[SQLObject] Thread Safety and SQLObject

[Brad B. <br...@bb...>]

I have a Webware servlet that has code like this:

    pid = os.fork()
    if not pid: 
        try:
            batch_file.process()
        except TooManyErrors, err:
            pass

At some point in the code that batch_file.process() is calling, I
instantiate one of my SQLObject-based classes which is mapped to a
database table that acts as a logger for purchase transactions:

    conn = PostgresConnection(
        host='localhost',
        db='foo',
        user='bar',
        passwd='somepass'
    )
        
    self.purchase_transaction =  PurchaseTransaction.new(
        merchantProxyID = self.merchant_proxy_id,
        transactionID = self.txID,
        transactionDate = now(),
        amount = self.amount,
        productDesc = self.description,
        cardholderName = self.cardholder_name,
        firstTwoCCDigits = self.card_number[0:2],
        lastFourCCDigits = self.card_number[-4:],
        expireMonth = self.card_expire_month,
        expireYear = self.card_expire_year,
        emailAddress = self.email,
        connection = conn
    )

I'm doing this because I want to return control to the web browser
whilst I go off and process lots of credit card transactions from the
batch_file in the background.

The problem is that if this batch_file.process() stuff is executing in
the background and I continue to do database retrievals and such
through the web, it's quite easy for me to create various kinds of
exceptions; Error: no results to fetch, OperationalError: not
connected to server, etc.

The error messages aren't consistent, but what *is* consistent is that
it's always dying on something to do with getting data from the
database whilst this child process is executing in the background. It
seems like the child and parent processes are trying to read from the
same socket, with obvious trouble happening from there.

Two questions then:

1. Why isn't connection = conn making this Do The Right Thing? I
thought the semantics I've shown above would be creating a new DB
connection every time, and thus hopefully have the child avoid
interfering with the parent.

2. Is there any way to use SQLObject safely in a threaded environment
like the os.fork'ing example I have above?

-- 
Brad Bollenbach
BBnet.ca