public async Task <ActionResult> Create(CreateSampleDataViewModel model)
{
if (!ModelState.IsValid)
{
return(View(model));
}
int changes;
using (var context = new SampleDataDbContext())
{
var sampleData = new SampleData {
Name = model.Name
};
context.Set <SampleData>().Add(sampleData);
changes = await context.SaveChangesAsync();
}
AddAlert(new SuccessAlert("Sample added", $"{changes} sample was saved to the database"));
return(RedirectToAction("Index"));
}
public async Task <ActionResult> ConcurrentDbTest()
{
// Spans should overlap (actually alternatively strictly "contain" the corresponding span on the other concurrent branch)
// [---------------- INSERT A.0 ------------------------] ... [-- INSERT A.N.before --] [-- INSERT A.N.after --]
// [-- INSERT B.0.before --] [-- INSERT B.0.after --] ... [---------------- INSERT B.N -----------------------]
const int numberOfConcurrentIterations = ConcurrentDbTestNumberOfIterations;
// Create table before concurrent inserts
using (var dbCtx = new SampleDataDbContext())
{
if (dbCtx.Set <SampleData>().Count() != 0)
{
throw new InvalidOperationException($"dbCtx.Set<SampleData>().Count(): {dbCtx.Set<SampleData>().Count()}");
}
}
var syncBarrier = new Barrier(2);
DbInterception.Add(new ConcurrentDbTestDbCommandInterceptor(syncBarrier));
var currentTx = Agent.Tracer.CurrentTransaction;
await Task.WhenAll(Task.Run(() => ConcurrentSpan("A", currentTx)), Task.Run(() => ConcurrentSpan("B", currentTx)));
using (var dbCtx = new SampleDataDbContext())
{
var sampleDataList = dbCtx.Set <SampleData>().ToList();
if (sampleDataList.Count != 3 * numberOfConcurrentIterations)
{
throw new InvalidOperationException($"sampleDataList.Count: {sampleDataList.Count}");
}
for (var i = 0; i < numberOfConcurrentIterations; ++i)
{
var(containingPrefix, containedPrefix) = i % 2 == 0 ? ("A", "B") : ("B", "A");
var expectedNames = new List <string>
{
$"{containedPrefix}.{i}.before", $"{containingPrefix}.{i}", $"{containedPrefix}.{i}.after"
};
var actualNames = new List <string> {
sampleDataList[3 * i].Name, sampleDataList[3 * i + 1].Name, sampleDataList[3 * i + 2].Name
};
if (!actualNames.SequenceEqual(expectedNames))
{
throw new InvalidOperationException(
$"actualNames: {string.Join(", ", actualNames)}, expectedNames: {string.Join(", ", expectedNames)}");
}
}
}
return(new HttpStatusCodeResult(HttpStatusCode.OK));
void ConcurrentSpan(string branchId, ITransaction tx)
{
tx.CaptureSpan(branchId, ConcurrentDbTestSpanType, () =>
{
for (var i = 0; i < numberOfConcurrentIterations; ++i)
{
var isIndexEven = i % 2 == 0;
var isContainedSpan = branchId == "B" ? isIndexEven : !isIndexEven;
var numberOfInserts = isContainedSpan ? 2 : 1;
for (var j = 0; j < numberOfInserts; ++j)
{
if (isContainedSpan)
{
syncBarrier.SignalAndWait();
}
using (var dbCtx = new SampleDataDbContext(/* attachedState: */ isContainedSpan))
{
var suffix = isContainedSpan ? j == 0 ? ".before" : ".after" : "";
dbCtx.Set <SampleData>().Add(new SampleData {
Name = $"{branchId}.{i}{suffix}"
});
dbCtx.SaveChanges();
}
if (isContainedSpan)
{
syncBarrier.SignalAndWait();
}
}
}
});
}
}