ABenchmarkingStory

CockroachDB:FromOLTPtoHTAP

presentedby ArjunNarayan

@cockroachdb

WARNING!• Opinionatedspeculationahead

• Here’swhatI wantCockroachDBtolooklike

• Notnecessarilywhatwillhappen

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HTAP: What is it?Here’s To A Perspective

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Databasestoday(simplified)

OLTP Database

OLAP Warehouse

ETL

TPC-C

TPC-H

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Databasestomorrow(simplified)

HTAP Database

TPC-C

TPC-H

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Dataarchitecturestoday(reality)

OLTP

OLTP

OLTP

OLTP

KAFKA

Hadoop

Vertica

Storm

Samza

Custom denormalizationmicroservices

Ad-hocData Science

Reporting

Realtime feeds

Dashboards

Memcache

@cockroachdb

Avisionfordataarchitecturestomorrow

Cockroach Zone: OLTP

Cockroach Zone:Incrementally Updated

Materialized Views

Ad-hocData Science

Reporting

Realtime feeds

Dashboards

Cache

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HTAP: How do we benchmark it?You are what you measure

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CockroachDB Architecture in 60 secondsScale out SQL

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ArchitectureOverview

Raft

Fully featured SQL API

Distributed Query Execution

Node 1

Node 2

Node 3

Replicas

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TheCockroachDBKVLayer

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UsingClocksforFastReads

Node 1

Lease

Node 2

Lease

Node 3

Lease

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DistributedQueryExecutioninCockroachDB

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Building CockroachDB

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BuildingCockroachDB:AnOrderofPriorities

Correctness •Jepsen testing

Stability •Chaos testing

Performance •Benchmarking

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BuildingCockroachDB:AnOrderofPriorities

Scale-outOLTP

• Where we are today

AcceptableOLAP

• Where we are keeping an eye on

HTAP • The distant future (the year 2000)

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CockroachDB: An HTAP vision

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HTAP:Astrawman

OLTP Database

OLAP Warehouse

ETL

TPC-C

TPC-H

HTAP Database

TPC-C

TPC-H

@cockroachdb

Dataarchitecturestoday

OLTP

OLTP

OLTP

OLTP

KAFKA

Hadoop

Vertica

Storm

Samza

Custom denormalizationmicroservices

Ad-hocData Science

Reporting

Realtime feeds

Dashboards

Memcache

@cockroachdb

HTAP:Desiderata

• Computeanalyticsqueriesandkeepresultsup-to-date

• ResourceisolationforOLTPwork

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Dataarchitecturestomorrow

KAFKA

Cockroach Zone: OLTP

Hadoop

Vertica

Storm

Samza

Ad-hocData Science

Reporting

Realtime feeds

Dashboards

Memcache

@cockroachdb

IncrementallyUpdatedMaterializedViews

• Real-timeChangefeedsfromOLTPreplicas

• DifferentialDataflowforincrementalcomputationofallSQLqueries

• BuiltrightintotheRDBMS,noseparateETLstep

• CockroachtimestampsindataflowgivesserializabletransactionsthatspanOLTP+OLAP

• “ReadyourOLTPwritesinOLAPreads”transactionalguarantees

• SeeNaiad(SOSP2013),DifferentialDataflow(CIDR2013),FrankMcSherry’s Blog(GitHub)

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Dataarchitecturesthedayafter

Cockroach Zone: OLTP

Cockroach Zone:Incrementally Updated

Materialized Views

Ad-hocData Science

Reporting

Realtime feeds

Dashboards

Memcache

@cockroachdb

BenchmarkingHTAP:Whatnottodo

• Don’tjustrunTPC-C+TPC-Honthesamesystem

• Why?MaterializedviewsbreakTPC-H

• It’snotjustaboutrunningad-hocTPC-Hqueries

• HTAPdoesn’tmatterifyoucan’tguaranteepredictableTPC-Cperformance

@cockroachdb

Benchmarkingmaterializedviews

• Howlongdoesittaketocomputeincrementalreports?

• Howlongdoesittaketocomputead-hocqueries?

• Howlongdoesittaketobuildamaterializedviewfromscratch?

• HowlongdoesittaketopropagateOLTPchanges?

• HowmuchoverheaddoweimposeontheOLTPsystem?

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Questions?