Tom Lane wrote:
Alvaro Herrera <alvherre@xxxxxxxxx> writes:
On Tue, Jun 28, 2005 at 07:38:43PM -0700, Mark Dilger wrote:
If, for a given row, the value of c is, say, approximately 2^30 bytes
large, then I would expect it to be divided up into 8K chunks in an
external table, and I should be able to fetch individual chunks of that
object (by offset) rather than having to detoast the whole thing.
I don't think you can do this with the TOAST mechanism. The problem is
that there's no API which allows you to operate on only certain chunks
of data.
There is the ability to fetch chunks of a toasted value (if it was
stored out-of-line but not compressed). There is no ability at the
moment to update it by chunks. If Mark needs the latter then large
objects are probably the best bet.
I'm not sure what it'd take to support chunkwise update of toasted
fields. Jan, any thoughts?
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your
message can get through to the mailing list cleanly
Ok,
If there appears to be a sane path to implementing this, I may be able to
contribute engineering effort to it. (I manage a group of engineers and could
spare perhaps half a man year towards this.) But I would like direction as to
how you all think this should be done, or whether it is just a bad idea.
I can also go with the large object approach. I'll look into that.
Mark Dilger
---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faq
