Hiperspace 2.1.3

• net8.0

  • Microsoft.Bcl.HashCode (>= 6.0.0)
  • protobuf-net.Core (>= 3.2.46)
  • System.Numerics.Tensors (>= 9.0.2)

• net9.0

  • Microsoft.Bcl.HashCode (>= 6.0.0)
  • protobuf-net.Core (>= 3.2.46)
  • System.Numerics.Tensors (>= 9.0.2)

# Overview
This release is primarily concerned with performance when used in a server context the volume if data is huge and accessed via `Hiperspace.DB` and many CPU-cores are available.

Performance is addressed with greater parallelism (graph `Node` and `Edge` queries already execute in parallel) and server-side filtering with using SQL queries.

## Parallelism
`PartitionSpace` and `GenerationSpace` have been updated to search each of the child spaces in parallel and collate results to return to a calling space.  For very large hiperspaces `PartitionSpace` enables `Hiperspace.DB` to match the performance of direct/local hiperspaces by executing access in parallel.  Hiperspace uses versioning to avoid transaction contention when multiple sessions are accessing a Space, as historical versions of a `GenerationSpace`  never ned to be updated they are opened with read-only option, which obviates the need for rockshare to mediate access to the underlying files.

## SQL Queries
Hiperspace is optimized for key or index access to efficiently search hiperspace for elements that match key or key-part criteria.

For the model `entity Customer ( Id : Int64 ) { Name : String, ...};`, a  client query `from c in space.Customers where c.Id == 42' is translated into 'space.Customers.Find (new Customer { Id = 42} )` which in turn is translated into `CustomerKeyPath.Get (42)`, which directly fetches the customer from Hiperspace.

For the model
```
entity Customer ( Id : Int64 ) { Name : String, ... [Accounts : Account ].
segment Account ( Id : Int64 ) { Title : String, ...};
```
A query `from as in space.CustomerAccounts where owner.Id == 42' is translated into 'space.CustomerAccounts.Find (new Account { owner = new Customer { Id = 42} })` which in turn is translated into `CustomerAccountKeyPath.Find (42)` retrieving all Accounts that are owned by Customer 42.

For the model
```
entity Customer ( Id : Int64 ) { Name : String, ...} [ Accounts : Account ( Customer = this ) ];
entity Account ( Id : Int64 ) { Title : String, Customer : Customer, ...};
```
A query `from as in space.Accounts where Customer.Id == 42' is translated into 'space.Accounts.Find (new Account { Customer = new Customer { Id = 42} })` which in turn is translated into `AccountCustonerIndex Path.Find (42)` retrieving all Accounts that have a Customer 42, because the Customer extension `Accounts : Account ( Customer = this )` causes an index to be created on Account.

**If** the extension `Accounts : Account ( Customer = this )` is omitted, the Account `SetSpace` is scanned (with a residual condition Customer.KeyType.Id of 42), but if the query is `from as in space.Accounts where Customer.Id < 42' the criteria is evaluated once the results have been returned - potentially a very large set.

### Query
The `Query` function allows 'space.Accounts.Query ("SELECT Account.* FROM Accounts WHERE Accounts.Customer.Id < 42") to be used to send the query to a `Hiperspace.DB` server where the results will be filtered before return to the client.