On 2020/06/24 9:38, Alvaro Herrera wrote:
On 2020-Jun-23, Fujii Masao wrote:
If restart_lsn of logical replication slot gets behind more than
max_slot_wal_keep_size from the current LSN, the logical replication
slot would be invalidated and its restart_lsn is reset to an invalid LSN.
If this logical replication slot with an invalid restart_lsn is specified
as the source slot in pg_copy_logical_replication_slot(), the function
causes the following assertion failure.
TRAP: FailedAssertion("!logical_slot", File: "slotfuncs.c", Line: 727)
Oops.
This assertion failure is caused by
/* Copying non-reserved slot doesn't make sense */
if (XLogRecPtrIsInvalid(src_restart_lsn))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot copy a replication slot that doesn't
reserve WAL")));
Heh, you pasted the code after your patch rather than the original.
oh.... sorry.
I think the errcode is a bit bogus considering the new case.
IMO ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE is more appropriate.
Agreed. So I updated the patch so this errcode is used instead.
Patch attached.
One could argue that the error message could also be different for the
case of a logical slot (or even a physical slot that has the upcoming
"invalidated_at" LSN set), maybe "cannot copy a replication slot that
has been invalidated" but maybe that's a pointless distinction.
I don't object to the patch as presented.
I have no strong opinion about this, but for now I kept the message as it is.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
diff --git a/src/backend/replication/slotfuncs.c
b/src/backend/replication/slotfuncs.c
index 06e4955de7..ce17d44227 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -723,12 +723,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool
logical_slot)
/* Copying non-reserved slot doesn't make sense */
if (XLogRecPtrIsInvalid(src_restart_lsn))
- {
- Assert(!logical_slot);
ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot copy a replication slot that
doesn't reserve WAL")));
- }
/* Overwrite params from optional arguments */
if (PG_NARGS() >= 3)
