Hi Sirisha, Thanks for identifying the bug and the solution. Some review comments inlined.
On Mon, Nov 21, 2022 at 2:49 PM Alvaro Herrera <alvhe...@alvh.no-ip.org> wrote: > > On 2022-Nov-20, sirisha chamarthi wrote: > > > Hi Hackers, > > > > forking this thread from the discussion [1] as suggested by Amit. > > > > Catalog_xmin is not advanced when a logical slot is invalidated (lost) > > until the invalidated slot is dropped. This patch ignores invalidated slots > > while computing the oldest xmin. Attached a small patch to address this and > > the output after the patch is as shown below. > > Oh wow, that's bad :-( I'll get it patched immediately. + /* ignore invalid slots while computing the oldest xmin */ + if (TransactionIdIsValid(invalidated_at_lsn)) + continue; I think the condition should be if (!XLogRecPtrIsInvalid(invalidated_at_lsn)) LSN and XID are different data types. and to be inline with pg_get_replication_slots() 361 if (XLogRecPtrIsInvalid(slot_contents.data.restart_lsn) && 362 !XLogRecPtrIsInvalid(slot_contents.data.invalidated_at)) 363 walstate = WALAVAIL_REMOVED; we should also check restart_lsn. I would write this as bool invalidated_slot = false; then under spinlock invalidated_slot = XLogRecPtrIsInvalid(s->data.restart_lsn) && !XLogRecPtrIsInvalid(s->data.invalidated_at); if (invalidated_slot) continue. -- Best Wishes, Ashutosh Bapat
