Performance Optimizations in Apache ImpalaCloudera, Inc.
Apache Impala is a modern, open-source MPP SQL engine architected from the ground up for the Hadoop data processing environment. Impala provides low latency and high concurrency for BI/analytic read-mostly queries on Hadoop, not delivered by batch frameworks such as Hive or SPARK. Impala is written from the ground up in C++ and Java. It maintains Hadoop’s flexibility by utilizing standard components (HDFS, HBase, Metastore, Sentry) and is able to read the majority of the widely-used file formats (e.g. Parquet, Avro, RCFile).
To reduce latency, such as that incurred from utilizing MapReduce or by reading data remotely, Impala implements a distributed architecture based on daemon processes that are responsible for all aspects of query execution and that run on the same machines as the rest of the Hadoop infrastructure. Impala employs runtime code generation using LLVM in order to improve execution times and uses static and dynamic partition pruning to significantly reduce the amount of data accessed. The result is performance that is on par or exceeds that of commercial MPP analytic DBMSs, depending on the particular workload. Although initially designed for running on-premises against HDFS-stored data, Impala can also run on public clouds and access data stored in various storage engines such as object stores (e.g. AWS S3), Apache Kudu and HBase. In this talk, we present Impala's architecture in detail and discuss the integration with different storage engines and the cloud.
How to use Impala query plan and profile to fix performance issuesCloudera, Inc.
Apache Impala is an exceptional, best-of-breed massively parallel processing SQL query engine that is a fundamental component of the big data software stack. Juan Yu demystifies the cost model Impala Planner uses and how Impala optimizes queries and explains how to identify performance bottleneck through query plan and profile and how to drive Impala to its full potential.
Performance Optimizations in Apache ImpalaCloudera, Inc.
Apache Impala is a modern, open-source MPP SQL engine architected from the ground up for the Hadoop data processing environment. Impala provides low latency and high concurrency for BI/analytic read-mostly queries on Hadoop, not delivered by batch frameworks such as Hive or SPARK. Impala is written from the ground up in C++ and Java. It maintains Hadoop’s flexibility by utilizing standard components (HDFS, HBase, Metastore, Sentry) and is able to read the majority of the widely-used file formats (e.g. Parquet, Avro, RCFile).
To reduce latency, such as that incurred from utilizing MapReduce or by reading data remotely, Impala implements a distributed architecture based on daemon processes that are responsible for all aspects of query execution and that run on the same machines as the rest of the Hadoop infrastructure. Impala employs runtime code generation using LLVM in order to improve execution times and uses static and dynamic partition pruning to significantly reduce the amount of data accessed. The result is performance that is on par or exceeds that of commercial MPP analytic DBMSs, depending on the particular workload. Although initially designed for running on-premises against HDFS-stored data, Impala can also run on public clouds and access data stored in various storage engines such as object stores (e.g. AWS S3), Apache Kudu and HBase. In this talk, we present Impala's architecture in detail and discuss the integration with different storage engines and the cloud.
How to use Impala query plan and profile to fix performance issuesCloudera, Inc.
Apache Impala is an exceptional, best-of-breed massively parallel processing SQL query engine that is a fundamental component of the big data software stack. Juan Yu demystifies the cost model Impala Planner uses and how Impala optimizes queries and explains how to identify performance bottleneck through query plan and profile and how to drive Impala to its full potential.
At Salesforce, we have deployed many thousands of HBase/HDFS servers, and learned a lot about tuning during this process. This talk will walk you through the many relevant HBase, HDFS, Apache ZooKeeper, Java/GC, and Operating System configuration options and provides guidelines about which options to use in what situation, and how they relate to each other.
Massive Data Processing in Adobe Using Delta LakeDatabricks
At Adobe Experience Platform, we ingest TBs of data every day and manage PBs of data for our customers as part of the Unified Profile Offering. At the heart of this is a bunch of complex ingestion of a mix of normalized and denormalized data with various linkage scenarios power by a central Identity Linking Graph. This helps power various marketing scenarios that are activated in multiple platforms and channels like email, advertisements etc. We will go over how we built a cost effective and scalable data pipeline using Apache Spark and Delta Lake and share our experiences.
What are we storing?
Multi Source – Multi Channel Problem
Data Representation and Nested Schema Evolution
Performance Trade Offs with Various formats
Go over anti-patterns used
(String FTW)
Data Manipulation using UDFs
Writer Worries and How to Wipe them Away
Staging Tables FTW
Datalake Replication Lag Tracking
Performance Time!
Improving SparkSQL Performance by 30%: How We Optimize Parquet Pushdown and P...Databricks
Parquet is a very popular column based format. Spark can automatically filter useless data using parquet file statistical data by pushdown filters, such as min-max statistics. On the other hand, Spark user can enable Spark parquet vectorized reader to read parquet files by batch. These features improve Spark performance greatly and save both CPU and IO. Parquet is the default data format of data warehouse in Bytedance. In practice, we find that parquet pushdown filters work poorly resulting in reading too much unnecessary data for statistical data has no discrimination across parquet row groups(column data is out of order when writing to parquet files by ETL jobs).
An Introduction to Cloudera Impala, shows how Impala works, and the internal processing of query of Impala, including architecture, frontend, query compilation, backend, code generation, HDFS-related stuff and performance comparison.
Oracle GoldenGate and Apache Kafka A Deep Dive Into Real-Time Data StreamingMichael Rainey
We produce quite a lot of data! Much of the data are business transactions stored in a relational database. More frequently, the data are non-structured, high volume and rapidly changing datasets known in the industry as Big Data. The challenge for data integration professionals is to combine and transform the data into useful information. Not just that, but it must also be done in near real-time and using a target system such as Hadoop. The topic of this session, real-time data streaming, provides a great solution for this challenging task. By integrating GoldenGate, Oracle’s premier data replication technology, and Apache Kafka, the latest open-source streaming and messaging system, we can implement a fast, durable, and scalable solution. Presented at KScope16.
3 Things to Learn About:
-How Kudu is able to fill the analytic gap between HDFS and Apache HBase
-The trade-offs between real-time transactional access and fast analytic performance
-How Kudu provides an option to achieve fast scans and random access from a single API
Using Apache Arrow, Calcite, and Parquet to Build a Relational CacheDremio Corporation
From DataEngConf 2017 - Everybody wants to get to data faster. As we move from more general solution to specific optimization techniques, the level of performance impact grows. This talk will discuss how layering in-memory caching, columnar storage and relational caching can combine to provide a substantial improvement in overall data science and analytical workloads. It will include a detailed overview of how you can use Apache Arrow, Calcite and Parquet to achieve multiple magnitudes improvement in performance over what is currently possible.
Amazon S3 Best Practice and Tuning for Hadoop/Spark in the CloudNoritaka Sekiyama
Amazon S3 Best Practice and Tuning for Hadoop/Spark in the Cloud (Hadoop / Spark Conference Japan 2019)
# English version #
http://hadoop.apache.jp/hcj2019-program/
A Thorough Comparison of Delta Lake, Iceberg and HudiDatabricks
Recently, a set of modern table formats such as Delta Lake, Hudi, Iceberg spring out. Along with Hive Metastore these table formats are trying to solve problems that stand in traditional data lake for a long time with their declared features like ACID, schema evolution, upsert, time travel, incremental consumption etc.
Parquet performance tuning: the missing guideRyan Blue
Ryan Blue explains how Netflix is building on Parquet to enhance its 40+ petabyte warehouse, combining Parquet’s features with Presto and Spark to boost ETL and interactive queries. Information about tuning Parquet is hard to find. Ryan shares what he’s learned, creating the missing guide you need.
Topics include:
* The tools and techniques Netflix uses to analyze Parquet tables
* How to spot common problems
* Recommendations for Parquet configuration settings to get the best performance out of your processing platform
* The impact of this work in speeding up applications like Netflix’s telemetry service and A/B testing platform
The Rise of ZStandard: Apache Spark/Parquet/ORC/AvroDatabricks
Zstandard is a fast compression algorithm which you can use in Apache Spark in various way. In this talk, I briefly summarized the evolution history of Apache Spark in this area and four main use cases and the benefits and the next steps:
1) ZStandard can optimize Spark local disk IO by compressing shuffle files significantly. This is very useful in K8s environments. It’s beneficial not only when you use `emptyDir` with `memory` medium, but also it maximizes OS cache benefit when you use shared SSDs or container local storage. In Spark 3.2, SPARK-34390 takes advantage of ZStandard buffer pool feature and its performance gain is impressive, too.
2) Event log compression is another area to save your storage cost on the cloud storage like S3 and to improve the usability. SPARK-34503 officially switched the default event log compression codec from LZ4 to Zstandard.
3) Zstandard data file compression can give you more benefits when you use ORC/Parquet files as your input and output. Apache ORC 1.6 supports Zstandardalready and Apache Spark enables it via SPARK-33978. The upcoming Parquet 1.12 will support Zstandard compression.
4) Last, but not least, since Apache Spark 3.0, Zstandard is used to serialize/deserialize MapStatus data instead of Gzip.
There are more community works to utilize Zstandard to improve Spark. For example, Apache Avro community also supports Zstandard and SPARK-34479 aims to support Zstandard in Spark’s avro file format in Spark 3.2.0.
How Adobe Does 2 Million Records Per Second Using Apache Spark!Databricks
Adobe’s Unified Profile System is the heart of its Experience Platform. It ingests TBs of data a day and is PBs large. As part of this massive growth we have faced multiple challenges in our Apache Spark deployment which is used from Ingestion to Processing.
Hudi: Large-Scale, Near Real-Time Pipelines at Uber with Nishith Agarwal and ...Databricks
Uber has real needs to provide faster, fresher data to data consumers & products, running hundreds of thousands of analytical queries everyday. Uber engineers will share the design, architecture & use-cases of the second generation of ‘Hudi’, a self contained Apache Spark library to build large scale analytical datasets designed to serve such needs and beyond. Hudi (formerly Hoodie) is created to effectively manage petabytes of analytical data on distributed storage, while supporting fast ingestion & queries. In this talk, we will discuss how we leveraged Spark as a general purpose distributed execution engine to build Hudi, detailing tradeoffs & operational experience. We will also show to ingest data into Hudi using Spark Datasource/Streaming APIs and build Notebooks/Dashboards on top using Spark SQL.
We can leverage Delta Lake, structured streaming for write-heavy use cases. This talk will go through a use case at Intuit whereby we built MOR as an architecture to allow for a very low SLA, etc. For MOR, there are different ways to view the fresh data, so we will also go over the methods used to perfTest the various ways that we were able to arrive at the best method for the given use case.
Deep Dive into the New Features of Apache Spark 3.0Databricks
Continuing with the objectives to make Spark faster, easier, and smarter, Apache Spark 3.0 extends its scope with more than 3000 resolved JIRAs. We will talk about the exciting new developments in the Spark 3.0 as well as some other major initiatives that are coming in the future.
Cost-Based Optimizer in Apache Spark 2.2 Ron Hu, Sameer Agarwal, Wenchen Fan ...Databricks
Apache Spark 2.2 ships with a state-of-art cost-based optimization framework that collects and leverages a variety of per-column data statistics (e.g., cardinality, number of distinct values, NULL values, max/min, avg/max length, etc.) to improve the quality of query execution plans. Leveraging these reliable statistics helps Spark to make better decisions in picking the most optimal query plan. Examples of these optimizations include selecting the correct build side in a hash-join, choosing the right join type (broadcast hash-join vs. shuffled hash-join) or adjusting a multi-way join order, among others. In this talk, we’ll take a deep dive into Spark’s cost based optimizer and discuss how we collect/store these statistics, the query optimizations it enables, and its performance impact on TPC-DS benchmark queries.
Cost-Based Optimizer in Apache Spark 2.2 Databricks
Apache Spark 2.2 ships with a state-of-art cost-based optimization framework that collects and leverages a variety of per-column data statistics (e.g., cardinality, number of distinct values, NULL values, max/min, avg/max length, etc.) to improve the quality of query execution plans. Leveraging these reliable statistics helps Spark to make better decisions in picking the most optimal query plan. Examples of these optimizations include selecting the correct build side in a hash-join, choosing the right join type (broadcast hash-join vs. shuffled hash-join) or adjusting a multi-way join order, among others. In this talk, we’ll take a deep dive into Spark’s cost based optimizer and discuss how we collect/store these statistics, the query optimizations it enables, and its performance impact on TPC-DS benchmark queries.
At Salesforce, we have deployed many thousands of HBase/HDFS servers, and learned a lot about tuning during this process. This talk will walk you through the many relevant HBase, HDFS, Apache ZooKeeper, Java/GC, and Operating System configuration options and provides guidelines about which options to use in what situation, and how they relate to each other.
Massive Data Processing in Adobe Using Delta LakeDatabricks
At Adobe Experience Platform, we ingest TBs of data every day and manage PBs of data for our customers as part of the Unified Profile Offering. At the heart of this is a bunch of complex ingestion of a mix of normalized and denormalized data with various linkage scenarios power by a central Identity Linking Graph. This helps power various marketing scenarios that are activated in multiple platforms and channels like email, advertisements etc. We will go over how we built a cost effective and scalable data pipeline using Apache Spark and Delta Lake and share our experiences.
What are we storing?
Multi Source – Multi Channel Problem
Data Representation and Nested Schema Evolution
Performance Trade Offs with Various formats
Go over anti-patterns used
(String FTW)
Data Manipulation using UDFs
Writer Worries and How to Wipe them Away
Staging Tables FTW
Datalake Replication Lag Tracking
Performance Time!
Improving SparkSQL Performance by 30%: How We Optimize Parquet Pushdown and P...Databricks
Parquet is a very popular column based format. Spark can automatically filter useless data using parquet file statistical data by pushdown filters, such as min-max statistics. On the other hand, Spark user can enable Spark parquet vectorized reader to read parquet files by batch. These features improve Spark performance greatly and save both CPU and IO. Parquet is the default data format of data warehouse in Bytedance. In practice, we find that parquet pushdown filters work poorly resulting in reading too much unnecessary data for statistical data has no discrimination across parquet row groups(column data is out of order when writing to parquet files by ETL jobs).
An Introduction to Cloudera Impala, shows how Impala works, and the internal processing of query of Impala, including architecture, frontend, query compilation, backend, code generation, HDFS-related stuff and performance comparison.
Oracle GoldenGate and Apache Kafka A Deep Dive Into Real-Time Data StreamingMichael Rainey
We produce quite a lot of data! Much of the data are business transactions stored in a relational database. More frequently, the data are non-structured, high volume and rapidly changing datasets known in the industry as Big Data. The challenge for data integration professionals is to combine and transform the data into useful information. Not just that, but it must also be done in near real-time and using a target system such as Hadoop. The topic of this session, real-time data streaming, provides a great solution for this challenging task. By integrating GoldenGate, Oracle’s premier data replication technology, and Apache Kafka, the latest open-source streaming and messaging system, we can implement a fast, durable, and scalable solution. Presented at KScope16.
3 Things to Learn About:
-How Kudu is able to fill the analytic gap between HDFS and Apache HBase
-The trade-offs between real-time transactional access and fast analytic performance
-How Kudu provides an option to achieve fast scans and random access from a single API
Using Apache Arrow, Calcite, and Parquet to Build a Relational CacheDremio Corporation
From DataEngConf 2017 - Everybody wants to get to data faster. As we move from more general solution to specific optimization techniques, the level of performance impact grows. This talk will discuss how layering in-memory caching, columnar storage and relational caching can combine to provide a substantial improvement in overall data science and analytical workloads. It will include a detailed overview of how you can use Apache Arrow, Calcite and Parquet to achieve multiple magnitudes improvement in performance over what is currently possible.
Amazon S3 Best Practice and Tuning for Hadoop/Spark in the CloudNoritaka Sekiyama
Amazon S3 Best Practice and Tuning for Hadoop/Spark in the Cloud (Hadoop / Spark Conference Japan 2019)
# English version #
http://hadoop.apache.jp/hcj2019-program/
A Thorough Comparison of Delta Lake, Iceberg and HudiDatabricks
Recently, a set of modern table formats such as Delta Lake, Hudi, Iceberg spring out. Along with Hive Metastore these table formats are trying to solve problems that stand in traditional data lake for a long time with their declared features like ACID, schema evolution, upsert, time travel, incremental consumption etc.
Parquet performance tuning: the missing guideRyan Blue
Ryan Blue explains how Netflix is building on Parquet to enhance its 40+ petabyte warehouse, combining Parquet’s features with Presto and Spark to boost ETL and interactive queries. Information about tuning Parquet is hard to find. Ryan shares what he’s learned, creating the missing guide you need.
Topics include:
* The tools and techniques Netflix uses to analyze Parquet tables
* How to spot common problems
* Recommendations for Parquet configuration settings to get the best performance out of your processing platform
* The impact of this work in speeding up applications like Netflix’s telemetry service and A/B testing platform
The Rise of ZStandard: Apache Spark/Parquet/ORC/AvroDatabricks
Zstandard is a fast compression algorithm which you can use in Apache Spark in various way. In this talk, I briefly summarized the evolution history of Apache Spark in this area and four main use cases and the benefits and the next steps:
1) ZStandard can optimize Spark local disk IO by compressing shuffle files significantly. This is very useful in K8s environments. It’s beneficial not only when you use `emptyDir` with `memory` medium, but also it maximizes OS cache benefit when you use shared SSDs or container local storage. In Spark 3.2, SPARK-34390 takes advantage of ZStandard buffer pool feature and its performance gain is impressive, too.
2) Event log compression is another area to save your storage cost on the cloud storage like S3 and to improve the usability. SPARK-34503 officially switched the default event log compression codec from LZ4 to Zstandard.
3) Zstandard data file compression can give you more benefits when you use ORC/Parquet files as your input and output. Apache ORC 1.6 supports Zstandardalready and Apache Spark enables it via SPARK-33978. The upcoming Parquet 1.12 will support Zstandard compression.
4) Last, but not least, since Apache Spark 3.0, Zstandard is used to serialize/deserialize MapStatus data instead of Gzip.
There are more community works to utilize Zstandard to improve Spark. For example, Apache Avro community also supports Zstandard and SPARK-34479 aims to support Zstandard in Spark’s avro file format in Spark 3.2.0.
How Adobe Does 2 Million Records Per Second Using Apache Spark!Databricks
Adobe’s Unified Profile System is the heart of its Experience Platform. It ingests TBs of data a day and is PBs large. As part of this massive growth we have faced multiple challenges in our Apache Spark deployment which is used from Ingestion to Processing.
Hudi: Large-Scale, Near Real-Time Pipelines at Uber with Nishith Agarwal and ...Databricks
Uber has real needs to provide faster, fresher data to data consumers & products, running hundreds of thousands of analytical queries everyday. Uber engineers will share the design, architecture & use-cases of the second generation of ‘Hudi’, a self contained Apache Spark library to build large scale analytical datasets designed to serve such needs and beyond. Hudi (formerly Hoodie) is created to effectively manage petabytes of analytical data on distributed storage, while supporting fast ingestion & queries. In this talk, we will discuss how we leveraged Spark as a general purpose distributed execution engine to build Hudi, detailing tradeoffs & operational experience. We will also show to ingest data into Hudi using Spark Datasource/Streaming APIs and build Notebooks/Dashboards on top using Spark SQL.
We can leverage Delta Lake, structured streaming for write-heavy use cases. This talk will go through a use case at Intuit whereby we built MOR as an architecture to allow for a very low SLA, etc. For MOR, there are different ways to view the fresh data, so we will also go over the methods used to perfTest the various ways that we were able to arrive at the best method for the given use case.
Deep Dive into the New Features of Apache Spark 3.0Databricks
Continuing with the objectives to make Spark faster, easier, and smarter, Apache Spark 3.0 extends its scope with more than 3000 resolved JIRAs. We will talk about the exciting new developments in the Spark 3.0 as well as some other major initiatives that are coming in the future.
Cost-Based Optimizer in Apache Spark 2.2 Ron Hu, Sameer Agarwal, Wenchen Fan ...Databricks
Apache Spark 2.2 ships with a state-of-art cost-based optimization framework that collects and leverages a variety of per-column data statistics (e.g., cardinality, number of distinct values, NULL values, max/min, avg/max length, etc.) to improve the quality of query execution plans. Leveraging these reliable statistics helps Spark to make better decisions in picking the most optimal query plan. Examples of these optimizations include selecting the correct build side in a hash-join, choosing the right join type (broadcast hash-join vs. shuffled hash-join) or adjusting a multi-way join order, among others. In this talk, we’ll take a deep dive into Spark’s cost based optimizer and discuss how we collect/store these statistics, the query optimizations it enables, and its performance impact on TPC-DS benchmark queries.
Cost-Based Optimizer in Apache Spark 2.2 Databricks
Apache Spark 2.2 ships with a state-of-art cost-based optimization framework that collects and leverages a variety of per-column data statistics (e.g., cardinality, number of distinct values, NULL values, max/min, avg/max length, etc.) to improve the quality of query execution plans. Leveraging these reliable statistics helps Spark to make better decisions in picking the most optimal query plan. Examples of these optimizations include selecting the correct build side in a hash-join, choosing the right join type (broadcast hash-join vs. shuffled hash-join) or adjusting a multi-way join order, among others. In this talk, we’ll take a deep dive into Spark’s cost based optimizer and discuss how we collect/store these statistics, the query optimizations it enables, and its performance impact on TPC-DS benchmark queries.
Spark SQL Adaptive Execution Unleashes The Power of Cluster in Large Scale wi...Databricks
Spark SQL is a very effective distributed SQL engine for OLAP and widely adopted in Baidu production for many internal BI projects. However, Baidu has also been facing many challenges for large scale including tuning the shuffle parallelism for thousands of jobs, inefficient execution plan, and handling data skew.
In this talk, we will explore Intel and Baidu’s joint efforts to address challenges in large scale and offer an overview of an adaptive execution mode we implemented for Baidu’s Big SQL platform which is based on Spark SQL. At runtime, adaptive execution can change the execution plan to use a better join strategy and handle skewed join automatically. It can also change the number of reducer to better fit the data scale. In general, adaptive execution decreases the effort involved in tuning SQL query parameters and improves the execution performance by choosing a better execution plan and parallelism at runtime.
We’ll also share our experience of using adaptive execution in Baidu’s production cluster with thousands of server, where adaptive execution helps to improve the performance of some complex queries by 200%. After further analysis we found that several special scenarios in Baidu data analysis can benefit from the optimization of choosing better join type. We got 2x performance improvement in the scenario where the user wanted to analysis 1000+ advertisers’ cost from both web and mobile side and each side has a full information table with 10 TB parquet file per-day. Now we are writing probe jobs to detect more scenarios from current daily jobs of our users. We are also considering to expose the strategy interface based on the detailed metrics collected form adaptive execution mode for the upper users.
Cost-Based Optimizer Framework for Spark SQL: Spark Summit East talk by Ron H...Spark Summit
In Spark SQL’s Catalyst optimizer, many rule based optimization techniques have been implemented, but the optimizer itself can still be improved. For example, without detailed column statistics information on data distribution, it is difficult to accurately estimate the filter factor, cardinality, and thus output size of a database operator. With the inaccurate and/or misleading statistics, it often leads the optimizer to choose suboptimal query execution plans.
We added a Cost-Based Optimizer framework to Spark SQL engine. In our framework, we use Analyze Table SQL statement to collect the detailed column statistics and save them into Spark’s catalog. For the relevant columns, we collect number of distinct values, number of NULL values, maximum/minimum value, average/maximal column length, etc. Also, we save the data distribution of columns in either equal-width or equal-height histograms in order to deal with data skew effectively. Furthermore, with the number of distinct values and number of records of a table, we can determine how unique a column is although Spark SQL does not support primary key. This helps determine, for example, the output size of join operation and multi-column group-by operation.
In our framework, we compute the cardinality and output size of each database operator. With reliable statistics and derived cardinalities, we are able to make good decisions in these areas: selecting the correct build side of a hash-join operation, choosing the right join type (broadcast hash-join versus shuffled hash-join), adjusting multi-way join order, etc. In this talk, we will show Spark SQL’s new Cost-Based Optimizer framework and its performance impact on TPC-DS benchmark queries.
What's new in 1.9.0 blink planner - Kurt Young, AlibabaFlink Forward
Flink 1.9.0 added the ability to support multiple SQL planners under the same API. With this help. we successfully merged a lot features which comes from Alibaba's internal flink version, called blink. In this talk, I will give a introduction about the architecture of the blink planner, and also share with you the functionalities and performance enhancements we added.
Optimizing InfluxDB Performance in the Real World by Dean Sheehan, Senior Dir...InfluxData
Dean will provide practical tips and techniques learned from helping hundreds of customers deploy InfluxDB and InfluxDB Enterprise. This includes hardware and architecture choices, schema design, configuration setup, and running queries.
Don’t optimize my queries, optimize my data!Julian Hyde
Your queries won't run fast if your data is not organized right. Apache Calcite optimizes queries, but can we evolve it so that it can optimize data? We had to solve several challenges. Users are too busy to tell us the structure of their database, and the query load changes daily, so Calcite has to learn and adapt.
We talk about new algorithms we developed for gathering statistics on massive database, and how we infer and evolve the data model based on the queries, suggesting materialized views that will make your queries run faster without you changing them.
A talk given by Julian Hyde at DataEngConf NYC, Columbia University, on 2017/10/30.
SnappyData, the Spark Database. A unified cluster for streaming, transactions...SnappyData
Apache Spark 2.0 offers many enhancements that make continuous analytics quite simple. In this talk, we will discuss many other things that you can do with your Apache Spark cluster. We explain how a deep integration of Apache Spark 2.0 and in-memory databases can bring you the best of both worlds! In particular, we discuss how to manage mutable data in Apache Spark, run consistent transactions at the same speed as state-the-art in-memory grids, build and use indexes for point lookups, and run 100x more analytics queries at in-memory speeds. No need to bridge multiple products or manage, tune multiple clusters. We explain how one can take regulation Apache Spark SQL OLAP workloads and speed them up by up to 20x using optimizations in SnappyData.
We then walk through several use-case examples, including IoT scenarios, where one has to ingest streams from many sources, cleanse it, manage the deluge by pre-aggregating and tracking metrics per minute, store all recent data in a in-memory store along with history in a data lake and permit interactive analytic queries at this constantly growing data. Rather than stitching together multiple clusters as proposed in Lambda, we walk through a design where everything is achieved in a single, horizontally scalable Apache Spark 2.0 cluster. A design that is simpler, a lot more efficient, and let’s you do everything from Machine Learning and Data Science to Transactions and Visual Analytics all in one single cluster.
Why does big data always have to go through a pipeline? multiple data copies, slow, complex and stale analytics? We present a unified analytics platform that brings streaming, transactions and adhoc OLAP style interactive analytics in a single in-memory cluster based on Spark.
(Randall Hauch, Confluent) Kafka Summit SF 2018
The Kafka Connect framework makes it easy to move data into and out of Kafka, and you want to write a connector. Where do you start, and what are the most important things to know? This is an advanced talk that will cover important aspects of how the Connect framework works and best practices of designing, developing, testing and packaging connectors so that you and your users will be successful. We’ll review how the Connect framework is evolving, and how you can help develop and improve it.
Data warehousing is a critical component for analysing and extracting actionable insights from your data. Amazon Redshift allows you to deploy a scalable data warehouse in a matter of minutes and starts to analyse your data right away using your existing business intelligence tools.
Hadoop Summit 2014: Query Optimization and JIT-based Vectorized Execution in ...Gruter
Apache Tajo is an open source big data warehouse system on Hadoop. This slide shows two high-tech efforts for performance improvement in Tajo project. First one is query optimization including cost-based join order and progressive optimization. The second effort is JIT-based vectorized processing.
Cloudera Data Impact Awards 2021 - Finalists Cloudera, Inc.
This annual program recognizes organizations who are moving swiftly towards the future and building innovative solutions by making what was impossible yesterday, possible today.
The winning organizations' implementations demonstrate outstanding achievements in fulfilling their mission, technical advancement, and overall impact.
The 2021 Data Impact Awards recognize organizations' achievements with the Cloudera Data Platform in seven categories:
Data Lifecycle Connection
Data for Enterprise AI
Cloud Innovation
Security & Governance Leadership
People First
Data for Good
Industry Transformation
2020 Cloudera Data Impact Awards FinalistsCloudera, Inc.
Cloudera is proud to present the 2020 Data Impact Awards Finalists. This annual program recognizes organizations running the Cloudera platform for the applications they've built and the impact their data projects have on their organizations, their industries, and the world. Nominations were evaluated by a panel of independent thought-leaders and expert industry analysts, who then selected the finalists and winners. Winners exemplify the most-cutting edge data projects and represent innovation and leadership in their respective industries.
Machine Learning with Limited Labeled Data 4/3/19Cloudera, Inc.
Cloudera Fast Forward Labs’ latest research report and prototype explore learning with limited labeled data. This capability relaxes the stringent labeled data requirement in supervised machine learning and opens up new product possibilities. It is industry invariant, addresses the labeling pain point and enables applications to be built faster and more efficiently.
Data Driven With the Cloudera Modern Data Warehouse 3.19.19Cloudera, Inc.
In this session, we will cover how to move beyond structured, curated reports based on known questions on known data, to an ad-hoc exploration of all data to optimize business processes and into the unknown questions on unknown data, where machine learning and statistically motivated predictive analytics are shaping business strategy.
Introducing Cloudera DataFlow (CDF) 2.13.19Cloudera, Inc.
Watch this webinar to understand how Hortonworks DataFlow (HDF) has evolved into the new Cloudera DataFlow (CDF). Learn about key capabilities that CDF delivers such as -
-Powerful data ingestion powered by Apache NiFi
-Edge data collection by Apache MiNiFi
-IoT-scale streaming data processing with Apache Kafka
-Enterprise services to offer unified security and governance from edge-to-enterprise
Introducing Cloudera Data Science Workbench for HDP 2.12.19Cloudera, Inc.
Cloudera’s Data Science Workbench (CDSW) is available for Hortonworks Data Platform (HDP) clusters for secure, collaborative data science at scale. During this webinar, we provide an introductory tour of CDSW and a demonstration of a machine learning workflow using CDSW on HDP.
Shortening the Sales Cycle with a Modern Data Warehouse 1.30.19Cloudera, Inc.
Join Cloudera as we outline how we use Cloudera technology to strengthen sales engagement, minimize marketing waste, and empower line of business leaders to drive successful outcomes.
Leveraging the cloud for analytics and machine learning 1.29.19Cloudera, Inc.
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1. Query Compilation in Impala
Query Compilation in Impala
Alexander Behm | Software Engineer
May 2014 @ Impala User Group
2. Query Compilation in Impala
Compile Query
Execute Query
Client
Client
SQL Text
Executable Plan
Query Results
Impala Frontend
(Java)
Impala Backend
(C++)
Focus of this talk
Flow of a SQL Query
3. Query Compilation in Impala
Client
SQL Text
Executable Plan
Query Compilation
Query
Compiler
SQL
Parsing
Semantic
Analysis
Query
Planning
Parse Tree
Parse Tree + Analyzer
4. Query Compilation in Impala
Query Parsing
SELECT c1, SUM(c2)
FROM t1 JOIN t2 USING(id)
WHERE c3 > 10 GROUP BY c1
SelectList TableRefs WhereClause
SelectStmt
GroupByClause
ColRef AggExpr
ColRef
BinaryPredicate
ColRef IntLiteral
ColRefTableRef TableRef
UsingClause
ColRef
• Applies SQL grammar, reports syntax errors
• Produces parse tree capturing syntactic structure of query
5. Query Compilation in Impala
Semantic Analysis…
• Precondition: Query is syntactically valid. Analysis operates on parse tree.
• Consults table metadata
• Do t1 and t2 exist? Does c1 exist in t1 or t2 (or both error)? Does id exist in t1 and t2?
• Does the user have privileges to SELECT from t1?
• Checks type compatibility of expressions, adds implicit casts
• c3 > 10 c3 > cast(10 as bigint)
• SQL rules (semantic, not syntactic)
• Does c1 appear in the GROUP BY clause?
SELECT c1, SUM(c2)
FROM t1 JOIN t2 USING(id)
WHERE c3 > 10 GROUP BY c1
6. Query Compilation in Impala
… Semantic Analysis
• Expression substitution for views
• Resolve column references against base tables
• Preparation for Planning
• Register state in analyzer for correct predicate assignment during planning
• Register predicates (WHERE, HAVING, ON, USING, etc.)
• Register outer-joined tables
• Compute value-transfer graph and equivalence classes for predicate inference
• (…)
• Postcondition: Query is valid. An executable plan can be produced.
SELECT c1, SUM(c2)
FROM (SELECT dept AS c1, revenue AS c2,
month AS c3 FROM t1) AS v
WHERE c3 > 10 GROUP BY c1
SELECT dept, SUM(revenue)
FROM t1
WHERE month > 10
GROUP BY dept
7. Query Compilation in Impala
• Generate executable plan (“tree” of operators)
• Maximize scan locality using DN block metadata
• Minimize data movement
• Full distribution of operators
• Query operators
• Scan, HashJoin, HashAggregation, Union, TopN,
Exchange
Query Planning: Goals
8. Query Compilation in Impala
Query Planning: Overview
Semantic
Analysis
Parse Tree + Analyzer
Query
Planner
Walk Parse Tree
Parallelize
& Fragment
Single-node Plan
Executable Plan
9. Query Compilation in Impala
Query Planning: Single-Node Plan
• Four major functions:
1. Parse Tree Plan Tree
2. Assigns predicates to lowest plan node
3. Optimizes join order
4. Prunes irrelevant columns
10. Query Compilation in Impala
Parse Tree Single-Node Plan Tree
HashJoin
Scan: t1
Scan: t3
Scan: t2
HashJoin
TopN
Agg
SELECT t1.dept, SUM(t2.revenue)
FROM LargeHdfsTable t1
JOIN HugeHdfsTable t2 ON (t1.id1 = t2.id)
JOIN SmallHbaseTable t3 ON (t1.id2 = t3.id)
WHERE t3.category = 'Online‘ AND t1.id > 10
GROUP BY t1.dept
HAVING COUNT(t2.revenue) > 10
ORDER BY revenue LIMIT 10
11. Query Compilation in Impala
SELECT t1.dept, SUM(t2.revenue)
FROM LargeHdfsTable t1
JOIN HugeHdfsTable t2 ON (t1.id1 = t2.id)
JOIN SmallHbaseTable t3 ON (t1.id2 = t3.id)
WHERE t3.category = 'Online‘ AND t1.id > 10
GROUP BY t1.dept
HAVING COUNT(t2.revenue) > 10
ORDER BY revenue LIMIT 10
Predicate Assignment & Inference
HashJoin
Scan: t1
Scan: t3
Scan: t2
HashJoin
TopN
Agg
COUNT(t2.revenue) > 10
t1.id2 = t3.id
t1.id1 = t2.id
id1 > 10
category = ‘Online’
id > 10
Inferred
Predicate
12. Query Compilation in Impala
Join-Order Optimization
• Inner joins are commutative and associative
• Query results correct independent of execution order
• Query execution costs vary dramatically!
• Hash table sizes, network transfers, #hash lookups
• Join-order optimization
• Impala only considers left-deep join trees
• (Right join input is a table, not another join)
• Find cheapest valid join order
• Relies heavily on table and column statistics
• Limitation: Choice of join order independent of join strategy
13. Query Compilation in Impala
Invalid Join Orders
SELECT t1.dept, SUM(t2.revenue)
FROM LargeHdfsTable t1
JOIN HugeHdfsTable t2 ON (t1.id1 = t2.id)
JOIN SmallHbaseTable t3 ON (t1.id2 = t3.id)
WHERE t3.category = 'Online‘ AND t1.id > 10
GROUP BY t1.dept
HAVING COUNT(t2.revenue) > 10
ORDER BY revenue LIMIT 10
No explicit or implicit
predicate between t2 and t3
14. Query Compilation in Impala
Join-Order Optimization
HashJoin
Scan: t1
Scan: t3
Scan: t2
HashJoin
HashJoin
Scan: t1
Scan: t2
Scan: t3
HashJoin
HashJoin
Scan: t2
Scan: t3
Scan: t1
HashJoin
HashJoin
Scan: t2
Scan: t1
Scan: t3
HashJoin
HashJoin
Scan: t3
Scan: t2
Scan: t1
HashJoin
HashJoin
Scan: t3
Scan: t1
Scan: t2
HashJoin
Order:
t1, t2, t3
Order:
t1, t3, t2
Order:
t2, t1, t3
Order:
t2, t3, t1
Order:
t3, t1, t2
Order:
t3, t2, t1
15. Query Compilation in Impala
Join-Order Optimization
• Impala’s Implementation:
1. Heuristic
• Order tables descending by size
• Best plan typically has largest table on the left (if valid)
2. Plan enumeration & costing
• Generate all possible join orders starting from a given
left-most table (starting with largest one)
• Ignore invalid join orders
• Estimate intermediate result sizes (key!)
• Choose plan that minimizes intermediate result sizes
16. Query Compilation in Impala
Query Planning: Overview
Semantic
Analysis
Parse Tree + Analyzer
Query
Planner
Walk Parse Tree
Parallelize
& Fragment
Single-node Plan
Executable Plan
17. Query Compilation in Impala
Query Planning: Distributed Plans
• Distributed Aggregation
• Pre-aggregation where data is first materialized
• Merge-aggregation partitioned by grouping columns
• Distinct aggregation: additional level of pre- and merge aggregation
• Distributed Top-N
• Initial Top-N where data is first materialized
• Final Top-N at coordinator
• Distributed Union
• Pre-aggregation/top-n placed into plans of each union operand
• Union-operand plans executed in parallel, merged via exchange
• Above strategies are currently fixed in Impala
• Independent of column/table stats
18. Query Compilation in Impala
Query Planning: Distributed Joins
• Broadcast Join
• Join is co-located with left input
• Broadcast right input to all nodes executing join
• Build hash table on right input, streaming probe from left input
• Preferred for small right side (relative to left side)
• Partitioned Join
• Both tables hash-partitioned on join columns
• Same build/probe procedure as above
• Preferred for joins where both left and right side are large
• Cost-based decision based on table/column stats
• Minimize required network transfer
19. Query Compilation in Impala
Query Planning: Distributed Plans
HashJoinScan: t2
Scan: t3
Scan: t1
HashJoin
TopN
Pre-Agg
MergeAgg
TopN
Broadcast
Merge
hash t2.idhash t1.id1
hash
t1.custid
at HDFS DN
at HBase RS
at coordinator
HashJoin
Scan: t2
Scan: t3
Scan: t1
HashJoin
TopN
Agg
Single-Node
Plan
20. Query Compilation in Impala
Explain Example: TPCDS Q42
SELECT d.d_year, i.i_category_id, i.i_category, SUM(ss_ext_sales_price)
FROM store_sales ss
JOIN date_dim d
ON (ss.ss_sold_date_sk = d.d_date_sk)
JOIN item i
ON (ss.ss_item_sk = i.i_item_sk)
WHERE i.i_manager_id = 1 AND d.d_moy = 12 AND d.d_year = 1998
GROUP BY d.d_year, i.i_category_id, i.i_category
ORDER BY total_sales DESC, d_year, i_category_id, i_category
LIMIT 100
24. Query Compilation in Impala
Conclusion
• Cost-based choice of join order and strategy
• Critical for performance
• Relies on table and column stats
• Other plan optimizations currently independent of stats
• Likely to expand plan choices in the future
• Likely to increase reliance on stats
• Helpful Impala commands
• compute stats
• show table/column stats
• explain query/insert stmt
• set explain_level=[0-3]
• set num_nodes=0 show single-node plan
25. Query Compilation in Impala
Try It Out!
•Questions/comments?
• Download: cloudera.com/impala
• Email: impala-user@cloudera.org
• Join: groups.cloudera.org
