28 Implementation overview

This describes the implementation of the cxPersistStore library.

The ROT can also call PersistStore::LoadObject() to implement a synchronous load
Analyse lifetime management at CSpace level.
Document and implement DestroyPSpace()
Do we have a concept of disabling the store? Do we need to commit locks?
Allow for other open modes
Allow for transferal of objects between PSpaces.
Unit test PSpaceTxnGroupMgr
Public headers should be very well commented
Search for "todo"
Can't use global variable EPrefVisitMode
Is tls_prefSerialiser needed?
[Maybe] Put all PersistStore configuration settings into a single struct.
Can we unit test the ROT or BindObjectGivenOid()?
Measure performance
Unit tests ensure invalid use causes assertion failures
Should assertion failure occur when there is a nested transaction on a PersistStore?
Allow for object cloning?
Allow for anonymous PSpaces

Rather than have cref and pref, can we just have pref and use template specialisation to get both versions? Haven't we already done that with GcRoot?
Find a way to allow validation of MarkAsDirty() to be enabled at run time with minimal performance penalty when it is turned off, rather than using a macro. This is so that application programmers built on top of CEDA can enable it as well.
Avoid the huge macros to implement DoubleLinkedList, PDeque and B+Trees. Rfactor the code to use normal C++ templates as much as possible.
Implement proposal to remove the PSpaceRoot
Support anonymous PSpaces

New much simpler implementation of the ROT. When there is a synchronous request for an object that is being loaded asynchonously treat as an unsual corner case and don't try to reuse effort
New AsyncObjectLoader uses two vectors of OIDs allowing for vary efficient of pusing oids to be async loaded, and io_context swaps the two vectors when it's ready to process more.
PersistStore implements LoadObject() which returns both an EAsyncBindResult and a unique_interface_ptr
Now that PSpace implements IOperationCallBacks the handlers can be simplified and made more efficient.
PSpaceTxn seems wrong - it is locking the CSpace which already does the transaction, then creating another transaction [redundant: PSpaceTxn doesn't even exist anymore].
Remove PSpaceLockMode, PersistStoreTxn, PSpaceTxn, PSpaceTxn2, PSpaceTransferTxn
PSpace implements IOperationCallBacks
Implement proposal to achieve better validation of MarkAsDirty() without need to call WriteAllDirtyObjectsToLss() when a transaction closes
CidMap looks up the ReflectClasses when it is first loaded from disk, not lazily
PSpaceDos is using a volatile bool
PSpaceDos is using a mutex to protect the deque under the assumption that a CSpace has an RW lock. The mutex doesn't seem necessary, the deque is only accessed by a thread that has locked the CSpace.

Source directory: Ceda/cxPersistStore