On 2020-Apr-06, Kyotaro Horiguchi wrote:
> > * Andres complained that the "distance" column was not a great value to
> > expose (20171106132050.6apzynxrqrzghb4r@alap3.anarazel.de). That's
> > right: it changes both by the insertion LSN as well as the slot's
> > consumption. Maybe we can expose the earliest live LSN (start of the
> > earliest segment?) as a new column. It'll be the same for all slots,
> > I suppose, but we don't care, do we?
>
> I don't care as far as users can calculate the "remain" of individual
> slots (that is, how far the current LSN can advance before the slot
> loses data). But the "earliest live LSN (EL-LSN) is really not
> relevant to the safeness of each slot. The distance from EL-LSN to
> restart_lsn or the current LSN doesn't generally suggest the safeness
> of individual slots. The only relevance would be if the distance from
> EL-LSN to the current LSN is close to max_slot_wal_keep_size, the most
> lagged slot could die in a short term.
Thanks for the revised version. Please note that you forgot to "git
add" the test file, to it's not in the patch.
I'm reviewing the patch now.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
