Problem: How data versioning works in FEAST?
I know how feature/feature set versioning works.
Just like I have a new code recomputing the value of a previously computed feature. I would like to know the history & from where this change is coming.
I can track what value was earlier. means like a versioning of value.
Compare and check.
If any blogs/tutorials/git link are available. It will be usefule.
Related
I am developing a system that updates the progress of tasks,
always incrementing by 1 a progress attribute into the dynamodb task table.
I want to do that using the atomic increment of the attribute.
How can I do that using aws-java-sdk 2.0?
I did several kinds of research related to this subject. But I didn't find anything.
https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateItem.html#API_UpdateItem_RequestSyntax under "UpdateExpression".
SET - Adds one or more attributes and values to an item. If any of these attribute already exist, they are replaced by the new values. You can also use SET to add or subtract from an attribute that is of type Number. For example: SET myNum = myNum + :val.
In this case :val always equals 1 then.
I can not give guaranties (and have not tested it) but this seems to me like it should be Atomic.
PS. One of my first StackOverflow comments, constructive feedback very welcome.
We are trying to use Gemfire in our work. We have a region where we store each request coming in and it goes through its lifecycle (For example, states are A --> B --> C --> D)
But we also have a requirement that we need to update the state to C only if the current state is B (as the state D is getting updated Async by some other process). We used to achieve it in cassandra by using ONLY IF key word. Looking for something similar in Gemfire. Obviously we cannot do Read, Check State and Update because its not atomic.
Other option was to do this by taking a distribted lock and then perform check-update as mentioned above. But this option comes with a performance overhead.
We were also thinking of attaching a CacheWriter and check the state in beforeUpdate(..). But came to know that what we get as parameter to beforeUpdate is a copy of the value and not the real value.
Does anyone have an idea of how to achieve it in a atomic fashion that we can try?
What you are looking for is this, Region.replace(key, oldValue, newValue). This is an atomic operation.
UPDATE: I should also clarify that is not currently possible to inspect certain properties of the mapped object value (e.g. someObject.state = XYZ) to ascertain whether to perform the update/replace. For that you will need a properly implemented Object.equals() method.
Some functionality in a big project is broken on the development system.
Pretty sure it worked a few hours ago.
How do I know, which ABAP objects have been changed lately?
(I think I can guess the transport and the package that contains the change if that helps)
The nearest answer that I found is table VRSD.
It contains the date of the version of an object.
This doesn't help, since you need to export the transport or create a manual version to get an entry in this table.
So which objects have been changed without creating a new version?
(Yes we will find the change with functional checks, but knowing the changed objects would be a nice shortcut)
For code - table TRDIR has a changed on date that updates when code is activated.
For data dictionary objects check the DD* tables. I know DD01L is domains and DD02L is tables. Both of these will have a change date. I'm sure there are others for the other data types.
There is also the table REPOLOAD which contains the ABAP byte code. There are 3 fields UDAT, UTIME and UNAME for date, time and user who did the last generation (PS: don't be confused by SDAT and STIME fields).
I have two Tables:
Articles(artID, artContents, artPublishDate, artCategoryID, publisherID).
ArticleUpdated(upArtID, upArtContents, upArtEditedData, upArtPublishDate, upArtCategory, upArtOriginalArticleID, upPublisherID)
A user logging in to the application and update an article's
contents at (artContents) column. I want to know about:
Which Changes the user made to the article's contents?
I want to store both versions of the Article, Original version and Edited Version!
What should I do for doing above two task:
Any necessary changes into the tables?
The query for getting exact edited data of (artContents).
(The exact edited data means, that there may 5000 characters in the coloumns, the user may edit 200 characters in the middle or somewhere else in column's characters, I want exact those edited characters, before of edit and after of edit)
Note: I am using ASP.NET with C# for Developing
You are not going to be able to do the exact editing using SQL. You need an algorithm such as the Unix diff on files (which works on the line level). At the character level, the algorithm would be some variation of Levenshtein distance. If diff meets your needs, you could download it, write a stored-procedure to call it, and then use it in the database. This would be rather expensive.
The part of your question of maintaining the different versions is much easier. I would add two colmnns EffDate and EndDate onto each record. You can get the most recent version by looking for EndDate is NULL and find the version active at any given time. Merge is generally useful for maintaining such a table.
Basically this type for requirement needs custom logging.
The example what you have provided i.e. "The exact edited data means, that there may 5000 characters in the coloumns, the user may edit 200 characters in the middle or somewhere else in column's characters, I want exact those edited characters, before of edit and after of edit"
Can have a case that user updates particular words from different place from the text.
You can use http://nlog-project.org/ for logging, its a fast and robust tool that normally we use for doing .net logging.
Also you can take a look
http://www.codeproject.com/Articles/38756/Two-Simple-Approaches-to-WinForms-Dirty-Tracking
Asp.net Event for change tracking of entities
What would be the best way to implement change tracking on an object
Above urls will clear some air, on how to do it.
You would obviously need to track down and store every change.
Out of the blue, i am getting this error when doing a number of updates using nhibernate.
Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [MyDomainObject]
there is no additional information in the error. Is there some recommended way to help identify the root issue or can someone give me a better explanation on what this error indicated or is a sympton around.
Some additional info
I looked at the object and all of the data looks fine, it has an ID, etc . .
Note this is running in a single call stack from an asp.net-mvc website so i wouldn't expect there to be any threading issues to worry about in terms of concurrency.
NHibernate has an object, let's call it theObject. theObject.Id has a value of 42. NHibernate notices that the object is dirty. The object's Id is different than the unsaved-value, which is zero (0) for integer primary keys. So NHibernate issues an update statement, but no rows are updated, which means that there is no row in the database for that type of object with an Id of 42. So the object has been deleted without NHibernate knowing about it. This could happen inside another transaction (e.g. you have threading issues) or if someone (or another application) deleted/altered the row using SQL directly against the database.
The other possibility is that your unsaved-value is wrong. e.g. You are using -1 to indicate an unsaved-entity, but your mapping has a unsaved-value of zero. This is unlikely as your application is generally working from the sounds of it. If the unsaved-value was wrong, you wouldn't have been able to save any entities to the database as NHibernate would have been issuing UPDATE statements when it should have been issuing INSERT.
It means that you have multiple transactions accessing the same data, thus producing concurrency issues. You should improve on your data access handling, you probably are updating data from multiple threads, syndicate the changed data into a queue first which handles all the access to the db.
An old post, but hopefully my info will help someone. I was getting a similar error but only when persisting associations, after I had added in a new object. The error was of the form:
NHibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) [My.Entity#0]
Note the zero on the end, which is my identifier property. It should not be trying to save with key zero as I was using identity specification in SQL Server (generator class=native). I had not changed my unsaved-value in my xml so I had no idea what the problem was; for some reason NHibernate was trying to do an update using key value as 0 instead of a save (and getting the next key identity) for my new object.
In the end I found the cause was that I was initialising Version number to 1 for the new object in my constructor! Even though my identifier property was zero, for some reason NHibernate was also looking for a version property of zero as well, to identify it as an unsaved transient instance. The book "NHibernate in Action" does actually mention this on page 120, but for some reason my objects were fine when persisting with version number of 1 normally, and only failing if saving a new object through an association.
So make sure you do not set your Version value (leave as zero or null).
You say that your data is ok, but check if for example you are mapping the ID as self generate. I had the exact same problem, but I was sending an object with an ID different from 0.
Hope it helps!
My problem was this:
[Bind(Include="Name")] EventType eventType
Should have been:
[Bind(Include="EventTypeId,Name")] EventType eventType
Just as other answers suggest nhibernate was using zero as the id for my entity.
If you have a trigger on the table, it can be the reason. In this case, add inside it
SET ROWCOUNT 0;
SET NOCOUNT ON;
This error happened to me in the following way:
List < Device > allDevices = new List < Device > ();
//Add Devices to the list
allDevices.Add(aDevice);
//Add allDevices to database //Will work fine
// allDevices.Clear(); //Should be used here
//Later we add more devices
allDevices.Add(anotherDevice);
//Add allDevices to Database -> We get the error
//Solution to this
allDevices.Clear(); //Before adding new transaction with the oldData,