[Zope-dev] Prototype Zope mxODBC DA

[Andrew M. Kuchling]

Michel Pelletier writes:
>Use the TM_THUNKED mixin instead of TM.  This will serialize *all* of
>your database requests across all database adapters at the transaction
>boundary (the old kludgy SybaseDA does this).  Guaranteed to be safe,
>but not very scalable.  The only way I can think of Zope trying to

This seems too paranoid to me -- across *all* database adapters?  (Or
do you mean it serializes requests across all DA objects of a given
class, or for a single DA object?)

The function which opens a connection looks like this:

    def __init__(self,connection):
        self.connection=connection
        # XXX this is really only correct for Solid
        L = split(connection)
        connstr = join(L[0:3], ' ')
        user = L[3] ; password=L[4]
        db=self.db=self.Database_Connection(connstr, user, password)
        self.cursor=db.cursor()

This is for Oracle, where it's OK to do multiple queries at a time
with the same connection.  For mxODBC, where that isn't possible, 
I was thinking that it would be sufficient to just have a dictionary
mapping thread IDs to a specific database connection for that thread.

Hmm... we're using PCGI.  Does PCGI actually support multiple Zope
threads?  (A quick look through pcgi_publisher.py suggests not, so it
might be academic until we start using ZServer.)

-- 
A.M. Kuchling			http://starship.python.net/crew/amk/
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    -- Delirum checks on their quarry, in SANDMAN #44: "Brief Lives:4"