Forum OpenACS Q&A: db pools with the 4.x api

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1: db pools with the 4.x api
Posted by Jonathan Ellis on 02/01/02 07:13 PM
how does splitting db handles available into separate pools affect
the 4.x db api?  It looks like "subquery" and "log" pools really
aren't limited to that... db_nth_pool_name just picks succeeding
pools for nested statments, so what we have is "top level" "1st
nested" and "2nd nested" in the example nsd conf.  Right?
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2: Response to db pools with the 4.x api (response to 1)
Posted by Don Baccus on 02/01/02 07:59 PM
My pools are named "pool1", "pool2", "pool3" in all my installs.  You don't need a default pool, either (you do with ACS Classic 4.x, though).

If you define a list of named "availpool"s it will only use those, very useful if you're talking to another database (migrating from 3.x to 4.x, for instance, or talking to a non-ACS database containing stuff you need).

Thus far I haven't seen any instance of needing more than three pools.

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3: Response to db pools with the 4.x api (response to 1)
Posted by Michael A. Cleverly on 02/01/02 10:49 PM
The number of pools you define equals the depth you can nest calls to the db_* api. So, with three pools, you could have: 
    db_foreach A { ... } {
        db_foreach B { ... } {
            db_foreach C { ... } {
                # but not db_foreach D { ... }
            }
        }
    }