Tag Archives: sql

Amazon Relational Database Service – Looking Back at 2017

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/amazon-relational-database-service-looking-back-at-2017/

The Amazon RDS team launched nearly 80 features in 2017. Some of them were covered in this blog, others on the AWS Database Blog, and the rest in What’s New or Forum posts. To wrap up my week, I thought it would be worthwhile to give you an organized recap. So here we go!

Certification & Security


Engine Versions & Features

Regional Support

Instance Support

Price Reductions

And That’s a Wrap
I’m pretty sure that’s everything. As you can see, 2017 was quite the year! I can’t wait to see what the team delivers in 2018.



How I built a data warehouse using Amazon Redshift and AWS services in record time

Post Syndicated from Stephen Borg original https://aws.amazon.com/blogs/big-data/how-i-built-a-data-warehouse-using-amazon-redshift-and-aws-services-in-record-time/

This is a customer post by Stephen Borg, the Head of Big Data and BI at Cerberus Technologies.

Cerberus Technologies, in their own words: Cerberus is a company founded in 2017 by a team of visionary iGaming veterans. Our mission is simple – to offer the best tech solutions through a data-driven and a customer-first approach, delivering innovative solutions that go against traditional forms of working and process. This mission is based on the solid foundations of reliability, flexibility and security, and we intend to fundamentally change the way iGaming and other industries interact with technology.

Over the years, I have developed and created a number of data warehouses from scratch. Recently, I built a data warehouse for the iGaming industry single-handedly. To do it, I used the power and flexibility of Amazon Redshift and the wider AWS data management ecosystem. In this post, I explain how I was able to build a robust and scalable data warehouse without the large team of experts typically needed.

In two of my recent projects, I ran into challenges when scaling our data warehouse using on-premises infrastructure. Data was growing at many tens of gigabytes per day, and query performance was suffering. Scaling required major capital investment for hardware and software licenses, and also significant operational costs for maintenance and technical staff to keep it running and performing well. Unfortunately, I couldn’t get the resources needed to scale the infrastructure with data growth, and these projects were abandoned. Thanks to cloud data warehousing, the bottleneck of infrastructure resources, capital expense, and operational costs have been significantly reduced or have totally gone away. There is no more excuse for allowing obstacles of the past to delay delivering timely insights to decision makers, no matter how much data you have.

With Amazon Redshift and AWS, I delivered a cloud data warehouse to the business very quickly, and with a small team: me. I didn’t have to order hardware or software, and I no longer needed to install, configure, tune, or keep up with patches and version updates. Instead, I easily set up a robust data processing pipeline and we were quickly ingesting and analyzing data. Now, my data warehouse team can be extremely lean, and focus more time on bringing in new data and delivering insights. In this post, I show you the AWS services and the architecture that I used.

Handling data feeds

I have several different data sources that provide everything needed to run the business. The data includes activity from our iGaming platform, social media posts, clickstream data, marketing and campaign performance, and customer support engagements.

To handle the diversity of data feeds, I developed abstract integration applications using Docker that run on Amazon EC2 Container Service (Amazon ECS) and feed data to Amazon Kinesis Data Streams. These data streams can be used for real time analytics. In my system, each record in Kinesis is preprocessed by an AWS Lambda function to cleanse and aggregate information. My system then routes it to be stored where I need on Amazon S3 by Amazon Kinesis Data Firehose. Suppose that you used an on-premises architecture to accomplish the same task. A team of data engineers would be required to maintain and monitor a Kafka cluster, develop applications to stream data, and maintain a Hadoop cluster and the infrastructure underneath it for data storage. With my stream processing architecture, there are no servers to manage, no disk drives to replace, and no service monitoring to write.

Setting up a Kinesis stream can be done with a few clicks, and the same for Kinesis Firehose. Firehose can be configured to automatically consume data from a Kinesis Data Stream, and then write compressed data every N minutes to Amazon S3. When I want to process a Kinesis data stream, it’s very easy to set up a Lambda function to be executed on each message received. I can just set a trigger from the AWS Lambda Management Console, as shown following.

I also monitor the duration of function execution using Amazon CloudWatch and AWS X-Ray.

Regardless of the format I receive the data from our partners, I can send it to Kinesis as JSON data using my own formatters. After Firehose writes this to Amazon S3, I have everything in nearly the same structure I received but compressed, encrypted, and optimized for reading.

This data is automatically crawled by AWS Glue and placed into the AWS Glue Data Catalog. This means that I can immediately query the data directly on S3 using Amazon Athena or through Amazon Redshift Spectrum. Previously, I used Amazon EMR and an Amazon RDS–based metastore in Apache Hive for catalog management. Now I can avoid the complexity of maintaining Hive Metastore catalogs. Glue takes care of high availability and the operations side so that I know that end users can always be productive.

Working with Amazon Athena and Amazon Redshift for analysis

I found Amazon Athena extremely useful out of the box for ad hoc analysis. Our engineers (me) use Athena to understand new datasets that we receive and to understand what transformations will be needed for long-term query efficiency.

For our data analysts and data scientists, we’ve selected Amazon Redshift. Amazon Redshift has proven to be the right tool for us over and over again. It easily processes 20+ million transactions per day, regardless of the footprint of the tables and the type of analytics required by the business. Latency is low and query performance expectations have been more than met. We use Redshift Spectrum for long-term data retention, which enables me to extend the analytic power of Amazon Redshift beyond local data to anything stored in S3, and without requiring me to load any data. Redshift Spectrum gives me the freedom to store data where I want, in the format I want, and have it available for processing when I need it.

To load data directly into Amazon Redshift, I use AWS Data Pipeline to orchestrate data workflows. I create Amazon EMR clusters on an intra-day basis, which I can easily adjust to run more or less frequently as needed throughout the day. EMR clusters are used together with Amazon RDS, Apache Spark 2.0, and S3 storage. The data pipeline application loads ETL configurations from Spring RESTful services hosted on AWS Elastic Beanstalk. The application then loads data from S3 into memory, aggregates and cleans the data, and then writes the final version of the data to Amazon Redshift. This data is then ready to use for analysis. Spark on EMR also helps with recommendations and personalization use cases for various business users, and I find this easy to set up and deliver what users want. Finally, business users use Amazon QuickSight for self-service BI to slice, dice, and visualize the data depending on their requirements.

Each AWS service in this architecture plays its part in saving precious time that’s crucial for delivery and getting different departments in the business on board. I found the services easy to set up and use, and all have proven to be highly reliable for our use as our production environments. When the architecture was in place, scaling out was either completely handled by the service, or a matter of a simple API call, and crucially doesn’t require me to change one line of code. Increasing shards for Kinesis can be done in a minute by editing a stream. Increasing capacity for Lambda functions can be accomplished by editing the megabytes allocated for processing, and concurrency is handled automatically. EMR cluster capacity can easily be increased by changing the master and slave node types in Data Pipeline, or by using Auto Scaling. Lastly, RDS and Amazon Redshift can be easily upgraded without any major tasks to be performed by our team (again, me).

In the end, using AWS services including Kinesis, Lambda, Data Pipeline, and Amazon Redshift allows me to keep my team lean and highly productive. I eliminated the cost and delays of capital infrastructure, as well as the late night and weekend calls for support. I can now give maximum value to the business while keeping operational costs down. My team pushed out an agile and highly responsive data warehouse solution in record time and we can handle changing business requirements rapidly, and quickly adapt to new data and new user requests.

Additional Reading

If you found this post useful, be sure to check out Deploy a Data Warehouse Quickly with Amazon Redshift, Amazon RDS for PostgreSQL and Tableau Server and Top 8 Best Practices for High-Performance ETL Processing Using Amazon Redshift.

About the Author

Stephen Borg is the Head of Big Data and BI at Cerberus Technologies. He has a background in platform software engineering, and first became involved in data warehousing using the typical RDBMS, SQL, ETL, and BI tools. He quickly became passionate about providing insight to help others optimize the business and add personalization to products. He is now the Head of Big Data and BI at Cerberus Technologies.




Security updates for Friday

Post Syndicated from jake original https://lwn.net/Articles/746988/rss

Security updates have been issued by Arch Linux (clamav), Debian (mailman, mpv, and simplesamlphp), Fedora (tomcat-native), openSUSE (docker, docker-runc, containerd,, kernel, mupdf, and python-mistune), Red Hat (kernel), and Ubuntu (mailman and postgresql-9.3, postgresql-9.5, postgresql-9.6).

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/746915/rss

Security updates have been issued by Debian (django-anymail, libtasn1-6, and postgresql-9.1), Fedora (w3m), Mageia (389-ds-base, gcc, libtasn1, and p7zip), openSUSE (flatpak, ImageMagick, libjpeg-turbo, libsndfile, mariadb, plasma5-workspace, pound, and spice-vdagent), Oracle (kernel), Red Hat (flash-plugin), SUSE (docker, docker-runc, containerd, golang-github-docker-libnetwork and kernel), and Ubuntu (libvirt, miniupnpc, and QEMU).

Build a Multi-Tenant Amazon EMR Cluster with Kerberos, Microsoft Active Directory Integration and EMRFS Authorization

Post Syndicated from Songzhi Liu original https://aws.amazon.com/blogs/big-data/build-a-multi-tenant-amazon-emr-cluster-with-kerberos-microsoft-active-directory-integration-and-emrfs-authorization/

One of the challenges faced by our customers—especially those in highly regulated industries—is balancing the need for security with flexibility. In this post, we cover how to enable multi-tenancy and increase security by using EMRFS (EMR File System) authorization, the Amazon S3 storage-level authorization on Amazon EMR.

Amazon EMR is an easy, fast, and scalable analytics platform enabling large-scale data processing. EMRFS authorization provides Amazon S3 storage-level authorization by configuring EMRFS with multiple IAM roles. With this functionality enabled, different users and groups can share the same cluster and assume their own IAM roles respectively.

Simply put, on Amazon EMR, we can now have an Amazon EC2 role per user assumed at run time instead of one general EC2 role at the cluster level. When the user is trying to access Amazon S3 resources, Amazon EMR evaluates against a predefined mappings list in EMRFS configurations and picks up the right role for the user.

In this post, we will discuss what EMRFS authorization is (Amazon S3 storage-level access control) and show how to configure the role mappings with detailed examples. You will then have the desired permissions in a multi-tenant environment. We also demo Amazon S3 access from HDFS command line, Apache Hive on Hue, and Apache Spark.

EMRFS authorization for Amazon S3

There are two prerequisites for using this feature:

  1. Users must be authenticated, because EMRFS needs to map the current user/group/prefix to a predefined user/group/prefix. There are several authentication options. In this post, we launch a Kerberos-enabled cluster that manages the Key Distribution Center (KDC) on the master node, and enable a one-way trust from the KDC to a Microsoft Active Directory domain.
  2. The application must support accessing Amazon S3 via Applications that have their own S3FileSystem APIs (for example, Presto) are not supported at this time.

EMRFS supports three types of mapping entries: user, group, and Amazon S3 prefix. Let’s use an example to show how this works.

Assume that you have the following three identities in your organization, and they are defined in the Active Directory:

To enable all these groups and users to share the EMR cluster, you need to define the following IAM roles:

In this case, you create a separate Amazon EC2 role that doesn’t give any permission to Amazon S3. Let’s call the role the base role (the EC2 role attached to the EMR cluster), which in this example is named EMR_EC2_RestrictedRole. Then, you define all the Amazon S3 permissions for each specific user or group in their own roles. The restricted role serves as the fallback role when the user doesn’t belong to any user/group, nor does the user try to access any listed Amazon S3 prefixes defined on the list.

Important: For all other roles, like emrfs_auth_group_role_data_eng, you need to add the base role (EMR_EC2_RestrictedRole) as the trusted entity so that it can assume other roles. See the following example:

  "Version": "2012-10-17",
  "Statement": [
      "Effect": "Allow",
      "Principal": {
        "Service": "ec2.amazonaws.com"
      "Action": "sts:AssumeRole"
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::511586466501:role/EMR_EC2_RestrictedRole"
      "Action": "sts:AssumeRole"

The following is an example policy for the admin user role (emrfs_auth_user_role_admin_user):

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Action": "s3:*",
            "Resource": "*"

We are assuming the admin user has access to all buckets in this example.

The following is an example policy for the data science group role (emrfs_auth_group_role_data_sci):

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Resource": [
            "Action": [

This role grants all Amazon S3 permissions to the emrfs-auth-data-science-bucket-demo bucket and all the objects in it. Similarly, the policy for the role emrfs_auth_group_role_data_eng is shown below:

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Resource": [
            "Action": [

Example role mappings configuration

To configure EMRFS authorization, you use EMR security configuration. Here is the configuration we use in this post

Consider the following scenario.

First, the admin user admin1 tries to log in and run a command to access Amazon S3 data through EMRFS. The first role emrfs_auth_user_role_admin_user on the mapping list, which is a user role, is mapped and picked up. Then admin1 has access to the Amazon S3 locations that are defined in this role.

Then a user from the data engineer group (grp_data_engineering) tries to access a data bucket to run some jobs. When EMRFS sees that the user is a member of the grp_data_engineering group, the group role emrfs_auth_group_role_data_eng is assumed, and the user has proper access to Amazon S3 that is defined in the emrfs_auth_group_role_data_eng role.

Next, the third user comes, who is not an admin and doesn’t belong to any of the groups. After failing evaluation of the top three entries, EMRFS evaluates whether the user is trying to access a certain Amazon S3 prefix defined in the last mapping entry. This type of mapping entry is called the prefix type. If the user is trying to access s3://emrfs-auth-default-bucket-demo/, then the prefix mapping is in effect, and the prefix role emrfs_auth_prefix_role_default_s3_prefix is assumed.

If the user is not trying to access any of the Amazon S3 paths that are defined on the list—which means it failed the evaluation of all the entries—it only has the permissions defined in the EMR_EC2RestrictedRole. This role is assumed by the EC2 instances in the cluster.

In this process, all the mappings defined are evaluated in the defined order, and the first role that is mapped is assumed, and the rest of the list is skipped.

Setting up an EMR cluster and mapping Active Directory users and groups

Now that we know how EMRFS authorization role mapping works, the next thing we need to think about is how we can use this feature in an easy and manageable way.

Active Directory setup

Many customers manage their users and groups using Microsoft Active Directory or other tools like OpenLDAP. In this post, we create the Active Directory on an Amazon EC2 instance running Windows Server and create the users and groups we will be using in the example below. After setting up Active Directory, we use the Amazon EMR Kerberos auto-join capability to establish a one-way trust from the KDC running on the EMR master node to the Active Directory domain on the EC2 instance. You can use your own directory services as long as it talks to the LDAP (Lightweight Directory Access Protocol).

To create and join Active Directory to Amazon EMR, follow the steps in the blog post Use Kerberos Authentication to Integrate Amazon EMR with Microsoft Active Directory.

After configuring Active Directory, you can create all the users and groups using the Active Directory tools and add users to appropriate groups. In this example, we created users like admin1, dataeng1, datascientist1, grp_data_engineering, and grp_data_science, and then add the users to the right groups.

Join the EMR cluster to an Active Directory domain

For clusters with Kerberos, Amazon EMR now supports automated Active Directory domain joins. You can use the security configuration to configure the one-way trust from the KDC to the Active Directory domain. You also configure the EMRFS role mappings in the same security configuration.

The following is an example of the EMR security configuration with a trusted Active Directory domain EMRKRB.TEST.COM and the EMRFS role mappings as we discussed earlier:

The EMRFS role mapping configuration is shown in this example:

We will also provide an example AWS CLI command that you can run.

Launching the EMR cluster and running the tests

Now you have configured Kerberos and EMRFS authorization for Amazon S3.

Additionally, you need to configure Hue with Active Directory using the Amazon EMR configuration API in order to log in using the AD users created before. The following is an example of Hue AD configuration.








Note: In the preceding configuration JSON file, change the values as required before pasting it into the software setting section in the Amazon EMR console.

Now let’s use this configuration and the security configuration you created before to launch the cluster.

In the Amazon EMR console, choose Create cluster. Then choose Go to advanced options. On the Step1: Software and Steps page, under Edit software settings (optional), paste the configuration in the box.

The rest of the setup is the same as an ordinary cluster setup, except in the Security Options section. In Step 4: Security, under Permissions, choose Custom, and then choose the RestrictedRole that you created before.

Choose the appropriate subnets (these should meet the base requirement in order for a successful Active Directory join—see the Amazon EMR Management Guide for more details), and choose the appropriate security groups to make sure it talks to the Active Directory. Choose a key so that you can log in and configure the cluster.

Most importantly, choose the security configuration that you created earlier to enable Kerberos and EMRFS authorization for Amazon S3.

You can use the following AWS CLI command to create a cluster.

aws emr create-cluster --name "TestEMRFSAuthorization" \ 
--release-label emr-5.10.0 \ --instance-type m3.xlarge \ 
--instance-count 3 \ 
--ec2-attributes InstanceProfile=EMR_EC2_DefaultRole,KeyName=MyEC2KeyPair \ --service-role EMR_DefaultRole \ 
--security-configuration MyKerberosConfig \ 
--configurations file://hue-config.json \
--applications Name=Hadoop Name=Hive Name=Hue Name=Spark \ 
--kerberos-attributes Realm=EC2.INTERNAL, \ KdcAdminPassword=<YourClusterKDCAdminPassword>, \ ADDomainJoinUser=<YourADUserLogonName>,ADDomainJoinPassword=<YourADUserPassword>, \ 

Note: If you create the cluster using CLI, you need to save the JSON configuration for Hue into a file named hue-config.json and place it on the server where you run the CLI command.

After the cluster gets into the Waiting state, try to connect by using SSH into the cluster using the Active Directory user name and password.

ssh -l [email protected] <EMR IP or DNS name>

Quickly run two commands to show that the Active Directory join is successful:

  1. id [user name] shows the mapped AD users and groups in Linux.
  2. hdfs groups [user name] shows the mapped group in Hadoop.

Both should return the current Active Directory user and group information if the setup is correct.

Now, you can test the user mapping first. Log in with the admin1 user, and run a Hadoop list directory command:

hadoop fs -ls s3://emrfs-auth-data-science-bucket-demo/

Now switch to a user from the data engineer group.

Retry the previous command to access the admin’s bucket. It should throw an Amazon S3 Access Denied exception.

When you try listing the Amazon S3 bucket that a data engineer group member has accessed, it triggers the group mapping.

hadoop fs -ls s3://emrfs-auth-data-engineering-bucket-demo/

It successfully returns the listing results. Next we will test Apache Hive and then Apache Spark.


To run jobs successfully, you need to create a home directory for every user in HDFS for staging data under /user/<username>. Users can configure a step to create a home directory at cluster launch time for every user who has access to the cluster. In this example, you use Hue since Hue will create the home directory in HDFS for the user at the first login. Here Hue also needs to be integrated with the same Active Directory as explained in the example configuration described earlier.

First, log in to Hue as a data engineer user, and open a Hive Notebook in Hue. Then run a query to create a new table pointing to the data engineer bucket, s3://emrfs-auth-data-engineering-bucket-demo/table1_data_eng/.

You can see that the table was created successfully. Now try to create another table pointing to the data science group’s bucket, where the data engineer group doesn’t have access.

It failed and threw an Amazon S3 Access Denied error.

Now insert one line of data into the successfully create table.

Next, log out, switch to a data science group user, and create another table, test2_datasci_tb.

The creation is successful.

The last task is to test Spark (it requires the user directory, but Hue created one in the previous step).

Now let’s come back to the command line and run some Spark commands.

Login to the master node using the datascientist1 user:

Start the SparkSQL interactive shell by typing spark-sql, and run the show tables command. It should list the tables that you created using Hive.

As a data science group user, try select on both tables. You will find that you can only select the table defined in the location that your group has access to.


EMRFS authorization for Amazon S3 enables you to have multiple roles on the same cluster, providing flexibility to configure a shared cluster for different teams to achieve better efficiency. The Active Directory integration and group mapping make it much easier for you to manage your users and groups, and provides better auditability in a multi-tenant environment.

Additional Reading

If you found this post useful, be sure to check out Use Kerberos Authentication to Integrate Amazon EMR with Microsoft Active Directory and Launching and Running an Amazon EMR Cluster inside a VPC.

About the Authors

Songzhi Liu is a Big Data Consultant with AWS Professional Services. He works closely with AWS customers to provide them Big Data & Machine Learning solutions and best practices on the Amazon cloud.





Security updates for Tuesday

Post Syndicated from ris original https://lwn.net/Articles/746701/rss

Security updates have been issued by Debian (xen), Fedora (clamav, community-mysql, dnsmasq, flatpak, libtasn1, mupdf, p7zip, rsync, squid, thunderbird, tomcat, unbound, and zziplib), Mageia (clamav, curl, dovecot, ffmpeg, gcab, kernel, libtiff, libvpx, php-smarty, pure-ftpd, redis, and thunderbird), openSUSE (apache-commons-email), Red Hat (rh-mariadb100-mariadb), SUSE (firefox), and Ubuntu (clamav, squid3, and systemd).

Reactive Microservices Architecture on AWS

Post Syndicated from Sascha Moellering original https://aws.amazon.com/blogs/architecture/reactive-microservices-architecture-on-aws/

Microservice-application requirements have changed dramatically in recent years. These days, applications operate with petabytes of data, need almost 100% uptime, and end users expect sub-second response times. Typical N-tier applications can’t deliver on these requirements.

Reactive Manifesto, published in 2014, describes the essential characteristics of reactive systems including: responsiveness, resiliency, elasticity, and being message driven.

Being message driven is perhaps the most important characteristic of reactive systems. Asynchronous messaging helps in the design of loosely coupled systems, which is a key factor for scalability. In order to build a highly decoupled system, it is important to isolate services from each other. As already described, isolation is an important aspect of the microservices pattern. Indeed, reactive systems and microservices are a natural fit.

Implemented Use Case
This reference architecture illustrates a typical ad-tracking implementation.

Many ad-tracking companies collect massive amounts of data in near-real-time. In many cases, these workloads are very spiky and heavily depend on the success of the ad-tech companies’ customers. Typically, an ad-tracking-data use case can be separated into a real-time part and a non-real-time part. In the real-time part, it is important to collect data as fast as possible and ask several questions including:,  “Is this a valid combination of parameters?,””Does this program exist?,” “Is this program still valid?”

Because response time has a huge impact on conversion rate in advertising, it is important for advertisers to respond as fast as possible. This information should be kept in memory to reduce communication overhead with the caching infrastructure. The tracking application itself should be as lightweight and scalable as possible. For example, the application shouldn’t have any shared mutable state and it should use reactive paradigms. In our implementation, one main application is responsible for this real-time part. It collects and validates data, responds to the client as fast as possible, and asynchronously sends events to backend systems.

The non-real-time part of the application consumes the generated events and persists them in a NoSQL database. In a typical tracking implementation, clicks, cookie information, and transactions are matched asynchronously and persisted in a data store. The matching part is not implemented in this reference architecture. Many ad-tech architectures use frameworks like Hadoop for the matching implementation.

The system can be logically divided into the data collection partand the core data updatepart. The data collection part is responsible for collecting, validating, and persisting the data. In the core data update part, the data that is used for validation gets updated and all subscribers are notified of new data.

Components and Services

Main Application
The main application is implemented using Java 8 and uses Vert.x as the main framework. Vert.x is an event-driven, reactive, non-blocking, polyglot framework to implement microservices. It runs on the Java virtual machine (JVM) by using the low-level IO library Netty. You can write applications in Java, JavaScript, Groovy, Ruby, Kotlin, Scala, and Ceylon. The framework offers a simple and scalable actor-like concurrency model. Vert.x calls handlers by using a thread known as an event loop. To use this model, you have to write code known as “verticles.” Verticles share certain similarities with actors in the actor model. To use them, you have to implement the verticle interface. Verticles communicate with each other by generating messages in  a single event bus. Those messages are sent on the event bus to a specific address, and verticles can register to this address by using handlers.

With only a few exceptions, none of the APIs in Vert.x block the calling thread. Similar to Node.js, Vert.x uses the reactor pattern. However, in contrast to Node.js, Vert.x uses several event loops. Unfortunately, not all APIs in the Java ecosystem are written asynchronously, for example, the JDBC API. Vert.x offers a possibility to run this, blocking APIs without blocking the event loop. These special verticles are called worker verticles. You don’t execute worker verticles by using the standard Vert.x event loops, but by using a dedicated thread from a worker pool. This way, the worker verticles don’t block the event loop.

Our application consists of five different verticles covering different aspects of the business logic. The main entry point for our application is the HttpVerticle, which exposes an HTTP-endpoint to consume HTTP-requests and for proper health checking. Data from HTTP requests such as parameters and user-agent information are collected and transformed into a JSON message. In order to validate the input data (to ensure that the program exists and is still valid), the message is sent to the CacheVerticle.

This verticle implements an LRU-cache with a TTL of 10 minutes and a capacity of 100,000 entries. Instead of adding additional functionality to a standard JDK map implementation, we use Google Guava, which has all the features we need. If the data is not in the L1 cache, the message is sent to the RedisVerticle. This verticle is responsible for data residing in Amazon ElastiCache and uses the Vert.x-redis-client to read data from Redis. In our example, Redis is the central data store. However, in a typical production implementation, Redis would just be the L2 cache with a central data store like Amazon DynamoDB. One of the most important paradigms of a reactive system is to switch from a pull- to a push-based model. To achieve this and reduce network overhead, we’ll use Redis pub/sub to push core data changes to our main application.

Vert.x also supports direct Redis pub/sub-integration, the following code shows our subscriber-implementation:

vertx.eventBus().<JsonObject>consumer(REDIS_PUBSUB_CHANNEL_VERTX, received -> {

JsonObject value = received.body().getJsonObject("value");

String message = value.getString("message");

JsonObject jsonObject = new JsonObject(message);



redis.subscribe(Constants.REDIS_PUBSUB_CHANNEL, res -> {

if (res.succeeded()) {

LOGGER.info("Subscribed to " + Constants.REDIS_PUBSUB_CHANNEL);

} else {




The verticle subscribes to the appropriate Redis pub/sub-channel. If a message is sent over this channel, the payload is extracted and forwarded to the cache-verticle that stores the data in the L1-cache. After storing and enriching data, a response is sent back to the HttpVerticle, which responds to the HTTP request that initially hit this verticle. In addition, the message is converted to ByteBuffer, wrapped in protocol buffers, and send to an Amazon Kinesis Data Stream.

The following example shows a stripped-down version of the KinesisVerticle:

public class KinesisVerticle extends AbstractVerticle {

private static final Logger LOGGER = LoggerFactory.getLogger(KinesisVerticle.class);

private AmazonKinesisAsync kinesisAsyncClient;

private String eventStream = "EventStream";


public void start() throws Exception {

EventBus eb = vertx.eventBus();

kinesisAsyncClient = createClient();

eventStream = System.getenv(STREAM_NAME) == null ? "EventStream" : System.getenv(STREAM_NAME);

eb.consumer(Constants.KINESIS_EVENTBUS_ADDRESS, message -> {

try {

TrackingMessage trackingMessage = Json.decodeValue((String)message.body(), TrackingMessage.class);

String partitionKey = trackingMessage.getMessageId();

byte [] byteMessage = createMessage(trackingMessage);

ByteBuffer buf = ByteBuffer.wrap(byteMessage);

sendMessageToKinesis(buf, partitionKey);



catch (KinesisException exc) {





Kinesis Consumer
This AWS Lambda function consumes data from an Amazon Kinesis Data Stream and persists the data in an Amazon DynamoDB table. In order to improve testability, the invocation code is separated from the business logic. The invocation code is implemented in the class KinesisConsumerHandler and iterates over the Kinesis events pulled from the Kinesis stream by AWS Lambda. Each Kinesis event is unwrapped and transformed from ByteBuffer to protocol buffers and converted into a Java object. Those Java objects are passed to the business logic, which persists the data in a DynamoDB table. In order to improve duration of successive Lambda calls, the DynamoDB-client is instantiated lazily and reused if possible.

Redis Updater
From time to time, it is necessary to update core data in Redis. A very efficient implementation for this requirement is using AWS Lambda and Amazon Kinesis. New core data is sent over the AWS Kinesis stream using JSON as data format and consumed by a Lambda function. This function iterates over the Kinesis events pulled from the Kinesis stream by AWS Lambda. Each Kinesis event is unwrapped and transformed from ByteBuffer to String and converted into a Java object. The Java object is passed to the business logic and stored in Redis. In addition, the new core data is also sent to the main application using Redis pub/sub in order to reduce network overhead and converting from a pull- to a push-based model.

The following example shows the source code to store data in Redis and notify all subscribers:

public void updateRedisData(final TrackingMessage trackingMessage, final Jedis jedis, final LambdaLogger logger) {

try {

ObjectMapper mapper = new ObjectMapper();

String jsonString = mapper.writeValueAsString(trackingMessage);

Map<String, String> map = marshal(jsonString);

String statusCode = jedis.hmset(trackingMessage.getProgramId(), map);


catch (Exception exc) {

if (null == logger)






public void notifySubscribers(final TrackingMessage trackingMessage, final Jedis jedis, final LambdaLogger logger) {

try {

ObjectMapper mapper = new ObjectMapper();

String jsonString = mapper.writeValueAsString(trackingMessage);

jedis.publish(Constants.REDIS_PUBSUB_CHANNEL, jsonString);


catch (final IOException e) {

log(e.getMessage(), logger);



Similarly to our Kinesis Consumer, the Redis-client is instantiated somewhat lazily.

Infrastructure as Code
As already outlined, latency and response time are a very critical part of any ad-tracking solution because response time has a huge impact on conversion rate. In order to reduce latency for customers world-wide, it is common practice to roll out the infrastructure in different AWS Regions in the world to be as close to the end customer as possible. AWS CloudFormation can help you model and set up your AWS resources so that you can spend less time managing those resources and more time focusing on your applications that run in AWS.

You create a template that describes all the AWS resources that you want (for example, Amazon EC2 instances or Amazon RDS DB instances), and AWS CloudFormation takes care of provisioning and configuring those resources for you. Our reference architecture can be rolled out in different Regions using an AWS CloudFormation template, which sets up the complete infrastructure (for example, Amazon Virtual Private Cloud (Amazon VPC), Amazon Elastic Container Service (Amazon ECS) cluster, Lambda functions, DynamoDB table, Amazon ElastiCache cluster, etc.).

In this blog post we described reactive principles and an example architecture with a common use case. We leveraged the capabilities of different frameworks in combination with several AWS services in order to implement reactive principles—not only at the application-level but also at the system-level. I hope I’ve given you ideas for creating your own reactive applications and systems on AWS.

About the Author

Sascha Moellering is a Senior Solution Architect. Sascha is primarily interested in automation, infrastructure as code, distributed computing, containers and JVM. He can be reached at [email protected]



Blizzard Targets Fan-Created ‘World of Warcraft’ Legacy Server

Post Syndicated from Ernesto original https://torrentfreak.com/blizzard-targets-fan-created-world-of-warcraft-legacy-server-180203/

Over the years video game developer Blizzard Entertainment has published many popular game titles, including World of Warcraft (WoW).

First released in 2004, the multiplayer online role-playing game has been a massive success. It holds the record for the most popular MMORPG in history, with over 100 million subscribers.

While the current game looks entirely different from its first release, there are many nostalgic gamers who still enjoy the earlier editions. Unfortunately, however, they can’t play them. At least not legally.

The only option WoW fans have is to go to unauthorized fan projects which recreate the early gaming experience, such as Light’s Hope.

“We are what’s known as a ‘Legacy Server’ project for World of Warcraft, which seeks to emulate the experience of playing the game in its earliest iterations, including advancing through early expansions,” the project explains.

“If you’ve ever wanted to see what World of Warcraft was like back in 2004 then this is the place to be. Our goal is to maintain the same feel and structure as the realms back then while maintaining an open platform for development and operation.”

In recent years the project has captured the hearts of tens of thousands of die-hard WoW fans. At the time of writing, the most popular realm has more than 6,000 people playing from all over the world. Blizzard, however, is less excited.

The company has asked the developer platform GitHub to remove the code repository published by Light’s Hope. Blizzard’s notice targets several SQL databases stating that the layout and structure is nearly identical to the early WoW databases.

“The LightsHope spell table has identical layout and typically identical field names as the table from early WoW. We use database tables to represent game data, like spells, in WoW,” Blizzard writes.

“In our code, we use .sql files to represent the data layout of each table […]. MaNGOS, the platform off of which Light’s Hope appears to be built, uses a similar structure. The LightsHope spell_template table matches almost exactly the layout and field names of early WoW client database tables.”

This takedown notice had some effect, as people now see a “repository unavailable due to DMCA takedown” message when they access it in their browser.

While this may slow down development temporarily, it appears that the server itself is still running just fine. There were some downtime reports earlier this week, but it’s unknown whether that was related.

In addition to the GitHub repository, the official Twitter account was also suspended recently.

TorrentFreak contacted both Blizzard and Light’s Hope earlier this week for a comment on the situation. At the time of publication, we haven’t heard back.

Blizzard’s takedown notice comes just weeks after several organizations and gaming fans asked the US Copyright Office to make a DMCA circumvention exemption for “abandoned” games, including older versions of popular MMORPGs.

While it’s possible that such an exemption is granted in the future, it’s unlikely to apply to the public at large. The more likely scenario is that it would permit libraries, researchers, and museums to operate servers for these abandoned games.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN discounts, offers and coupons

Haas: DO or UNDO – there is no VACUUM

Post Syndicated from corbet original https://lwn.net/Articles/745789/rss

PostgreSQL developer Robert Haas describes
a new storage module
that is under development. “We are working
to build a new table storage format for PostgreSQL, which we’re calling
zheap. In a zheap, whenever possible, we handle an UPDATE by moving the old
row version to an undo log, and putting the new row version in the place
previously occupied by the old one. If the transaction aborts, we retrieve
the old row version from undo and put it back in the original location; if
a concurrent transaction needs to see the old row version, it can find it
in undo. […] This means that there is no need for VACUUM, or any similar
process, to scan the table looking for dead rows.

2017 Weather Station round-up

Post Syndicated from Richard Hayler original https://www.raspberrypi.org/blog/2017-weather-station/

As we head into 2018 and start looking forward to longer days in the Northern hemisphere, I thought I’d take a look back at last year’s weather using data from Raspberry Pi Oracle Weather Stations. One of the great things about the kit is that as well as uploading all its readings to the shared online Oracle database, it stores them locally on the Pi in a MySQL or MariaDB database. This means you can use the power of SQL queries coupled with Python code to do automatic data analysis.

Soggy Surrey

My Weather Station has only been installed since May, so I didn’t have a full 52 weeks of my own data to investigate. Still, my station recorded more than 70000 measurements. Living in England, the first thing I wanted to know was: which was the wettest month? Unsurprisingly, both in terms of average daily rainfall and total rainfall, the start of the summer period — exactly when I went on a staycation — was the soggiest:

What about the global Weather Station community?

Even soggier Bavaria

Here things get slightly trickier. Although we have a shiny Oracle database full of all participating schools’ sensor readings, some of the data needs careful interpretation. Many kits are used as part of the school curriculum and do not always record genuine outdoor conditions. Nevertheless, it appears that Adalbert Stifter Gymnasium in Bavaria, Germany, had an even wetter 2017 than my home did:

View larger map

Where the wind blows

The records Robert-Dannemann Schule in Westerstede, Germany, is a good example of data which was most likely collected while testing and investigating the weather station sensors, rather than in genuine external conditions. Unless this school’s Weather Station was transported to a planet which suffers from extreme hurricanes, it wasn’t actually subjected to wind speeds above 1000km/h in November. Dismissing these and all similarly suspect records, I decided to award the ‘Windiest location of the year’ prize to CEIP Noalla-Telleiro, Spain.

View larger map

This school is right on the coast, and is subject to some strong and squally weather systems.

Weather Station at CEIP Noalla - Telleiro

Weather Station at CEIP Noalla-Telleiro

They’ve mounted their wind vane and anemometer nice and high, so I can see how they were able to record such high wind velocities.

A couple of Weather Stations have recently been commissioned in equally exposed places — it will be interesting to see whether they will record even higher speeds during 2018.

Highs and lows

After careful analysis and a few disqualifications (a couple of Weather Stations in contention for this category were housed indoors), the ‘Hottest location’ award went to High School of Chalastra in Thessaloniki, Greece. There were a couple of Weather Stations (the one at The Marwadi Education Foundation in India, for example) that reported higher average temperatures than Chalastra’s 24.54 ºC. However, they had uploaded far fewer readings and their data coverage of 2017 was only partial.

View larger map

At the other end of the thermometer, the location with the coldest average temperature is École de la Rose Sauvage in Calgary, Canada, with a very chilly 9.9 ºC.

Ecole de la Rose sauvage Weather Station

Weather Station at École de la Rose Sauvage

I suspect this school has a good chance of retaining the title: their lowest 2017 temperature of -24 ºC is likely to be beaten in 2018 due to extreme weather currently bringing a freezing start to the year in that part of the world.

View larger map

Analyse your own Weather Station data

If you have an Oracle Raspberry Pi Weather Station and would like to perform an annual review of your local data, you can use this Python script as a starting point. It will display a monthly summary of the temperature and rainfall for 2017, and you should be able to customise the code to focus on other sensor data or on a particular time of year. We’d love to see your results, so please share your findings with weathe[email protected], and we’ll send you some limited-edition Weather Station stickers.

The post 2017 Weather Station round-up appeared first on Raspberry Pi.

Security updates for Friday

Post Syndicated from jake original https://lwn.net/Articles/745493/rss

Security updates have been issued by CentOS (389-ds-base, dhcp, kernel, and nautilus), Debian (curl, openssh, and wireshark), Fedora (clamav, firefox, java-9-openjdk, and poco), Gentoo (clamav), openSUSE (curl, libevent, mupdf, mysql-community-server, newsbeuter, php5, redis, and tre), Oracle (389-ds-base, dhcp, kernel, and nautilus), Slackware (mozilla), and Ubuntu (kernel and linux-hwe, linux-azure, linux-gcp, linux-oem).

Top 8 Best Practices for High-Performance ETL Processing Using Amazon Redshift

Post Syndicated from Thiyagarajan Arumugam original https://aws.amazon.com/blogs/big-data/top-8-best-practices-for-high-performance-etl-processing-using-amazon-redshift/

An ETL (Extract, Transform, Load) process enables you to load data from source systems into your data warehouse. This is typically executed as a batch or near-real-time ingest process to keep the data warehouse current and provide up-to-date analytical data to end users.

Amazon Redshift is a fast, petabyte-scale data warehouse that enables you easily to make data-driven decisions. With Amazon Redshift, you can get insights into your big data in a cost-effective fashion using standard SQL. You can set up any type of data model, from star and snowflake schemas, to simple de-normalized tables for running any analytical queries.

To operate a robust ETL platform and deliver data to Amazon Redshift in a timely manner, design your ETL processes to take account of Amazon Redshift’s architecture. When migrating from a legacy data warehouse to Amazon Redshift, it is tempting to adopt a lift-and-shift approach, but this can result in performance and scale issues long term. This post guides you through the following best practices for ensuring optimal, consistent runtimes for your ETL processes:

  • COPY data from multiple, evenly sized files.
  • Use workload management to improve ETL runtimes.
  • Perform table maintenance regularly.
  • Perform multiple steps in a single transaction.
  • Loading data in bulk.
  • Use UNLOAD to extract large result sets.
  • Use Amazon Redshift Spectrum for ad hoc ETL processing.
  • Monitor daily ETL health using diagnostic queries.

1. COPY data from multiple, evenly sized files

Amazon Redshift is an MPP (massively parallel processing) database, where all the compute nodes divide and parallelize the work of ingesting data. Each node is further subdivided into slices, with each slice having one or more dedicated cores, equally dividing the processing capacity. The number of slices per node depends on the node type of the cluster. For example, each DS2.XLARGE compute node has two slices, whereas each DS2.8XLARGE compute node has 16 slices.

When you load data into Amazon Redshift, you should aim to have each slice do an equal amount of work. When you load the data from a single large file or from files split into uneven sizes, some slices do more work than others. As a result, the process runs only as fast as the slowest, or most heavily loaded, slice. In the example shown below, a single large file is loaded into a two-node cluster, resulting in only one of the nodes, “Compute-0”, performing all the data ingestion:

When splitting your data files, ensure that they are of approximately equal size – between 1 MB and 1 GB after compression. The number of files should be a multiple of the number of slices in your cluster. Also, I strongly recommend that you individually compress the load files using gzip, lzop, or bzip2 to efficiently load large datasets.

When loading multiple files into a single table, use a single COPY command for the table, rather than multiple COPY commands. Amazon Redshift automatically parallelizes the data ingestion. Using a single COPY command to bulk load data into a table ensures optimal use of cluster resources, and quickest possible throughput.

2. Use workload management to improve ETL runtimes

Use Amazon Redshift’s workload management (WLM) to define multiple queues dedicated to different workloads (for example, ETL versus reporting) and to manage the runtimes of queries. As you migrate more workloads into Amazon Redshift, your ETL runtimes can become inconsistent if WLM is not appropriately set up.

I recommend limiting the overall concurrency of WLM across all queues to around 15 or less. This WLM guide helps you organize and monitor the different queues for your Amazon Redshift cluster.

When managing different workloads on your Amazon Redshift cluster, consider the following for the queue setup:

  • Create a queue dedicated to your ETL processes. Configure this queue with a small number of slots (5 or fewer). Amazon Redshift is designed for analytics queries, rather than transaction processing. The cost of COMMIT is relatively high, and excessive use of COMMIT can result in queries waiting for access to the commit queue. Because ETL is a commit-intensive process, having a separate queue with a small number of slots helps mitigate this issue.
  • Claim extra memory available in a queue. When executing an ETL query, you can take advantage of the wlm_query_slot_count to claim the extra memory available in a particular queue. For example, a typical ETL process might involve COPYing raw data into a staging table so that downstream ETL jobs can run transformations that calculate daily, weekly, and monthly aggregates. To speed up the COPY process (so that the downstream tasks can start in parallel sooner), the wlm_query_slot_count can be increased for this step.
  • Create a separate queue for reporting queries. Configure query monitoring rules on this queue to further manage long-running and expensive queries.
  • Take advantage of the dynamic memory parameters. They swap the memory from your ETL to your reporting queue after the ETL job has completed.

3. Perform table maintenance regularly

Amazon Redshift is a columnar database, which enables fast transformations for aggregating data. Performing regular table maintenance ensures that transformation ETLs are predictable and performant. To get the best performance from your Amazon Redshift database, you must ensure that database tables regularly are VACUUMed and ANALYZEd. The Analyze & Vacuum schema utility helps you automate the table maintenance task and have VACUUM & ANALYZE executed in a regular fashion.

  • Use VACUUM to sort tables and remove deleted blocks

During a typical ETL refresh process, tables receive new incoming records using COPY, and unneeded data (cold data) is removed using DELETE. New rows are added to the unsorted region in a table. Deleted rows are simply marked for deletion.

DELETE does not automatically reclaim the space occupied by the deleted rows. Adding and removing large numbers of rows can therefore cause the unsorted region and the number of deleted blocks to grow. This can degrade the performance of queries executed against these tables.

After an ETL process completes, perform VACUUM to ensure that user queries execute in a consistent manner. The complete list of tables that need VACUUMing can be found using the Amazon Redshift Util’s table_info script.

Use the following approaches to ensure that VACCUM is completed in a timely manner:

  • Use wlm_query_slot_count to claim all the memory allocated in the ETL WLM queue during the VACUUM process.
  • DROP or TRUNCATE intermediate or staging tables, thereby eliminating the need to VACUUM them.
  • If your table has a compound sort key with only one sort column, try to load your data in sort key order. This helps reduce or eliminate the need to VACUUM the table.
  • Consider using time series This helps reduce the amount of data you need to VACUUM.
  • Use ANALYZE to update database statistics

Amazon Redshift uses a cost-based query planner and optimizer using statistics about tables to make good decisions about the query plan for the SQL statements. Regular statistics collection after the ETL completion ensures that user queries run fast, and that daily ETL processes are performant. The Amazon Redshift utility table_info script provides insights into the freshness of the statistics. Keeping the statistics off (pct_stats_off) less than 20% ensures effective query plans for the SQL queries.

4. Perform multiple steps in a single transaction

ETL transformation logic often spans multiple steps. Because commits in Amazon Redshift are expensive, if each ETL step performs a commit, multiple concurrent ETL processes can take a long time to execute.

To minimize the number of commits in a process, the steps in an ETL script should be surrounded by a BEGIN…END statement so that a single commit is performed only after all the transformation logic has been executed. For example, here is an example multi-step ETL script that performs one commit at the end:

CREATE temporary staging_table;
INSERT INTO staging_table SELECT .. FROM source (transformation logic);
DELETE FROM daily_table WHERE dataset_date =?;
INSERT INTO daily_table SELECT .. FROM staging_table (daily aggregate);
DELETE FROM weekly_table WHERE weekending_date=?;
INSERT INTO weekly_table SELECT .. FROM staging_table(weekly aggregate);

5. Loading data in bulk

Amazon Redshift is designed to store and query petabyte-scale datasets. Using Amazon S3 you can stage and accumulate data from multiple source systems before executing a bulk COPY operation. The following methods allow efficient and fast transfer of these bulk datasets into Amazon Redshift:

  • Use a manifest file to ingest large datasets that span multiple files. The manifest file is a JSON file that lists all the files to be loaded into Amazon Redshift. Using a manifest file ensures that Amazon Redshift has a consistent view of the data to be loaded from S3, while also ensuring that duplicate files do not result in the same data being loaded more than one time.
  • Use temporary staging tables to hold the data for transformation. These tables are automatically dropped after the ETL session is complete. Temporary tables can be created using the CREATE TEMPORARY TABLE syntax, or by issuing a SELECT … INTO #TEMP_TABLE query. Explicitly specifying the CREATE TEMPORARY TABLE statement allows you to control the DISTRIBUTION KEY, SORT KEY, and compression settings to further improve performance.
  • User ALTER table APPEND to swap data from the staging tables to the target table. Data in the source table is moved to matching columns in the target table. Column order doesn’t matter. After data is successfully appended to the target table, the source table is empty. ALTER TABLE APPEND is much faster than a similar CREATE TABLE AS or INSERT INTO operation because it doesn’t involve copying or moving data.

6. Use UNLOAD to extract large result sets

Fetching a large number of rows using SELECT is expensive and takes a long time. When a large amount of data is fetched from the Amazon Redshift cluster, the leader node has to hold the data temporarily until the fetches are complete. Further, data is streamed out sequentially, which results in longer elapsed time. As a result, the leader node can become hot, which not only affects the SELECT that is being executed, but also throttles resources for creating execution plans and managing the overall cluster resources. Here is an example of a large SELECT statement. Notice that the leader node is doing most of the work to stream out the rows:

Use UNLOAD to extract large results sets directly to S3. After it’s in S3, the data can be shared with multiple downstream systems. By default, UNLOAD writes data in parallel to multiple files according to the number of slices in the cluster. All the compute nodes participate to quickly offload the data into S3.

If you are extracting data for use with Amazon Redshift Spectrum, you should make use of the MAXFILESIZE parameter to and keep files are 150 MB. Similar to item 1 above, having many evenly sized files ensures that Redshift Spectrum can do the maximum amount of work in parallel.

7. Use Redshift Spectrum for ad hoc ETL processing

Events such as data backfill, promotional activity, and special calendar days can trigger additional data volumes that affect the data refresh times in your Amazon Redshift cluster. To help address these spikes in data volumes and throughput, I recommend staging data in S3. After data is organized in S3, Redshift Spectrum enables you to query it directly using standard SQL. In this way, you gain the benefits of additional capacity without having to resize your cluster.

For tips on getting started with and optimizing the use of Redshift Spectrum, see the previous post, 10 Best Practices for Amazon Redshift Spectrum.

8. Monitor daily ETL health using diagnostic queries

Monitoring the health of your ETL processes on a regular basis helps identify the early onset of performance issues before they have a significant impact on your cluster. The following monitoring scripts can be used to provide insights into the health of your ETL processes:

Script Use when… Solution
commit_stats.sql – Commit queue statistics from past days, showing largest queue length and queue time first DML statements such as INSERT/UPDATE/COPY/DELETE operations take several times longer to execute when multiple of these operations are in progress Set up separate WLM queues for the ETL process and limit the concurrency to < 5.
copy_performance.sql –  Copy command statistics for the past days Daily COPY operations take longer to execute • Follow the best practices for the COPY command.
• Analyze data growth with the incoming datasets and consider cluster resize to meet the expected SLA.
table_info.sql – Table skew and unsorted statistics along with storage and key information Transformation steps take longer to execute • Set up regular VACCUM jobs to address unsorted rows and claim the deleted blocks so that transformation SQL execute optimally.
• Consider a table redesign to avoid data skewness.
v_check_transaction_locks.sql – Monitor transaction locks INSERT/UPDATE/COPY/DELETE operations on particular tables do not respond back in timely manner, compared to when run after the ETL Multiple DML statements are operating on the same target table at the same moment from different transactions. Set up ETL job dependency so that they execute serially for the same target table.
v_get_schema_priv_by_user.sql – Get the schema that the user has access to Reporting users can view intermediate tables Set up separate database groups for reporting and ETL users, and grants access to objects using GRANT.
v_generate_tbl_ddl.sql – Get the table DDL You need to create an empty table with same structure as target table for data backfill Generate DDL using this script for data backfill.
v_space_used_per_tbl.sql – monitor space used by individual tables Amazon Redshift data warehouse space growth is trending upwards more than normal

Analyze the individual tables that are growing at higher rate than normal. Consider data archival using UNLOAD to S3 and Redshift Spectrum for later analysis.

Use unscanned_table_summary.sql to find unused table and archive or drop them.

top_queries.sql – Return the top 50 time consuming statements aggregated by its text ETL transformations are taking longer to execute Analyze the top transformation SQL and use EXPLAIN to find opportunities for tuning the query plan.

There are several other useful scripts available in the amazon-redshift-utils repository. The AWS Lambda Utility Runner runs a subset of these scripts on a scheduled basis, allowing you to automate much of monitoring of your ETL processes.

Example ETL process

The following ETL process reinforces some of the best practices discussed in this post. Consider the following four-step daily ETL workflow where data from an RDBMS source system is staged in S3 and then loaded into Amazon Redshift. Amazon Redshift is used to calculate daily, weekly, and monthly aggregations, which are then unloaded to S3, where they can be further processed and made available for end-user reporting using a number of different tools, including Redshift Spectrum and Amazon Athena.

Step 1:  Extract from the RDBMS source to a S3 bucket

In this ETL process, the data extract job fetches change data every 1 hour and it is staged into multiple hourly files. For example, the staged S3 folder looks like the following:

 [[email protected] ~]$ aws s3 ls s3://<<S3 Bucket>>/batch/2017/07/02/
2017-07-02 01:59:58   81900220 20170702T01.export.gz
2017-07-02 02:59:56   84926844 20170702T02.export.gz
2017-07-02 03:59:54   78990356 20170702T03.export.gz
2017-07-02 22:00:03   75966745 20170702T21.export.gz
2017-07-02 23:00:02   89199874 20170702T22.export.gz
2017-07-02 00:59:59   71161715 20170702T23.export.gz

Organizing the data into multiple, evenly sized files enables the COPY command to ingest this data using all available resources in the Amazon Redshift cluster. Further, the files are compressed (gzipped) to further reduce COPY times.

Step 2: Stage data to the Amazon Redshift table for cleansing

Ingesting the data can be accomplished using a JSON-based manifest file. Using the manifest file ensures that S3 eventual consistency issues can be eliminated and also provides an opportunity to dedupe any files if needed. A sample manifest20170702.json file looks like the following:

  "entries": [
    {"url":" s3://<<S3 Bucket>>/batch/2017/07/02/20170702T01.export.gz", "mandatory":true},
    {"url":" s3://<<S3 Bucket>>/batch/2017/07/02/20170702T02.export.gz", "mandatory":true},
    {"url":" s3://<<S3 Bucket>>/batch/2017/07/02/20170702T23.export.gz", "mandatory":true}

The data can be ingested using the following command:

SET wlm_query_slot_count TO <<max available concurrency in the ETL queue>>;
COPY stage_tbl FROM 's3:// <<S3 Bucket>>/batch/manifest20170702.json' iam_role 'arn:aws:iam::0123456789012:role/MyRedshiftRole' manifest;

Because the downstream ETL processes depend on this COPY command to complete, the wlm_query_slot_count is used to claim all the memory available to the queue. This helps the COPY command complete as quickly as possible.

Step 3: Transform data to create daily, weekly, and monthly datasets and load into target tables

Data is staged in the “stage_tbl” from where it can be transformed into the daily, weekly, and monthly aggregates and loaded into target tables. The following job illustrates a typical weekly process:

INSERT into ETL_LOG (..) values (..);
DELETE from weekly_tbl where dataset_week = <<current week>>;
INSERT into weekly_tbl (..)
  SELECT date_trunc('week', dataset_day) AS week_begin_dataset_date, SUM(C1) AS C1, SUM(C2) AS C2
	FROM   stage_tbl
GROUP BY date_trunc('week', dataset_day);
INSERT into AUDIT_LOG values (..);

As shown above, multiple steps are combined into one transaction to perform a single commit, reducing contention on the commit queue.

Step 4: Unload the daily dataset to populate the S3 data lake bucket

The transformed results are now unloaded into another S3 bucket, where they can be further processed and made available for end-user reporting using a number of different tools, including Redshift Spectrum and Amazon Athena.

unload ('SELECT * FROM weekly_tbl WHERE dataset_week = <<current week>>’) TO 's3:// <<S3 Bucket>>/datalake/weekly/20170526/' iam_role 'arn:aws:iam::0123456789012:role/MyRedshiftRole';


Amazon Redshift lets you easily operate petabyte-scale data warehouses on the cloud. This post summarized the best practices for operating scalable ETL natively within Amazon Redshift. I demonstrated efficient ways to ingest and transform data, along with close monitoring. I also demonstrated the best practices being used in a typical sample ETL workload to transform the data into Amazon Redshift.

If you have questions or suggestions, please comment below.


About the Author

Thiyagarajan Arumugam is a Big Data Solutions Architect at Amazon Web Services and designs customer architectures to process data at scale. Prior to AWS, he built data warehouse solutions at Amazon.com. In his free time, he enjoys all outdoor sports and practices the Indian classical drum mridangam.


Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/745373/rss

Security updates have been issued by CentOS (firefox), Debian (firefox-esr, gcab, and poppler), Fedora (clamav and firefox), Mageia (bind, firefox, glibc, graphicsmagick, squid, systemd, and virtualbox), openSUSE (firefox, GraphicsMagick, libexif, and libvpx), Red Hat (389-ds-base, dhcp, kernel, kernel-alt, kernel-rt, and nautilus), Scientific Linux (389-ds-base, dhcp, kernel, and nautilus), Slackware (curl), SUSE (kernel and webkit2gtk3), and Ubuntu (firefox, libtasn1-6, and mysql-5.5).

When You Have A Blockchain, Everything Looks Like a Nail

Post Syndicated from Bozho original https://techblog.bozho.net/blockchain-everything-looks-like-nail/

Blockchain, AI, big data, NoSQL, microservices, single page applications, cloud, SOA. What do these have in common? They have been or are hyped. At some point they were “the big thing” du jour. Everyone was investigating the possibility of using them, everyone was talking about them, there were meetups, conferences, articles on Hacker news and reddit. There are more examples, of course (which is the javascript framework this month?) but I’ll focus my examples on those above.

Another thing they have in common is that they are useful. All of them have some pretty good applications that are definitely worth the time and investment.

Yet another thing they have in common is that they are far from universally applicable. I’ve argued that monoliths are often still the better approach and that microservices introduce too much complexity for the average project. Big Data is something very few organizations actually have; AI/machine learning can help a wide variety of problems, but it is just a tool in a toolbox, not the solution to all problems. Single page applications are great for, yeah, applications, but most websites are still websites, not feature-rich frontends – you don’t need an SPA for every type of website. NoSQL has solved niche issues, and issues of scale that few companies have had, but nothing beats a good old relational database for the typical project out there. “The cloud” is not always where you want your software to be; and SOA just means everything (ESBs, direct integrations, even microservices, according to some). And the blockchain – it seems to be having limited success beyond cryptocurrencies.

And finally, another trait many of them share is that the hype has settled down. Only yesterday I read an article about the “death of the microservices madness”. I don’t see nearly as many new NoSQL databases as a few years ago, some of the projects that have been popular have faded. SOA and “the cloud” are already “boring”, and we’ve realized we don’t actually have big data if it fits in an Excel spreadsheet. SPAs and AI are still high in popularity, but we are getting a good understanding as a community why and when they are useful.

But it seems that nuanced reality has never stopped us from hyping a particular technology or approach. And maybe that’s okay in order to get a promising, though niche, technology, the spotlight and let it shine in the particular usecases where it fits.

But countless projects have and will suffer from our collective inability to filter through these hypes. I’d bet millions of developer hours have been wasted in trying to use the above technologies where they just didn’t fit. It’s like that scene from Idiocracy where a guy tries to fit a rectangular figure into a circular hole.

And the new one is not “the blockchain”. I won’t repeat my rant, but in summary – it doesn’t solve many of the problems companies are trying to solve with it right now just because it’s cool. Or at least it doesn’t solve them better than existing solutions. Many pilots will be carried out, many hours will be wasted in figuring out why that thing doesn’t work. A few of those projects will be a good fit and will actually bring value.

Do you need to reach multi-party consensus for the data you store? Can all stakeholder support the infrastructure to run their node(s)? Do they have the staff to administer the node(s)? Do you need to execute distributed application code on the data? Won’t it be easier to just deploy RESTful APIs and integrate the parties through that? Do you need to store all the data, or just parts of it, to guarantee data integrity?

“If you have is a hammer, everything looks like a nail” as the famous saying goes. In the software industry we repeatedly find new and cool hammers and then try to hit as many nails as we can. But only few of them are actual nails. The rest remain ugly, hard to support, “who was the idiot that wrote this” and “I wasn’t here when the decisions were made” types of projects.

I don’t have the illusion that we will calm down and skip the next hypes. Especially if adding the hyped word to your company raises your stock price. But if there’s one thing I’d like people to ask themselves when choosing a technology stack, it is “do we really need that to solve our problems?”.

If the answer is really “yes”, then great, go ahead and deploy the multi-organization permissioned blockchain, or fork Ethereum, or whatever. If not, you can still do a project a home that you can safely abandon. And if you need some pilot project to figure out whether the new piece of technology would be beneficial – go ahead and try it. But have a baseline – the fact that it somehow worked doesn’t mean it’s better than old, tested models of doing the same thing.

The post When You Have A Blockchain, Everything Looks Like a Nail appeared first on Bozho's tech blog.

Security updates for Monday

Post Syndicated from ris original https://lwn.net/Articles/745042/rss

Security updates have been issued by CentOS (bind), Debian (openocd), Mageia (unbound), Oracle (bind and microcode_ctl), Red Hat (bind, java-1.6.0-sun, libvirt, and qemu-kvm), Scientific Linux (bind), SUSE (kernel and perl-XML-LibXML), and Ubuntu (gimp, intel-microcode, mysql-5.5, mysql-5.7, and openssh).

Security updates for Monday

Post Syndicated from ris original https://lwn.net/Articles/744905/rss

Security updates have been issued by Debian (bind9, couchdb, lucene-solr, mysql-5.5, openocd, and php5), Mageia (gdk-pixbuf2.0, golang, and mariadb), openSUSE (curl, gd, ImageMagick, lxterminal, ncurses, newsbeuter, perl-XML-LibXML, and xmltooling), Oracle (kernel), and SUSE (xmltooling).

Security updates for Friday

Post Syndicated from ris original https://lwn.net/Articles/744791/rss

Security updates have been issued by Arch Linux (bind, irssi, nrpe, perl-xml-libxml, and transmission-cli), CentOS (java-1.8.0-openjdk), Debian (awstats, libgd2, mysql-5.5, rsync, smarty3, and transmission), Fedora (keycloak-httpd-client-install and rootsh), and Red Hat (java-1.7.0-oracle and java-1.8.0-oracle).

Optimize Delivery of Trending, Personalized News Using Amazon Kinesis and Related Services

Post Syndicated from Yukinori Koide original https://aws.amazon.com/blogs/big-data/optimize-delivery-of-trending-personalized-news-using-amazon-kinesis-and-related-services/

This is a guest post by Yukinori Koide, an the head of development for the Newspass department at Gunosy.

Gunosy is a news curation application that covers a wide range of topics, such as entertainment, sports, politics, and gourmet news. The application has been installed more than 20 million times.

Gunosy aims to provide people with the content they want without the stress of dealing with a large influx of information. We analyze user attributes, such as gender and age, and past activity logs like click-through rate (CTR). We combine this information with article attributes to provide trending, personalized news articles to users.

In this post, I show you how to process user activity logs in real time using Amazon Kinesis Data Firehose, Amazon Kinesis Data Analytics, and related AWS services.

Why does Gunosy need real-time processing?

Users need fresh and personalized news. There are two constraints to consider when delivering appropriate articles:

  • Time: Articles have freshness—that is, they lose value over time. New articles need to reach users as soon as possible.
  • Frequency (volume): Only a limited number of articles can be shown. It’s unreasonable to display all articles in the application, and users can’t read all of them anyway.

To deliver fresh articles with a high probability that the user is interested in them, it’s necessary to include not only past user activity logs and some feature values of articles, but also the most recent (real-time) user activity logs.

We optimize the delivery of articles with these two steps.

  1. Personalization: Deliver articles based on each user’s attributes, past activity logs, and feature values of each article—to account for each user’s interests.
  2. Trends analysis/identification: Optimize delivering articles using recent (real-time) user activity logs—to incorporate the latest trends from all users.

Optimizing the delivery of articles is always a cold start. Initially, we deliver articles based on past logs. We then use real-time data to optimize as quickly as possible. In addition, news has a short freshness time. Specifically, day-old news is past news, and even the news that is three hours old is past news. Therefore, shortening the time between step 1 and step 2 is important.

To tackle this issue, we chose AWS for processing streaming data because of its fully managed services, cost-effectiveness, and so on.


The following diagrams depict the architecture for optimizing article delivery by processing real-time user activity logs

There are three processing flows:

  1. Process real-time user activity logs.
  2. Store and process all user-based and article-based logs.
  3. Execute ad hoc or heavy queries.

In this post, I focus on the first processing flow and explain how it works.

Process real-time user activity logs

The following are the steps for processing user activity logs in real time using Kinesis Data Streams and Kinesis Data Analytics.

  1. The Fluentd server sends the following user activity logs to Kinesis Data Streams:
{"article_id": 12345, "user_id": 12345, "action": "click"}
{"article_id": 12345, "user_id": 12345, "action": "impression"}
  1. Map rows of logs to columns in Kinesis Data Analytics.

  1. Set the reference data to Kinesis Data Analytics from Amazon S3.

a. Gunosy has user attributes such as gender, age, and segment. Prepare the following CSV file (user_id, gender, segment_id) and put it in Amazon S3:


b. Add the application reference data source to Kinesis Data Analytics using the AWS CLI:

$ aws kinesisanalytics add-application-reference-data-source \
  --application-name <my-application-name> \
  --current-application-version-id <version-id> \
  --reference-data-source '{
  "S3ReferenceDataSource": {
    "BucketARN": "arn:aws:s3:::<my-bucket-name>",
    "FileKey": "mydata.csv",
    "ReferenceRoleARN": "arn:aws:iam::<account-id>:role/..."
  "ReferenceSchema": {
    "RecordFormat": {
      "RecordFormatType": "CSV",
      "MappingParameters": {
        "CSVMappingParameters": {"RecordRowDelimiter": "\n", "RecordColumnDelimiter": ","}
    "RecordEncoding": "UTF-8",
    "RecordColumns": [
      {"Name": "USER_ID", "Mapping": "0", "SqlType": "INTEGER"},
      {"Name": "GENDER",  "Mapping": "1", "SqlType": "VARCHAR(32)"},
      {"Name": "SEGMENT_ID", "Mapping": "2", "SqlType": "INTEGER"}

This application reference data source can be referred on Kinesis Data Analytics.

  1. Run a query against the source data stream on Kinesis Data Analytics with the application reference data source.

a. Define the temporary stream named TMP_SQL_STREAM.


b. Insert the joined source stream and application reference data source into the temporary stream.


c. Define the destination stream named DESTINATION_SQL_STREAM.


d. Insert the processed temporary stream, using a tumbling window, into the destination stream per minute.


The results look like the following:

  1. Insert the results into Amazon Elasticsearch Service (Amazon ES).
  2. Batch servers get results from Amazon ES every minute. They then optimize delivering articles with other data sources using a proprietary optimization algorithm.

How to connect a stream to another stream in another AWS Region

When we built the solution, Kinesis Data Analytics was not available in the Asia Pacific (Tokyo) Region, so we used the US West (Oregon) Region. The following shows how we connected a data stream to another data stream in the other Region.

There is no need to continue containing all components in a single AWS Region, unless you have a situation where a response difference at the millisecond level is critical to the service.


The solution provides benefits for both our company and for our users. Benefits for the company are cost savings—including development costs, operational costs, and infrastructure costs—and reducing delivery time. Users can now find articles of interest more quickly. The solution can process more than 500,000 records per minute, and it enables fast and personalized news curating for our users.


In this post, I showed you how we optimize trending user activities to personalize news using Amazon Kinesis Data Firehose, Amazon Kinesis Data Analytics, and related AWS services in Gunosy.

AWS gives us a quick and economical solution and a good experience.

If you have questions or suggestions, please comment below.

Additional Reading

If you found this post useful, be sure to check out Implement Serverless Log Analytics Using Amazon Kinesis Analytics and Joining and Enriching Streaming Data on Amazon Kinesis.

About the Authors

Yukinori Koide is the head of development for the Newspass department at Gunosy. He is working on standardization of provisioning and deployment flow, promoting the utilization of serverless and containers for machine learning and AI services. His favorite AWS services are DynamoDB, Lambda, Kinesis, and ECS.




Akihiro Tsukada is a start-up solutions architect with AWS. He supports start-up companies in Japan technically at many levels, ranging from seed to later-stage.





Yuta Ishii is a solutions architect with AWS. He works with our customers to provide architectural guidance for building media & entertainment services, helping them improve the value of their services when using AWS.






Scale Your Web Application — One Step at a Time

Post Syndicated from Saurabh Shrivastava original https://aws.amazon.com/blogs/architecture/scale-your-web-application-one-step-at-a-time/

I often encounter people experiencing frustration as they attempt to scale their e-commerce or WordPress site—particularly around the cost and complexity related to scaling. When I talk to customers about their scaling plans, they often mention phrases such as horizontal scaling and microservices, but usually people aren’t sure about how to dive in and effectively scale their sites.

Now let’s talk about different scaling options. For instance if your current workload is in a traditional data center, you can leverage the cloud for your on-premises solution. This way you can scale to achieve greater efficiency with less cost. It’s not necessary to set up a whole powerhouse to light a few bulbs. If your workload is already in the cloud, you can use one of the available out-of-the-box options.

Designing your API in microservices and adding horizontal scaling might seem like the best choice, unless your web application is already running in an on-premises environment and you’ll need to quickly scale it because of unexpected large spikes in web traffic.

So how to handle this situation? Take things one step at a time when scaling and you may find horizontal scaling isn’t the right choice, after all.

For example, assume you have a tech news website where you did an early-look review of an upcoming—and highly-anticipated—smartphone launch, which went viral. The review, a blog post on your website, includes both video and pictures. Comments are enabled for the post and readers can also rate it. For example, if your website is hosted on a traditional Linux with a LAMP stack, you may find yourself with immediate scaling problems.

Let’s get more details on the current scenario and dig out more:

  • Where are images and videos stored?
  • How many read/write requests are received per second? Per minute?
  • What is the level of security required?
  • Are these synchronous or asynchronous requests?

We’ll also want to consider the following if your website has a transactional load like e-commerce or banking:

How is the website handling sessions?

  • Do you have any compliance requests—like the Payment Card Industry Data Security Standard (PCI DSS compliance) —if your website is using its own payment gateway?
  • How are you recording customer behavior data and fulfilling your analytics needs?
  • What are your loading balancing considerations (scaling, caching, session maintenance, etc.)?

So, if we take this one step at a time:

Step 1: Ease server load. We need to quickly handle spikes in traffic, generated by activity on the blog post, so let’s reduce server load by moving image and video to some third -party content delivery network (CDN). AWS provides Amazon CloudFront as a CDN solution, which is highly scalable with built-in security to verify origin access identity and handle any DDoS attacks. CloudFront can direct traffic to your on-premises or cloud-hosted server with its 113 Points of Presence (102 Edge Locations and 11 Regional Edge Caches) in 56 cities across 24 countries, which provides efficient caching.
Step 2: Reduce read load by adding more read replicas. MySQL provides a nice mirror replication for databases. Oracle has its own Oracle plug for replication and AWS RDS provide up to five read replicas, which can span across the region and even the Amazon database Amazon Aurora can have 15 read replicas with Amazon Aurora autoscaling support. If a workload is highly variable, you should consider Amazon Aurora Serverless database  to achieve high efficiency and reduced cost. While most mirror technologies do asynchronous replication, AWS RDS can provide synchronous multi-AZ replication, which is good for disaster recovery but not for scalability. Asynchronous replication to mirror instance means replication data can sometimes be stale if network bandwidth is low, so you need to plan and design your application accordingly.

I recommend that you always use a read replica for any reporting needs and try to move non-critical GET services to read replica and reduce the load on the master database. In this case, loading comments associated with a blog can be fetched from a read replica—as it can handle some delay—in case there is any issue with asynchronous reflection.

Step 3: Reduce write requests. This can be achieved by introducing queue to process the asynchronous message. Amazon Simple Queue Service (Amazon SQS) is a highly-scalable queue, which can handle any kind of work-message load. You can process data, like rating and review; or calculate Deal Quality Score (DQS) using batch processing via an SQS queue. If your workload is in AWS, I recommend using a job-observer pattern by setting up Auto Scaling to automatically increase or decrease the number of batch servers, using the number of SQS messages, with Amazon CloudWatch, as the trigger.  For on-premises workloads, you can use SQS SDK to create an Amazon SQS queue that holds messages until they’re processed by your stack. Or you can use Amazon SNS  to fan out your message processing in parallel for different purposes like adding a watermark in an image, generating a thumbnail, etc.

Step 4: Introduce a more robust caching engine. You can use Amazon Elastic Cache for Memcached or Redis to reduce write requests. Memcached and Redis have different use cases so if you can afford to lose and recover your cache from your database, use Memcached. If you are looking for more robust data persistence and complex data structure, use Redis. In AWS, these are managed services, which means AWS takes care of the workload for you and you can also deploy them in your on-premises instances or use a hybrid approach.

Step 5: Scale your server. If there are still issues, it’s time to scale your server.  For the greatest cost-effectiveness and unlimited scalability, I suggest always using horizontal scaling. However, use cases like database vertical scaling may be a better choice until you are good with sharding; or use Amazon Aurora Serverless for variable workloads. It will be wise to use Auto Scaling to manage your workload effectively for horizontal scaling. Also, to achieve that, you need to persist the session. Amazon DynamoDB can handle session persistence across instances.

If your server is on premises, consider creating a multisite architecture, which will help you achieve quick scalability as required and provide a good disaster recovery solution.  You can pick and choose individual services like Amazon Route 53, AWS CloudFormation, Amazon SQS, Amazon SNS, Amazon RDS, etc. depending on your needs.

Your multisite architecture will look like the following diagram:

In this architecture, you can run your regular workload on premises, and use your AWS workload as required for scalability and disaster recovery. Using Route 53, you can direct a precise percentage of users to an AWS workload.

If you decide to move all of your workloads to AWS, the recommended multi-AZ architecture would look like the following:

In this architecture, you are using a multi-AZ distributed workload for high availability. You can have a multi-region setup and use Route53 to distribute your workload between AWS Regions. CloudFront helps you to scale and distribute static content via an S3 bucket and DynamoDB, maintaining your application state so that Auto Scaling can apply horizontal scaling without loss of session data. At the database layer, RDS with multi-AZ standby provides high availability and read replica helps achieve scalability.

This is a high-level strategy to help you think through the scalability of your workload by using AWS even if your workload in on premises and not in the cloud…yet.

I highly recommend creating a hybrid, multisite model by placing your on-premises environment replica in the public cloud like AWS Cloud, and using Amazon Route53 DNS Service and Elastic Load Balancing to route traffic between on-premises and cloud environments. AWS now supports load balancing between AWS and on-premises environments to help you scale your cloud environment quickly, whenever required, and reduce it further by applying Amazon auto-scaling and placing a threshold on your on-premises traffic using Route 53.