I'm new to Dynatrace and I'm trying to analyze PurePaths for application performance. I've searched for it in the Dynatrace documentation but no luck. Could anyone please tell what is Size referred here
The size is the actual length of the PurePath, so the number of nodes you see in the PurePath tree when you select the PurePath.
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I’ve tapped into an RS-485 bus and dumped some data. I’d like to implement a strawman/MITM device to intercept the traffic and send commands independent of the existing master/slave.
Here are some screenshots of some logic samples I captured in Saleae Logic 2:
zoom 1
zoom 2
zoom 3
My problem is it doesn’t look like it’s framed properly. I’ve got the analyzer set to Modbus RTU master, 9600 baud, no parity bit, one stop bit.
Could anyone tell me if this looks correct or incorrect based on these screenshots? Is this Modbus protocol, or something different? Trying to see if I’m on the right path here. Thanks. Any additional info I’m happy to supply if requested.
Tried several different ways of applying analyzers trying to get a solid stream of info
6.30.15 - HOW CAN I MAKE THIS QUESTION BETTER AND MORE HELPFUL TO OTHERS? FEEDBACK WOULD BE HELPFUL. THANKS!
I am developing a web application that will handle/manage a VERY LARGE data set - Currently any kind of heavy load causes the browser to lock up - whether I'm in the Django Rest Framework API or in the Dojo/Dgrid. This is kind of a dual question.
I've researched and can't find a clear way to do this on either side.
How do I limit how much the database sends at one time to the Django Rest Framework and/ or The Dojo Dgrid. The Dgrid pulls the data from the Django Rest API. The DRF pulls data directly from the MySQL database.
If I can control how much data is sent at one time, then hopefully it won't lock up the browser as much. ANY suggestions, advice, help, examples would be very helpful. Thanks in advance!
UPDATED 6.22.15 -
Alright, I FINALLY Got the pagination to work and it display the limit/offset in the headers. :) YAY!!!! I can also see the data in the Response headers. HOWEVER... the grid won't populate and I keep getting this odd error:
TypeError: transform(...) is null
return transform(value, key).toString();
instrum...tion.js (line 20)
I've gotten this error before, but I've never been able to find a solution to it. After researching, there's not much I can find on HOW to fix or really even what it is. Any help with this would be greatly appreciated!! I'm SO CLOSE to getting this thing to work correctly after WEEKS and WEEKS of beating my head against a wall. Please help! :) Thanks in advance!!!
2nd Update - This was an answer from a previous post - but I'm still not sure how to fix it. When I addressed another issue - it went away for awhile, but I still have no idea how to correct the issue.
Problem 3: "transform(...) is null return transform(value, key).toString();"
This sounds largely tangential to the original issue, but the most common cause is a widget template that is referencing a property via ${...} that doesn't actually exist in the widget.
I don't know how to answer this on the layer between DRF and the database, but as discussed in other SO questions like this one, DRF allows you to limit the amount of data sent with requests via page or offset/limit parameters.
Based on the phrasing of your question, it sounds like the client side is actually requesting too much data. I'll outline how the flow should work, so hopefully you can spot what you've missed:
A dgrid instance is set up with a collection referencing a dstore/Rest instance
The dstore/Rest instance is created with appropriate properties set. In this case, based on the DRF Documentation:
useRangeHeaders: false (this is already the default)
rangeStartParam: 'offset'
rangeCountParam: 'limit'
As a result, when the grid renders, you should see requests sent to your server e.g. endpoint?offset=0&limit=25 - if you don't see those two parameters, that would be why you're getting too much data
The server will need to query the database with the respective OFFSET and LIMIT
The server must provide a response with the expected number of items (except if it reaches the end of the data set first, which should be reflected by the total property in the response, presuming the customization in the previous SO answer I linked is used)
Ultimately, if the service is working as expected, the grid should only be requesting a handful of items at a time, and should only be firing one or two requests at any given time.
Would add as a comment, but not enough reputation at the moment ....
Your question is pretty general, but one strategy would be to allow the user to select the number of items they wish to view at a time and then allow the user to page through the data with 'next x items' and 'prev x items' buttons. Your data object query would then use the current position +/- 'x' as the index range to reduce the number of data objects sent to the browser. This is the basic flow for Ebay, Amazon, Google, or any site with thousands of items to display. The 'next' and 'prev' actions could be wired as POST requests.
We are creating a speed limit map application using different colors to highlight street with different speed limits (similar to ITO speed limit map: http://www.itoworld.com/map/124?lon=-79.37151&lat=43.74796&zoom=12).
The problem we have is that we are conducting our own research and have our own speed limit data instead of pulling the data from OpenStreetMap or Google Map like ITO map. We also need to create a data storage in order to dynamically update the map as we add more speed limit information in the future.
Is there anyway to create our own instance of OpenStreetMap and replace only the speed limit information with our own data? We don't have any vector data and we have no experience working with them.
Is there any suggestion of tools to use for creating highlighting layers based on the speed limit we have? Is OpenLayers a good option?
Any help is appreciated, thank you very much.
Update 2013/11/20
Thank you very much for your answers, now we have a much better understanding of your problem. This is a university design project so we basically have no budget. We are looking for:
1) A basic "base map" that include the basic tile information (openstreetmap seems a good choice since google map api doesn't provide free road information as long as we can find)
2) A geo data server that can host our own street speed limit data (looks like geoserver and mapserver are good choices), or a design simple database that can fulfill our need(doesn't know is it possible yet)
3) A plotting tool that can render our speed limit data as "group of lines" on the map since these data will be changed frequently (openlayers and leaflet are good candidates).
Is there anything else needed?
What you want to do is a trivial programming task once you have decided a few things:
These are probably the three biggest questions you need to answer. I added some commentary, but look at each of these questions beyond this post to find what works for you.
Who do you want to use for your map? Since you only have one type of data you will want to display that data on someone else's nice looking map. The big choices are Bing, Google, OpenLayers/OSM, and ESRI. Your choice will most likely be driven by the licensing of the above services and if you are willing to pay or not. A need to support mobile devices may also factor into your decision. Since the map is what your users will see, choose the best looking map you can afford.
How will you serve up your data? You have several options to serve your speed limit data. GeoServer and MapServer and ESRI are some popular mapping software packages. If you only displaying a few layers of data all mapping software will be overkill. The actual software to render your map data will most likely affect only your pocket book, so free is good here usually.
Tiles vs Lines
You will server your data as either a group of lines sent to the browser, or as pre-rendered tiles to be loaded on top of the map. If you data changes frequently you will want to serve it dynamically as line data (an array of points.) If your data does not change frequently, you should consider tiling your data. Tiling involves pre-rending of the entire map at all zoom levels. This allows the map to be loaded very fast and this how almost all base maps are rendered. The downside is that the tile generation can take a long amount of time and tiles can take a large amount of space.
This is a very broad question. There are many components to drawing your own speed limit map.
On the front-end, there is a web browser map interface. OpenLayers is good at that. There are plenty of other tools that can do this as well, such as Leaflet or even Google Maps API.
Next is something to provide the actual speed limit route data. This can be served as a vector layer or a raster layer. There are plenty of tools here, too. UMN Mapserver is free and reasonably good. ESRI makes a whole fleet of products in this area as well.
The speed limit route data also needs to be saved somehow. This can be done in files or in a database such as PostGIS. Again, lots of great options.
It is the role of the system architect to determine which technologies to employ to solve the problem.
I am looking into plotting a very large data. I've tried with FLOT, FLOTR and PROTOVIS (and other JS based packages) but there is one constant problem I'm faced with. I've tested 1600, 3000, 5000, 8000 and 10k points on a 1000w 500h graph which are rendered all within a reasonable time on PC browsers (IE and FF). But when rendered on MACs FF/Safari, starting with 500 data points, the page becomes significantly slow and/or crashes.
Has anyone come across this issue?
Yes, don't do that. It seems pretty unlikely to me that 10k points are actually going to be visible/useful to the user all at once.
You should aggregate your data (server-side) and then if they want to zoom in on areas of the data, use AJAX requests to get that area and replot.
If you use flot, they have examples showing selection, i.e. here: http://people.iola.dk/olau/flot/examples/zooming.html
(I can't comment the Ryley answer yet, that's why I put some remarks here)
What about an offline use. Html is a great format for documents, set aside the server/client stuff.
JavaScript, Canvas and all those fancy client-side technologies could be used to build nice interactive files, like data reports containing graphs with zoom and pan features ...
It's no secret that application logs can go well beyond the limits of naive log viewers, and the desired viewer functionality (say, filtering the log based on a condition, or highlighting particular message types, or splitting it into sublogs based on a field value, or merging several logs based on a time axis, or bookmarking etc.) is beyond the abilities of large-file text viewers.
I wonder:
Whether decent specialized applications exist (I haven't found any)
What functionality might one expect from such an application? (I'm asking because my student is writing such an application, and the functionality above has already been implemented to a certain extent of usability)
I've been using Log Expert lately.
alt text http://www.log-expert.de/images/stories/logexpertshowcard.gif
I can take a while to load large files, but it will in fact load them. I couldn't find the file size limit (if there is any) on the site, but just to test it, I loaded a 300mb log file, so it can at least go that high.
Windows Commander has a built-in program called Lister which works very quickly for any file size. I've used it with GBs worth of log files without a problem.
http://www.ghisler.com/lister/
A slightly more powerful tool I sometimes use it Universal Viewer from http://www.uvviewsoft.com/.