[Pdns-users] pdns recursor - unthreaded vs threaded operation

Fabio Sangiovanni sangiovanni at nweb.it
Fri Dec 30 10:00:50 UTC 2011

Ok I'm kind of a newbie here :)
My understanding of the problem is:
if I have 2 threads, running at the same time, both of them executing the same SQL transaction (made up of more select or update queries), how can I predict which one is executed first? It's just like you said: I'd need the whole thing to happen in a single inter-thread transaction :)
The solution, for now, is limiting Lua sessions to 1 lowering the total number of threads to 1. 


Il giorno 30/dic/2011, alle ore 10:32, Nils Breunese (Lemonbit) ha scritto:

> Fabio Sangiovanni wrote:
>> Database transactions help in terms of integrity, but they can do nothing about the order of data updates. If 2 threads work independently and execute the same update query on the db, I can't predict with certainty which one will occur first.
> AFAIK no updates are committed until the transaction is committed, so all queries within a transaction are guaranteed to happen as if they were one modification to the database. If the order of transactions is important then I think you might need to rethink your logic, because then the whole thing would need to happen in a transaction. I'm not sure what you're trying to do exactly, but it sounds like transactions should be able to help here.
> Nils.
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