Hi Brian,
On Dec 4, 2009, at 9:59 PM, Brian Aker wrote:
On Dec 4, 2009, at 3:12 AM, Paul McCullagh wrote:
If we have a startStatement() call, then it could be used in place
of beginAlter(), assuming we can determine the statement type, and
the tables involved.
The problem with relying on statement type is that at some point
statement type will be pluggable... which means you would constantly
need to update your engine for new statements.
Yuck!
I was talking to Toru about this, and another possibility is that we
have statements declare a needed "lock type" that any plugin could
then query.
Yup, that's a good idea.
I outlined the solution for Toru, but I don't know if he has written
the patch yet :)
Well, he has had the whole weekend now! ;)
Then, when a handle is returned to the pool it is deleted, instead
of adding it back to the pool.
BTW very soon engines will own their Cursor objects and will be free
to reuse them.
Ah, you mean Drizzle will no longer manage a pool of handlers/cursors?
If this was the job of the engine, this would be good, because then
closing all cursors on ALTER TABLE can be managed by the engine.
The locking thread waits until all handles are returned and deleted
before it can proceed. The lock on the pool then prevents a new
table handle from being created while the locking thread is busy.
Either way, it would be good if Drizzle closes all handlers/cursors
before a table is deleted or renamed.
I would say that long term this will be optional, based on what the
engine requires.
OK, this make things a lot simpler! Indeed, if we don't need to
support LOCK TABLE then external_lock() can be removed altogether.
Tried removing the external_lock() right now and seeing if any
issues pop up?
Great. Without LOCAL TABLE, I think external_lock() is now only used
to determine the start of statements and transactions. So, with the
addition of beginTransaction and startStatement, there should be no
adverse affects.
Best regards,
Paul
--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com
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