Based on the following use case, how flexible are pentaho tools to accomplish a dynamic transformation?
The user needs to make a first choice from a catalog. (using a web interface)
Based on the previously selected item, the user has to select from another catalog (this second catalog must be filtered based on the first selection).
steps 1 and 2 may repeat in some cases, (i.e. more than two dynamic and dependent parameters).
From what the user chose in step 1 and 2, the ETL has to extract information from a database. The tables to select data from will depend on what the user chose in previous steps. Most of the tables have a similar structure but different name based on the selected item. Some tables have different structure and the user have to be able to select the fields in step 2, again based on the selection of step 1.
All the selections made by the user should be able to be saved, so the user doesn't have to repeat the selection in the future, only re-run the process to get updated information based on the pre-selected filters. However he/she must be able to make a different selection and save it for further use if he/she wants different parameters.
Is there any web-based tool to allow the user to make all this choices based? I made the whole process using kettle but not dynamically, since all the parameters need to be passed when running the process in the console. The thing is, the end user doesn't know all the parameter values unless you show them and let them chose, and some parameters depend on a previous selection. When testing I can use my test-case scenario parameters, so I have no problem, but in production there is no way to know in advance what combination the user will chose.
I found a similar question, but it doesn't seem to require user input between transformation steps.
I'd appreciate any comments about the capabilities of Pentaho tools to accomplish the aforementioned use case.
I would disagree with the other answer here. If you use CDE it is possible to build a front end that will easily do those prompts you suggest. And the beauty of CDE is that a transformation can be a native data source via the CDA data access layer. In this environment kettle is barely any slower than executing the query directly.
The key thing with PDI performance is to avoid starting the JVM again and again - when running in a web app you're already going so performance will be good.
Also; The latest release of PDI5 will have the "light jdbc" driver (EE customers) which is basically a SQL interface on PDI jobs. So that again shows that PDI is much more these days than just a "batch" etl process.
This is completely outside the realm of a Kettle use case. The response time from Kettle is far too slow for anything user facing. It's real strength is in running batch ETL processes.
See, for example, this slideshow (especially slide 11) for examples of typical Kettle use cases.
Related
Our team uses Spotfire to host online analyses and also prepare monthly reports. One pain point that we have is around validation. The reports are all prepared reports, and the process for creating them each month is as simple as 1) refresh the data (through Infolink connected to Oracle) and 2) Press button to export each report. The format of the final product is a PDF.
The issue is that there are a lot of small things that can go wrong with the reports (filter accidentally applied, wrong month selected, data didn't refresh, new department not grouped correctly, etc.) meaning that someone on our team has to manually validate each of the reports. We create almost 20 reports each month and some of them are as many as 100 pages.
We've done a great job automating the creation of the reports, but now we have this weird imbalance where it takes like 25 minutes to create all the reports but 4+ hours to validate each one.
Does anyone know of a good way to automate, or even cut down, the time we have to spend each month validating the reports? I did a brief google and all I could find was in the realm of validating reports to meet government regulation standards
It depends on 2 factors:
Do your reports have the same template (format) each time you extract them? You said that you pull them out automatically so I guess the answer is Yes.
What exactly are you trying to check/validate? You need to have a clear list on what are you validating. You mentioned month, grouping, data values (for the refresh)). But the clearer the picture you have for validation, the more likely the process can be fully automated.
There are so called RPA (robot process automation) tools that can automate complex workflows.
A "data extract" task, which is part of a workflow, can detect and collect data from documents (PDF for example).
A robot that runs on the validating machine can:
batch read all your PDF reports from specified locations on your computer (or on another computer);
based on predefined templates it can read through the documents for specific fields that you specify (through defined anchors on the templates) and collect the exact data from there;
compare the extracted data with the baseline that you set (compare the month to be correct, compare a data field to confirm proper refresh of the data, another data field to confirm grouping, etc.);
It takes a bit of time to dissect the PDF for each report template and correctly set the anchors but then it runs seamless each time.
One such tool I used is called Atomatik. It has a studio environment where you design the robot (or robots) and run the process.
I'm endeavoring to develop an application that uses Oracle as the database back-end. The application will calculate several statistics from the various tables in the database. The front-end will most likely be a web application and this front-end will display various charts and calculated statistics. Now, I imagine that it would be more efficient to perform the calculations in the database rather than in the service layer because said calculations would need to be performed for every web request. That being the case, I'm not sure which mechanism to use. (e.g. stored procedure, function, view) To illustrate what I'm going for, suppose I want to keep statistics of student grades for many students. I would like to have a web interface that lets me view those statistics on student-by-student basis and also an all-inclusive basis. Some of the stats are dependent on aggregates (e.g. average, min, max) of all of the student grades and some stats are dependent only on an individual student. In this situation, every time a record is added or updated, the aggregates would have to be recalculated. So I am speculating that if I had a special table that held all of the calculated values I need and a trigger(s) to recalculate everything when a record is added/updated then all I would need to do from a web request point-of-view is have the service layer pull the desired values from this special table. I'm just not sure if this is the best way to go or not so I am asking the community for any input/advice. Note: Although I'm using Oracle, I'm open to using PostgreSQL or mySQL.
Thanks in advance
The scenario you are describing would be ideal for using materialized views. They can be designed to refresh automatically (and incrementally) every time the source data is updated by your application. The calculations would be built in to the view definition. No triggers required, and likely no stored procedures unless your calculations involve multiple steps. Check here: https://oracle-base.com/articles/misc/materialized-views and here: https://medium.com/oracledevs/lightning-fast-sql-with-real-time-materialized-views-12-things-developers-will-love-about-oracle-54bcc9eac358 for more info.
So I will be embarking on designing a dashboard that will display KPI's and other relevant information for my team. Since I am in the early stages of this project and am not very familiar on the technical process behind designing a dashboard, I need some questions vetted out first before I go and shop for some solutions to avoid reinventing the wheel.
Here are some of my questions:
We want a dashboard that can provide live-time information via our data sources (or as close to live-time as possible). What function allows a dashboard to update itself with concurrent datasources? From a conceptual standpoint, I can understand creating a dashboard out of Microsoft Excel, and having the dashboard dependent on the values you may have set within your pivot table.
How do you make a dashboard request information from multiple datasources on its own? Just like the excel example, a user may have to go into the pivot tables to update values, but I want to know how would a dashboard request this by itself and what is the exact method from a programming standpoint? Does the code execute itself every time you refresh the webpage?
How do you create datasources organically? I know for some solutions such as SharePoint BI Center, there are pre-supported datasources like an excel sheet or SharePoint and it's as easy as uploading your document and letting the design handle the rest. However, there are going to be some datasources that I know that will need to be fetched. Do I need to understand something else like an event recorder in order to navigate this issue?
Introduction
The dashboard (or a report, respectively) is usually the result of a long chain of steps. Very much simplified it could look like this:
src1
|------\
src2 | /---- Dashboards
|------+---[DWH]-[BR]-+
src n | | \---- Reports etc.
|------/ [Big Data]
Keep in mind, this is only a very, very simple structure of a data backend / frontend.
DWH means Data Warehouse, where data might be stored temporarily (you referred to this as fetching). This could be a database, could be a Big Data engine, could be a combination of both...
Afterwards, there are Business Rules (BR). Those might be specific rules in how different departments calculate and relate to data, but also simple things like algebra.
Questions
So, the main question should not be about the technology:
What software should we choose?
How can we create a dashboard?
but on the contrary focused on your business processes (see it like a top-down view):
How does our core process look like? Where would I like to measure data?
How would department a calculate sales in difference to department b? Should all use the same rule?
Where does everyone store the data? Can we access it? Do we need structural data?
And, very easy to forget but also easily sometimes one of the biggest parts: Is the identifier of a business object (say, sales id) everywhere build and formatted in the same way?
Conclusion
When those questions are at least in the back of your head and you keep working in this direction, more or less automatically data will spill out at certain points of that process.
Then it won't matter if you use Excel, a small-to medium app like Tableau, Tibco Spotfire, QlikView, Power BI or you want to go full scale with a big Hadoop backend, databases and JasperReports, Apache Drill, Pentaho, SSIS on top of it... it will come out eventually.
TL;DR
Focus on the processes first. Make sure to understand them. Draft in Excel. Then proceed in getting the data and the tools you need to help your use cases. It will work out much better from a "top-down" approach than trying to solve your requirements with tools only.
So I was thinking... Imagine you have to write a program that would represent a schedule of a whole college.
That schedule has several dimensions (e.g.):
time
location
indivitual(s) attending it
lecturer(s)
subject
You would have to be able to display the schedule from several standpoints:
everything held in one location in certain timeframe
everything attended by individual in certain timeframe
everything lecturered by a certain lecturer in certain timeframe
etc.
How would you save such data, and yet keep the ability to view it from different angles?
Only way I could think of was to save it in every form you might need it:
E.g. you have folder "students" and in it each student has a file and it contains when and why and where he has to be. However, you also have a folder "locations" and each location has a file which contains who and why and when has to be there. The more angles you have, the more size-per-info ratio increases.
But that seems highly inefficinet, spacewise.
Is there any other way?
My knowledge of Javascript is 0, but I wonder if such things would be possible with it, even in this space inefficient form.
If not that, I wonder if it would work in any other standard (C++, C#, Java, etc.) language, primarily in Java...
EDIT: Could this be done by using MySQL database?
Basically, you are trying to first store data and then present it under different views.
SQL databases were made exactly for that: from one side you build a schema and instantiate it in a database to store your data (the language is called Data Definition Language, DDL), then you make requests on it with the query language (SQL), what you call "views". There are even "views" objects in SQL databases to build these views Inside the database (rather than having to the code of the request in the user code).
MySQL can do that for sure, note that it is possible to compile some SQL engine for Javascript (SQLite for example) and use local web store to store the data.
There is another aspect to your question: optimization of the queries. While SQL can do most of the request job for your views. It is sometimes preferred to create actual copies of the requests results in so called "datamarts" (this is called de-normalizing a request), so that the hard work of selecting or computing aggregate/groups functions and so on is done once per period of time (imagine that a specific view changes only on Monday), then requesters just have to read these results. It is important in this case to separate at least semantically what is primary data from what is secondary data (and for performance/user rights reasons, physical separation is often a good idea).
Note that as you cited MySQL, I wrote about SQL but mostly any database technology could do that what you searched to do (hierarchical, object oriented, XML...) as long as the particular implementation that you use is flexible enough for your data and requests.
So in short:
I would use a SQL database to store the data
make appropriate views / requests
if I need huge request performance, make appropriate de-normalized data available
the language is not important there, any will do
Looking for a bit of advice on how to optimise one of our projects. We have a ASP.NET/C# system that retrieves data from a SQL2008 data and presents it on a DevExpress ASPxGridView. The data that's retrieved can come from one of a number of databases - all of which are slightly different and are being added and removed regularly. The user is presented with a list of live "companies", and the data is retrieved from the corresponding database.
At the moment, data is being retrieved using a standard SqlDataSource and a dynamically-created SQL SELECT statement. There are a few JOINs in the statement, as well as optional WHERE constraints, again dynamically-created depending on the database and the user's permission level.
All of this works great (honest!), apart from performance. When it comes to some databases, there are several hundreds of thousands of rows, and retrieving and paging through the data is quite slow (the databases are already properly indexed). I've therefore been looking at ways of speeding the system up, and it seems to boil down to two choices: XPO or LINQ.
LINQ seems to be the popular choice, but I'm not sure how easy it will be to implement with a system that is so dynamic in nature - would I need to create "definitions" for each database that LINQ could access? I'm also a bit unsure about creating the LINQ queries dynamically too, although looking at a few examples that part at least seems doable.
XPO, on the other hand, seems to allow me to create a XPO Data Source on the fly. However, I can't find too much information on how to JOIN to other tables.
Can anyone offer any advice on which method - if any - is the best to try and retro-fit into this project? Or is the dynamic SQL model currently used fundamentally different from LINQ and XPO and best left alone?
Before you go and change the whole way that your app talks to the database, have you had a look at the following:
Run your code through a performance profiler (such as Redgate's performance profiler), the results are often surprising.
If you are constructing the SQL string on the fly, are you using .Net best practices such as String.Concat("str1", "str2") instead of "str1" + "str2". Remember, multiple small gains add up to big gains.
Have you thought about having a summary table or database that is periodically updated (say every 15 mins, you might need to run a service to update this data automatically.) so that you are only hitting one database. New connections to databases are quiet expensive.
Have you looked at the query plans for the SQL that you are running. Today, I moved a dynamically created SQL string to a sproc (only 1 param changed) and shaved 5-10 seconds off the running time (it was being called 100-10000 times depending on some conditions).
Just a warning if you do use LINQ. I have seen some developers who have decided to use LINQ write more inefficient code because they did not know what they are doing (pulling 36,000 records when they needed to check for 1 for example). This things are very easily overlooked.
Just something to get you started on and hopefully there is something there that you haven't thought of.
Cheers,
Stu
As far as I understand you are talking about so called server mode when all data manipulations are done on the DB server instead of them to the web server and processing them there. In this mode grid works very fast with data sources that can contain hundreds thousands records. If you want to use this mode, you should either create the corresponding LINQ classes or XPO classes. If you decide to use LINQ based server mode, the LINQServerModeDataSource provides the Selecting event which can be used to set a custom IQueryable and KeyExpression. I would suggest that you use LINQ in your application. I hope, this information will be helpful to you.
I guess there are two points where performance might be tweaked in this case. I'll assume that you're accessing the database directly rather than through some kind of secondary layer.
First, you don't say how you're displaying the data itself. If you're loading thousands of records into a grid, that will take time no matter how fast everything else is. Obviously the trick here is to show a subset of the data and allow the user to page, etc. If you're not doing this then that might be a good place to start.
Second, you say that the tables are properly indexed. If this is the case, and assuming that you're not loading 1,000 records into the page at once and retreiving only subsets at a time, then you should be OK.
But, if you're only doing an ExecuteQuery() against an SQL connection to get a dataset back I don't see how Linq or anything else will help you. I'd say that the problem is obviously on the DB side.
So to solve the problem with the database you need to profile the different SELECT statements you're running against it, examine the query plan and identify the places where things are slowing down. You might want to start by using the SQL Server Profiler, but if you have a good DBA, sometimes just looking at the query plan (which you can get from Management Studio) is usually enough.