Re: pointer questions

["Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk>]

On Wed, 02 Nov 2005 03:46:41 +0000, Jeffrey R. Carter wrote:

> Dr. Adrian Wrigley wrote:
> 
>> This is exactly the situation.  The "Things" were about 36 bytes each
>> and I changed to having around 20 million pointers to things.
>> Single bit errors in pointers had a much more significant effect
>> than single bit errors in "Things" (which tended to be ignored
>> for various reasons).
> 
> Right. I don't think I'd ever want to consider a continually running program 
> with 20 million pointers. What did that buy you over the single-pointer version?

It was a simple 2-D array of stock data (time/date, ticker).  But some
tickers had large gaps (no data for long periods).  I had been hitting
various memory limits.  Adding a level of indirection allowed only the
valid data to consume memory, keeping the program within those limits.

It's still a rather simple architecture, compared to a more traditional
SQL database system for this application.  But it is *very* fast
and (now) very robust.
-- 
Adrian