Tino Wildenhain wrote:
You guys can correct me if I'm wrong, but the key feature that's
missing from Postgres's flexible indexing is the ability to maintain
state across queries. Something like this:
select a, b, my_index_state() from foo where ...
offset 100 limit 10 using my_index(prev_my_index_state);
Yes, you are wrong :-) The technique is called "CURSOR"
if you maintain persistent connection per session
(e.g. stand allone application or clever pooling webapplication)
That's my whole point: If relational databases had a simple mechanism for storing their internal state in an external application, the need for cursors, connection pools, and all those other tricks would be eliminated.
As I said earlier, relational technology was invented in an earlier era, and hasn't caught up with the reality of modern web apps.
If its a naive web application you just store your session
in tables where you can easily maintain the scroll state
as well.
One thing I've learned in 25 years of software development is that people who use my software have problems I never imagined. I've been the one who was naive when I said similar things about my customers, and was later embarrassed to learn that their problems were more complex than I ever imagined.
Craig
