Return data pointer in DBreezeObjectInsertResult after call ObjectInsert method
vladimir-shurakov opened this issue · 7 comments
Hi guys,
Is it possible to return direct pointer to inserted data when ObjectInsert method is used? We need to store this pointer in another table to perform synchronization operations. An example is given below:
public void InsertOrUpdateObject<TEntity
>(List<TEntity
> entityList)
{
string tableName = typeof(TEntity).Name.ToLower();
string syncTableName = tableName + "sync";
using (Transaction tran = _engine.GetTransaction())
{
tran.SynchronizeTables(tableName, syncTableName);
foreach (var entity in entityList)
{
var id = tran.ObjectGetNewIdentity<long>(tableName);
List<DBreezeIndex> indexes = GetIndexedByIndicies(entity);
var newObject = new DBreezeObject<TEntity>
{
Indexes = indexes,
Entity = entity
};
DBreezeObjectInsertResult<TEntity> res = tran.ObjectInsert(tableName, newObject);
//it will be good to have data pointer in DBreezeObjectInsertResult
tran.Insert<byte[], byte[]>(syncTableName, 1.ToIndex(_synchronizationManager.SyncTransactionId, id), res.DataPointer);
}
tran.Commit();
}
}
Regards
Hi, unless you setup
tran.ObjectInsert(tableName, newObject, speedUpdate=true);
it is possible that even changed entity will reside the same disk space (if its size will be less or equal to the previous entity version size).
So, this logic can break your sync.
But if you setup speedUpdate to true (that is actually good not for each situation) you will get higher disk space consumption.
I would suggest to change sync event tracing logic.
Serialized objects can be compared on the byte[] level using extension function from DBreeze.Utils
var theyAreEqual = byte[] {2,3,4}._ByteArrayEquals(new byte[]{2,3,5});
Version 1.91 solves it and DBreezeObjectInsertResult has now PtrToObject,
also DBreezeObjectInsertResult has EntityWasInserted, so the code could look like
DBreezeObjectInsertResult<TEntity> res = tran.ObjectInsert(tableName, newObject);
if(res.EntityWasInserted )
tran.Insert<byte[], byte[]>(syncTableName, 1.ToIndex(_synchronizationManager.SyncTransactionId, id), res.PtrToObject);
Hopefully, it can be retrieved by tran.ObjectGetByFixedAddress
Thanks for quick response and suggestion!
Could you please shed the light on following situation (see code below):
class Entity()
{
int Id {get;set;}
string Name {get; set;}
}
//#1 step
var newEntity = new Entity() {Id = 1, Name = "New Entity"};
var newEntityRes = tran.ObjectInsert(tableName, new DBreezeObject<Entity
>{ Entity = newEntity }, true);
var newEntityPtr = newEntityRes.PtrToObject;
//#2 step
var smallerEntity = new Entity() {Id = 1, Name = "Entity"};
var smallerEntityRes = tran.ObjectInsert(tableName, new DBreezeObject<Entity
>{ Entity = smallerEntity}, false);
var smallerEntityPtr = smallerEntityRes.PtrToObject;
//#3 step
var biggerEntity = new Entity() {Id = 1, Name = "Bigger Entity"};
var biggerEntityRes = tran.ObjectInsert(tableName, new DBreezeObject<Entity
>{ Entity = biggerEntity}, false);
var biggerEntityPtr = biggerEntityRes.PtrToObject;
//#4 step
var row = tran.SelectDirect<int, byte[]>("t1", newEntityPtr);
var exists = row.Exists;
My questions is:
1)
newEntityPtr == smallerEntityPtr (always)
newEntityPtr == biggerEntityPtr (if there are no Entities with with Id>1)
newEntityPtr != biggerEntityPtr otherwise
what value of exists variable in step 4:
my answer is:
true - if there are no Entities with with Id>1
false - otherwise
Regards!
First of all, in the newest NuGet release 1.91 renamed PtrToEntity->PtrToObject.
//Inserting new entity
using (var tran = engine.GetTransaction())
{
var x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 1, 2, 3 },
//NewEntity = true, //this is another speed optimzation flag, can be skipped until is really necessary
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)1){ PrimaryIndex = true }
}
}, false); //inserting entity
tran.Commit();
}
//Testing updates
using (var tran = engine.GetTransaction())
{
var x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 1, 2, 3 },
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)1){ PrimaryIndex = true }
}
}, false); //Speed insert is off, the equal entity on the level of byte[] will not be overwritten
//--> will be false
Console.Write(x1.EntityWasInserted);
x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 1, 2, 3 },
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)1){ PrimaryIndex = true }
}
}, true); //Speed insert is on - entity will be overwritten (new PtToObject will be generated)
//--> will be true
Console.Write(x1.EntityWasInserted);
x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 1, 2, 3, 4 },
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)1){ PrimaryIndex = true }
}
}, false); //Speed insert is off
//--> will be true because entity has changed
Console.Write(x1.EntityWasInserted);
tran.Commit();
}
To get inserted value:
//Inserting
byte[] ptr1 = null;
byte[] ptr2 = null;
using (var tran = engine.GetTransaction())
{
var x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 1, 2, 3 },
NewEntity = true,
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)1){ PrimaryIndex = true }
}
});
ptr1 = x1.PtrToObject;
x1 = tran.ObjectInsert<byte[]>("t1", new DBreeze.Objects.DBreezeObject<byte[]>()
{
Entity = new byte[] { 2, 6, 3 },
NewEntity = true,
Indexes = new List<DBreeze.Objects.DBreezeIndex>()
{
new DBreeze.Objects.DBreezeIndex(1, (long)2){ PrimaryIndex = true }
}
});
ptr2 = x1.PtrToObject;
tran.Commit();
}
//Getting
using (var tran = engine.GetTransaction())
{
//Variant 1 via index
var exp = tran.Select<byte[], byte[]>("t1", 1.ToIndex((long)1))
.ObjectGet<byte[]>();
//via pointer
var do1 = tran.ObjectGetByFixedAddress<byte[]>("t1", ptr1);
Console.WriteLine(do1.Entity.ToBytesString());
do1 = tran.ObjectGetByFixedAddress<byte[]>("t1", ptr2);
Console.WriteLine(do1.Entity.ToBytesString());
}
SelectDirect
byte[] ptr1 = null;
using (var tran = engine.GetTransaction())
{
tran.Insert<int, int>("t2", 1, 1, out ptr1);
tran.Commit();
}
using (var tran = engine.GetTransaction())
{
var row = tran.SelectDirect<int, int>("t2", ptr1);
Console.WriteLine(row.Exists); //->true
//row = tran.SelectDirect<int, int>("t2", new byte[] { 5,6,7}); //error non-existing
row = tran.SelectDirect<int, int>("t2", null); //ok
Console.WriteLine(row.Exists); //->false
}
PtrToEntity->PtrToObject renamed in my previous comment.
Thanks a lot for good examples.
It's time to close the issue.
Good luck.