Hi!
Interesting feature, but it's not very obvious how to use it. I'd like to see
some example(s) in documentation.
And I see an implementation of AVL tree in psql source code
(src/bin/psql/crosstabview.c). Postgres already has a Red-Black tree
implementation in
src/include/lib/rbtree.h and src/backend/lib/rbtree.c. Is any advantage of using
AVL tree here? I have some doubt about that and this implementation, obviously,
will not be well tested. But I see in comments that implementation is reduced to
insert only and it doesn't use the fact of ordering tree, so, even hash could be
used.
Daniel Verite wrote:
Pavel Stehule wrote:
1. maybe we can decrease name to shorter "crossview" ?? I am happy with
crosstabview too, just crossview is correct too, and shorter
I'm in favor of keeping crosstabview. It's more explicit, only
3 characters longer and we have tab completion anyway.
2. Columns used for ordering should not be displayed by default. I can live
with current behave, but hiding ordering columns is much more practical for
me
I can see why, but I'm concerned about a consequence:
say we have 4 columns A,B,C,D and user does \crosstabview +A:B +C:D
If B and D are excluded by default, then there's nothing
left to display inside the grid.
It doesn't feel quite right. There's something counter-intuitive
in the fact that values in the grid would disappear depending on
whether and how headers are sorted.
With the 3rd argument, we let the user decide what they want
to see.
3. This code is longer, so some regress tests are recommended - attached
simple test case
I've added a few regression tests to the psql testsuite
based on your sample data. New patch with these tests
included is attached, make check passes.
Best regards,
--
Teodor Sigaev E-mail: teo...@sigaev.ru
WWW: http://www.sigaev.ru/
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