 HBase Replication HBase Replication

16. How does data get in and out of HBase? HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 16 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

17. What system is most efficient? • It is all physics • You have a limited I/O budget • Use all your I/O by parallelizing access and read/write sequentially. • Choose the system and features that reduces I/O in general • Pick the systems best for your workload 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 17 IOPs/s/disk

18. The physics of Hadoop Storage Systems Workload HBase HDFS Low latency ms, cached mins, MR + seconds, Impala Random Read primary index - index?, small files problem Short Scan sorted + partition Full Scan 0 live table + (MR on snapshots) MR, Hive, Impala Random Write log structured - Not supported Sequential Write hbase overhead bulk load minimal overhead Updates log structured - Not supported 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 18

19. The physics of Hadoop Storage Systems Workload HBase HDFS Low latency ms, cached mins, MR + seconds, Impala Random Read primary index - index?, small files problem Short Scan sorted + partition Full Scan 0 live table + (MR on snapshots) MR, Hive, Impala Random Write log structured - Not supported Sequential Write hbase overhead bulk load minimal overhead Updates log structured - Not supported 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 19

20. The physics of Hadoop Storage Systems Workload HBase HDFS Low latency ms, cached mins, MR + seconds, Impala Random Read primary index - index?, small files problem Short Scan sorted + partition Full Scan 0 live table + (MR on snapshots) MR, Hive, Impala Random Write log structured - not supported Sequential Write HBase overhead bulk load minimal overhead Updates log structured - not supported 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 20

21. The Archetypes HBase Applications 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 21

22. HBase application use cases • The Good • Simple Entities • Messaging Store • Graph Store • Metrics Store • The Bad • Large Blobs • Naïve RDBMS port • Analytic Archive • The Maybe • Time series DB • Combined workloads 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 22

23. Archetypes: The Good HBase, you are my soul mate. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 23

24. Archetype: Simple Entities • Purely entity data, no relation between entities • Batch or real-time, random writes • Real-time, random reads • Could be a well-done denormalized RDBMS port. • Often from many different sources, with poly-structured data • Schema: • Row per entity • Row key => entity ID, or hash of entity ID • Col qualifier => Property / field, possibly time stamp • Geolocation data • Search index building • Use solr to make text data searchable. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 24

25. Simple Entities access pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 25 HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner HBase Replication Solr

26. Archetype: Messaging Store • Messaging Data: • Realtime Random writes: Emails, SMS, MMS, IM • Realtime random updates: Msg read, starred, moved, deleted • Reading of top-N entries, sorted by time • Records are of varying size • Some time series, but mostly random read/write • Schema: • Row = users/feed/inbox • Row key = UID or UID + time • Column Qualifier = time or conversation id + time. • Use CF’s for indexes. • Examples: • Facebook Messages, Xiaomi Messages • Telco SMS/MMS services • Feeds like tumblr, pinterest 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 26

27. Facebook Messages - Statistics Source: HBaseCon 2012 - Anshuman Singh 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 27

28. Messages Access Pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 28 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

29. Archetype: Graph Data • Graph Data: All entities and relations • Batch or realtime, random writes • Batch or realtime, random reads • Its an entity with relation edges • Schema: • Row = Node. • Row key => Node ID. • Col qualifier => Edge ID, or properties:values • Examples: • Web Caches – Yahoo!, Trend Micro • Titan Graph DB with HBase storage backend • Sessionization (financial transactions, clicks streams, network traffic) • Government (connect the bad guy) 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 29

30. Graph Data Access Pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 30 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

31. Archetype: Metrics • Frequently updated Metrics • Increments • Roll ups generated by MR and bulk loaded to HBase • Poor man’s datacubes • Examples • Campaign Impression/Click counts (Ad tech) • Sensor data (Energy, Manufacturing, Auto) 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 31

32. Metrics Access Pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 32 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

33. CONFIDENTIAL - RESTRICTED Archetypes: The Bad These are not the droids you are looking for 33

34. Current HBase weak spots • HBase’s architecture can handle a lot • We make engineering trade offs to optimize for them. • HBase can still do things it is not optimal for. • However, other systems are fundamentally more efficient for some workloads. • We’ve often seen some folks forcing apps into HBase. • If one of these is your only workloads on this data, use another system • If you are in a mixed workload case, some of these become “maybes”. • Just because it is not good today, doesn’t mean it cant be better tomorrow. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 34

35. Bad Archetype: Large Blob Store • Saving large objects >3MB per cell • Schema: • Normal entity pattern, but with some columns with large cells. • Examples • Raw photo or video storage in HBase • Large frequently updated structs as a single cell • Problems: • Will get crushed due to write amplification when reoptimizing data for read. (compactions on large unchanging data) • Will crush write pipeline if there are large structs with frequently updated subfields. Cells are atomic, and hbase must rewrite an entire cell. • Some work adding LOB support • This requires new architecture elements 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 35

36. Bad Archetype: Naïve RDBMS port • A naïve port the RDBMS onto HBase, directly copying the schema. • Schema • Many tables, just like an RDBMS schema. • Row key: primary key or auto-incrementing key, like RDBMS schema • Column qualifiers: field names • Manually do joins, or secondary indexes (not consistent) • Solution: • HBase is not a SQL Database. • No multi-region/multi-table in HBase transactions (yet). • Must to denormalize your schema to use Hbase. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 36

37. Large blob store, Naïve RDBMS port access patterns HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 37 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

38. Bad Archetype: Analytic archive • Store purely chronological data, partitioned by time • Real time writes, chronological time as primary index • Column-centric aggregations over all rows. • Bulk reads out, generally for generating periodic reports • Schema • Row key: date+xxx or salt+date+xxx • Column qualifiers: properties with data or counters • Example • Machine logs organized by date. • Full fidelity clickstream 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 38

39. Bad Archetype: Analytic archive Problems • HBase non-optimal as primary use case. • Will get crushed by frequent full table scans. • Will get crushed by large compactions. • Will get crushed by write-side region hot spotting. • Instead • Store in HDFS; Use Parquet columnar data storage + Impala/Hive • Build rollups in HDFS+MR; store and serve rollups in HBase 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 39

40. Analytic Archive access patterns HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 40 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

41. And this is crazy | But here’s my data, | serve it, maybe! Archetypes: The Maybe 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 41

42. The Maybe’s • For some applications, doing it right gets complicated. • These more sophisticated or nuanced cases require considing these questions: • When do you choose HBase vs HDFS storage for time series data? • Are there times where bad archetypes are ok? 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 42

43. Time Series: in HBase or HDFS? • IO Patterns: • Reads: Collocate related data • Make reads cheap and fast. • Writes: Spread writes out as much as possible • Maximize write throughput • HBase: Tension between these goals • Spreading writes spreads data making reads inefficient • Colocating on write causes hotspots, underutilizes resources by limiting write throughput • HDFS: The sweet spot. • Sequential writes and and sequential read. • Just write more files in date-dirs; physically spreads writes but logically groups data. • Reads for time centric quieries just read files in date-dir 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 43

44. Time Series data flows • Ingest • Flume or similar direct tool via app • HDFS • Batch queries and generate rollups in Hive/MR • Faster queries in Impala • No user time serving • HBase for recent, HDFS for historical • HBase • Serve individual events • Serve pre-computed aggregates 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 44

45. Archetype: Entity Time Series • A time series access pattern suitable for HBase • Random write to event data, random read specific event or aggregate data • Generate aggregates via counters, don’t directly compute aggregate on query • HBase is system of record • Schema: • Rowkey: entity-timestamp or hash(entity)-timestamp, possibly with salt added after entity. • Col qualifiers: property • Use custom aggretation to consolidate old data • Use TTL’s to bound and age off old data • Examples: • OpenTSDB does this well for numeric values; Lazily aggregates cells for better performance. • Facebook Insights, ODS 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 45

46. Entity Time Series access pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 46 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner Flume Custom App

47. Archetypes: Hybrid Entity Time Series • Essentially a combo of the Metric Archetype and Entity Time Series Archetype, with bulk loads of rollups via HDFS. • Land data in HDFS and HBase • Keep all data in HDFS for future use • Aggregate in HDFS and write to HBase • HBase can do some aggregates too (counters) • Keep serve-able data in HBase. • Use TTL to discard old values from Hbase. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 47

48. Hybrid time series access pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Hive or MR: Bulk Import HBase Client 48 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner HDFS Flume

49. Meta Archetype: Combined workloads • In these cases, the use of HBase depends on workload • Cases where we have multiple workloads styles. • Many cases we want to do multiple things with the same data • primary use case (real time, random access) • secondary use case (analytical) • Pick for your primary, here’s some patterns on how to do your secondary. 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 49

50. Real time workloads and Analytical access 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan 50 poor latency! full scans interfere with latency! high throughput MapReduce HBase Scanner HBase Client Put, Incr, Append Bulk Import HBase Client HBase Replication

51. Real time workloads and Analytical access 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan 51 HBase Replication low latency Isolated from full scans high throughput MapReduce HBase Scanner HBase Client Put, Incr, Append Bulk Import HBase Client HBase Replication high throughput

52. MR over Table Snapshots (0.98, CDH5.0) • Previously MapReduce jobs over HBase required online full table scan • Take a snapshot and run MR job over snapshot files • Doesn’t use HBase client • Avoid affecting HBase caches • 3-5x perf boost. • Still requires more IOPs than hdfs raw files 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh map map map map map map map map reduce reduce reduce map map map map map map map map reduce reduce reduce snapshot 52

53. Analytic Archive access pattern HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Get, Scan Bulk Import HBase Client 53 HBase Replication HBase Replication low latency high throughput Gets Short scan Full Scan, MapReduce HBase Scanner

54. Analytic Archive Snapshot access pattern HDFS HBase Client Put, Incr, Append 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh HBase Client Snapshot Scan, MR HBase Scanner Bulk Import HBase Client 54 HBase Replication HBase Replication low latency Higher throughput Table snapshot Gets Short scan

55. Multitenancy (in progress) • We want to MR for analytics while serving low-latency requests in one cluster. • Performance Isolation • Limit performance impact load on one table has on others. (HBASE- 6721) • Request prioritization and scheduling • Toda default is FIFO • Need to schedule some requests before others (HBASE-10994) 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 55 1 1 2 1 1 3 1 1 1 21 1 31 Delayed by long scan requests Rescheduled so new request get priority Mixed workload Isolated workload

56. Conclusions 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 56

57. Big Data Workloads 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 57 Low latency Batch Random Access Full ScanShort Scan HDFS + MR (Hive/pig) HBase HBase + Snapshots -> HDFS + MR HDFS + Impala HBase + MR

58. Big Data Workloads 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 58 Low latency Batch Random Access Full ScanShort Scan HDFS + MR (Hive/pig) HBase HBase + Snapshots -> HDFS + MR HDFS + Impala HBase + MR Current Metrics Graph data Simple Entities Hybrid Entity Time series + Rollup serving Messages Analytic archive Hybrid Entity Time series + Rollup generation Index building Entity Time series

59. HBase is evolving to be an Operational Database • Excels at consistent single row centric operations • Dev efforts aimed at using all machine resources efficiently, reducing MTTR, and improving latency predictability. • Projects built on HBase that enable secondary indexing and multi-row transactions • Apache Phoenix (incubating) or Impala provide a SQL skin for simplified application development • Analytic workloads? • Can be done but will be beaten by direct HDFS + MR/Spark/Impala 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 59

60. Questions? @larsgeorge @jmhsieh 5/5/14 HBaseCon 2014; Lars George, Jon Hsieh 60