Re: Read Uncommitted regression test coverage

Mark Dilger <hornschnorter(at)gmail(dot)com> writes:
>> The one in src/test/isolation doesn't look very comprehensive.  I'd
>> at least expect a test that verifies you don't get a syntax error
>> when you request READ UNCOMMITTED isolation from SQL.

> The attached patch set adds a modicum of test coverage for this.
> Do others feel these tests are worth the small run time overhead
> they add?

No. As you pointed out yourself, READ UNCOMMITTED is the same as READ
COMMITTED, so there's hardly any point in testing its semantic behavior.
One or two tests that check that it is accepted by the grammar seem
like plenty (and even there, what's there to break? If bison starts
failing us to that extent, we've got bigger problems.)

Obviously, if we made it behave differently from READ COMMITTED, then
it would need testing ... but the nature and extent of such testing
would depend a lot on what we did to it, so I'm not eager to try to
predict the need in advance.

regards, tom lane