Re: OO and relation "impedance mismatch"
Date: 4 Oct 2004 12:28:32 -0700
Message-ID: <1096918112.494407.14410_at_k17g2000odb.googlegroups.com>
> If you have 2 gigabytes of RAM, and you keep 80% of it for table
storage,
> and your average row length is 160 bytes, there's room enough for 10
> million rows in RAM, if I've done the math right.
Most of the sql boxes I work with, have more than 1 table. They typically have several database/schemas with multiple tables in each. The boxes' hardware are relatively cheap. The raid arrays and SANs are expensive though.
> What makes a database different from temporary storage is not RAM vs
Disk,
> IMO. It's persistence and shareability.
> If persistent and shareable data gets irreparably lost or corrupted,
or if
> its off the air when it's supposed to be on the air, the damage
measured in
> dollars can pile up awfully fast. That's the real reason for
backups.
??? Time is money. Data is money.
> It takes time to update an index, that's why it's sometimes done
overnight
> rather than on the fly.
One of the theoretical benefits of having an RAM-based DBMS instead of a disk-based DBMS, is that it isn't necessary to defrag an index.
> Likewise, it's the shareability of data that makes caution advisable
when
> modifying its logical features on the fly. In essence, you may be
breaking
> a contract with a potential user of the data. I mean "contract" in
the IT
> sense, rather than the legal sense, although there's some overlap in
the
> two.
The best analogy I can come up with is the music CD player. The CD is a "permanent" storage device. The music player "streams" the data to the listener. It doesn't create an object for every 10second chunk of music. Received on Mon Oct 04 2004 - 21:28:32 CEST