public static ChangeVectorEntry[] MergeVectors(ChangeVectorEntry[] vectorA, ChangeVectorEntry[] vectorB)
{
var merged = new ChangeVectorEntry[Math.Max(vectorA.Length, vectorB.Length)];
var inx = 0;
foreach (var entryA in vectorA)
{
var etagA = entryA.Etag;
ChangeVectorEntry first = new ChangeVectorEntry();
foreach (var e in vectorB)
{
if (e.DbId == entryA.DbId)
{
first = e;
break;
}
}
var etagB = first.Etag;
merged[inx++] = new ChangeVectorEntry
{
DbId = entryA.DbId,
Etag = Math.Max(etagA, etagB)
};
}
return(merged);
}
public static ChangeVectorEntry[] ReadChangeVectorFrom(Tree tree)
{
var changeVector = new ChangeVectorEntry[tree.State.NumberOfEntries];
using (var iter = tree.Iterate(false))
{
if (iter.Seek(Slices.BeforeAllKeys) == false)
{
return(changeVector);
}
var buffer = new byte[sizeof(Guid)];
int index = 0;
do
{
var read = iter.CurrentKey.CreateReader().Read(buffer, 0, sizeof(Guid));
if (read != sizeof(Guid))
{
throw new InvalidDataException($"Expected guid, but got {read} bytes back for change vector");
}
changeVector[index].DbId = new Guid(buffer);
changeVector[index].Etag = iter.CreateReaderForCurrent().ReadBigEndianInt64();
index++;
} while (iter.MoveNext());
}
return(changeVector);
}
public async Task PUT_of_conflicted_document_with_outdated_etag_throws_concurrency_exception()
{
using (var storeA = GetDocumentStore())
using (var storeB = GetDocumentStore())
{
using (var session = storeA.OpenSession())
{
session.Store(new User {
Name = "John Doe"
}, "users/1");
session.SaveChanges();
}
using (var session = storeB.OpenSession())
{
session.Store(new User {
Name = "Jane Doe"
}, "users/1");
session.SaveChanges();
}
await SetupReplicationAsync(storeA, storeB);
await SetupReplicationAsync(storeB, storeA);
WaitUntilHasConflict(storeA, "users/1");
long maxConflictEtag;
using (var session = storeA.OpenSession())
{
var ex = Assert.Throws <DocumentConflictException>(() => session.Load <User>("users/1"));
maxConflictEtag = ex.LargestEtag;
}
//should throw concurrency exception because we use lower etag then max etag of existing conflicts
using (var session = storeA.OpenSession())
{
var db = GetDocumentDatabaseInstanceFor(storeA).Result;
var cv = new ChangeVectorEntry[1];
cv[0] = new ChangeVectorEntry
{
DbId = db.DbBase64Id,
Etag = maxConflictEtag - 1
};
session.Store(new User {
Name = "James Doe"
}, cv.SerializeVector(), "users/1");
Assert.Throws <ConcurrencyException>(() => session.SaveChanges());
}
//now this should _not_ throw, since we do not specify expected conflict etag, so...
using (var session = storeA.OpenSession())
{
session.Store(new User {
Name = "James Doe"
}, "users/1");
session.SaveChanges();
}
}
}
public static ChangeVectorEntry[] GetChangeVectorEntriesFromTableValueReader(TableValueReader tvr, int index)
{
int size;
var pChangeVector = (ChangeVectorEntry *)tvr.Read(index, out size);
var changeVector = new ChangeVectorEntry[size / sizeof(ChangeVectorEntry)];
for (int i = 0; i < changeVector.Length; i++)
{
changeVector[i] = pChangeVector[i];
}
return(changeVector);
}
private ChangeVectorEntry[] GetMergedConflictChangeVectorsAndDeleteConflicts(Transaction tx, TransactionOperationContext context, Slice name, long newEtag, ChangeVectorEntry[] existing = null)
{
var conflictChangeVectors = DeleteConflictsFor(tx, name);
//no conflicts, no need to merge
if (conflictChangeVectors.Count == 0)
{
if (existing != null)
{
return(ReplicationUtils.UpdateChangeVectorWithNewEtag(_environment.DbId, newEtag, existing));
}
return(new[]
{
new ChangeVectorEntry
{
Etag = newEtag,
DbId = _environment.DbId
}
});
}
// need to merge the conflict change vectors
var maxEtags = new Dictionary <Guid, long>
{
[_environment.DbId] = newEtag
};
foreach (var conflictChangeVector in conflictChangeVectors)
{
foreach (var entry in conflictChangeVector)
{
long etag;
if (maxEtags.TryGetValue(entry.DbId, out etag) == false ||
etag < entry.Etag)
{
maxEtags[entry.DbId] = entry.Etag;
}
}
}
var changeVector = new ChangeVectorEntry[maxEtags.Count];
var index = 0;
foreach (var maxEtag in maxEtags)
{
changeVector[index].DbId = maxEtag.Key;
changeVector[index].Etag = maxEtag.Value;
index++;
}
return(changeVector);
}
public async Task DELETE_of_conflicted_document_with_outdated_etag_throws_concurrency_exception()
{
using (var storeA = GetDocumentStore(options: new Options
{
ModifyDatabaseRecord = record =>
{
record.ConflictSolverConfig = new ConflictSolver
{
ResolveToLatest = false,
ResolveByCollection = new Dictionary <string, ScriptResolver>()
};
}
}))
using (var storeB = GetDocumentStore(options: new Options
{
ModifyDatabaseRecord = record =>
{
record.ConflictSolverConfig = new ConflictSolver
{
ResolveToLatest = false,
ResolveByCollection = new Dictionary <string, ScriptResolver>()
};
}
}))
{
using (var session = storeA.OpenSession())
{
session.Store(new User {
Name = "John Doe"
}, "users/1");
session.SaveChanges();
}
using (var session = storeB.OpenSession())
{
session.Store(new User {
Name = "Jane Doe"
}, "users/1");
session.SaveChanges();
}
await SetupReplicationAsync(storeA, storeB);
await SetupReplicationAsync(storeB, storeA);
WaitUntilHasConflict(storeA, "users/1");
long maxConflictEtag;
using (var session = storeA.OpenSession())
{
var ex = Assert.Throws <DocumentConflictException>(() => session.Load <User>("users/1"));
maxConflictEtag = ex.LargestEtag;
}
//should throw concurrency exception because we use lower etag then max etag of existing conflicts
using (var session = storeA.OpenSession())
{
var db = Databases.GetDocumentDatabaseInstanceFor(storeA).Result;
var cv = new ChangeVectorEntry[1];
cv[0] = new ChangeVectorEntry
{
DbId = db.DbBase64Id,
Etag = maxConflictEtag - 1
};
session.Delete("users/1", cv.SerializeVector());
Assert.Throws <ConcurrencyException>(() => session.SaveChanges());
}
//now this should _not_ throw, since we do not specify expected conflict etag, so...
using (var session = storeA.OpenSession())
{
session.Delete("users/1");
session.SaveChanges();
}
}
}
