Hi,
I had some trouble today with a misbehaving logical replication client
which had confirmed a flush of an LSN far into the future. Debugging it
was a bit of a pain for a number of reasons, but I think the most
important one was that confirmed_flush isn't exposed in
pg_stat_replication_slots. Attached patch exposes it, as
confirmed_flush_lsn (to make it look like restart_lsn; not sure whether
we should just keep the internal name or not).
Adding this one to the next commit fest, but any feedback welcome in the
meanwhile.
.m
diff --git a/src/backend/catalog/system_views.sql
b/src/backend/catalog/system_views.sql
index e82a53a..ffaf451 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -674,7 +674,8 @@ CREATE VIEW pg_replication_slots AS
L.active_pid,
L.xmin,
L.catalog_xmin,
- L.restart_lsn
+ L.restart_lsn,
+ L.confirmed_flush_lsn
FROM pg_get_replication_slots() AS L
LEFT JOIN pg_database D ON (L.datoid = D.oid);
diff --git a/src/backend/replication/slotfuncs.c
b/src/backend/replication/slotfuncs.c
index 9a2793f..90d75ce 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -206,6 +206,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
TransactionId xmin;
TransactionId catalog_xmin;
XLogRecPtr restart_lsn;
+ XLogRecPtr confirmed_flush_lsn;
pid_t active_pid;
Oid database;
NameData slot_name;
@@ -224,6 +225,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
catalog_xmin = slot->data.catalog_xmin;
database = slot->data.database;
restart_lsn = slot->data.restart_lsn;
+ confirmed_flush_lsn = slot->data.confirmed_flush;
namecpy(&slot_name, &slot->data.name);
namecpy(&plugin, &slot->data.plugin);
@@ -273,6 +275,11 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
else
nulls[i++] = true;
+ if (confirmed_flush_lsn != InvalidTransactionId)
+ values[i++] = LSNGetDatum(confirmed_flush_lsn);
+ else
+ nulls[i++] = true;
+
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 6fd1278..aee82d2 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -5183,7 +5183,7 @@ DATA(insert OID = 3779 (
pg_create_physical_replication_slot PGNSP PGUID 12 1 0
DESCR("create a physical replication slot");
DATA(insert OID = 3780 ( pg_drop_replication_slot PGNSP PGUID 12 1 0 0 0 f f
f f f f v 1 0 2278 "19" _null_ _null_ _null_ _null_ _null_
pg_drop_replication_slot _null_ _null_ _null_ ));
DESCR("drop a replication slot");
-DATA(insert OID = 3781 ( pg_get_replication_slots PGNSP PGUID 12 1 10 0 0
f f f f f t s 0 0 2249 "" "{19,19,25,26,16,23,28,28,3220}"
"{o,o,o,o,o,o,o,o,o}"
"{slot_name,plugin,slot_type,datoid,active,active_pid,xmin,catalog_xmin,restart_lsn}"
_null_ _null_ pg_get_replication_slots _null_ _null_ _null_ ));
+DATA(insert OID = 3781 ( pg_get_replication_slots PGNSP PGUID 12 1 10 0 0
f f f f f t s 0 0 2249 "" "{19,19,25,26,16,23,28,28,3220,3220}"
"{o,o,o,o,o,o,o,o,o,o}"
"{slot_name,plugin,slot_type,datoid,active,active_pid,xmin,catalog_xmin,restart_lsn,confirmed_flush_lsn}"
_null_ _null_ pg_get_replication_slots _null_ _null_ _null_ ));
DESCR("information about replication slots currently in use");
DATA(insert OID = 3786 ( pg_create_logical_replication_slot PGNSP PGUID 12 1
0 0 0 f f f f f f v 2 0 2249 "19 19" "{19,19,25,3220}" "{i,i,o,o}"
"{slot_name,plugin,slot_name,xlog_position}" _null_ _null_
pg_create_logical_replication_slot _null_ _null_ _null_ ));
DESCR("set up a logical replication slot");
diff --git a/src/test/regress/expected/rules.out
b/src/test/regress/expected/rules.out
index cd53375..63cd323 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1416,8 +1416,9 @@ pg_replication_slots| SELECT l.slot_name,
l.active_pid,
l.xmin,
l.catalog_xmin,
- l.restart_lsn
- FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid,
active, active_pid, xmin, catalog_xmin, restart_lsn)
+ l.restart_lsn,
+ l.confirmed_flush_lsn
+ FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid,
active, active_pid, xmin, catalog_xmin, restart_lsn, confirmed_flush_lsn)
LEFT JOIN pg_database d ON ((l.datoid = d.oid)));
pg_roles| SELECT pg_authid.rolname,
pg_authid.rolsuper,
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