Archive for category SQL
Databases are ideal for storing and organizing data that requires a high volume of transaction-oriented query processing while maintaining data integrity. In contrast, data warehouses are designed for performing data analytics on vast amounts of data from one or more disparate sources. In our fast-paced, hyper-connected world, those sources often take the form of continuous streams of web application logs, e-commerce transactions, social media feeds, online gaming activities, financial trading transactions, and IoT sensor readings. Streaming data must be analyzed in near real-time, while often first requiring cleansing, transformation, and enrichment.
In the following post, we will demonstrate the use of Amazon Kinesis Data Firehose, Amazon Redshift, and Amazon QuickSight to analyze streaming data. We will simulate time-series data, streaming from a set of IoT sensors to Kinesis Data Firehose. Kinesis Data Firehose will write the IoT data to an Amazon S3 Data Lake, where it will then be copied to Redshift in near real-time. In Amazon Redshift, we will enhance the streaming sensor data with data contained in the Redshift data warehouse, which has been gathered and denormalized into a star schema.
In Redshift, we can analyze the data, asking questions like, what is the min, max, mean, and median temperature over a given time period at each sensor location. Finally, we will use Amazon Quicksight to visualize the Redshift data using rich interactive charts and graphs, including displaying geospatial sensor data.
The following AWS services are discussed in this post.
Amazon Kinesis Data Firehose
According to Amazon, Amazon Kinesis Data Firehose can capture, transform, and load streaming data into data lakes, data stores, and analytics tools. Direct Kinesis Data Firehose integrations include Amazon S3, Amazon Redshift, Amazon Elasticsearch Service, and Splunk. Kinesis Data Firehose enables near real-time analytics with existing business intelligence (BI) tools and dashboards.
According to Amazon, Amazon Redshift is the most popular and fastest cloud data warehouse. With Redshift, users can query petabytes of structured and semi-structured data across your data warehouse and data lake using standard SQL. Redshift allows users to query and export data to and from data lakes. Redshift can federate queries of live data from Redshift, as well as across one or more relational databases.
Amazon Redshift Spectrum
According to Amazon, Amazon Redshift Spectrum can efficiently query and retrieve structured and semistructured data from files in Amazon S3 without having to load the data into Amazon Redshift tables. Redshift Spectrum tables are created by defining the structure for data files and registering them as tables in an external data catalog. The external data catalog can be AWS Glue or an Apache Hive metastore. While Redshift Spectrum is an alternative to copying the data into Redshift for analysis, we will not be using Redshift Spectrum in this post.
According to Amazon, Amazon QuickSight is a fully managed business intelligence service that makes it easy to deliver insights to everyone in an organization. QuickSight lets users easily create and publish rich, interactive dashboards that include Amazon QuickSight ML Insights. Dashboards can then be accessed from any device and embedded into applications, portals, and websites.
What is a Data Warehouse?
According to Amazon, a data warehouse is a central repository of information that can be analyzed to make better-informed decisions. Data flows into a data warehouse from transactional systems, relational databases, and other sources, typically on a regular cadence. Business analysts, data scientists, and decision-makers access the data through business intelligence tools, SQL clients, and other analytics applications.
All the source code for this post can be found on GitHub. Use the following command to git clone a local copy of the project.
Use the two AWS CloudFormation templates, included in the project, to build two CloudFormation stacks. Please review the two templates and understand the costs of the resources before continuing.
The first CloudFormation template, redshift.yml, provisions a new Amazon VPC with associated network and security resources, a single-node Redshift cluster, and two S3 buckets.
The second CloudFormation template, kinesis-firehose.yml, provisions an Amazon Kinesis Data Firehose delivery stream, associated IAM Policy and Role, and an Amazon CloudWatch log group and two log streams.
REDSHIFT_PASSWORD value to ensure your security. Optionally, change the
REDSHIFT_USERNAME value. Make sure that the first stack completes successfully, before creating the second stack.
Review AWS Resources
To confirm all the AWS resources were created correctly, use the AWS Management Console.
Kinesis Data Firehose
In the Amazon Kinesis Dashboard, you should see the new Amazon Kinesis Data Firehose delivery stream, redshift-delivery-stream.
The Details tab of the new Amazon Kinesis Firehose delivery stream should look similar to the following. Note the IAM Role, FirehoseDeliveryRole, which was created and associated with the delivery stream by CloudFormation.
We are not performing any transformations of the incoming messages. Note the new S3 bucket that was created and associated with the stream by CloudFormation. The bucket name was randomly generated. This bucket is where the incoming messages will be written.
Note the buffer conditions of 1 MB and 60 seconds. Whenever the buffer of incoming messages is greater than 1 MB or the time exceeds 60 seconds, the messages are written in JSON format, using GZIP compression, to S3. These are the minimal buffer conditions, and as close to real-time streaming to Redshift as we can get.
COPY command, which is used to copy the messages from S3 to the
message table in Amazon Redshift. Kinesis uses the IAM Role, ClusterPermissionsRole, created by CloudFormation, for credentials. We are using a Manifest to copy the data to Redshift from S3. According to Amazon, a Manifest ensures that the
COPY command loads all of the required files, and only the required files, for a data load. The Manifests are automatically generated and managed by the Kinesis Firehose delivery stream.
In the Amazon Redshift Console, you should see a new single-node Redshift cluster consisting of one Redshift dc2.large Dense Compute node type.
Note the new VPC, Subnet, and VPC Security Group created by CloudFormation. Also, observe that the Redshift cluster is publically accessible from outside the new VPC.
Redshift Ingress Rules
The single-node Redshift cluster is assigned to an AWS Availability Zone in the US East (N. Virginia) us-east-1 AWS Region. The cluster is associated with a VPC Security Group. The Security Group contains three inbound rules, all for Redshift port 5439. The IP addresses associated with the three inbound rules provide access to the following: 1) a
/27 CIDR block for Amazon QuickSight in us-east-1, a
/27 CIDR block for Amazon Kinesis Firehose in us-east-1, and to you, a
/32 CIDR block with your current IP address. If your IP address changes or you do not use the us-east-1 Region, you will need to change one or all of these IP addresses. The list of Kinesis Firehose IP addresses is here. The list of QuickSight IP addresses is here.
If you cannot connect to Redshift from your local SQL client, most often, your IP address has changed and is incorrect in the Security Group’s inbound rule.
Redshift SQL Client
You can choose to use the Redshift Query Editor to interact with Redshift or use a third-party SQL client for greater flexibility. To access the Redshift Query Editor, use the user credentials specified in the redshift.yml CloudFormation template.
There is a lot of useful functionality in the Redshift Console and within the Redshift Query Editor. However, a notable limitation of the Redshift Query Editor, in my opinion, is the inability to execute multiple SQL statements at the same time. Whereas, most SQL clients allow multiple SQL queries to be executed at the same time.
I prefer to use JetBrains PyCharm IDE. PyCharm has out-of-the-box integration with RedShift. Using PyCharm, I can edit the project’s Python, SQL, AWS CLI shell, and CloudFormation code, all from within PyCharm.
If you use any of the common SQL clients, you will need to set-up a JDBC (Java Database Connectivity) or ODBC (Open Database Connectivity) connection to Redshift. The ODBC and JDBC connection strings can be found in the Redshift cluster’s Properties tab or in the Outputs tab from the CloudFormation stack,
You will also need the RedShift database username and password you included in the
aws cloudformation create-stack AWS CLI command you executed previously. Below, we see PyCharm’s Project Data Sources window containing a new data source for the Redshift
Database Schema and Tables
When CloudFormation created the Redshift cluster, it also created a new database,
dev. Using the Redshift Query Editor or your SQL client of choice, execute the following series of SQL commands to create a new database schema,
sensor, and six tables in the
The tables represent denormalized data, taken from one or more relational database sources. The tables form a star schema. The star schema is widely used to develop data warehouses. The star schema consists of one or more fact tables referencing any number of dimension tables. The
history tables are dimension tables. The
sensors table is a fact table.
In the diagram below, the foreign key relationships are virtual, not physical. The diagram was created using PyCharm’s schema visualization tool. Note the schema’s star shape. The
message table is where the streaming IoT data will eventually be written. The
message table is related to the
sensors fact table through the common
Sample Data to S3
Next, copy the sample data, included in the project, to the S3 data bucket created with CloudFormation. Each CSV-formatted data file corresponds to one of the tables we previously created. Since the bucket name is semi-random, we can use the AWS CLI and jq to get the bucket name, then use it to perform the copy commands.
The output from the AWS CLI should look similar to the following.
Sample Data to RedShift
Whereas a relational database, such as Amazon RDS is designed for online transaction processing (OLTP), Amazon Redshift is designed for online analytic processing (OLAP) and business intelligence applications. To write data to Redshift we typically use the
COPY command versus frequent, individual
INSERT statements, as with OLTP, which would be prohibitively slow. According to Amazon, the Redshift
COPY command leverages the Amazon Redshift massively parallel processing (MPP) architecture to read and load data in parallel from files on Amazon S3, from a DynamoDB table, or from text output from one or more remote hosts.
In the following series of SQL statements, replace the placeholder,
your_bucket_name, in five places with your S3 data bucket name. The bucket name will start with the prefix,
redshift-stack-databucket. The bucket name can be found in the Outputs tab of the CloudFormation stack,
redshift-stack. Next, replace the placeholder,
cluster_permissions_role_arn, with the ARN (Amazon Resource Name) of the ClusterPermissionsRole. The ARN is formatted as follows,
arn:aws:iam::your-account-id:role/ClusterPermissionsRole. The ARN can be found in the Outputs tab of the CloudFormation stack,
Using the Redshift Query Editor or your SQL client of choice, execute the SQL statements to copy the sample data from S3 to each of the corresponding tables in the Redshift
dev database. The
TRUNCATE commands guarantee there is no previous sample data present in the tables.
Next, create four Redshift database Views. These views may be used to analyze the data in Redshift, and later, in Amazon QuickSight.
- sensor_msg_detail: Returns aggregated sensor details, using the
sensorsfact table and all five dimension tables in a SQL Join.
- sensor_msg_count: Returns the number of messages received by Redshift, for each sensor.
- sensor_avg_temp: Returns the average temperature from each sensor, based on all the messages received from each sensor.
- sensor_avg_temp_current: View is identical for the previous view but limited to the last 30 minutes.
Using the Redshift Query Editor or your SQL client of choice, execute the following series of SQL statements.
At this point, you should have a total of six tables and four views in the
sensor schema of the
dev database in Redshift.
Test the System
With all the necessary AWS resources and Redshift database objects created and sample data in the Redshift database, we can test the system. The included Python script, kinesis_put_test_msg.py, will generate a single test message and send it to Kinesis Data Firehose. If everything is working, the message should be delivered from Kinesis Data Firehose to S3, then copied to Redshift, and appear in the
Install the required Python packages and then execute the Python script.
Run the following SQL query to confirm the record is in the
message table of the
dev database. It will take at least one minute for the message to appear in Redshift.
Once the message is confirmed to be present in the
message table, delete the record by truncating the table.
Assuming the test message worked, we can proceed with simulating the streaming IoT sensor data. The included Python script, kinesis_put_streaming_data.py, creates six concurrent threads, representing six temperature sensors. The simulated data uses an algorithm that follows an oscillating sine wave or sinusoid, representing rising and falling temperatures. In the script, I have configured each thread to start with an arbitrary offset to add some randomness to the simulated data.
The variables within the script can be adjusted to shorten or lengthen the time it takes to stream the simulated data. By default, each of the six threads creates 400 messages per sensor, in one-minute increments. Including the offset start of each proceeding thread, the total runtime of the script is about 7.5 hours to generate 2,400 simulated IoT sensor temperature readings and push to Kinesis Data Firehose. Make sure you can guarantee you will maintain a connection to the Internet for the entire runtime of the script. I normally run the script in the background, from a small EC2 instance.
To use the Python script, execute either of the two following commands. Using the first command will run the script in the foreground. Using the second command will run the script in the background.
If you used the foreground command, you should see messages being generated by each thread and sent to Kinesis Data Firehose. Each message contains the GUID of the sensor, a timestamp, and a temperature reading.
The messages are sent to Kinesis Data Firehose, which in turn writes the messages to S3. The messages are written in JSON format using GZIP compression. Below, we see an example of the GZIP compressed JSON files in S3. The JSON files are partitioned by year, month, day, and hour.
Confirm Data Streaming to Redshift
From the Amazon Kinesis Firehose Console Metrics tab, you should see incoming messages flowing to S3 and on to Redshift.
Executing the following SQL query should show an increasing number of messages.
How Near Real-time?
Earlier, we saw how the Amazon Kinesis Data Firehose delivery stream was configured to buffer data at the rate of 1 MB or 60 seconds. Whenever the buffer of incoming messages is greater than 1 MB or the time exceeds 60 seconds, the messages are written to S3. Each record in the
message table has two timestamps. The first timestamp, ts, is when the temperature reading was recorded. The second timestamp, created, is when the message was written to Redshift, using the
COPY command. We can calculate the delta in seconds between the two timestamps using the following SQL query in Redshift.
Using the results of the Redshift query, we can visualize the results in Amazon QuickSight. In my own tests, we see that for 2,400 messages, over approximately 7.5 hours, the minimum delay was 1 second, and a maximum delay was 64 seconds. Hence, near real-time, in this case, is about one minute or less, with an average latency of roughly 30 seconds.
Analyzing the Data with Redshift
I suggest waiting at least thirty minutes for a significant number of messages copied into Redshift. With the data streaming into Redshift, execute each of the database views we created earlier. You should see the streaming message data, joined to the existing static data in RedShift. As data continues to stream into Redshift, the views will display different results based on the current
message table contents.
Here, we see the first ten results of the
Next, we see the results of the
In a recent post, Getting Started with Data Analysis on AWS using AWS Glue, Amazon Athena, and QuickSight: Part 2, I detailed getting started with Amazon QuickSight. In this post, I will assume you are familiar with QuickSight.
Amazon recently added a full set of
aws quicksight APIs for interacting with QuickSight. Though, for this part of the demonstration, we will be working directly in the Amazon QuickSight Console, as opposed to the AWS CLI, AWS CDK, or CloudFormation.
Redshift Data Sets
To visualize the data from Amazon Redshift, we start by creating Data Sets in QuickSight. QuickSight supports a large number of data sources for creating data sets. We will use the Redshift data source. If you recall, we added an inbound rule for QuickSight, allowing us to connect to our Redshift cluster in us-east-1.
We will select the
sensor schema, which is where the tables and views for this demonstration are located.
We can choose any of the tables or views in the Redshift
dev database that we want to use for visualization.
Below, we see examples of two new data sets, shown in the QuickSight Data Prep Console. Note how QuickSight automatically recognizes field types, including dates, latitude, and longitude.
Using the data sets, QuickSight allows us to create a wide number of rich visualizations. Below, we see the simulated time-series data from the six temperature sensors.
Next, we see an example of QuickSight’s ability to show geospatial data. The Map shows the location of each sensor and the average temperature recorded by that sensor.
To remove the resources created for this post, use the following series of AWS CLI commands.
In this brief post, we have learned how streaming data can be analyzed in near real-time, in Amazon Redshift, using Amazon Kinesis Data Firehose. Further, we explored how the results of those analyses can be visualized in Amazon QuickSight. For customers that depend on a data warehouse for data analytics, but who also have streaming data sources, the use of Amazon Kinesis Data Firehose or Amazon Redshift Spectrum is an excellent choice.
This blog represents my own viewpoints and not of my employer, Amazon Web Services.
In part one, we learned how to ingest, transform, and enrich raw, semi-structured data, in multiple formats, using Amazon S3, AWS Glue, Amazon Athena, and AWS Lambda. We built an S3-based data lake and learned how AWS leverages open-source technologies, including Presto, Apache Hive, and Apache Parquet. In part two of this post, we will use the transformed and enriched data sources, stored in the data lake, to create compelling visualizations using Amazon QuickSight.
If you recall the demonstration from part one of the post, we had adopted the persona of a large, US-based electric energy provider. The energy provider had developed and sold its next-generation Smart Electrical Monitoring Hub (Smart Hub) to residential customers. Customers can analyze their electrical usage with a fine level of granularity, per device and over time. The goal of the Smart Hub is to enable the customers, using data, to reduce their electrical costs. The provider benefits from a reduction in load on the existing electrical grid and a better distribution of daily electrical load as customers shift usage to off-peak times to save money.
Data Visualization and BI
The data analysis process in the demonstration was divided into four logical stages: 1) Raw Data Ingestion, 2) Data Transformation, 3) Data Enrichment, and 4) Data Visualization and Business Intelligence (BI).
In the final, Data Visualization and Business Intelligence (BI) stage, the enriched data is presented and analyzed. There are many enterprise-grade services available for data visualization and business intelligence, which integrate with Amazon Athena. Amazon services include Amazon QuickSight, Amazon EMR, and Amazon SageMaker. Third-party solutions from AWS Partners, many available on the AWS Marketplace, include Tableau, Looker, Sisense, and Domo.
In this demonstration, we will focus on Amazon QuickSight. Amazon QuickSight is a fully managed business intelligence (BI) service. QuickSight lets you create and publish interactive dashboards that include ML Insights. Dashboards can be accessed from any device, and embedded into your applications, portals, and websites. QuickSight serverlessly scales automatically from tens of users to tens of thousands without any infrastructure management.
Amazon recently added a full set of
aws quicksight APIs for interacting with QuickSight. For example, to preview the three QuickSight data sets created for this part of the demo, with the AWS CLI, we would use the
To examine details of a single data set, with the AWS CLI, we would use the
However, for this final part of the demonstration, we will be working from the Amazon QuickSight Console, as opposed to the AWS CLI, AWS CDK, or CloudFormation templates.
Signing Up for QuickSight
To use Amazon QuickSight, you must sign up for QuickSight.
There are two Editions of Amazon QuickSight, Standard and Enterprise. For this demonstration, the Standard Edition will suffice.
QuickSight Data Sets
Amazon QuickSight uses Data Sets as the basis for all data visualizations. According to AWS, QuickSight data sets can be created from a wide variety of data sources, including Amazon RDS, Amazon Aurora, Amazon Redshift, Amazon Athena, and Amazon S3. You can also upload Excel spreadsheets or flat files (CSV, TSV, CLF, ELF, and JSON), connect to on-premises databases like SQL Server, MySQL, and PostgreSQL and import data from SaaS applications like Salesforce. Below, we see a list of the latest data sources available in the QuickSight New Data Set Console.
Demonstration Data Sets
For the demonstration, I have created three QuickSight data sets, all based on Amazon Athena. You have two options when using Amazon Athena as a data source. The first option is to select a table from an AWS Glue Data Catalog database, such as the database we created in part one of the post, ‘smart_hub_data_catalog.’ The second option is to create a custom SQL query, based on one or more tables in an AWS Glue Data Catalog database.
Of the three data sets created for part two of this demonstration, two data sets use tables directly from the Data Catalog, including ‘etl_output_parquet’ and ‘electricity_rates_parquet.’ The third data set uses a custom SQL query, based on the single Data Catalog table, ‘smart_hub_locations_parquet.’ All three tables used to create the data sets represent the enriched, highly efficient Parquet-format data sources in the S3-based Data Lake.
Data Set Features
There are a large number of features available when creating and configuring data sets. We cannot possibly cover all of them in this post. Let’s look at three features: geospatial field types, calculated fields, and custom SQL.
Geospatial Data Types
QuickSight can intelligently detect common types of geographic fields in a data source and assign QuickSight geographic data type, including Country, County, City, Postcode, and State. QuickSight can also detect geospatial data, including Latitude and Longitude. We will take advantage of this QuickSight feature for our three data set’s data sources, including the State, Postcode, Latitude, and Longitude field types.
A commonly-used QuickSight data set feature is the ‘Calculated field.’ For the ‘etl_output_parquet’ data set, I have created a new field (column),
cost field is the electrical cost of the device, over a five minute time interval, in cents (¢). The calculated
cost_dollar field is the quotient of the
cost field divided by 100. This value represents the electrical cost of the device, over a five minute time interval, in dollars ($). This is a straightforward example. However, a calculated field can be very complex, built from multiple arithmetic, comparison, and conditional functions, string calculations, and data set fields.
Data set calculated fields can also be created and edited from the QuickSight Analysis Console (discussed later).
The third QuickSight data set is based on an Amazon Athena custom SQL query.
Although you can write queries in the QuickSight Data Prep Console, I prefer to write custom Athena queries using the Athena Query Editor. Using the Editor, you can write, run, debug, and optimize queries to ensure they function correctly, first.
The Athena query can then be pasted into the Custom SQL window. Clicking ‘Finish’ in the window is the equivalent of ‘Run query’ in the Athena Query Editor Console. The query runs and returns data.
Similar to the Athena Query Editor, queries executed in the QuickSight Data Prep Console will show up in the Athena History tab, with a
/* QuickSight */ comment prefix.
You will notice the three QuickSight data sets are labeled, ‘SPICE.’ According to AWS, the acronym, SPICE, stands for ‘Super-fast, Parallel, In-memory, Calculation Engine.’ QuickSight’s in-memory calculation engine, SPICE, achieves blazing fast performance at scale. SPICE automatically replicates data for high availability allowing thousands of users to simultaneously perform fast, interactive analysis while shielding your underlying data infrastructure, saving you time and resources. With the Standard Edition of QuickSight, as the first Author, you get 1 GB of SPICE in-memory data for free.
The QuickSight Analysis Console is where Analyses are created. A specific QuickSight Analysis will contain a collection of data sets and data visualizations (visuals). Each visual is associated with a single data set.
Types of QuickSight Analysis visuals include: horizontal and vertical, single and stacked bar charts, line graphs, combination charts, area line charts, scatter plots, heat maps, pie and donut charts, tree maps, pivot tables, gauges, key performance indicators (KPI), geospatial diagrams, and word clouds. Individual visual titles, legends, axis, and other visual aspects can be easily modified. Visuals can contain drill-downs.
A data set’s fields can be modified from within the Analysis Console. Field types and formats, such as date, numeric, currency fields, can be customized for display. The Analysis can include a Title and subtitle. There are some customizable themes available to change the overall look of the Analysis.
Data displayed in the visuals can be further shaped using a combination of Filters, Conditional formatting, and Parameters. Below, we see an example of a typical filter based on a range of dates and times. The data set contains two full days’ worth of data. Here, we are filtering the data to a 14-hour peak electrical usage period, between 8 AM and 10 PM on the same day, 12/21/2019.
Drill-Down, Drill-Up, Focus, and Exclude
According to AWS, all visual types except pivot tables offer the ability to create a hierarchy of fields for a visual element. The hierarchy lets you drill down or up to see data at different levels of the hierarchy. Focus allows you to concentrate on a single element within a hierarchy of fields. Exclude allows you to remove an element from a hierarchy of fields. Below, we see an example of all four of these features, available to apply to the ‘Central Air Conditioner’. Since the AC unit is the largest consumer of electricity on average per day, applying these filters to understand its impact on the overall electrical usage may be useful to an analysis. We can also drill down to minutes from hours or up to days from hours.
Example QuickSight Analysis
A QuickSight Analysis is shared by the Analysis Author as a QuickSight Dashboard. Below, we see an example of a QuickSight Dashboard, built and shared for this demonstration. The ‘Residential Electrical Usage Analysis’ is built from the three data sets created earlier. From those data sets, we have constructed several visuals, including a geospatial diagram, donut chart, heat map, KPI, combination chart, stacked vertical bar chart, and line graph. Each visual’s title, layout, and field display has all customized. The data displayed in the visuals have been filtered differently, including by date and time, by customer id (loc_id), and by state. Conditional formatting is used to enhance the visual appearance of visuals, such as the ‘Total Electrical Cost’ KPI.
In part one, we learned how to ingest, transform, and enrich raw, semi-structured data, in multiple formats, using Amazon S3, AWS Glue, Amazon Athena, and AWS Lambda. We built an S3-based data lake and learned how AWS leverages open-source technologies, including Presto, Apache Hive, and Apache Parquet. In part two of this post, we used the transformed and enriched datasets, stored in the data lake, to create compelling visualizations using Amazon QuickSight.
All opinions expressed in this post are my own and not necessarily the views of my current or past employers or their clients.
According to Amazon, Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL. Amazon Athena supports and works with a variety of popular data file formats, including CSV, JSON, Apache ORC, Apache Avro, and Apache Parquet.
The underlying technology behind Amazon Athena is Presto, the popular, open-source distributed SQL query engine for big data, created by Facebook. According to AWS, the Athena query engine is based on Presto 0.172. Athena is ideal for quick, ad-hoc querying, but it can also handle complex analysis, including large joins, window functions, and arrays. In addition to Presto, Athena also uses Apache Hive to define tables.
Athena Query Editor
In the previous post, Getting Started with Data Analysis on AWS using AWS Glue, Amazon Athena, and QuickSight, we used the Athena Query Editor to construct and test SQL queries against semi-structured data in an S3-based Data Lake. The Athena Query Editor has many of the basic features Data Engineers and Analysts expect, including SQL syntax highlighting, code auto-completion, and query formatting. Queries can be run directly from the Editor, saved for future reference, and query results downloaded. The Editor can convert
SELECT queries to
CREATE TABLE AS (CTAS) and
CREATE VIEW AS statements. Access to AWS Glue data sources is also available from within the Editor.
Although the Athena Query Editor is fairly functional, many Engineers perform a majority of their software development work in a fuller-featured IDE. The choice of IDE may depend on one’s predominant programming language. According to the PYPL Index, the ten most popular, current IDEs are:
- Microsoft Visual Studio
- Android Studio
- Visual Studio Code
- Apache NetBeans
- JetBrains PyCharm
- JetBrains IntelliJ
- Apple Xcode
- Sublime Text
Within the domains of data science, big data analytics, and data analysis, languages such as SQL, Python, Java, Scala, and R are common. Although I work in a variety of IDEs, my go-to choices are JetBrains PyCharm for Python (including for PySpark and Jupyter Notebook development) and JetBrains IntelliJ for Java and Scala (including Apache Spark development). Both these IDEs also support many common SQL-based technologies, out-of-the-box, and are easily extendable to add new technologies.
Athena Integration with PyCharm
Utilizing the extensibility of the JetBrains suite of professional development IDEs, it is simple to add Amazon Athena to the list of available database drivers and make JDBC (Java Database Connectivity) connections to Athena instances on AWS.
Downloading the Athena JDBC Driver
To start, download the Athena JDBC Driver from Amazon. There are two versions, based on your choice of Java JDKs. Considering Java 8 was released six years ago (March 2014), most users will likely want the AthenaJDBC42-2.0.9.jar is compatible with JDBC 4.2 and JDK 8.0 or later.
AWS also supplies a JDBC Driver Installation and Configuration Guide. The guide, as well as the Athena JDBC and ODBC Drivers, are produced by Simba Technologies (acquired by Magnitude Software). Instructions for creating an Athena Driver starts on page 23.
Creating a New Athena Driver
From PyCharm’s Database Tool Window, select the Drivers dialog box, select the downloaded Athena JDBC Driver JAR. Select
com.simba.athena.jdbc.Driver in the Class dropdown. Name the Driver, ‘Amazon Athena.’
You can configure the Athena Driver further, using the Options and Advanced tabs.
Creating a New Athena Data Source
From PyCharm’s Database Tool Window, select the Data Source dialog box to create a new connection to your Athena instance. Choose ‘Amazon Athena’ from the list of available Database Drivers.
You will need four items to create an Athena Data Source:
- Your IAM User Access Key ID
- Your IAM User Secret Access Key
- The AWS Region of your Athena instance (e.g., us-east-1)
- An existing S3 bucket location to store query results
The Athena connection URL is a combination of the AWS Region and the S3 bucket, items 3 and 4, above. The format of the Athena connection URL is as follows.
Give the new Athena Data Source a logical Name, input the User (Access Key ID), Password (Secret Access Key), and the Athena URL. To test the Athena Data Source, use the ‘Test Connection’ button.
You can create multiple Athena Data Sources using the Athena Driver. For example, you may have separate Development, Test, and Production instances of Athena, each in a different AWS Account.
Once a successful connection has been made, switching to the Schemas tab, you should see a list of available AWS Glue Data Catalog databases. Below, we see the AWS Glue Catalog, which we created in the prior post. This Glue Data Catalog database contains ten metadata tables, each corresponding to a semi-structured, file-based data source in an S3-based data lake.
In the example below, I have chosen to limit the new Athena Data Source to a single Data Catalog database, to which the Data Source’s IAM User has access. Applying the core AWS security principle of granting least privilege, IAM Users should only have the permissions required to perform a specific set of approved tasks. This principle applies to the Glue Data Catalog databases, metadata tables, and the underlying S3 data sources.
Querying Athena from PyCharm
From within the PyCharm’s Database Tool Window, you should now see a list of the metadata tables defined in your AWS Glue Data Catalog database(s), as well as the individual columns within each table.
Similar to the Athena Query Editor, you can write SQL queries against the database tables in PyCharm. Like the Athena Query Editor, PyCharm has standard features SQL syntax highlighting, code auto-completion, and query formatting. Right-click on the Athena Data Source and choose New, then Console, to start.
Be mindful when writing queries and searching the Internet for SQL references, the Athena query engine is based on Presto 0.172. The current version of Presto, 0.234, is more than 50 releases ahead of the current Athena version. Both Athena and Presto functionality continue to change and diverge. There are also additional considerations and limitations for SQL queries in Athena to be aware of.
Whereas the Athena Query Editor is limited to only one query per query tab, in PyCharm, we can write and run multiple SQL queries in the same console window and have multiple console sessions opened to Athena at the same time.
By default, PyCharm’s query results are limited to the first ten rows of data. The number of rows displayed, as well as many other preferences, can be changed in the PyCharm’s Database Preferences dialog box.
Saving Queries and Exporting Results
In PyCharm, Athena queries can be saved as part of your PyCharm projects, as .sql files. Whereas the Athena Query Editor is limited to CSV, in PyCharm, query results can be exported in a variety of standard data file formats.
Athena Query History
All Athena queries ran from PyCharm are recorded in the History tab of the Athena Console. Although PyCharm shows query run times, the Athena History tab also displays the amount of data scanned. Knowing the query run time and volume of data scanned is useful when performance tuning queries.
The technique shown for JetBrains PyCharm can also be applied to other JetBrains products, including GoLand, DataGrip, PhpStorm, and IntelliJ (shown below).
This blog represents my own view points and not of my employer, Amazon Web Services.