Re: SQL PLan Cache

[DrFranken <midrange@xxxxxxxxxxxx>]

Just the iASP would be flashed. Vary off, End flash copy, Restart flash 
copy, Vary on.

Because the iASP is a separate database it makes me think the system may 
clear all the entries for that iASP in this sequence.

You are correct that an IPL would clear it but we would not be doing an 
IPL. However if I understand everything correctly we are 'sorta' doing 
an IPL of the database on the iASP.

        - Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 12/18/2018 12:23 PM, Roberto José Etcheverry Romero wrote:
> Dr, when you say "re flash" do you mean an iASP or an entire "I flash the
> LPAR complete, load source and all" Flashcopy?. If iASP I have NO idea
> where the plan cache lives and worse, what would happen if the underlying
> data changes and the plan cache isn't aware of it (maybe invalidate the
> cache when doing a varyoff?), I assume that an entire Flashcopy would bring
> the plan cache from the LPAR but, doesn't the plan cache expire on IPL?
>
> Roberto
>
>
> On Tue, Dec 18, 2018 at 2:15 PM DrFranken <midrange@xxxxxxxxxxxx> wrote:
>
> > Suppose I have a Storwize full of SSDs. I have all my data in iASP
> > because I use PowerHA. I already do flash copies for other reasons such
> > as Backup and training. However there are a group of folks that do
> > ad-hoc queries all day from windows servers and they often submit a half
> > a kabilion of these things all at once. THEN they have the nerve to
> > complain that they get different totals when they compare. Well querying
> > the data at different points in the day will do that on live data, DUH!
> >
> > Flash copy to the rescue I believe. Now they can query last night's
> > data. Also it nicely boxes them into x CPU and y Memory. And while the
> > I/O itself is the same physical disks that's not been a problem for
> > performance.
> >
> > QUESTION though is what happens to the plan cache for all their queries
> > when I re-flash the disk. Does it get flushed in a flash? That would
> > sorta suck.
> >
> > --
> >
> >           - Larry "DrFranken" Bolhuis
> >
> > www.Frankeni.com
> > www.iDevCloud.com - Personal Development IBM i timeshare service.
> > www.iInTheCloud.com - Commercial IBM i Cloud Hosting.
> > --
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