TransitionResult is an internal implementation detail that tells
an invocation of StateMachine::step() to continue looping, but it
is of no use to other callers.
For this reason, just return an IOResult from StateMachine::step()
which simplifies the result handling.
Currently header changes are tracked through pager by reading page 1.
MVCC has it's own layer to track changes during txn so this commit makes
it so that headers are tracked by each txn separately.
On commit we update the _global_ header which is used to update
`database_size` because pager commits require it to be up to date. This
also makes it _simpler_ to keep track of header updates and update
pager's header accordingly.
The `run_once()` name is just a historical accident. Furthermore, it now
started to appear elsewhere as well, so let's just call it IO::step() as we
should have from the beginning.
We were storing `txid` in `ProgramState`, this meant it was impossible
to track interactive transactions. This was extracted to `Connection`
instead.
Moreover, transaction state for mvcc now is reset on commit.
Closes#2689
This not only changes schema_did_change on commit_txn for mvcc, but also
extracts the connection transaction state from non mvcc transactions to
mvcc too.
We have so many cursor types that it will be unbearable to properly make
all of them work. Let's simplify this and only focus on lazy cursor
which in the future will load from database in case we need it.
The logging code that writes out transactions to disk needs to write out
the byte array that we actually use. The code is less hairly without the
generics so drop them.
