Re: [HACKERS] [WIP] Effective storage of duplicates in B-tree index.

On Fri, Jul 19, 2019 at 12:32 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> On Fri, Jul 19, 2019 at 10:53 AM Anastasia Lubennikova
> <a(dot)lubennikova(at)postgrespro(dot)ru> wrote:
> > Patch 0002 (must be applied on top of 0001) implements preserving of
> > correct TID order
> > inside posting list when inserting new tuples.
> > This version passes all regression tests including amcheck test.
> > I also used following script to test insertion into the posting list:
>
> Nice!

Hmm. So, the attached test case fails amcheck verification for me with
the latest version of the patch:

$ psql -f amcheck-compress-test.sql
DROP TABLE
CREATE TABLE
CREATE INDEX
CREATE EXTENSION
INSERT 0 2001
psql:amcheck-compress-test.sql:6: ERROR: down-link lower bound
invariant violated for index "idx_desc_nl"
DETAIL: Parent block=3 child index tid=(2,2) parent page lsn=10/F87A3438.

Note that this test only has an INSERT statement. You have to use
bt_index_parent_check() to see the problem -- bt_index_check() will
not detect the problem.

--
Peter Geoghegan