darioquintana / nhibernate-shards

Shards for NHibernate

darioquintana

nhibernate-shards's Issues

Sharding does not implement Future Queries

I'm converting my sessions to use sharded sessions based on a tenant model (explictly open a session factory and then the session from that). My future queries are throwing an error:

NHibernate.Shards.Session.ShardedSessionImpl+DelegatingSessionImpl requires to implement NHibernate.Impl.AbstractSessionImpl class to support future batch

Are there any plans to implement Future batch queries? I appreciate that it's not really appropriate for cross-shard queries but the shard-per-tenant model is common and there is nothing to stop future queries in that scenario.

My alternative is to get a real session instead...

I can see that the IShardedSession api has a "GetSessionForObject" that returns an ISession (but at this stage I don't have an associated object to use) and the ShardedSessionImpl class has a private AnySession (but not exposed) and an EstablishFor(IShard shard) method but the only way I can see to get a shard is to use the ShardedSessionImpl Shards property - knowing that I only have the one shard.

Can any of these methods be exposed via the interface? (e.g the EstablishFor and Shard method/property?)

Is there a better way to do this?

Shard selection based on business id

Hi,

I’m trying work out if there is a sharding strategy based on business key (customer id). I can see the round robin example but that doesn’t seem appropriate.

We are working with tenanted data.... so all entities in a session will belong to the same shard.... so conceptually when we create a session we want to say ‘create a session for customer X’ and the sharding framework will either know that X relates to shard Y or that X isn’t in a shard so it will assign one.

Is this available out of the box and I’ve missed it in the code?

Thanks

I need Cross Shard Assonciation - NHibernate.Shards.CrossShardAssociationException,

My works in a problem. https://github.com/mesutcakir/NHibernate-Shards?organization=mesutcakir&organization=mesutcakir

`İşlenmeyen Özel Durum: NHibernate.Shards.CrossShardAssociationException: Object of entity type 'NHibernate.Shards.Demo.Task' is on shard '0' but an associated object of type 'NHibernate.Shards.Demo.Project' is on shard '1'.
   konum: NHibernate.Shards.Session.ShardedSessionImpl.ThrowIfConflictingShardId(String entityName, ShardId shardId, KeyValuePair2 associatedShardId)
   konum: NHibernate.Shards.Session.ShardedSessionImpl.TryGetShardIdOfAssociatedObject(String entityName, Object entity, ShardId& result)
   konum: NHibernate.Shards.Session.ShardedSessionImpl.SelectShardIdForNewEntity(String entityName, Object entity)
   konum: NHibernate.Shards.Session.ShardedSessionImpl.Save(String entityName, Object obj)
   konum: NHibernate.Shards.Session.ShardedSessionImpl.Save(Object obj)
   konum: NHibernate.Shards.Demo.FirmBasedApp.CreateTask(ISession session, Project project, String name, DayBase dayBase)
   konum: NHibernate.Shards.Demo.FirmBasedApp.AddData()
   konum: NHibernate.Shards.Demo.FirmBasedApp.Run()
   konum: NHibernate.Shards.Demo.FirmBasedApp.Main(String[] args)
Press any key to continue . . .`

I search this referances. Virtual Shards - https://docs.jboss.org/hibernate/stable/shards/reference/en/html/shards-resharding.html

But not working. "System.Collections.Generic.KeyNotFoundException"

`var virtualShardMap = new Dictionary<short, short>
            {
                { 0, 0 },
                { 1, 0 },
                { 2, 0 },
                { 3, 0 }
            };
            return new ShardedConfiguration(prototypeConfig, shardConfigs, shardStrategyFactory, virtualShardMap);`

İşlenmeyen Özel Durum: System.Collections.Generic.KeyNotFoundException: Verilen anahtar sözlükte yoktu.
   konum: System.ThrowHelper.ThrowKeyNotFoundException()
   konum: System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   konum: NHibernate.Shards.ShardedConfiguration..ctor(Configuration prototypeConfiguration, IEnumerable`1 shardConfigs, IShardStrategyFactory shardStrategyFactory, Dictionary`2 virtualShardToShardMap)
   konum: NHibernate.Shards.Demo.FirmBasedApp.BuildShardedConfiguration()
   konum: NHibernate.Shards.Demo.FirmBasedApp.Run()
   konum: NHibernate.Shards.Demo.FirmBasedApp.Main(String[] args)
Press any key to continue . . .

NHibernate.Shards => ShardedConfiguration

if (virtualShardToShardMap.Count != 0)
{
    // build the map from shard to set of virtual shards
    shardToVirtualShardIdMap = new Dictionary<short, ICollection<ShardId>>();
    foreach (var pair in virtualShardToShardMap)
    {
        var set = shardToVirtualShardIdMap[(pair.Value)]; //**Problem Here.**
        // see if we already have a set of virtual shards
        if (set == null)
        {
             // we don't, so create it and add it to the map
             set = new HashSet<ShardId>();
             shardToVirtualShardIdMap.Add(pair.Value, set);
        }
        set.Add(new ShardId(pair.Key));
        }
    }