Is it possible to use TransactionScope with a Typed Dataset?
as in:
using (var transaction = new TransactionScope())
{
typedDataSet.DeleteStuff(id);
typedDataSet2.DeleteSomeOtherStuff(id2);
transaction.Complete();
}
Will the the sql queries related to DeleteStuff(id) and DeleteSomeOtherStuff(id) actually be transactional if an error is thrown?
I have read this article by Bogdan Chernyachuk on Using Transactions with Strongly Typed datasets and I am hoping that I do not have to do it this way.
Short answer: Yes this is transactional.
Wasn't too hard to test either. I threw an exception just before the transaction.Complete() and the data wasn't deleted from the database.
using (var transaction = new TransactionScope())
{
typedDataSet.DeleteStuff(id);
typedDataSet2.DeleteSomeOtherStuff(id2);
throw new NullReferenceException();
transaction.Complete();
}
Weirdly though I profiled what was going on in the db with SQL SERVER Profiler and the stored procedures that were referenced through the typed dataset were executed on the server. However the data was somehow rolled back.
Related
we have a 3-node dev Cassandra cluster running 3.11.13 that we have upgraded to 4.0.7, and we’ve been basically sending DDL statements through our Java applications using spring-data-cassandra:3.4.6 which uses the DataStax Java Driver version 4.14.1, and ever since we hadn’t had faced any issues with it until the upgrade to 4.0.7
The main issue with 4.0.7 that we’re facing is the schema disagreements that we’ve been seeing due to the tables created programmatically that has been a non-issue for us since 3.11.x. Although DDL statements made through cqlsh is working as expected, it’s only through the programmatic creation that we’re seeing the schema disagreements.
We’ve tried different cluster setups, C* versions, and Ubuntu versions, but we still face the same issue:
3-node, single-rack DC (Ubuntu 18.04, 20.04, 22.04) (4.0.x, 4.1.x)
3-node, 3-rack DC (Ubuntu 18.04, 20.04, 22.04) (4.0.x, 4.1.x) — This is the setup we’ve been using since 3.11.x
We’ve also tried fiddling with the driver configurations like adjusting the timeouts and disabling debouncing, but with no luck, face the same issue.
advanced.control-connection {
schema-agreement {
interval = 500 milliseconds
timeout = 10 seconds
warn-on-failure = true
}
},
advanced.metadata {
topology-event-debouncer {
window = 1 milliseconds
max-events = 1
}
schema {
request-timeout = 5 seconds
debouncer {
window = 1 milliseconds
max-events = 1
}
}
}
We’re creating tables programmatically through the following snippets:
#Override
protected abstract List<String> getStartupScripts();
#Bean
SessionFactoryInitializer sessionFactoryInitializer(SessionFactory sessionFactory) {
SessionFactoryInitializer initializer = new SessionFactoryInitializer();
initializer.setSessionFactory(sessionFactory);
final ResourceKeyspacePopulator resourceKeyspacePopulator = new ResourceKeyspacePopulator();
getStartupScripts().forEach(script ->
{
resourceKeyspacePopulator.addScript(scriptOf(script));
});
initializer.setKeyspacePopulator(resourceKeyspacePopulator);
return initializer;
}
And create one like:
#Override
protected List<String> getStartupScripts() {
return Arrays.asList(testTable());
}
private String testTable() {
return "CREATE TABLE IF NOT EXISTS test_table ("
+ "test text, "
+ "test2 text, "
+ "createdat bigint, "
+ "PRIMARY KEY(test, test2))";
}
But we end up in a loop until it timeouts due to the schema disagreement with the following errors:
DEBUG com.datastax.oss.driver.internal.core.metadata.SchemaAgreementChecker - [s1] Schema agreement not reached yet ([09989a2c-7348-3117-8b4a-d5cad549bc09, f4c8755d-6fec-38fe-984f-4083f4a0a0a0]), rescheduling in 500 ms
WARN org.springframework.context.support.GenericApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactoryInitializer' defined in com.bitcoin.wallet.config.CassandraConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.cassandra.core.cql.session.init.SessionFactoryInitializer]: Factory method 'sessionFactoryInitializer' threw exception; nested exception is org.springframework.data.cassandra.core.cql.session.init.ScriptStatementFailedException: Failed to execute CQL script statement #1 of Byte array resource [resource loaded from byte array]: CREATE TABLE IF NOT EXISTS test_table (test text,test2 text,createdat bigint,PRIMARY KEY(test, test2)); nested exception is com.datastax.oss.driver.api.core.DriverTimeoutException: Query timed out after PT10S
So two things come to mind when reading through this:
Schema disagreements are often a symptom of some larger issue.
Does the node have its CPU pegged at 100%? Schema disagreement. Inefficient network routing? Schema disagreement. Disk IOPS maxed-out causing write back-pressure? Schema disagreement.
I'd have a look at the activity on the nodes and see if any of the above stand out.
Programmatic schema changes are often problematic.
Each node needs to store the complete schema, so each schema change gets sent to all nodes, essentially making schema changes running at an asynchronous ALL level of consistency. Because of that, there's no margin for error. And programmatic schema changes are often sent from within an application much faster than Cassandra can reconcile them.
My recommendations for making any schema changes:
Execute during off-peak times.
Only run when all nodes are UN.
Run them using cqlsh (not from application code).
Verify each individual change using nodetool describecluster.
When using db.SaveAll(collection) and a Sqlite database it seems to trigger the below error if the collection is too large:
SqliteException: SQLite Error 1: 'too many SQL variables'.
The collections are not that big, maybe a couple of thousand entries at most. Is this a Sqlite limit? Can I configure this?
I have done workaround of inserting items one by one (works extremely slow), would just like to know for future reference if this is intended behaviour or I am doing something wrong.
Thanks.
Edit: seems the insert limit for sqlite is 500. I am guessing I have to batch this myself
The answer was to do inside a transaction. It changed it from 10mins to insert 10,000 records to 7 seconds.
using (var dbLite = _sqlLiteFactory.Open())
{
using (IDbTransaction trans = dbLite.OpenTransaction())
{
collection.Each(x => dbLite.Save(x));
trans.Commit();
}
}
I want to do a simple thing: get the database names on a RavenDB server. Looks straightforward according to the docs (https://ravendb.net/docs/article-page/4.1/csharp/client-api/operations/server-wide/get-database-names), however I'm facing a chicken-and-egg problem.
The problem comes because I want to get the database names without knowing them in advance. The code in the docs works great, but requires to have an active connection to a DocumentStore. And to get an active connection to a DocumentStore, is mandatory to select a valid database. Otherwise I can't execute the GetDatabaseNamesOperation.
That makes me think that I'm missing something. Is there any way to get the database names without having to know at least one of them?
The database isn't mandatory to open a store. Following code works with no problems:
using (var store = new DocumentStore
{
Urls = new[] { "http://live-test.ravendb.net" }
})
{
store.Initialize();
var dbs = store.Maintenance.Server.Send(new GetDatabaseNamesOperation(0, 25));
}
We send GetDatabaseNamesOperation to the ServerStore, which is common for all databases and holds common data (like database names).
Is there any solution to create record in other DBs from the CRM 2011 records? When a record such as "cost" was created in CRM 2011, we want a record would be created in out Oracle DB. Could it be done through a plugin? Or a service should be created for this?
Could you please provide me references or solutions for this.
Any helps would be greatly appreciated.
We had a similar request from a customer a while ago. They claimed that CRM's database wasn't to be trusted and wanted to securely store a copy of the records created in - guess what - SQL Server too. (Yes, we do understand the irony. They didn't.)
The way we've resolved it was to create a plugin. However, bear in mind that simply reacting to the message of Create won't really do. You need to set up a listener for three of the CRUD operations (retrieval doesn't affect the external database so it's rather C_UD operations, then).
Here's the skeleton of the main Execute method.
public void Execute(IServiceProvider serviceProvider)
{
Context = GetContextFromProvider(serviceProvider);
Service = GetServiceFromProvider(serviceProvider);
switch (Context.MessageName)
{
case "Create": ExecuteCreate(); break;
case "Update": ExecuteUpdate(); break;
case "Delete": ExecuteDelete(); break;
}
}
After this dispatcher, you can implement the actual calls to the other database. There are three gotchas I'd like to give you head-up on.
Remember to provide a suitable value to the outer DB when CRM doesn't offer you one.
Register the plugin as asynchronous since you'll be talking to an external resource.
Consider the problem with entity references, whether to store them recursively as well.
Walk-through for plugin construction
Link to CRM SDK if you haven't got that
Information on registering the plugin
And besides that, I've got a walk-through (including code and structure) on the subject in my blog. The URL to it, you'll have to figure out yourself - I'm not going to self-promote but it's got to do with my name and WP. Google is your friend. :)
You could use a plugin to create a record in another system, although you would need to think about syncing and ensure you don't get duplicates, but it certainly can be done.
Tutorial on plugins can be found here.
You need to write a plugin that runs on Create and uses the information on the created Cost entity to create a record in your Oracle DB.
As an example:
public void Execute(IServiceProvider serviceProvider)
{
var context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
//get the created entity from CRM
var theCreatedEntity = context.InputParameters["Target"] as Entity;
//build up a stored procedure call
using (OracleConnection objConn = new OracleConnection("connection string"))
{
var cmd = new OracleCommand();
cmd.Connection = objConn;
cmd.CommandText = "stored procedure name";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("param1", OracleType.Number).Value = theCreatedEntity.GetAttributeValue<int>("Attribute1");
cmd.Parameters.Add("param2", OracleType.Number).Value = theCreatedEntity.GetAttributeValue<int>("Attribute2");
//etc
cmd.ExecuteNonQuery();
}
}
That should give you enough to get going
Im fairly new to ASP.NET MVC 3, and to coding in general really.
I have a very very small application i want to upload to my webhosting domain.
I am using entity framework, and it works fine on my local machine.
I've entered a new connection string to use my remote database instead however it dosen't really work, first of all i have 1 single MSSQL database, which cannot be de dropped and recreated, so i cannot use that strategy in my initializer, i tried to supply null in the strategy, but to no avail, my tables simply does not get created in my database and thats the problem, i don't know how i am to do that with entity framework.
When i run the application, it tries to select the data from the database, that part works fine, i just dont know how to be able to create those tabes in my database through codefirst.
I could probaly get it to work through manually recreating the tables, but i want to know the solution through codefirst.
This is my initializer class
public class EntityInit : DropCreateDatabaseIfModelChanges<NewsContext>
{
private NewsContext _db = new NewsContext();
protected override void Seed(NewsContext context)
{
new List<News>
{
new News{ Author="Michael Brandt", Title="Test News 1 ", NewsBody="Bblablabalblaaaaa1" },
new News{ Author="Michael Brandt", Title="Test News 2 ", NewsBody="Bblablabalblaaaaa2" },
new News{ Author="Michael Brandt", Title="Test News 3 ", NewsBody="Bblablabalblaaaaa3" },
new News{ Author="Michael Brandt", Title="Test News 4 ", NewsBody="Bblablabalblaaaaa4" },
}.ForEach(a => context.News.Add(a));
base.Seed(context);
}
}
As i said, im really new to all this, so excuse me, if im lacking to provide the proper information you need to answer my question, just me know and i will answer it
Initialization strategies do not support upgrade strategies at the moment.
Initialization strategies should be used to initialise a new database. all subsequent changes should be done using scripts at the moment.
the best practice as we speak is to modify the database with a script, and then adjust by hand the code to reflect this change.
in future releases, upgrade / migration strategies will be available.
try to execute the scripts statement by statement from a custom IDatabaseInitializer
then from this you can read the database version in the db and apply the missing scripts to your database. simply store a db version in a table. then level up with change scripts.
public class Initializer : IDatabaseInitializer<MyContext>
{
public void InitializeDatabase(MyContext context)
{
if (!context.Database.Exists() || !context.Database.CompatibleWithModel(false))
{
context.Database.Delete();
context.Database.Create();
var jobInstanceStateList = EnumExtensions.ConvertEnumToDictionary<JobInstanceStateEnum>().ToList();
jobInstanceStateList.ForEach(kvp => context.JobInstanceStateLookup.Add(
new JobInstanceStateLookup()
{
JobInstanceStateLookupId = kvp.Value,
Value = kvp.Key
}));
context.SaveChanges();
}
}
}
Have you tried to use the CreateDatabaseOnlyIfNotExists
– Every time the context is initialized, database will be recreated if it does not exist.
The database initializer can be set using the SetInitializer method of the Database class.If nothing is specified it will use the CreateDatabaseOnlyIfNotExists class to initialize the database.
Database.SetInitializer(null);
-
Database.SetInitializer<NewsContext>(new CreateDatabaseOnlyIfNotExists<NewsContext>());
I'm not sure if this is the exact syntax as I have not written this in a while. But it should be very similar.
If you are using a very small application, you maybe could go for SQL CE 4.0.
The bin-deployment should allow you to run SQL CE 4.0 even if your provider doesn't have the binaries installed for it. You can read more here.
That we you can actually use whatever initializer you want, since you now don't have the problem of not being able to drop databases and delete tables.
could this be of any help?