Speed up Interactive Analytic Queries over Existing Big Data on Hadoop with Presto

Liang-Chi Hsieh

HadoopCon 2014 in Taiwan

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In Today’s talk

• Introduction of Presto

• Distributed architecture

• Query model

• Deployment and configuration

• Data visualization with Presto - Demo

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SQL on/over Hadoop• Hive

• Matured and proven solution (0.13.x)

• Drawbacks: execution model based on MapReduce

• Better execution engines: Hive-Tez and Hive-Spark

!

• Alternative and usually faster options including

• Impala, Presto, Drill, ...

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Presto• Presto is a distributed SQL query engine optimized

for ad-hoc analysis at interactive speed

• Data scale: GBs to PBs

!

• Deployment at:

• Facebook, Netflix, Dropbox, Treasure Data, Airbnb, Qubole

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History of Presto• Fall 2012

• The development on Presto started at Facebook

• Spring 2013

• It was rolled out to the entire company and became major interactive data warehouse

• Winter 2013

• Open-sourced

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The Problems to Solve• Hive is not optimized for interactive data analysis as

the data size grows to petabyte scale

• In practice, we do need to have reduced data stored in an interactive DB that provides quick query response

• Redundant maintenance cost, out of date data view, data transferring, ...

• The need to incorporate other data that are not stored in HDFS

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Typical Batch Data Architecture

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HDFS

Data Flow Batch Run

DB

Query• Views generated in batch maybe out of date

• Batch workflow is too slow

Interactive Query on HDFS

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HDFS

Data Flow Interactive query

Presto

Query

Interactive Query on HDFS and other Data Sources

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HDFS

Data Flow Interactive query

Presto

QueryMySQL Cassandra

Distributed Architecture• Coordinator

• Parsing statements

• Planning queries

• Managing Presto workers !

• Worker

• Executing tasks

• Processing data

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Storage Plugins• Connectors

• Providing interfaces for fetching metadata, getting data locations, accessing the data

• Current connectors (v0.76)

• Hive: Hadoop 1.x, Hadoop 2.x, CDH 4, CDH 5

• Cassandra

• MySQL

• Kafka

• PostgreSQL

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Presto Clients

• Protocol: HTTP + JSON

!

• Client libraries available in several programming languages:

• Python, PHP, Ruby, Node.js, Java, R

!

• ODBC through Prestogres

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Query Model

• Presto’s execution engine does not use MapReduce

• It employs a custom query and execution engine

• Based on DAG that is more like Apache Tez, Spark or MPP databases

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Query Execution• Presto executes ANSI-compatible SQL statements

!

• Coordinator

• SQL parser

• Query planner

• Execution planner

• Workers

• Task execution scheduler

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Query Execution

Query planner

AST Query planExecution planner

Connector

Metadata

Execution plan

NodeManager

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Query Planner

SELECT name, count(*) from logs GROUP BY name

Logical query plan:

Table scan GROUP BY Output

Distributed query plan:

SQL:

Table scan

Stage-2

Partial aggregation

Output buffer

Exchange client

Final aggregation

Output buffer

Exchange client

Output

Stage-1 Stage-0

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Distributed query plan:

Table scan

Stage-2

Partial aggregation

Output buffer

Exchange client

Final aggregation

Output buffer

Exchange client

Output

Stage-1 Stage-0

Worker 1

Worker 2

Table scan

Partial aggregation

Output buffer

Exchange client

Final aggregation

Output buffer

Exchange client

Output

Table scan

Partial aggregation

Output buffer

Exchange client

Final aggregation

Output buffer

* Tasks run on workers

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Query Execution on Presto

• SQL is converted into stages, tasks, drivers

• Tasks operate on splits that are sections of data

• Lowest stages retrieve splits from connectors

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Query Execution on Presto

• Tasks are run in parallel

• Pipelined to reduce wait time between stages

• One task fails then the query fails

!

• No disk I/O

• If aggregated data does not fit in memory, the query fails

• May spill to disk in future

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Deployment & Configuration

• Basically, there are four configurations to set up for Presto

• Node properties: environment configuration specific to each node

• JVM config

• Config properties: configuration for Presto server

• Catalog properties: configuration for connectors !

• Detailed documents are provided on Presto site

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Node Properties

• etc/node.properties

• Minimal configuration:

node.environment=production node.id=ffffffff-ffff-ffff-ffff-ffffffffffff node.data-dir=/var/presto/data

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Config Properties

• etc/config.properties

• Minimal configuration for coordinator:

coordinator=true node-scheduler.include-coordinator=false http-server.http.port=8080 task.max-memory=1GB discovery-server.enabled=true discovery.uri=http://example.net:8080

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Config Properties

• Minimal configuration for worker:

coordinator=false http-server.http.port=8080 task.max-memory=1GB discovery.uri=http://example.net:8080

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Catalog Properties

• Presto connectors are mounted in catalogs

• Create catalog properties in etc/catalog

• For example, the configuration etc/catalog/hive.properties for Hive connector:

connector.name=hive-hadoop2 hive.metastore.uri=thrift://example.net:9083

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Presto’s Roadmap

• In next year:

• Complex data structures

• Create table with partitioning

• Huge joins and aggregations

• Spill to disk

• Basic task recovery

• Native store

• Authentication & authorization

* Based on the Presto Meetup, May 201427

Data Visualization with Presto - Demo

• There will be official ODBC driver for connecting Presto to major BI tools, according to Presto’s roadmap

• Prestogres provides alternative solution for now

• Use PostgreSQL’s ODBC driver

!

• It is also not difficult to integrate Presto with other data visualization tools such as Grafana

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Grafana

• An open source metrics dashboard and graph editor for Graphite, InfluxDB & OpenTSDB

• But we may not be satisfied with these DBs or just want to visualize data on HDFS, especially for large-scale data

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Integrating Presto with Grafana

• Presto provides many useful date & time functions

• current_date -> date

• current_time -> time with time zone

• current_timestamp -> timestamp with time zone

• from_unixtime(unixtime) → timestamp

• localtime -> time

• now() → timestamp with time zone

• to_unixtime(timestamp) → double

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Integrating Presto with Grafana

• Presto also supports many common aggregation functions

• avg(x) → double

• count(x) → bigint

• max(x) → [same as input]

• min(x) → [same as input]

• sum(x) → [same as input]

• …..

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Integrating Presto with Grafana

• So we implemented a custom datasource for Presto to work with Grafana

• Interactively visualize data on HDFS

HDFS

Interactive query

Presto

Grafana

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Demo

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References• Martin Traverso, “Presto: Interacting with petabytes of data at

Facebook”

• Sadayuki Furuhashi, “Presto: Interactive SQL Query Engine for Big Data”

• Sundstrom, “Presto: Past, Present, and Future”

• “Presto Concepts” on Presto’s documents

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