Re: How much memory I can add - additional question?

[<dieter.bender@xxxxxxxxxxxx>]

... the factor is much greater. reading a record from database is in the 
region of millisecond, cpu operations in the region of microseconds, access 
to main memory should be even faster.
To th OPs question. It depends on workload and if you are interested in SQL 
performance on the bottleneck. If your query sits for instance waiting on a 
record lock, you could throw in as many hardware as you want, it will sit 
and wait 60 seconds untill the concurrent transaction will give up. Or if a 
missing access path is built by the fly, the creation of an additional index 
might speed up a query from minutes to milliseconds without needing any 
hardware. Best starting point for this might be to start the database 
monitor for measurement what the database is doing.

D*B


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From: "Nathan Andelin" <nandelin@xxxxxxxxx>
Sent: Monday, January 17, 2011 3:42 PM
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Subject: Re: How much memory I can add - additional question?

> I really don't understand the question. But I attended an IBM briefing 
> last year
> where the relative performance of RAM, traditional DASD, and Solid State 
> Drives
> were discussed. Now I wish I had kept the handout. I seem to recall that 
> moving
> data around in RAM was something like 100 times faster than moving data 
> from
> traditional DASD to RAM. But I really don't remember. So please don't 
> quote me.
> I'll just ask, would of your jobs, and all of your data fit in existing 
> RAM all
> of the time? And is your CPU busy 100% of the time? If not, then I think 
> that
> adding more RAM will increase the efficiency of your system.
>
> -Nathan
>
>
>
>
> ----- Original Message ----
> From: Tomasz Skorża <t.skorza@xxxxxxxxxxx>
> To: midrange-l@xxxxxxxxxxxx
> Sent: Sun, January 16, 2011 2:30:47 PM
> Subject: How much memory I can add - additional question?
>
> Thabks for answer about memories ... I have one more question.
> Is it possible to estimate (even approximately) how much the system 
> efficiency
> will grow together
>
> with memory grow?
> 4 GB to 8GB? 10%? 20% more efficiency?
> 4 to 16?
> 4 to 32?
>
> I'm interested in time of get result of SQL queries.
>
> Regards
>
> Tomek
>
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