At 01:44 PM 6/30/99 +0100, Stuart Norton wrote:
>ie. firstly we'll get a*******, and
>then b*******. All we want is the stars. I presume this can be placed in a
>single 16 byte record. Is this an effective use of the database though; only
>one record?
The overhead per record is 20 bytes (Dave's Message indicated 16 bytes ...
I seem to rememeber it being 20, I'm not sure which is correct), which
means that storing 8 or 16 bytes per record would be very inefficient. You
should probably think about putting a predetermined number of readings in
each record (maybe everything for a particular minute)
30 readings per record * 16 bytes per reading + 20 bytes record overhead *
60 * 8 + 84 bytes database overhead = around 235K
>
>Also, what are the time overheads for writing a database record. It must be
>low, otherwise we will have to re-think. Your help would be appreciated.
>
reading/writing to a database is slowed compared to reading/writing from
memory. You can compare it to reading/writing to a harddrive. i.e. It's
very fast on a 2 second time scale. (If all you are doing is taking a
measurement every two seconds & writing it to a database, you don't need to
worry about it)
