Re: Dr. Miguel 'Optimistic Locking' Arroz [was Re: WebObjects stress Testing tool?]
Re: Dr. Miguel 'Optimistic Locking' Arroz [was Re: WebObjects stress Testing tool?]
- Subject: Re: Dr. Miguel 'Optimistic Locking' Arroz [was Re: WebObjects stress Testing tool?]
- From: Miguel Arroz <email@hidden>
- Date: Thu, 3 Dec 2009 21:06:53 +0000
Hi!
On 2009/12/03, at 20:53, Kieran Kelleher wrote:
1) Yes, there is a ERXJDBCConnectionBroker that does what you say. I
have not used it though.
I must check that.
2) Creating another OSC is not much overhead (IMHO) itself ...... it
is all the EO's and snapshots that are the overhead.
I know, but creating a DB connection is, specially under heavy load
(I don't want to create and destroy dozens of connections per
second!). The snapshots would not worry me too much, in a critical
section, you would have only the snapshots you really needed, and you
would dispose the OSC after doing your stuff.
I create new OSCs for most background tasks. The one thing is that I
dispose() on it at the end of the task .... and the dispose() is
only useful if you use ERXJDBCAdaptor is used since the regular WO
5.3 jdbc adaptor opens two connections for every OSC and leaves the
stupid things open forever. ERXJDBCAdaptor only opens one db
connection and releases it when u call dispose() IIRC.
Dude! <http://terminalapp.net/webobjects-postgresql-and-db-growing-and-growing/
> ;)
3) If you use OSC synchronization (ERXOSCSynchronizer and
ERJGroupsSync) you will still haev the problem of snapshots changing
underneath you if you don't lock the OSC. So IMHO, the
OptimisticLockAction approach works well ..... and if the approach
"ain't broke, why fix it" :-)
I don't use the synchronizer... I think it increases the
concurrency chaos by several orders of magnitude. :) Anyway, those
"critical" OSCs would not synchronize, as that would defeat their
purpose.
Yours
Miguel Arroz
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