Re: old_snapshot_threshold's interaction with hash index

On Fri, May 6, 2016 at 12:45 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
> On Wed, May 4, 2016 at 7:48 PM, Kevin Grittner <kgrittn(at)gmail(dot)com> wrote:
>> On Tue, May 3, 2016 at 11:48 AM, Robert Haas <robertmhaas(at)gmail(dot)com>
wrote:
>>
>>> OK, I see now: the basic idea here is that we can't prune based on the
>>> newer XID unless the page LSN is guaranteed to advance whenever data
>>> is removed. Currently, we attempt to limit bloat in non-unlogged,
>>> non-catalog tables. You're saying we can instead attempt to limit
>>> bloat only in non-unlogged, non-catalog tables without hash indexes,
>>> and that will fix this issue. Am I right?
>>
>> As a first cut, something like the attached.
>
> Patch looks good to me. I have done some testing with hash and
> btree indexes and it works as expected.

Pushed with the addition of a paragraph to the docs regarding this
and some other situations where people have been unclear about what
to expect.

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