Alexey,
It is great that you added a test case, but you made a mistake
in the SHOW STATUS clause.
> +SELECT DISTINCT b FROM t1 LEFT JOIN t2 USING(a) WHERE c <= 3;
> +SHOW STATUS LIKE 'Handler_read*';
Here it must be:
SHOW STATUS LIKE 'Handler_read%';
as I suggested in my previous email. This mistakes means that you
didn't verify at all the test result :(.
<cut>
Please fix the above mistake, then run the test both *with* and
*without* your patch, compare the results, and verify what you get
is consistent with what you expect from the fix. Also please send
me both results.
Timour