Re: Measuring the Query Optimizer Effect: Turning off the QO?

> On Jul 7, 2019, at 5:22 PM, Tom Mercha <mercha_t(at)hotmail(dot)com> wrote:
>
> Hi All
>
> As we know, a query goes through number of stages before it is executed.
> One of these stages is query optimization (QO).
>
> There are various parameters to try and influence optimizer decisions
> and costs. But I wanted to measure the effect of such a stage by turning
> it off completely and I can't find such a parameter which explicitly
> does that. Then I could execute a query to get the effect of "QO active
> and "QO inactive" and compare.
>
> Obviously, I know well what the results would generally look like but I
> am just interested in measuring the differences for various types of
> queries. I am also aware that this is a simple comparison - there are
> more interesting comparisons to perform with QO tweaks, but right now I
> am interested in something basic.
>
> So how would one shut down QO? Or at least, obtaining the guarantee of
> generating the worst plan possible, ideally without touching many
> parameters?
>
> Best,
> Tom

Drop all indices?