Обсуждение: [HACKERS] GSoC 2017 weekly progress reports (week 2)

2017-06-13 18:00 GMT+05:00 Shubham Barai <shubhambaraiss@gmail.com>:
>
> Project: Explicitly support predicate locks in index AMs besides b-tree
>
Hi, Shubham
Good job!

So, in current HEAD test predicate_gist_2.spec generate false
positives, but with your patch, it does not?
I'd suggest keeping spec tests with your code in the same branch, it's
easier. Also it worth to clean up specs style and add some words to
documentation.

Kevin, all, how do you think, is it necessary to expand these tests
not only on Index Only Scan, but also on Bitmap Index Scan? And may be
KNN version of scan too?
I couldn't find such tests for B-tree, do we have them?

Best regards, Andrey Borodin, Octonica.

On Tue, Jun 13, 2017 at 1:02 PM, Andrew Borodin <borodin@octonica.com> wrote:
> 2017-06-13 18:00 GMT+05:00 Shubham Barai <shubhambaraiss@gmail.com>:

> Good job!

+1!  :-)

> So, in current HEAD test predicate_gist_2.spec generate false
> positives, but with your patch, it does not?

Keep in mind, that false positives do not break *correctness* of serializable
transactions as long as it involves another transaction.  (It *would* be a bug
if a transaction running alone could cause a serialization failure.)  A false
*negative* is always a bug.

That said, false positives hurt performance, so we should keep the rate as low
as practicable.

> I'd suggest keeping spec tests with your code in the same branch, it's
> easier.

+1

> Also it worth to clean up specs style and add some words to
> documentation.

+1

> Kevin, all, how do you think, is it necessary to expand these tests
> not only on Index Only Scan, but also on Bitmap Index Scan? And may be
> KNN version of scan too?
> I couldn't find such tests for B-tree, do we have them?

Off-hand, I don't know.  It would be interesting to run regression tests with
code coverage and look at the index AMs.

https://www.postgresql.org/docs/9.6/static/regress-coverage.html

-- 
Kevin Grittner
VMware vCenter Server
https://www.vmware.com/

Shubham Barai wrote:
> Hi,
> 
> I have made some changes in tests and pushed them to my branch.
> 
> Thanks for helping me out with testing.
> 
> Now, current head produces false positives but, with my patch, it doesn't.
> 
> Here is the link for updated tests:
> https://github.com/shubhambaraiss/postgres/commit/2c02685a50a2b30654beb5c52542a57a46219c39

Nice.  Please provide patches, so that it can be considered for commit.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services