Subject Re: [IB-Architect] Isolation level implemetation
Author Toni Martir
> If I understand, you want a transaction mode that will not interfere
> with garbage collection. Most of the work has been done make read-only
> read-committed transactions run as "pre-committed" so they don't affect
> garbage collection.

What does it mean run as "pre-committed", how can I start a transaction that
don't affect the OAT in Interbase 6?

>Read-write read-committed transactions could be
> made not to affect the Oldest Active Transaction, but would require a
> different mechanism.

Read-write transactions should be always short in time because modified
records are locked for write by other transactions.
The main problem becomes when the client operation is interactive (the user
must clic to fetch next row), the user can go to make a coffee or go
vacation and garbage collection is not done.

> Serializing write transactions is not an option. Table locking is bad
> enough - locking the entire database is serious overkill.

I understand the way to do it now is table reservation. It has the aditional
work of reserving/unreserving new touched tables when the programmer
modifies the client application.
Are this transaction always serializable?
- Snapshot, read
- Snapshot, write, table reservation of tables to write.
Or I must use also table stability for write transactions?

Is table stability the equivalent to SQL92 serializable isolation level?