Re: Support tid range scan in parallel? - Mailing list pgsql-hackers

From Cary Huang
Subject Re: Support tid range scan in parallel?
Date
Msg-id 18f79068b8e.1080e4d9f1664370.4629381154825725760@highgo.ca
Whole thread Raw
In response to Re: Support tid range scan in parallel?  (David Rowley <dgrowleyml@gmail.com>)
List pgsql-hackers
> You should add a test that creates a table with a very low fillfactor,
> low enough so only 1 tuple can fit on each page and insert a few dozen
> tuples. The test would do SELECT COUNT(*) to ensure you find the
> correct subset of tuples. You'd maybe want MIN(ctid) and MAX(ctid) in
> there too for extra coverage to ensure that the correct tuples are
> being counted.  Just make sure and EXPLAIN (COSTS OFF) the query first
> in the test to ensure that it's always testing the plan you're
> expecting to test.

thank you for the test suggestion. I moved the regress tests from select_parallel
to tidrangescan instead. I follow the existing test table creation in tidrangescan
with the lowest fillfactor of 10, I am able to get consistent 5 tuples per page
instead of 1. It should be okay as long as it is consistently 5 tuples per page so
the tuple count results from parallel tests would be in multiples of 5.

The attached v4 patch includes the improved regression tests.

Thank you very much!

Cary Huang
-------------
HighGo Software Inc. (Canada)
cary.huang@highgo.ca
www.highgo.ca







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