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Category: Misc Languages

RESULT_SCAN() in Snowflake

Published 2020-02-06 by Kevin Feasel

Koen Verbeeck introduces us to the RESULT_SCAN() function in Snowflake DB:

I’m doing a little series on some of the nice features/capabilities in Snowflake (the cloud data warehouse). In each part, I’ll highlight something that I think it’s interesting enough to share. It might be some SQL function that I’d really like to be in SQL Server, it might be something else.

This post builds upon part 6 of the series, which dealt with query history. There it is explained how Snowflake caches the query results. You can find a query in the history and take a look at what was returned. Using the RESULT_SCAN table function, you can do this with SQL. Let’s take a look at an example.

This is an interesting function. Click through to see it in action.

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Queueing Event Notifications with Service Broker

Published 2020-02-03 by Kevin Feasel

Max Vernon ties event notifications to Service Broker:

My previous post shows how to configure an Event Notification to fire whenever a login event occurs. The post uses Service Broker to receive those Event Notifications into a queue, which is then processed by a stored procedure and saved into a standard SQL Server database. This post provides a quick+dirty VB.Net command line monitor that shows how full a Service Broker queue is.

The following code should be pasted into a blank Visual Studio VB.Net console project. It is trivially easy to translate this into C#, but I like VB – what can I say.

Click through for the code. No F# translation from me, however, as I am lazy.

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An Introduction to gRPC

Published 2020-01-29 by Kevin Feasel

Munander Singh explains why you might want to use gRPC for cross-process communications:

When the client invokes the service, the client-side gRPC library uses the protocol buffer and marshals the remote procedure call, which is then sent over HTTP2. Server un-marshal the request and executes the respective procedure invocation using protocol buffers. The response follows a similar execution flow from the server to the client.

The main advantage of developing services and clients with gRPC is that your service code or client side code doesn’t need to worry about parsing JSON or similar text-based message formats (within the code or implicitly inside the underlying libraries such as Jackson, which is hidden from service code). What comes in the wire is a binary format, which is unmarshalled into an object. Also, having first-class support for defining a service interface via an IDL is a powerful feature when we have to deal with multiple microservices and ensure and maintain interoperability.

The “yes, but” here is that based on your language of choice, gRPC can be a bit tricky to get going.

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ACID Transactions with Cosmos DB

Published 2020-01-28 by Kevin Feasel

Hasan Savran shows how you can use the Cosmos DB SDK to create ACID transactions:

What about Azure Cosmos DB? It’s a NoSQL database, probably you can’t do ACID Transactions right? WRONG! Azure Cosmos DB has been supporting ACID transaction for some time now. We were able to create ACID transactions by using stored procedures of Cosmos DB. Last year (2019) Cosmos DB team introduced ACID transactions to Cosmos DB SDK. Now, we can create transactions by using C# just like writing transactions by using SQLClient class for SQL Server!

      To create an ACID transaction in Cosmos DB SDK, we need to use TransactionalBatch object. You need add all operations in transaction to TransactionalBatch object. All the operations attached to the TransactionalBatch object must share the same partition key. In the following example, I created three objects and attach them to TransactionalBatch object. To start the transaction, I ran the ExecuteAsync() function.  This function runs the transaction and returns the responses for each operation.

I’d think you would need to set a strong consistency level as well.

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Migrating Oracle Exadata Workloads to Azure

Published 2020-01-23 by Kevin Feasel

Kellyn Pot’vin-Gorman shows the process of moving from an Exadata system to Oracle on Azure:

An Exadata is an engineered system-  database nodes, secondary cell nodes, (also referred to as storage nodes/cell disks), InfiniBand for fast network connectivity between the nodes, specialized cache, along with software features such as Real Application Clusters, (RAC), hybrid columnar compression, (HCC), storage indexes, (indexes in memory) offloading technology that has logic built into it to move object scans and other intensive workloads to cell nodes from the primary database nodes.  There are considerable other features, but understanding that Exadata is an ENGINEERED system, not a hardware solution is important and its both a blessing and a curse for those databases supported by one.  The database engineer must understand both Exadata architecture and software along with database administration.  There is an added tier of performance knowledge, monitoring and patching that is involved, including knowledge of the Cell CLI, the command line interface for the cell nodes.  I could go on for hours on more details, but let’s get down to what is required when I am working on a project to migrate an Exadata to Azure.

Click through for the process.

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Strongly Type Table-Valued Parameters

Published 2020-01-22 by Kevin Feasel

Jonathan Kehayias shows the benefits of using the MaxLength parameter when calling a table-valued parameter from .NET code:

We can see that the MaxLength for the string columns is set at -1, meaning they are being passed over TDS to SQL Server as LOBs (Large Objects) or essentially as MAX datatyped columns, and this can impact performance in a negative manner. If we change the .NET DataTable definition to be strongly-typed to the schema definition of the user-defined table type as follows and look at the MaxLength of the same column using a debug break:

This can be important, especially if you make a lot of calls or use fairly large TVP sizes.

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Installing .NET Core on a Raspberry Pi 4

Published 2020-01-15 by Kevin Feasel

Hasan Savran continues a series on Microsoft + Pi:

I have been writing about Azure IOT Hub and Raspberry Pi 4. So far, I bought a Raspberry Pi 4. I registered it as Azure IOT Edge device. Now, I am ready to write some code in Raspberry Pi. In this post, I will show you how install .NET Core 3.1 to Raspberry Pi so we can write some code to generate some data and push this data to Azure IOT Hub.

     First, you need to go to the .NET Core homepage to get the latest version’s url. Following page lists all .NET Core version, 3.1 was the latest when I was writing this blog. Pick the latest one from this list.

Another route might be to install Docker on your Pi.

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sqlcmd and Complex Passwords

Published 2020-01-13 by Kevin Feasel

Randolph West hits one of my bugbears with respect to the Windows command shell:

Using accepted good practice, the password and script were escaped with double quotes. (note that instance, password and database are the replacement values in question):

sqlcmd -S instance -U maintenanceUser -P "password" -Q "dbcc checkdb ('database') with DATA_PURITY, NO_INFOMSGS;"

Unfortunately, one of the passwords started with a double quotation mark which led to the command failing for one specific Express Edition instance.

Read on to see the mess as well as a way to extricate yourself from the mess.

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Functional Java

Published 2019-12-19 by Kevin Feasel

Rishi Khandelwal lays out imperative versus functional Java with several examples:

As a java developer, you must have confused, whether should I move to the functional programming paradigm? What are the benefits it provide to us? People are talking about it everywhere. So let’s give it a try once and then you can decide whether you should go to the functional paradigm or not.

We will see the functional programming features one by one with the code examples and will compare it with the imperative way of java programming.

The snide part of me says “Hey, look, Java’s almost caught up to C# 3.0!” But that’s pushing it a little far. I think these functional pieces improve the language similarly to how they did C#, but if I were a regular Java developer, I’d probably look to Scala or Kotlin instead (says the guy who won’t shut up already about F#).

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Making an Executable JAR from sbt

Published 2019-12-18 by Kevin Feasel

Sakshi Gawande walks us through two problems you might hit when building Scala projects into JARs:

Now, before going to see the solution we first understand why this problem occurs. When you uses Simple Build Tool Command ‘sbt package’, it creates a jar file that includes the class files from your source code and also the content from your src/main/resources folder.

But there are mainly two things which is important to execute jar file, are not included

Read on for these two things.

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