databus | time series data in cassandra with visualization | Dashboard library
kandi X-RAY | databus Summary
kandi X-RAY | databus Summary
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Top functions reviewed by kandi - BETA
- Difference between two lines .
- Parse the input stream .
- Run the CGI process .
- Return the power of two numbers .
- Initialize the GUI .
- Helper function to read a module .
- Create a bytecode representation of a list .
- Default MIME types .
- Analyse a scalar .
- Format data as string .
databus Key Features
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Community Discussions
Trending Discussions on databus
QUESTION
I have a program where I need to read and write data to a common (central?) object from most other obejcts. In a way it acts like a database or perhaps databus if you like. I cannot write it to a file. Currently I do it like this:
...ANSWER
Answered 2021-Feb-18 at 15:09The real answer is "don't".
You can use the Singleton pattern; but, by doing so you are avoiding "object oriented programming" which is the method that Java uses to make the programs maintainable and repairable.
Once you have a single, central object, you can't modify your code easily in many ways without investigating how the central object is impacted, and then investigating how all the other objects that also use the central object are impacted through the central object.
Instead create an object for each scenario. This allows you to process two scenarios at a time, which will make life easier when you start to make your programs multi-threaded, something you'll want to do sooner or later, because otherwise you'll only use 1 core in that 8 core processor.
Your language assumes a central object, so I can't provide an example in your scenario. I'll modify Commmon to Context where Context means "the scenario I'm dealing with now".
Note that with such a change, you probably shouldn't own the context, you should pass it along.
QUESTION
Looking for an Open source alternative to GoldenGate that will stream all the DML operation in the source Oracle to a compacted kafka topic. My employer acknowledge that Larry doesn't possibly need another island. So licensing Oracle GoldenGate is not an option.
Looked at https://gitter.im/linkedin/brooklin, https://github.com/linkedin/databus , https://github.com/debezium/debezium so far. I couldn't find any documentation that states how to do Oracle CDC using these. Any pointer will be greatly appreciated. I am not asking any opinions or recommendations, I am seeking viable alternatives of GoldenGate.
EditI got this from Debezium gitter/slack channel, https://debezium.io/docs/connectors/oracle/. But this still needs GoldenGate license.
...ANSWER
Answered 2019-Sep-19 at 23:15Here are all your options: https://rmoff.net/2018/12/12/streaming-data-from-oracle-into-kafka-december-2018/
It's worth noting there are cheaper commercial alternatives to GoldenGate, so your choice is not purely between open source and GoldenGate only.
QUESTION
We have an NServiceBus 6 environment with a number of services that send files between each other using DataBusProperty over a custom SqlDataBus : IDataBus.
This works fine on NSB6 using the built in JSON serializer, but is now broken after we moved to NSB7 and the NewtonsoftSerializer.
Removing DataBusProperty from our classes and just using byte[] works fine. We also tried changing the DataBus to FileShareDataBus but got the same exception:
...ANSWER
Answered 2019-Jun-27 at 18:57Although data bus properties should work there is also an alternative to data bus properties which is using stream attachments via send options:
Depending on the use case using Streams might be a more efficient approach.
QUESTION
I would like to use expandable connector (e.g. a Bus-like structure) to model (mainly) input and output connections for more complex subsystems (An array will not allow having different units for its elements and flattened lists get unwieldly while a record does not afaik allow for easily connecting only one of its variables without writing equations).
While you may simply connect a variable to an empty expandable connector without problems, its unit (and other attributes) will not be passed on. Thus I would like to flexbily declare variables inside an expandable connector (e.g. like x[:]) and have their dimensions be determined by the actual connection.
Unfortunately neither does this validate in OpenModelica and Wolfram System Modeler:
...ANSWER
Answered 2019-Jun-19 at 08:55What could work is using RealInputs and RealOutputs instead of just Real. This way the connection works and the units are passed correctly.
QUESTION
I tried to save these special characters:
© ™ ® ± ≠ ≤ ≥ ≅ ∞ µ α β Ω Σ Φ φ <> ° & %
into a MySQL databuse using a Java application, but its not working.
While implementing the JDBC driver into my application, I made sure to do it this way:
...ANSWER
Answered 2017-May-29 at 09:41Try this
QUESTION
I'm connecting an ILI9341 display controller to an STM32F407vg microcontroller (STM32 Discovery board). The display is connected to the STM32 with a 16-bit parallel databus.
To achieve high datarates I use the FSMC of the STM32. The FSMC is configured as a static RAM controller. I don't use chip select or read. The interface works, I can send data to the display, but it is slow.
I tried writing to the LCD with a for loop, but also with DMA in memory to memory mode. I tried writing data from flash, but also from RAM. Optimizing various DMA settings. All these changes didn't affect the speed at all. So to me there seems to be a huge bottleneck somewhere.
The figure below shows a measurement of a 16-bit word transfer (only the first 8 lines are measured). As you can see, the display's WR line toggles with only 558kHz.
The figure below shows the FSMC timing as explained in the reference manual. NWE (write enable) is WR in my measurement. A16 is D/C.
ADDSET and DATAST are in HCLK (AHB clock) cycles. The AHB clock is configured at its maximum speed of 168MHz. ADDSET and DATAST are set to 0 and 1. So I configured a speed of 84MHz. I don't expect to achieve 84MHz, because the DMA controller is slower (see below). But I would at least expect to achieve the DMA speed.
With ST's HAL v1.6.0.0 library I set the clock to the maximum speed:
...ANSWER
Answered 2017-Jan-24 at 20:30I found a very short piece of code here which shows how to configure FSMC with only CMSIS.
With one line of HAL code to activate the clock, this piece of code looks like this:
QUESTION
Assembly:
Consider the Intel 8080. To handle an interrupt (for example from the keyboard), you simply have the keyboard pull the 'INT' pin high and place a 'vector' on the databus. The vector points to the location of the interrupt service routine (ISR) in the assembly program code. See this answer for more details.
High level language:
Consider the concept of attaching event listeners. For example consider Javascript's keydown event listener. An example:
ANSWER
Answered 2018-Jul-10 at 15:27It's a long and complex journey from a key being pressed and the code in a JavaScript keydown event listener being run. Assuming a USB keyboard, the path through hardware and software layers is something like this:
- keyboard (hardware layer)
- USB controller (hardware layer)
- USB controller driver (kernel layer)
- USB generic driver (kernel layer)
- HID generic driver (kernel layer)
- HID keyboard driver (kernel layer)
- OS UI event processing (kernel/user layer)
- browser UI event loop (user layer)
- browser UI event handler (user layer)
- JavaScript engine event handler (user layer)
keydownevent listener (user layer)
Most of this doesn't work how you're probably assuming. In particular there's no keyboard interrupt. Instead there's a USB interrupt but it doesn't quite work the way you might assume. When you press a key on USB keyboard it doesn't result in a message being sent to the computer and an interrupt generated. Instead the keyboard adds the key press to its internal queue and waits for the computer to poll it.
This is because USB communication is entirely scheduled by the USB host (the computer). USB devices aren't allowed to talk on the bus except in response to a request by the host. As USB transactions are scheduled into one millisecond frames, normally an operating system will only poll a USB keyboard once a millisecond, asking it to report any events that have occurred since it last polled the device. Only once the keyboard responds to this request (or maybe when all the scheduled transfers in the frame have completed), will the USB controller generate an interrupt.
The response from the keyboard will be in the form a HID (Human Interface Device) report. The HID stack will decode it to see what keyboard events have been reported, converting them into a format common to all keyboard types. This will be further processed by some sort of user-interface layer in the operating system (eg. The "Win32" API layer on Windows, or an X Server on Linux) and then put on the UI event queue for the browser.
The browser will not be "interrupted" as a result of the key being pressed. Instead the browser will have a main UI interface event loop and events will only be processed one a time at a single defined point in the program. All this loop does is pull events from the UI event queue and dispatches them to the appropriate code in the browser. When the queue is empty, which is normally almost all of the time, the loop simply waits for an event. While it's waiting, the event loop's thread is not scheduled by the OS and is not running on any CPU.
Once the UI event loop gets a keyboard event, it's passed onto the browser's keyboard event handler which will then pass it to the JavaScript engine. The engine will then execute the function assigned as the keydown event listener. The engine may have its own event queue, as JavaScript events are normally also only processed one at a time.
None of this will be written in assembly except a tiny amount of code in the kernel that acts as a landing point for interrupts and system calls before calling the C code that actually dispatches them.
QUESTION
Publish/Subscribe Design Pattern
To me they seem the same, what's the key difference between the two?
...ANSWER
Answered 2017-Dec-03 at 07:55From the url you provided:
DataBusPattern is related to, but not exactly the same as PublishSubscribeModel. DataBusPattern decouples the sender and receiver by adding an intermediary (the DataBus). In PublishSubscribeModel, the sender and receiver must be aware of each other.
QUESTION
I have code that makes unique combinations of elements. There are 6 types, and there are about 100 of each. So there are 100^6 combinations. Each combination has to be calculated, checked for relevance and then either be discarded or saved.
The relevant bit of the code looks like this:
...ANSWER
Answered 2017-Nov-25 at 16:03you can run your function in this way:
QUESTION
I am trying to make a type of progress bar to track a percentage of tasks completed. I want to v-bind:styles and pass it {width: dynamicWidth + '%'} in order to control the progression of this bar. So far I have created a computed variable that will return the percentage complete I want to bar to display, and I have set up my dynamic style in the data object
...ANSWER
Answered 2017-Jul-28 at 06:02why not just use :
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