Implicit_PDQ

Is anybody using Implicit_PDQ? How effective is this? Informix 11.7 UC8 on AIX 6.1 Cheers

Hi Ali, implicit PDQ is generally not recommanded on a OLTP system, because it will generate more Informix CPU activity in a global manner. In this case, just some, or even worse many queries will create additional threads that may in a way make those queries faster, but also steal CPU time from other users who will probably not appreciate that. This is true specially if your server is not very rich in terms of CPU power (ie number of cores/cpu vps) Generally, when used, PDQPRIORITY is set at the session level, in the application code or even in an environment variable (PDQPRIORITY). I think that setting it global will contribute quickly to a terrible system overload if some queries start to use it heavily ( and if they can, they will!) So this is something I would definately avoid in a global manner. Eric

Oops, I validated the response too fast .... I wanted to add that if your instance is exclusively a decision support instance, setting global pdqpriority is not a bad idea. But please test before rolling out. Eric