[ZODB-Dev] Multi-Threaded Access

[Jared Smith]

I'm looking at using ZODB and have two different databases stored in
different files where different threads will be periodically
insert/update/delete various records in both databases.  Couple of questions
to make sure this is feasible:

When one of the threads wants to do an insert of a set of records I need to
ensure that those changes are submitted in a transaction that does not
overlap with the records being inserted in another thread.  Looks like the
default API assumes there is a single global transaction
 (transaction.commit())  however I saw mention of creating your own
transaction.manager that you can bind at DB.open() time.

Does this mean to support this model I have to re-open the database and do
the binding of a transaction manager in every method where I want to do this
transactional action?  For the moment I was assuming a DB access object that
is shared (singleton access class).

Is the better model to have something like a pool of DB access classes where
each one maintains a DB handle and a transaction and one of the access
classes would be taken out of the pool and used every time a transaction
needs to be run?  Worried a bit about the overhead of re-opening the DB is
this not something to worry about?


Thanks appreciate any advice.  I'm new to Python and ZODB trying to figure
out the best pattern to support a multi-user web scenario with multiple
databases.

--Jared
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