Re: Why is a newly created index contains the invalidLSN?

Amit Kapila wrote:
> On Thu, Aug 25, 2016 at 7:55 PM, Yury Zhuravlev
> <u.zhuravlev@postgrespro.ru> wrote:
>> Hello hackers.
>>
>> I have a small question. While working on an incremental
>> backup I noticed a
>> strange thing.
>> Newly created index is contains the invalid LSN (0/0).
>> Exmaple: ...
>
> For some of the indexes like btree which are built outside shared
> buffers, we don't write WAL unless wal_level >= REPLICA.  I think
> Robert has explained it very well how we handle the crash recovery
> situation for such indexes.  However, for some other indexes which
> don't bypass shared buffers like BRIN, GIN we do write WAL for such
> cases as well, so you must see LSN for those type of indexes.  I am
> less sure, if there will be any problem, if don't write WAL for those
> indexes as well when wal_level < REPLICA.
>

Thanks all.
Now understand LSN strongly connected with WAL.
However how difficult put last system LSN instead 0?
It's not so important but will allow make use LSN more consistent.

--
Yury Zhuravlev
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company