Re: [HACKERS] [Proposal] Allow users to specify multiple tables inVACUUM commands

On Tue, Sep 5, 2017 at 12:24 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> On Tue, Sep 5, 2017 at 12:05 PM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>> In get_rel_oids() we often switch the memory context to vac_context
>> and switch back. As a result almost code in get_rel_oids() is working
>> in vac_context. Maybe we can switch memory context before and after
>> the calling get_rel_oids?
>
> I thought about that as well, and it seemed to me that the current
> patch approach is less bug-prone for the future if get_rel_oids() gets
> called in some future code paths.

Okay, I agree. Also I found that dedupe_relations() eventually
allocates the list in current memory context that may not be
vac_context and set it to *relations at the end of that function. I
think we should switch the memory context to vac_context before doing
that. Or to more simplify the code maybe we can do the all treatment
of the relations list after switching to vac_context. For example,

oldcontext = MemoryContextSwtichTo(vac_context)
relations = copyObject(relations);
get_rel_oids(&relations);
check_colums_exist(relations);
dedupe_relations(&relations);
MemoryContextSwtichTo(oldcontext);

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center