On Fri, Mar 27, 2015 at 3:41 AM, Vincent Veyron <vv.lists@wanadoo.fr> wrote:
On Thu, 26 Mar 2015 00:25:09 +0000 "Lavrenz, Steven M" <slavrenz@purdue.edu> wrote:
> I have a second table (TABLE B) with all of the object_ids and channels that are supposed to be reporting in each day. For cases where a certain channel does not check in, I want to add a column that indicates the comm failure.
Not sure if your context allows it, but if you can change your program's logic, it might be easier to :
-add a boolean field (e.g. 'checked') to table B, set to false -whenever an object checks in do 'update table B set checked = true where object_id = X and channel = Y' -run a cron job once a day that -runs 'select * from B where checked = false' and stores results somewhere -resets B with 'update B set checked = false'
This is a performance optimization that I would avoid at nearly any cost, and there are likely better ways to limit the processing scope without having to trust the a cron job runs daily
in order to not lose data. Now, there are other points of failure here that are of a similar nature already but still adding one for (pre-mature...) optimization doesn't seem like a good move.
