[sldev] Why hasn't Linden Lab implemented WRITING to NOTECARD?

[Dale Mahalko]

Saving a notecard makes a new one. The old data hangs around in the
asset server apparently forever, so if you have 16k of temporary data
and you change 1 byte of it and save the change, you're burning 16 kb
per write. Over time this could end up being gigabytes to terabytes of
wasted space in the asset system across thousands of program write
operations, and LL has to provide expensive RAID and do tape
archiving, etc etc of all that..

UUIDs are not reused when objects are modified because of some design
concept regarding data-access efficiency and caching. Woohoo, don't
you love clear and direct answers? I think this was discussed a long
while back but I don't see anything in my SLDev keyword searches.


Okay, um, if I recall right, saving UUID changes would make the cached
asset state stale and then you need to add mechanisms to keep the
cache up to date with the main db, or for the main db to notify cache
siblings of UUID state changes.

If you don't ever allow UUID changes then the cached state never needs
to be checked and can always be handed out to clients at much greater
speed than if state checks were needed, but this speed comes at the
price of poor storage efficiency of not recovering space used by
changed UUIDs that may never be accessed ever again.


There's no way to assess whether a saved asset was just temporary data
that will never be used again vs a UUID that just won't be used again
for a very very long time. LL can prune "infrequently used" UUIDs out
of the main db running on expensive 15,000 RPM SAS drives, and move
the infrequent assets to slower less-expensive "nearline storage", but
LL can't ever really delete anything since there's no way to know if
it might be needed by a user, or really never again.

The slack from unused objects that were temporary and will never be
accessed, probably accounts for a certain sizable chunk of those
terabytes of growing asset storage you sometimes hear about.

- Dale Mahalko / Scalar Tardis


On Wed, Jun 10, 2009 at 7:35 PM, Fire<fire at b3dmultitech.com> wrote:
> just wondering (and I am sure this question has been asked before)
> but why, oh why, hasn't LL implemented the feature of writing to notecards?
>
> Wouldnt this solve a lot of our scripting nightmares?  Ie: List memory
> limits
> etc?