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Re: When to use Berkeley transactions.

From: Greg Hudson <ghudson_at_MIT.EDU>
Date: 2003-02-21 08:35:53 CET

On Fri, 2003-02-21 at 02:19, Branko Čibej wrote:
>> But if we're already locking the representation (using transactions or
>> not), why can't we just rewrite the representation--without changing its
>> key, of course--in multiple steps?

> It would also make moving to locks for representation reads much more
> complicated.

I don't understand why. Either way you have to lock around the
representation before reading it or rewriting it.

> And given caching, I don't think the extra indirection is all that
> important.

My intuition says that caching probably isn't helping us here, since the
important operations iterate through data sets larger than the cache.

> Let's just keep things clean, the way they are now.

I don't think the current situation is very clean. It presents the
possiblities of representations pointing to nonexistent strings and
strings with no representations pointing to them. It means an extra
step to remove the old string when the representation is updated. It's
an extra step on every access.

(I admit that the transition from two tables to one would be pretty
harsh. I'm just not sure why we designed it this way in the first
place.)

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Received on Fri Feb 21 08:36:37 2003

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