Re: snapshot too old, configured by time

On Tue, Mar 1, 2016 at 12:58 AM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Tue, Mar 1, 2016 at 9:35 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> On 2016-02-29 18:30:27 -0600, Kevin Grittner wrote:
>>> Basically, a connection needs to remain open and interleave
>>> commands with other connections, which the isolation tester does
>>> just fine; but it needs to do that using a custom postgresql.conf
>>> file, which TAP does just fine. I haven't been able to see the
>>> right way to get a TAP test to set up a customized installation to
>>> run isolation tests against. If I can get that working, I have
>>> additional tests I can drop into that.

>> Check contrib/test_decoding's makefile. It does just that with
>> isolationtester.
>
> pg_isolation_regress --temp-config is the key item here, you can
> enforce a test to run on a server with a wanted configuration set.

Thanks for the tips. Attached is a minimal set of isolation tests.
I can expand on it if needed, but wanted:

(1) to confirm that this is the right way to do this, and

(2) how long people were willing to tolerate these tests running.

Since we're making this time-based (by popular demand), there must
be delays to see the new behavior. This very minimal pair of tests
runs in just under one minute on my i7. Decent coverage of all the
index AMs would probably require tests which run for at least 10
minutes, and probably double that. I don't recall any satisfactory
resolution to prior discussions about long-running tests.

This is a follow-on patch, just to add isolation testing; the prior
patch must be applied, too.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company