On Wed, Apr 3, 2024 at 6:46 PM Bertrand Drouvot
<bertranddrouvot...@gmail.com> wrote:
>
> Just one comment on v32-0001:
>
> +# Synced slot on the standby must get its own inactive_since.
> +is( $standby1->safe_psql(
> + 'postgres',
> + "SELECT '$inactive_since_on_primary'::timestamptz <=
> '$inactive_since_on_standby'::timestamptz AND
> + '$inactive_since_on_standby'::timestamptz <=
> '$slot_sync_time'::timestamptz;"
> + ),
> + "t",
> + 'synchronized slot has got its own inactive_since');
> +
>
> By using <= we are not testing that it must get its own inactive_since (as we
> allow them to be equal in the test). I think we should just add some usleep()
> where appropriate and deny equality during the tests on inactive_since.
Thanks. It looks like we can ignore the equality in all of the
inactive_since comparisons. IIUC, all the TAP tests do run with
primary and standbys on the single BF animals. And, it looks like
assigning the inactive_since timestamps to perl variables is giving
the microseconds precision level
(./tmp_check/log/regress_log_040_standby_failover_slots_sync:inactive_since
2024-04-03 14:30:09.691648+00). FWIW, we already have some TAP and SQL
tests relying on stats_reset timestamps without equality. So, I've
left the equality for the inactive_since tests.
> Except for the above, v32-0001 LGTM.
Thanks. Please see the attached v33-0001 patch after removing equality
on inactive_since TAP tests.
On Wed, Apr 3, 2024 at 1:47 PM Bertrand Drouvot
<bertranddrouvot...@gmail.com> wrote:
>
> Some comments regarding v31-0002:
>
> === testing the behavior
>
> T1 ===
>
> > - synced slots don't get invalidated due to inactive timeout because
> > such slots not considered active at all as they don't perform logical
> > decoding (of course, they will perform in fast_forward mode to fix the
> > other data loss issue, but they don't generate changes for them to be
> > called as *active* slots)
>
> It behaves as described. OTOH non synced logical slots on the standby and
> physical slots on the standby are invalidated which is what is expected.
Right.
> T2 ===
>
> In case the slot is invalidated on the primary,
>
> primary:
>
> postgres=# select slot_name, inactive_since, invalidation_reason from
> pg_replication_slots where slot_name = 's1';
> slot_name | inactive_since | invalidation_reason
> -----------+-------------------------------+---------------------
> s1 | 2024-04-03 06:56:28.075637+00 | inactive_timeout
>
> then on the standby we get:
>
> standby:
>
> postgres=# select slot_name, inactive_since, invalidation_reason from
> pg_replication_slots where slot_name = 's1';
> slot_name | inactive_since | invalidation_reason
> -----------+------------------------------+---------------------
> s1 | 2024-04-03 07:06:43.37486+00 | inactive_timeout
>
> shouldn't the slot be dropped/recreated instead of updating inactive_since?
The sync slots that are invalidated on the primary aren't dropped and
recreated on the standby. There's no point in doing so because
invalidated slots on the primary can't be made useful. However, I
found that the synced slot is acquired and released unnecessarily
after the invalidation_reason is synced from the primary. I added a
skip check in synchronize_one_slot to skip acquiring and releasing the
slot if it's locally found inactive. With this, inactive_since won't
get updated for invalidated sync slots on the standby as we don't
acquire and release the slot.
> === code
>
> CR1 ===
>
> + Invalidates replication slots that are inactive for longer the
> + specified amount of time
>
> s/for longer the/for longer that/?
Fixed.
> CR2 ===
>
> + <literal>true</literal>) as such synced slots don't actually perform
> + logical decoding.
>
> We're switching in fast forward logical due to [1], so I'm not sure that's
> 100%
> accurate here. I'm not sure we need to specify a reason.
Fixed.
> CR3 ===
>
> + errdetail("This slot has been invalidated because it was inactive for more
> than the time specified by replication_slot_inactive_timeout parameter.")));
>
> I think we can remove "parameter" (see for example the error message in
> validate_remote_info()) and reduce it a bit, something like?
>
> "This slot has been invalidated because it was inactive for more than
> replication_slot_inactive_timeout"?
Done.
> CR4 ===
>
> + appendStringInfoString(&err_detail, _("The slot has been inactive for more
> than the time specified by replication_slot_inactive_timeout parameter."));
>
> Same.
Done. Changed it to "The slot has been inactive for more than
replication_slot_inactive_timeout."
> CR5 ===
>
> + /*
> + * This function isn't expected to be called for inactive timeout
> based
> + * invalidation. A separate function
> InvalidateInactiveReplicationSlot is
> + * to be used for that.
>
> Do you think it's worth to explain why?
Hm, I just wanted to point out the actual function here. I modified it
to something like the following, if others feel we don't need that, I
can remove it.
/*
* Use InvalidateInactiveReplicationSlot for inactive timeout based
* invalidation.
*/
> CR6 ===
>
> + if (replication_slot_inactive_timeout == 0)
> + return false;
> + else if (slot->inactive_since > 0)
>
> "else" is not needed here.
Nothing wrong there, but removed.
> CR7 ===
>
> + SpinLockAcquire(&slot->mutex);
> +
> + /*
> + * Check if the slot needs to be invalidated due to
> + * replication_slot_inactive_timeout GUC. We do this with the
> spinlock
> + * held to avoid race conditions -- for example the
> inactive_since
> + * could change, or the slot could be dropped.
> + */
> + now = GetCurrentTimestamp();
>
> We should not call GetCurrentTimestamp() while holding a spinlock.
I was thinking why to add up the wait time to acquire
LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);. Now that I
moved it up before the spinlock but after the LWLockAcquire.
> CR8 ===
>
> +# Testcase start: Invalidate streaming standby's slot as well as logical
> +# failover slot on primary due to inactive timeout GUC. Also, check the
> logical
>
> s/inactive timeout GUC/replication_slot_inactive_timeout/?
Done.
> CR9 ===
>
> +# Start: Helper functions used for this test file
> +# End: Helper functions used for this test file
>
> I think that's the first TAP test with this comment. Not saying we should not
> but
> why did you feel the need to add those?
Hm. Removed.
> [1]:
> https://www.postgresql.org/message-id/os0pr01mb5716b3942ae49f3f725aca9294...@os0pr01mb5716.jpnprd01.prod.outlook.com
On Wed, Apr 3, 2024 at 2:58 PM shveta malik <shveta.ma...@gmail.com> wrote:
>
> v31-002:
> (I had reviewed v29-002 but missed to post comments, I think these
> are still applicable)
>
> 1) I think replication_slot_inactivity_timeout was recommended here
> (instead of replication_slot_inactive_timeout, so please give it a
> thought):
> https://www.postgresql.org/message-id/202403260739.udlp7lxixktx%40alvherre.pgsql
Yeah. It's synonymous with inactive_since. If others have an opinion
to have replication_slot_inactivity_timeout, I'm fine with it.
> 2) Commit msg:
> a)
> "It is often easy for developers to set a timeout of say 1
> or 2 or 3 days at slot level, after which the inactive slots get
> dropped."
>
> Shall we say invalidated rather than dropped?
Right. Done that.
> b)
> "To achieve the above, postgres introduces a GUC allowing users
> set inactive timeout and then a slot stays inactive for this much
> amount of time it invalidates the slot."
>
> Broken sentence.
Reworded it a bit.
Please find the attached v33 patches.
--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
From 03a9e02df871dc86846b79a62a2aaf00e7152f14 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 3 Apr 2024 14:38:38 +0000
Subject: [PATCH v33 1/2] Allow synced slots to have their own inactive_since.
The slot's inactive_since isn't currently maintained for
synced slots on the standby. The commit a11f330b55 prevents
updating inactive_since with RecoveryInProgress() check in
RestoreSlotFromDisk(). But, the issue is that
RecoveryInProgress() always returns true in
RestoreSlotFromDisk() as 'xlogctl->SharedRecoveryState' is
always 'RECOVERY_STATE_CRASH' at that time. Because of this,
inactive_since is always NULL on a promoted standby for all
synced slots even after server restart.
Above issue led us to a question as to why we can't just let
standby maintain its own inactive_since for synced slots. This is
consistent with any regular slots and also indicates the last
synchronization time of the slot. This approach simplifies things
when compared to just copying inactive_since received from the
remote slot on the primary (for instance, there can exists clock
drift between primary and standby so just copying inactive_since
from the primary slot to the standby sync slot may not represent
the correct value).
This commit does two things:
1) Maintains inactive_since for sync slots whenever the slot is
released just like any other regular slot.
2) Ensures the value is set to current timestamp during the
shutdown of slot sync machinery to help correctly interpret the
time if the standby gets promoted without a restart.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik
Discussion: https://www.postgresql.org/message-id/CALj2ACWLctoiH-pSjWnEpR54q4DED6rw_BRJm5pCx86_Y01MoQ%40mail.gmail.com
---
doc/src/sgml/system-views.sgml | 7 +++
src/backend/replication/logical/slotsync.c | 51 +++++++++++++++
src/backend/replication/slot.c | 22 +++----
src/test/perl/PostgreSQL/Test/Cluster.pm | 31 ++++++++++
src/test/recovery/t/019_replslot_limit.pl | 26 +-------
.../t/040_standby_failover_slots_sync.pl | 62 +++++++++++++++++++
6 files changed, 160 insertions(+), 39 deletions(-)
diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 3c8dca8ca3..7ed617170f 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -2530,6 +2530,13 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
<para>
The time since the slot has become inactive.
<literal>NULL</literal> if the slot is currently being used.
+ Note that for slots on the standby that are being synced from a
+ primary server (whose <structfield>synced</structfield> field is
+ <literal>true</literal>), the
+ <structfield>inactive_since</structfield> indicates the last
+ synchronization (see
+ <xref linkend="logicaldecoding-replication-slots-synchronization"/>)
+ time.
</para></entry>
</row>
diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 9ac847b780..755bf40a9a 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -150,6 +150,7 @@ typedef struct RemoteSlot
} RemoteSlot;
static void slotsync_failure_callback(int code, Datum arg);
+static void update_synced_slots_inactive_since(void);
/*
* If necessary, update the local synced slot's metadata based on the data
@@ -584,6 +585,11 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid)
* overwriting 'invalidated' flag to remote_slot's value. See
* InvalidatePossiblyObsoleteSlot() where it invalidates slot directly
* if the slot is not acquired by other processes.
+ *
+ * XXX: If it ever turns out that slot acquire/release is costly for
+ * cases when none of the slot property is changed then we can do a
+ * pre-check to ensure that at least one of the slot property is
+ * changed before acquiring the slot.
*/
ReplicationSlotAcquire(remote_slot->name, true);
@@ -1355,6 +1361,48 @@ ReplSlotSyncWorkerMain(char *startup_data, size_t startup_data_len)
Assert(false);
}
+/*
+ * Update the inactive_since property for synced slots.
+ *
+ * Note that this function is currently called when we shutdown the slot sync
+ * machinery. This helps correctly interpret the inactive_since if the standby
+ * gets promoted without a restart.
+ */
+static void
+update_synced_slots_inactive_since(void)
+{
+ TimestampTz now = 0;
+
+ /* The slot sync worker mustn't be running by now */
+ Assert(SlotSyncCtx->pid == InvalidPid);
+
+ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
+
+ for (int i = 0; i < max_replication_slots; i++)
+ {
+ ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
+
+ /* Check if it is a synchronized slot */
+ if (s->in_use && s->data.synced)
+ {
+ Assert(SlotIsLogical(s));
+
+ /*
+ * We get the current time beforehand and only once to avoid
+ * system calls while holding the spinlock.
+ */
+ if (now == 0)
+ now = GetCurrentTimestamp();
+
+ SpinLockAcquire(&s->mutex);
+ s->inactive_since = now;
+ SpinLockRelease(&s->mutex);
+ }
+ }
+
+ LWLockRelease(ReplicationSlotControlLock);
+}
+
/*
* Shut down the slot sync worker.
*/
@@ -1368,6 +1416,7 @@ ShutDownSlotSync(void)
if (SlotSyncCtx->pid == InvalidPid)
{
SpinLockRelease(&SlotSyncCtx->mutex);
+ update_synced_slots_inactive_since();
return;
}
SpinLockRelease(&SlotSyncCtx->mutex);
@@ -1400,6 +1449,8 @@ ShutDownSlotSync(void)
}
SpinLockRelease(&SlotSyncCtx->mutex);
+
+ update_synced_slots_inactive_since();
}
/*
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index d778c0b921..3bddaae022 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -690,13 +690,10 @@ ReplicationSlotRelease(void)
}
/*
- * Set the last inactive time after marking the slot inactive. We don't
- * set it for the slots currently being synced from the primary to the
- * standby because such slots are typically inactive as decoding is not
- * allowed on those.
+ * Set the time since the slot has become inactive. We get the current
+ * time beforehand to avoid system call while holding the spinlock.
*/
- if (!(RecoveryInProgress() && slot->data.synced))
- now = GetCurrentTimestamp();
+ now = GetCurrentTimestamp();
if (slot->data.persistency == RS_PERSISTENT)
{
@@ -2369,16 +2366,11 @@ RestoreSlotFromDisk(const char *name)
slot->active_pid = 0;
/*
- * We set the last inactive time after loading the slot from the disk
- * into memory. Whoever acquires the slot i.e. makes the slot active
- * will reset it. We don't set it for the slots currently being synced
- * from the primary to the standby because such slots are typically
- * inactive as decoding is not allowed on those.
+ * Set the time since the slot has become inactive after loading the
+ * slot from the disk into memory. Whoever acquires the slot i.e.
+ * makes the slot active will reset it.
*/
- if (!(RecoveryInProgress() && slot->data.synced))
- slot->inactive_since = GetCurrentTimestamp();
- else
- slot->inactive_since = 0;
+ slot->inactive_since = GetCurrentTimestamp();
restored = true;
break;
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index b08296605c..54e1008ae5 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -3276,6 +3276,37 @@ sub create_logical_slot_on_standby
=pod
+=item $node->validate_slot_inactive_since(self, slot_name, reference_time)
+
+Validate inactive_since value of a given replication slot against the reference
+time and return it.
+
+=cut
+
+sub validate_slot_inactive_since
+{
+ my ($self, $slot_name, $reference_time) = @_;
+ my $name = $self->name;
+
+ my $inactive_since = $self->safe_psql('postgres',
+ qq(SELECT inactive_since FROM pg_replication_slots
+ WHERE slot_name = '$slot_name' AND inactive_since IS NOT NULL;)
+ );
+
+ # Check that the inactive_since is sane
+ is($self->safe_psql('postgres',
+ qq[SELECT '$inactive_since'::timestamptz > to_timestamp(0) AND
+ '$inactive_since'::timestamptz > '$reference_time'::timestamptz;]
+ ),
+ 't',
+ "last inactive time for slot $slot_name is valid on node $name")
+ or die "could not validate captured inactive_since for slot $slot_name";
+
+ return $inactive_since;
+}
+
+=pod
+
=item $node->advance_wal(num)
Advance WAL of node by given number of segments.
diff --git a/src/test/recovery/t/019_replslot_limit.pl b/src/test/recovery/t/019_replslot_limit.pl
index 3b9a306a8b..96b60cedbb 100644
--- a/src/test/recovery/t/019_replslot_limit.pl
+++ b/src/test/recovery/t/019_replslot_limit.pl
@@ -443,7 +443,7 @@ $primary4->safe_psql(
# Get inactive_since value after the slot's creation. Note that the slot is
# still inactive till it's used by the standby below.
my $inactive_since =
- capture_and_validate_slot_inactive_since($primary4, $sb4_slot, $slot_creation_time);
+ $primary4->validate_slot_inactive_since($sb4_slot, $slot_creation_time);
$standby4->start;
@@ -502,7 +502,7 @@ $publisher4->safe_psql('postgres',
# Get inactive_since value after the slot's creation. Note that the slot is
# still inactive till it's used by the subscriber below.
$inactive_since =
- capture_and_validate_slot_inactive_since($publisher4, $lsub4_slot, $slot_creation_time);
+ $publisher4->validate_slot_inactive_since($lsub4_slot, $slot_creation_time);
$subscriber4->start;
$subscriber4->safe_psql('postgres',
@@ -540,26 +540,4 @@ is( $publisher4->safe_psql(
$publisher4->stop;
$subscriber4->stop;
-# Capture and validate inactive_since of a given slot.
-sub capture_and_validate_slot_inactive_since
-{
- my ($node, $slot_name, $slot_creation_time) = @_;
-
- my $inactive_since = $node->safe_psql('postgres',
- qq(SELECT inactive_since FROM pg_replication_slots
- WHERE slot_name = '$slot_name' AND inactive_since IS NOT NULL;)
- );
-
- # Check that the captured time is sane
- is( $node->safe_psql(
- 'postgres',
- qq[SELECT '$inactive_since'::timestamptz > to_timestamp(0) AND
- '$inactive_since'::timestamptz >= '$slot_creation_time'::timestamptz;]
- ),
- 't',
- "last inactive time for an active slot $slot_name is sane");
-
- return $inactive_since;
-}
-
done_testing();
diff --git a/src/test/recovery/t/040_standby_failover_slots_sync.pl b/src/test/recovery/t/040_standby_failover_slots_sync.pl
index 869e3d2e91..e7d92e3276 100644
--- a/src/test/recovery/t/040_standby_failover_slots_sync.pl
+++ b/src/test/recovery/t/040_standby_failover_slots_sync.pl
@@ -35,6 +35,13 @@ my $subscriber1 = PostgreSQL::Test::Cluster->new('subscriber1');
$subscriber1->init;
$subscriber1->start;
+# Capture the time before the logical failover slot is created on the
+# primary. We later call this publisher as primary anyway.
+my $slot_creation_time_on_primary = $publisher->safe_psql(
+ 'postgres', qq[
+ SELECT current_timestamp;
+]);
+
# Create a slot on the publisher with failover disabled
$publisher->safe_psql('postgres',
"SELECT 'init' FROM pg_create_logical_replication_slot('lsub1_slot', 'pgoutput', false, false, false);"
@@ -174,6 +181,11 @@ $primary->poll_query_until(
"SELECT COUNT(*) FROM pg_catalog.pg_replication_slots WHERE slot_name = 'lsub1_slot' AND active = 'f'",
1);
+# Capture the inactive_since of the slot from the primary. Note that the slot
+# is not yet active.
+my $inactive_since_on_primary =
+ $primary->validate_slot_inactive_since('lsub1_slot', $slot_creation_time_on_primary);
+
# Wait for the standby to catch up so that the standby is not lagging behind
# the subscriber.
$primary->wait_for_replay_catchup($standby1);
@@ -181,6 +193,11 @@ $primary->wait_for_replay_catchup($standby1);
# Synchronize the primary server slots to the standby.
$standby1->safe_psql('postgres', "SELECT pg_sync_replication_slots();");
+my $slot_sync_time = $standby1->safe_psql(
+ 'postgres', qq[
+ SELECT current_timestamp;
+]);
+
# Confirm that the logical failover slots are created on the standby and are
# flagged as 'synced'
is( $standby1->safe_psql(
@@ -190,6 +207,19 @@ is( $standby1->safe_psql(
"t",
'logical slots have synced as true on standby');
+# Capture the inactive_since of the synced slot on the standby
+my $inactive_since_on_standby =
+ $standby1->validate_slot_inactive_since('lsub1_slot', $slot_creation_time_on_primary);
+
+# Synced slot on the standby must get its own inactive_since.
+is( $standby1->safe_psql(
+ 'postgres',
+ "SELECT '$inactive_since_on_primary'::timestamptz < '$inactive_since_on_standby'::timestamptz AND
+ '$inactive_since_on_standby'::timestamptz < '$slot_sync_time'::timestamptz;"
+ ),
+ "t",
+ 'synchronized slot has got its own inactive_since');
+
##################################################
# Test that the synchronized slot will be dropped if the corresponding remote
# slot on the primary server has been dropped.
@@ -237,6 +267,13 @@ is( $standby1->safe_psql(
$standby1->append_conf('postgresql.conf', 'max_slot_wal_keep_size = -1');
$standby1->reload;
+# Capture the time before the logical failover slot is created on the primary.
+# Note that the subscription creates the slot again on the primary.
+$slot_creation_time_on_primary = $publisher->safe_psql(
+ 'postgres', qq[
+ SELECT current_timestamp;
+]);
+
# To ensure that restart_lsn has moved to a recent WAL position, we re-create
# the subscription and the logical slot.
$subscriber1->safe_psql(
@@ -257,6 +294,11 @@ $primary->poll_query_until(
"SELECT COUNT(*) FROM pg_catalog.pg_replication_slots WHERE slot_name = 'lsub1_slot' AND active = 'f'",
1);
+# Capture the inactive_since of the slot from the primary. Note that the slot
+# is not yet active but has been dropped and recreated.
+$inactive_since_on_primary =
+ $primary->validate_slot_inactive_since('lsub1_slot', $slot_creation_time_on_primary);
+
# Wait for the standby to catch up so that the standby is not lagging behind
# the subscriber.
$primary->wait_for_replay_catchup($standby1);
@@ -808,8 +850,28 @@ $primary->reload;
$standby1->start;
$primary->wait_for_replay_catchup($standby1);
+# Capture the time before the standby is promoted
+my $promotion_time_on_primary = $standby1->safe_psql(
+ 'postgres', qq[
+ SELECT current_timestamp;
+]);
+
$standby1->promote;
+# Capture the inactive_since of the synced slot after the promotion.
+# Expectation here is that the slot gets its own inactive_since as part of the
+# promotion. We do this check before the slot is enabled on the new primary
+# below, otherwise the slot gets active setting inactive_since to NULL.
+my $inactive_since_on_new_primary =
+ $standby1->validate_slot_inactive_since('lsub1_slot', $promotion_time_on_primary);
+
+is( $standby1->safe_psql(
+ 'postgres',
+ "SELECT '$inactive_since_on_new_primary'::timestamptz > '$inactive_since_on_primary'::timestamptz"
+ ),
+ "t",
+ 'synchronized slot has got its own inactive_since on the new primary after promotion');
+
# Update subscription with the new primary's connection info
my $standby1_conninfo = $standby1->connstr . ' dbname=postgres';
$subscriber1->safe_psql('postgres',
--
2.34.1
From abe5113e8431e0a691ef61c04288dea6a0f4a2ac Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 3 Apr 2024 14:39:36 +0000
Subject: [PATCH v33 2/2] Add inactive_timeout based replication slot
invalidation.
Till now, postgres has the ability to invalidate inactive
replication slots based on the amount of WAL (set via
max_slot_wal_keep_size GUC) that will be needed for the slots in
case they become active. However, choosing a default value for
max_slot_wal_keep_size is tricky. Because the amount of WAL a
customer generates, and their allocated storage will vary greatly
in production, making it difficult to pin down a one-size-fits-all
value. It is often easy for developers to set a timeout of say 1
or 2 or 3 days at slot level, after which the inactive slots get
invalidated.
To achieve the above, postgres introduces a GUC allowing users
set inactive timeout. The replication slots that are inactive
for longer than specified amount of time get invalidated.
The invalidation check happens at various locations to help being
as latest as possible, these locations include the following:
- Whenever the slot is acquired and the slot acquisition errors
out if invalidated.
- During checkpoint
Note that this new invalidation mechanism won't kick-in for the
slots that are currently being synced from the primary to the
standby.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik
Discussion: https://www.postgresql.org/message-id/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com
---
doc/src/sgml/config.sgml | 32 ++
doc/src/sgml/system-views.sgml | 7 +
.../replication/logical/logicalfuncs.c | 2 +-
src/backend/replication/logical/slotsync.c | 11 +-
src/backend/replication/slot.c | 208 ++++++++++++-
src/backend/replication/slotfuncs.c | 2 +-
src/backend/replication/walsender.c | 4 +-
src/backend/utils/adt/pg_upgrade_support.c | 2 +-
src/backend/utils/misc/guc_tables.c | 12 +
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/replication/slot.h | 8 +-
src/test/recovery/meson.build | 1 +
src/test/recovery/t/044_invalidate_slots.pl | 274 ++++++++++++++++++
13 files changed, 540 insertions(+), 24 deletions(-)
create mode 100644 src/test/recovery/t/044_invalidate_slots.pl
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 624518e0b0..626eac7125 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4547,6 +4547,38 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem>
</varlistentry>
+ <varlistentry id="guc-replication-slot-inactive-timeout" xreflabel="replication_slot_inactive_timeout">
+ <term><varname>replication_slot_inactive_timeout</varname> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>replication_slot_inactive_timeout</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Invalidates replication slots that are inactive for longer than
+ specified amount of time. If this value is specified without units,
+ it is taken as seconds. A value of zero (which is default) disables
+ the timeout mechanism. This parameter can only be set in
+ the <filename>postgresql.conf</filename> file or on the server
+ command line.
+ </para>
+
+ <para>
+ The timeout is measured from the time since the slot has become
+ inactive (known from its
+ <structfield>inactive_since</structfield> value) until it gets
+ used (i.e., its <structfield>active</structfield> is set to true).
+ </para>
+
+ <para>
+ Note that the inactive timeout invalidation mechanism is not
+ applicable for slots on the standby that are being synced from a
+ primary server (whose <structfield>synced</structfield> field is
+ <literal>true</literal>).
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-track-commit-timestamp" xreflabel="track_commit_timestamp">
<term><varname>track_commit_timestamp</varname> (<type>boolean</type>)
<indexterm>
diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 7ed617170f..063638beda 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -2580,6 +2580,13 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
perform logical decoding. It is set only for logical slots.
</para>
</listitem>
+ <listitem>
+ <para>
+ <literal>inactive_timeout</literal> means that the slot has been
+ inactive for the duration specified by
+ <xref linkend="guc-replication-slot-inactive-timeout"/> parameter.
+ </para>
+ </listitem>
</itemizedlist>
</para></entry>
</row>
diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c
index b4dd5cce75..56fc1a45a9 100644
--- a/src/backend/replication/logical/logicalfuncs.c
+++ b/src/backend/replication/logical/logicalfuncs.c
@@ -197,7 +197,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
else
end_of_wal = GetXLogReplayRecPtr(NULL);
- ReplicationSlotAcquire(NameStr(*name), true);
+ ReplicationSlotAcquire(NameStr(*name), true, true);
PG_TRY();
{
diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 755bf40a9a..080edc0d74 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -362,7 +362,7 @@ drop_local_obsolete_slots(List *remote_slot_list)
if (synced_slot)
{
- ReplicationSlotAcquire(NameStr(local_slot->data.name), true);
+ ReplicationSlotAcquire(NameStr(local_slot->data.name), true, false);
ReplicationSlotDropAcquired();
}
@@ -575,6 +575,13 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid)
" name slot \"%s\" already exists on the standby",
remote_slot->name));
+ /*
+ * Skip the sync if the local slot is already invalidated. We do this
+ * beforehand to save on slot acquire and release.
+ */
+ if (slot->data.invalidated != RS_INVAL_NONE)
+ return false;
+
/*
* The slot has been synchronized before.
*
@@ -591,7 +598,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid)
* pre-check to ensure that at least one of the slot property is
* changed before acquiring the slot.
*/
- ReplicationSlotAcquire(remote_slot->name, true);
+ ReplicationSlotAcquire(remote_slot->name, true, false);
Assert(slot == MyReplicationSlot);
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 3bddaae022..e5ee934b24 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -107,10 +107,11 @@ const char *const SlotInvalidationCauses[] = {
[RS_INVAL_WAL_REMOVED] = "wal_removed",
[RS_INVAL_HORIZON] = "rows_removed",
[RS_INVAL_WAL_LEVEL] = "wal_level_insufficient",
+ [RS_INVAL_INACTIVE_TIMEOUT] = "inactive_timeout",
};
/* Maximum number of invalidation causes */
-#define RS_INVAL_MAX_CAUSES RS_INVAL_WAL_LEVEL
+#define RS_INVAL_MAX_CAUSES RS_INVAL_INACTIVE_TIMEOUT
StaticAssertDecl(lengthof(SlotInvalidationCauses) == (RS_INVAL_MAX_CAUSES + 1),
"array length mismatch");
@@ -140,6 +141,7 @@ ReplicationSlot *MyReplicationSlot = NULL;
/* GUC variables */
int max_replication_slots = 10; /* the maximum number of replication
* slots */
+int replication_slot_inactive_timeout = 0;
/*
* This GUC lists streaming replication standby server slot names that
@@ -158,6 +160,7 @@ static XLogRecPtr ss_oldest_flush_lsn = InvalidXLogRecPtr;
static void ReplicationSlotShmemExit(int code, Datum arg);
static void ReplicationSlotDropPtr(ReplicationSlot *slot);
+static bool InvalidatePossiblyInactiveSlot(ReplicationSlot *slot);
/* internal persistency functions */
static void RestoreSlotFromDisk(const char *name);
@@ -535,9 +538,14 @@ ReplicationSlotName(int index, Name name)
*
* An error is raised if nowait is true and the slot is currently in use. If
* nowait is false, we sleep until the slot is released by the owning process.
+ *
+ * If check_for_timeout_invalidation is true, the slot is checked for
+ * invalidation based on replication_slot_inactive_timeout GUC, and an error is
+ * raised after making the slot ours.
*/
void
-ReplicationSlotAcquire(const char *name, bool nowait)
+ReplicationSlotAcquire(const char *name, bool nowait,
+ bool check_for_timeout_invalidation)
{
ReplicationSlot *s;
int active_pid;
@@ -615,6 +623,34 @@ retry:
/* We made this slot active, so it's ours now. */
MyReplicationSlot = s;
+ /*
+ * Check if the given slot can be invalidated based on its inactive
+ * timeout. If yes, persist the invalidated state to disk and then error
+ * out. We do this only after making the slot ours to avoid anyone else
+ * acquiring it while we check for its invalidation.
+ */
+ if (check_for_timeout_invalidation)
+ {
+ /* The slot is ours by now */
+ Assert(s->active_pid == MyProcPid);
+
+ if (InvalidateInactiveReplicationSlot(s, true))
+ {
+ /*
+ * If the slot has been invalidated, recalculate the resource
+ * limits.
+ */
+ ReplicationSlotsComputeRequiredXmin(false);
+ ReplicationSlotsComputeRequiredLSN();
+
+ ereport(ERROR,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("can no longer get changes from replication slot \"%s\"",
+ NameStr(MyReplicationSlot->data.name)),
+ errdetail("This slot has been invalidated because it was inactive for more than replication_slot_inactive_timeout.")));
+ }
+ }
+
/*
* The call to pgstat_acquire_replslot() protects against stats for a
* different slot, from before a restart or such, being present during
@@ -781,7 +817,7 @@ ReplicationSlotDrop(const char *name, bool nowait)
{
Assert(MyReplicationSlot == NULL);
- ReplicationSlotAcquire(name, nowait);
+ ReplicationSlotAcquire(name, nowait, false);
/*
* Do not allow users to drop the slots which are currently being synced
@@ -804,7 +840,7 @@ ReplicationSlotAlter(const char *name, bool failover)
{
Assert(MyReplicationSlot == NULL);
- ReplicationSlotAcquire(name, false);
+ ReplicationSlotAcquire(name, false, true);
if (SlotIsPhysical(MyReplicationSlot))
ereport(ERROR,
@@ -980,6 +1016,20 @@ ReplicationSlotDropPtr(ReplicationSlot *slot)
LWLockRelease(ReplicationSlotAllocationLock);
}
+/*
+ * Helper for ReplicationSlotSave
+ */
+static inline void
+SaveGivenReplicationSlot(ReplicationSlot *slot, int elevel)
+{
+ char path[MAXPGPATH];
+
+ Assert(slot != NULL);
+
+ sprintf(path, "pg_replslot/%s", NameStr(slot->data.name));
+ SaveSlotToPath(slot, path, elevel);
+}
+
/*
* Serialize the currently acquired slot's state from memory to disk, thereby
* guaranteeing the current state will survive a crash.
@@ -987,12 +1037,21 @@ ReplicationSlotDropPtr(ReplicationSlot *slot)
void
ReplicationSlotSave(void)
{
- char path[MAXPGPATH];
+ SaveGivenReplicationSlot(MyReplicationSlot, ERROR);
+}
- Assert(MyReplicationSlot != NULL);
+/*
+ * Helper for ReplicationSlotMarkDirty
+ */
+static inline void
+MarkGivenReplicationSlotDirty(ReplicationSlot *slot)
+{
+ Assert(slot != NULL);
- sprintf(path, "pg_replslot/%s", NameStr(MyReplicationSlot->data.name));
- SaveSlotToPath(MyReplicationSlot, path, ERROR);
+ SpinLockAcquire(&slot->mutex);
+ slot->just_dirtied = true;
+ slot->dirty = true;
+ SpinLockRelease(&slot->mutex);
}
/*
@@ -1005,14 +1064,7 @@ ReplicationSlotSave(void)
void
ReplicationSlotMarkDirty(void)
{
- ReplicationSlot *slot = MyReplicationSlot;
-
- Assert(MyReplicationSlot != NULL);
-
- SpinLockAcquire(&slot->mutex);
- MyReplicationSlot->just_dirtied = true;
- MyReplicationSlot->dirty = true;
- SpinLockRelease(&slot->mutex);
+ MarkGivenReplicationSlotDirty(MyReplicationSlot);
}
/*
@@ -1506,6 +1558,9 @@ ReportSlotInvalidation(ReplicationSlotInvalidationCause cause,
case RS_INVAL_WAL_LEVEL:
appendStringInfoString(&err_detail, _("Logical decoding on standby requires wal_level >= logical on the primary server."));
break;
+ case RS_INVAL_INACTIVE_TIMEOUT:
+ appendStringInfoString(&err_detail, _("The slot has been inactive for more than replication_slot_inactive_timeout."));
+ break;
case RS_INVAL_NONE:
pg_unreachable();
}
@@ -1550,6 +1605,12 @@ InvalidatePossiblyObsoleteSlot(ReplicationSlotInvalidationCause cause,
XLogRecPtr initial_restart_lsn = InvalidXLogRecPtr;
ReplicationSlotInvalidationCause invalidation_cause_prev PG_USED_FOR_ASSERTS_ONLY = RS_INVAL_NONE;
+ /*
+ * Use InvalidateInactiveReplicationSlot for inactive timeout based
+ * invalidation.
+ */
+ Assert(cause != RS_INVAL_INACTIVE_TIMEOUT);
+
for (;;)
{
XLogRecPtr restart_lsn;
@@ -1619,6 +1680,10 @@ InvalidatePossiblyObsoleteSlot(ReplicationSlotInvalidationCause cause,
if (SlotIsLogical(s))
invalidation_cause = cause;
break;
+ case RS_INVAL_INACTIVE_TIMEOUT:
+ /* not reachable */
+ Assert(false);
+ break;
case RS_INVAL_NONE:
pg_unreachable();
}
@@ -1772,6 +1837,7 @@ InvalidatePossiblyObsoleteSlot(ReplicationSlotInvalidationCause cause,
* - RS_INVAL_HORIZON: requires a snapshot <= the given horizon in the given
* db; dboid may be InvalidOid for shared relations
* - RS_INVAL_WAL_LEVEL: is logical
+ * - RS_INVAL_INACTIVE_TIMEOUT: inactive slot timeout occurs
*
* NB - this runs as part of checkpoint, so avoid raising errors if possible.
*/
@@ -1787,6 +1853,12 @@ InvalidateObsoleteReplicationSlots(ReplicationSlotInvalidationCause cause,
Assert(cause != RS_INVAL_WAL_REMOVED || oldestSegno > 0);
Assert(cause != RS_INVAL_NONE);
+ /*
+ * Use InvalidateInactiveReplicationSlot for inactive timeout based
+ * invalidation.
+ */
+ Assert(cause != RS_INVAL_INACTIVE_TIMEOUT);
+
if (max_replication_slots == 0)
return invalidated;
@@ -1823,6 +1895,95 @@ restart:
return invalidated;
}
+/*
+ * Invalidate given slot based on replication_slot_inactive_timeout GUC.
+ *
+ * Returns true if the slot has got invalidated.
+ *
+ * NB - this function also runs as part of checkpoint, so avoid raising errors
+ * if possible.
+ */
+bool
+InvalidateInactiveReplicationSlot(ReplicationSlot *slot, bool persist_state)
+{
+ if (!InvalidatePossiblyInactiveSlot(slot))
+ return false;
+
+ /* Make sure the invalidated state persists across server restart */
+ MarkGivenReplicationSlotDirty(slot);
+
+ if (persist_state)
+ SaveGivenReplicationSlot(slot, ERROR);
+
+ ReportSlotInvalidation(RS_INVAL_INACTIVE_TIMEOUT, false, 0,
+ slot->data.name, InvalidXLogRecPtr,
+ InvalidXLogRecPtr, InvalidTransactionId);
+
+ return true;
+}
+
+/*
+ * Helper for InvalidateInactiveReplicationSlot
+ */
+static bool
+InvalidatePossiblyInactiveSlot(ReplicationSlot *slot)
+{
+ ReplicationSlotInvalidationCause inavidation_cause = RS_INVAL_NONE;
+
+ /*
+ * Note that we don't invalidate slot on the standby that's currently
+ * being synced from the primary, because such slots are typically
+ * considered not active as they don't actually perform logical decoding.
+ */
+ if (RecoveryInProgress() && slot->data.synced)
+ return false;
+
+ if (replication_slot_inactive_timeout == 0)
+ return false;
+
+ if (slot->inactive_since > 0)
+ {
+ TimestampTz now;
+
+ /*
+ * Do not invalidate the slots which are currently being synced from
+ * the primary to the standby.
+ */
+ if (RecoveryInProgress() && slot->data.synced)
+ return false;
+
+ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
+
+ /*
+ * We get the current time beforehand to avoid system call while
+ * holding the spinlock.
+ */
+ now = GetCurrentTimestamp();
+
+ SpinLockAcquire(&slot->mutex);
+
+ /*
+ * Check if the slot needs to be invalidated due to
+ * replication_slot_inactive_timeout GUC. We do this with the spinlock
+ * held to avoid race conditions -- for example the inactive_since
+ * could change, or the slot could be dropped.
+ */
+ if (TimestampDifferenceExceeds(slot->inactive_since, now,
+ replication_slot_inactive_timeout * 1000))
+ {
+ inavidation_cause = RS_INVAL_INACTIVE_TIMEOUT;
+ slot->data.invalidated = RS_INVAL_INACTIVE_TIMEOUT;
+ }
+
+ SpinLockRelease(&slot->mutex);
+ LWLockRelease(ReplicationSlotControlLock);
+
+ return (inavidation_cause == RS_INVAL_INACTIVE_TIMEOUT);
+ }
+
+ return false;
+}
+
/*
* Flush all replication slots to disk.
*
@@ -1835,6 +1996,7 @@ void
CheckPointReplicationSlots(bool is_shutdown)
{
int i;
+ bool invalidated = false;
elog(DEBUG1, "performing replication slot checkpoint");
@@ -1858,6 +2020,13 @@ CheckPointReplicationSlots(bool is_shutdown)
/* save the slot to disk, locking is handled in SaveSlotToPath() */
sprintf(path, "pg_replslot/%s", NameStr(s->data.name));
+ /*
+ * Here's an opportunity to invalidate inactive replication slots
+ * based on timeout, so let's do it.
+ */
+ if (InvalidateInactiveReplicationSlot(s, false))
+ invalidated = true;
+
/*
* Slot's data is not flushed each time the confirmed_flush LSN is
* updated as that could lead to frequent writes. However, we decide
@@ -1884,6 +2053,13 @@ CheckPointReplicationSlots(bool is_shutdown)
SaveSlotToPath(s, path, LOG);
}
LWLockRelease(ReplicationSlotAllocationLock);
+
+ /* If the slot has been invalidated, recalculate the resource limits */
+ if (invalidated)
+ {
+ ReplicationSlotsComputeRequiredXmin(false);
+ ReplicationSlotsComputeRequiredLSN();
+ }
}
/*
diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c
index dd6c1d5a7e..9ad3e55704 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -539,7 +539,7 @@ pg_replication_slot_advance(PG_FUNCTION_ARGS)
moveto = Min(moveto, GetXLogReplayRecPtr(NULL));
/* Acquire the slot so we "own" it */
- ReplicationSlotAcquire(NameStr(*slotname), true);
+ ReplicationSlotAcquire(NameStr(*slotname), true, true);
/* A slot whose restart_lsn has never been reserved cannot be advanced */
if (XLogRecPtrIsInvalid(MyReplicationSlot->data.restart_lsn))
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index bc40c454de..96eeb8b7d2 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -846,7 +846,7 @@ StartReplication(StartReplicationCmd *cmd)
if (cmd->slotname)
{
- ReplicationSlotAcquire(cmd->slotname, true);
+ ReplicationSlotAcquire(cmd->slotname, true, true);
if (SlotIsLogical(MyReplicationSlot))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
@@ -1459,7 +1459,7 @@ StartLogicalReplication(StartReplicationCmd *cmd)
Assert(!MyReplicationSlot);
- ReplicationSlotAcquire(cmd->slotname, true);
+ ReplicationSlotAcquire(cmd->slotname, true, true);
/*
* Force a disconnect, so that the decoding code doesn't need to care
diff --git a/src/backend/utils/adt/pg_upgrade_support.c b/src/backend/utils/adt/pg_upgrade_support.c
index c54b08fe18..82956d58d3 100644
--- a/src/backend/utils/adt/pg_upgrade_support.c
+++ b/src/backend/utils/adt/pg_upgrade_support.c
@@ -299,7 +299,7 @@ binary_upgrade_logical_slot_has_caught_up(PG_FUNCTION_ARGS)
slot_name = PG_GETARG_NAME(0);
/* Acquire the given slot */
- ReplicationSlotAcquire(NameStr(*slot_name), true);
+ ReplicationSlotAcquire(NameStr(*slot_name), true, false);
Assert(SlotIsLogical(MyReplicationSlot));
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index c12784cbec..4149ff1ffe 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -2971,6 +2971,18 @@ struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
+ {
+ {"replication_slot_inactive_timeout", PGC_SIGHUP, REPLICATION_SENDING,
+ gettext_noop("Sets the amount of time to wait before invalidating an "
+ "inactive replication slot."),
+ NULL,
+ GUC_UNIT_S
+ },
+ &replication_slot_inactive_timeout,
+ 0, 0, INT_MAX,
+ NULL, NULL, NULL
+ },
+
{
{"commit_delay", PGC_SUSET, WAL_SETTINGS,
gettext_noop("Sets the delay in microseconds between transaction commit and "
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index baecde2841..2e1ad2eaca 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -335,6 +335,7 @@
#wal_sender_timeout = 60s # in milliseconds; 0 disables
#track_commit_timestamp = off # collect timestamp of transaction commit
# (change requires restart)
+#replication_slot_inactive_timeout = 0 # in seconds; 0 disables
# - Primary Server -
diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h
index 7b937d1a0c..f0ac324ce9 100644
--- a/src/include/replication/slot.h
+++ b/src/include/replication/slot.h
@@ -53,6 +53,8 @@ typedef enum ReplicationSlotInvalidationCause
RS_INVAL_HORIZON,
/* wal_level insufficient for slot */
RS_INVAL_WAL_LEVEL,
+ /* inactive slot timeout has occurred */
+ RS_INVAL_INACTIVE_TIMEOUT,
} ReplicationSlotInvalidationCause;
extern PGDLLIMPORT const char *const SlotInvalidationCauses[];
@@ -230,6 +232,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot;
/* GUCs */
extern PGDLLIMPORT int max_replication_slots;
extern PGDLLIMPORT char *standby_slot_names;
+extern PGDLLIMPORT int replication_slot_inactive_timeout;
/* shmem initialization functions */
extern Size ReplicationSlotsShmemSize(void);
@@ -245,7 +248,8 @@ extern void ReplicationSlotDrop(const char *name, bool nowait);
extern void ReplicationSlotDropAcquired(void);
extern void ReplicationSlotAlter(const char *name, bool failover);
-extern void ReplicationSlotAcquire(const char *name, bool nowait);
+extern void ReplicationSlotAcquire(const char *name, bool nowait,
+ bool check_for_timeout_invalidation);
extern void ReplicationSlotRelease(void);
extern void ReplicationSlotCleanup(void);
extern void ReplicationSlotSave(void);
@@ -264,6 +268,8 @@ extern bool InvalidateObsoleteReplicationSlots(ReplicationSlotInvalidationCause
XLogSegNo oldestSegno,
Oid dboid,
TransactionId snapshotConflictHorizon);
+extern bool InvalidateInactiveReplicationSlot(ReplicationSlot *slot,
+ bool persist_state);
extern ReplicationSlot *SearchNamedReplicationSlot(const char *name, bool need_lock);
extern int ReplicationSlotIndex(ReplicationSlot *slot);
extern bool ReplicationSlotName(int index, Name name);
diff --git a/src/test/recovery/meson.build b/src/test/recovery/meson.build
index 712924c2fa..0437ab5c46 100644
--- a/src/test/recovery/meson.build
+++ b/src/test/recovery/meson.build
@@ -52,6 +52,7 @@ tests += {
't/041_checkpoint_at_promote.pl',
't/042_low_level_backup.pl',
't/043_wal_replay_wait.pl',
+ 't/044_invalidate_slots.pl',
],
},
}
diff --git a/src/test/recovery/t/044_invalidate_slots.pl b/src/test/recovery/t/044_invalidate_slots.pl
new file mode 100644
index 0000000000..8f7967a253
--- /dev/null
+++ b/src/test/recovery/t/044_invalidate_slots.pl
@@ -0,0 +1,274 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+# Test for replication slots invalidation
+use strict;
+use warnings FATAL => 'all';
+
+use PostgreSQL::Test::Utils;
+use PostgreSQL::Test::Cluster;
+use Test::More;
+use Time::HiRes qw(usleep);
+
+# =============================================================================
+# Testcase start: Invalidate streaming standby's slot as well as logical
+# failover slot on primary due to replication_slot_inactive_timeout. Also,
+# check the logical failover slot synced on to the standby doesn't invalidate
+# the slot on its own, but gets the invalidated state from the remote slot on
+# the primary.
+
+# Initialize primary node
+my $primary = PostgreSQL::Test::Cluster->new('primary');
+$primary->init(allows_streaming => 'logical');
+
+# Avoid checkpoint during the test, otherwise, the test can get unpredictable
+$primary->append_conf(
+ 'postgresql.conf', q{
+checkpoint_timeout = 1h
+autovacuum = off
+});
+$primary->start;
+
+# Take backup
+my $backup_name = 'my_backup';
+$primary->backup($backup_name);
+
+# Create a standby linking to the primary using the replication slot
+my $standby1 = PostgreSQL::Test::Cluster->new('standby1');
+$standby1->init_from_backup($primary, $backup_name, has_streaming => 1);
+
+my $connstr_1 = $primary->connstr;
+$standby1->append_conf(
+ 'postgresql.conf', qq(
+hot_standby_feedback = on
+primary_slot_name = 'sb1_slot'
+primary_conninfo = '$connstr_1 dbname=postgres'
+));
+
+# Create sync slot on the primary
+$primary->psql('postgres',
+ q{SELECT pg_create_logical_replication_slot('lsub1_sync_slot', 'test_decoding', false, false, true);}
+);
+
+$primary->safe_psql(
+ 'postgres', qq[
+ SELECT pg_create_physical_replication_slot(slot_name := 'sb1_slot');
+]);
+
+$standby1->start;
+
+my $standby1_logstart = -s $standby1->logfile;
+
+# Wait until standby has replayed enough data
+$primary->wait_for_catchup($standby1);
+
+# Synchronize the primary server slots to the standby.
+$standby1->safe_psql('postgres', "SELECT pg_sync_replication_slots();");
+
+# Confirm that the logical failover slot is created on the standby and is
+# flagged as 'synced'.
+is( $standby1->safe_psql(
+ 'postgres',
+ q{SELECT count(*) = 1 FROM pg_replication_slots
+ WHERE slot_name = 'lsub1_sync_slot' AND synced AND NOT temporary;}
+ ),
+ "t",
+ 'logical slot has synced as true on standby');
+
+my $logstart = -s $primary->logfile;
+
+# Set timeout so that the next checkpoint will invalidate the inactive
+# replication slot.
+$primary->safe_psql(
+ 'postgres', qq[
+ ALTER SYSTEM SET replication_slot_inactive_timeout TO '2s';
+]);
+$primary->reload;
+
+# Wait for the logical failover slot to become inactive on the primary. Note
+# that nobody has acquired that slot yet, so due to
+# replication_slot_inactive_timeout setting above it must get invalidated.
+wait_for_slot_invalidation($primary, 'lsub1_sync_slot', $logstart);
+
+# Set timeout on the standby also to check the synced slots don't get
+# invalidated due to timeout on the standby.
+$standby1->safe_psql(
+ 'postgres', qq[
+ ALTER SYSTEM SET replication_slot_inactive_timeout TO '2s';
+]);
+$standby1->reload;
+
+# Now, sync the logical failover slot from the remote slot on the primary.
+# Note that the remote slot has already been invalidated due to inactive
+# timeout. Now, the standby must also see it as invalidated.
+$standby1->safe_psql('postgres', "SELECT pg_sync_replication_slots();");
+
+# Wait for the inactive replication slot to be invalidated.
+$standby1->poll_query_until(
+ 'postgres', qq[
+ SELECT COUNT(slot_name) = 1 FROM pg_replication_slots
+ WHERE slot_name = 'lsub1_sync_slot' AND
+ invalidation_reason = 'inactive_timeout';
+])
+ or die
+ "Timed out while waiting for replication slot lsub1_sync_slot invalidation to be synced on standby";
+
+# Synced slot mustn't get invalidated on the standby, it must sync invalidation
+# from the primary. So, we must not see the slot's invalidation message in server
+# log.
+ok( !$standby1->log_contains(
+ "invalidating obsolete replication slot \"lsub1_sync_slot\"",
+ $standby1_logstart),
+ 'check that syned slot has not been invalidated on the standby');
+
+# Stop standby to make the standby's replication slot on the primary inactive
+$standby1->stop;
+
+# Wait for the standby's replication slot to become inactive
+wait_for_slot_invalidation($primary, 'sb1_slot', $logstart);
+
+# Testcase end: Invalidate streaming standby's slot as well as logical failover
+# slot on primary due to replication_slot_inactive_timeout. Also, check the
+# logical failover slot synced on to the standby doesn't invalidate the slot on
+# its own, but gets the invalidated state from the remote slot on the primary.
+# =============================================================================
+
+# =============================================================================
+# Testcase start: Invalidate logical subscriber's slot due to
+# replication_slot_inactive_timeout.
+
+my $publisher = $primary;
+
+# Prepare for the next test
+$publisher->safe_psql(
+ 'postgres', qq[
+ ALTER SYSTEM SET replication_slot_inactive_timeout TO '0';
+]);
+$publisher->reload;
+
+# Create subscriber node
+my $subscriber = PostgreSQL::Test::Cluster->new('sub');
+$subscriber->init;
+$subscriber->start;
+
+# Create tables
+$publisher->safe_psql('postgres', "CREATE TABLE test_tbl (id int)");
+$subscriber->safe_psql('postgres', "CREATE TABLE test_tbl (id int)");
+
+# Insert some data
+$subscriber->safe_psql('postgres',
+ "INSERT INTO test_tbl VALUES (generate_series(1, 5));");
+
+# Setup logical replication
+my $publisher_connstr = $publisher->connstr . ' dbname=postgres';
+$publisher->safe_psql('postgres', "CREATE PUBLICATION pub FOR ALL TABLES");
+$publisher->safe_psql(
+ 'postgres', qq[
+ SELECT pg_create_logical_replication_slot(slot_name := 'lsub1_slot', plugin := 'pgoutput');
+]);
+
+$subscriber->safe_psql('postgres',
+ "CREATE SUBSCRIPTION sub CONNECTION '$publisher_connstr' PUBLICATION pub WITH (slot_name = 'lsub1_slot', create_slot = false)"
+);
+
+$subscriber->wait_for_subscription_sync($publisher, 'sub');
+
+my $result =
+ $subscriber->safe_psql('postgres', "SELECT count(*) FROM test_tbl");
+
+is($result, qq(5), "check initial copy was done");
+
+# Prepare for the next test
+$publisher->safe_psql(
+ 'postgres', qq[
+ ALTER SYSTEM SET replication_slot_inactive_timeout TO '2s';
+]);
+$publisher->reload;
+
+$logstart = -s $publisher->logfile;
+
+# Stop subscriber to make the replication slot on publisher inactive
+$subscriber->stop;
+
+# Wait for the replication slot to become inactive and then invalidated due to
+# timeout.
+wait_for_slot_invalidation($publisher, 'lsub1_slot', $logstart);
+
+# Testcase end: Invalidate logical subscriber's slot due to
+# replication_slot_inactive_timeout.
+# =============================================================================
+
+sub wait_for_slot_invalidation
+{
+ my ($node, $slot_name, $offset) = @_;
+ my $name = $node->name;
+
+ # Wait for the replication slot to become inactive
+ $node->poll_query_until(
+ 'postgres', qq[
+ SELECT COUNT(slot_name) = 1 FROM pg_replication_slots
+ WHERE slot_name = '$slot_name' AND active = 'f';
+ ])
+ or die
+ "Timed out while waiting for replication slot to become inactive";
+
+ # Wait for the replication slot info to be updated
+ $node->poll_query_until(
+ 'postgres', qq[
+ SELECT COUNT(slot_name) = 1 FROM pg_replication_slots
+ WHERE inactive_since IS NOT NULL
+ AND slot_name = '$slot_name' AND active = 'f';
+ ])
+ or die
+ "Timed out while waiting for info of replication slot $slot_name to be updated on node $name";
+
+ check_for_slot_invalidation_in_server_log($node, $slot_name, $offset);
+
+ # Wait for the inactive replication slot to be invalidated.
+ $node->poll_query_until(
+ 'postgres', qq[
+ SELECT COUNT(slot_name) = 1 FROM pg_replication_slots
+ WHERE slot_name = '$slot_name' AND
+ invalidation_reason = 'inactive_timeout';
+ ])
+ or die
+ "Timed out while waiting for inactive replication slot $slot_name to be invalidated on node $name";
+
+ # Check that the invalidated slot cannot be acquired
+ my ($result, $stdout, $stderr);
+
+ ($result, $stdout, $stderr) = $primary->psql(
+ 'postgres', qq[
+ SELECT pg_replication_slot_advance('$slot_name', '0/1');
+ ]);
+
+ ok( $stderr =~
+ /can no longer get changes from replication slot "$slot_name"/,
+ "detected error upon trying to acquire invalidated slot $slot_name on node $name"
+ )
+ or die
+ "could not detect error upon trying to acquire invalidated slot $slot_name";
+}
+
+# Check for invalidation of slot in server log.
+sub check_for_slot_invalidation_in_server_log
+{
+ my ($node, $slot_name, $offset) = @_;
+ my $invalidated = 0;
+
+ for (my $i = 0; $i < 10 * $PostgreSQL::Test::Utils::timeout_default; $i++)
+ {
+ $node->safe_psql('postgres', "CHECKPOINT");
+ if ($node->log_contains(
+ "invalidating obsolete replication slot \"$slot_name\"",
+ $offset))
+ {
+ $invalidated = 1;
+ last;
+ }
+ usleep(100_000);
+ }
+ ok($invalidated,
+ "check that slot $slot_name invalidation has been logged");
+}
+
+done_testing();
--
2.34.1
