Re: Doubt about AccessExclusiveLock in ALTER TABLE .. SET ( .. );

On Fri, Jul 31, 2015 at 11:28 AM, Andres Freund <andres@anarazel.de> wrote:
>
>> @@ -57,7 +57,8 @@ static relopt_bool boolRelOpts[] =
>
> If we go through this list, I'd rather make informed decisions about
> each reloption. Otherwise we're going to get patches for each of them
> separately over the next versions.

Just dropping quickly a reply: I meant table relopts only, excluding
the index stuff for now regarding the isolation tests.

>> +                     AccessExclusiveLock
>> +     foreach(cell, defList)
>> +     {
>> +             DefElem *def = (DefElem *) lfirst(cell);
>> +             int             i;
>> +
>> +             for (i = 0; relOpts[i]; i++)
>> +             {
>> +                     if (pg_strncasecmp(relOpts[i]->name, def->defname, relOpts[i]->namelen + 1) == 0)
>> +                     {
>> +                             if (lockmode < relOpts[i]->lockmode)
>> +                                     lockmode = relOpts[i]->lockmode;
>> +                     }
>> +             }
>> +     }
>> +
>> +     return lockmode;
>> +}
>
> We usually don't compare lock values that way, i.e. there's not
> guaranteed to be a strict monotonicity between lock levels. I don't
> really agree with that policy, but it's nonetheless there.

Yeah, there are some in lock.c but that's rather localized.
-- 
Michael