Hi Toru,
On Dec 7, 2009, at 3:31 AM, Toru Maesaka wrote:
Great to hear another use-case where knowing a statement type in
advance is useful :)
Yes, generally I need to know the following:
- If I have a update type statement (i.e. whether the statement
modifies rows).
- Whether I need a table lock (examples: ALTER TABLE, TRUNCATE, CHECK).
- If we have a SELECT FOR UPDATE.
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. I outlined the solution for Toru, but I don't
know if he has written the patch yet :)
I've taken notes from our discussion the other day. I'm planning on
working on it when I finish testing through my current progress of
BlitzDB.
Great! :)
For now, I'm happy with Jay's advise of using
current_session().
Cheers,
Toru
On Sat, Dec 5, 2009 at 5:59 AM, Brian Aker <[email protected]> wrote:
Hi!
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. I outlined the solution for Toru, but I don't
know if he has written the patch yet :)
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.
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?
Cheers,
-Brian
--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com
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