On Fri, Dec 12, 2025 at 10:59:53AM +0800, Chao Li wrote:
> I just reviewed the patch. My comments are mainly in 0001, and a few nits
> on 0003. For 0002, the code change is quite straightforward, I am not
> sure the value bumping to has been discussed.
Thanks!
> Where "(MaxTransactionId >> 1)” has the same value as PG_INT32_MAX. But
> if one day xid is changed to 64 bits, that code doesn’t need to updated,
> while these patched code will need to be updated.
>
> So, can we define a const in transom.h like:
> ```
> #define MaxTransactionId ((TransactionId) 0xFFFFFFFF)
> #define WrapAroundWindow (MaxTransactionId>>1)
> ```
>
> And use WrapAroundWindow in all places.
I think I'd rather just open-code the (MaxTransactionId / 2) here. I'm not
too concerned about 64-bit transaction IDs (there's a lot more than this to
change for that), but it does seem like a good idea to be consistent with
nearby code.
> ```
> + errdetail("Approximately
> %.2f%% of MultiXactIds are available for use.",
> ```
>
> “%.2f%%” shows only 2 digits after dot. xidWrapLimit is roughly 2B, when
> remaining goes down to 107374, it will shows “0.00%”. IMO, when remaining
> is a large number, percentage makes more sense, while an exact number is
> clearer when the number is relatively small. So, can we show both
> percentage and exact number? Or shows the exact number when percentage is
> 0.00%?
The errmsg part should already show the exact number of IDs remaining.
> ```
> + xidLogLimit = xidWrapLimit - 500000000;
> ```
>
> Instead of hardcode 500M, do we want to consider
> autovacuum_freeze_max_age? If a deployment sets autovacuum_freeze_max_age
> > 500M, then vacuum would be triggered first, then this log can get kinda
> non-intuitive. But if a vacuum cannot freeze anything tuple, then this
> log will still make sense. I am not sure. Maybe not a real problem.
IMHO we should still emit warnings about imminent wraparound even if
autovacuum_freeze_max_age is set to totally-inadvisable values. I think
the behavior you are describing only happens if users set it to north of
1.6B.
--
nathan
>From c1cb82c3fe80978c668ecc7c57654f62610e0e07 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <[email protected]>
Date: Fri, 14 Nov 2025 09:59:15 -0600
Subject: [PATCH v3 1/3] Add percentage of transaction IDs that are available
to wraparound warnings.
---
doc/src/sgml/maintenance.sgml | 1 +
src/backend/access/transam/multixact.c | 8 ++++++++
src/backend/access/transam/varsup.c | 8 ++++++++
3 files changed, 17 insertions(+)
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 08e6489afb8..257c6a5435d 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -674,6 +674,7 @@ SELECT datname, age(datfrozenxid) FROM pg_database;
<programlisting>
WARNING: database "mydb" must be vacuumed within 39985967 transactions
+DETAIL: Approximately 1.86% of transaction IDs are available for use.
HINT: To avoid XID assignment failures, execute a database-wide VACUUM in
that database.
</programlisting>
diff --git a/src/backend/access/transam/multixact.c
b/src/backend/access/transam/multixact.c
index f4fab7edfee..39e5b691573 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1017,6 +1017,8 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
multiWrapLimit - result,
oldest_datname,
multiWrapLimit - result),
+ errdetail("Approximately
%.2f%% of MultiXactIds are available for use.",
+ (double)
(multiWrapLimit - result) / (MaxMultiXactId / 2) * 100),
errhint("Execute a
database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
else
@@ -1026,6 +1028,8 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
multiWrapLimit - result,
oldest_datoid,
multiWrapLimit - result),
+ errdetail("Approximately
%.2f%% of MultiXactIds are available for use.",
+ (double)
(multiWrapLimit - result) / (MaxMultiXactId / 2) * 100),
errhint("Execute a
database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
}
@@ -2134,6 +2138,8 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
multiWrapLimit - curMulti,
oldest_datname,
multiWrapLimit - curMulti),
+ errdetail("Approximately %.2f%% of
MultiXactIds are available for use.",
+ (double)
(multiWrapLimit - curMulti) / (MaxMultiXactId / 2) * 100),
errhint("To avoid MultiXactId
assignment failures, execute a database-wide VACUUM in that database.\n"
"You might also need
to commit or roll back old prepared transactions, or drop stale replication
slots.")));
else
@@ -2143,6 +2149,8 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
multiWrapLimit - curMulti,
oldest_datoid,
multiWrapLimit - curMulti),
+ errdetail("Approximately %.2f%% of
MultiXactIds are available for use.",
+ (double)
(multiWrapLimit - curMulti) / (MaxMultiXactId / 2) * 100),
errhint("To avoid MultiXactId
assignment failures, execute a database-wide VACUUM in that database.\n"
"You might also need
to commit or roll back old prepared transactions, or drop stale replication
slots.")));
}
diff --git a/src/backend/access/transam/varsup.c
b/src/backend/access/transam/varsup.c
index f8c4dada7c9..32961b9acab 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -175,6 +175,8 @@ GetNewTransactionId(bool isSubXact)
(errmsg("database \"%s\" must
be vacuumed within %u transactions",
oldest_datname,
xidWrapLimit -
xid),
+ errdetail("Approximately
%.2f%% of transaction IDs are available for use.",
+ (double)
(xidWrapLimit - xid) / (MaxTransactionId / 2) * 100),
errhint("To avoid transaction
ID assignment failures, execute a database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
else
@@ -182,6 +184,8 @@ GetNewTransactionId(bool isSubXact)
(errmsg("database with OID %u
must be vacuumed within %u transactions",
oldest_datoid,
xidWrapLimit -
xid),
+ errdetail("Approximately
%.2f%% of transaction IDs are available for use.",
+ (double)
(xidWrapLimit - xid) / (MaxTransactionId / 2) * 100),
errhint("To avoid XID
assignment failures, execute a database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
}
@@ -490,6 +494,8 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
(errmsg("database \"%s\" must be
vacuumed within %u transactions",
oldest_datname,
xidWrapLimit - curXid),
+ errdetail("Approximately %.2f%% of
transaction IDs are available for use.",
+ (double)
(xidWrapLimit - curXid) / (MaxTransactionId / 2) * 100),
errhint("To avoid XID assignment
failures, execute a database-wide VACUUM in that database.\n"
"You might also need
to commit or roll back old prepared transactions, or drop stale replication
slots.")));
else
@@ -497,6 +503,8 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
(errmsg("database with OID %u must be
vacuumed within %u transactions",
oldest_datoid,
xidWrapLimit - curXid),
+ errdetail("Approximately %.2f%% of
transaction IDs are available for use.",
+ (double)
(xidWrapLimit - curXid) / (MaxTransactionId / 2) * 100),
errhint("To avoid XID assignment
failures, execute a database-wide VACUUM in that database.\n"
"You might also need
to commit or roll back old prepared transactions, or drop stale replication
slots.")));
}
--
2.39.5 (Apple Git-154)
>From 1bbbb093e409323b4e63feac79a0e8a805ab6c37 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <[email protected]>
Date: Fri, 12 Dec 2025 13:10:05 -0600
Subject: [PATCH v3 2/3] Bump transaction ID limit to warn at 100M.
---
doc/src/sgml/maintenance.sgml | 4 ++--
src/backend/access/transam/multixact.c | 6 +++---
src/backend/access/transam/varsup.c | 6 +++---
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 257c6a5435d..3960a23ad71 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -670,7 +670,7 @@ SELECT datname, age(datfrozenxid) FROM pg_database;
<para>
If for some reason autovacuum fails to clear old XIDs from a table, the
system will begin to emit warning messages like this when the database's
- oldest XIDs reach forty million transactions from the wraparound point:
+ oldest XIDs reach one hundred million transactions from the wraparound
point:
<programlisting>
WARNING: database "mydb" must be vacuumed within 39985967 transactions
@@ -824,7 +824,7 @@ HINT: Execute a database-wide VACUUM in that database.
<para>
Similar to the XID case, if autovacuum fails to clear old MXIDs from a
table, the
- system will begin to emit warning messages when the database's oldest
MXIDs reach forty
+ system will begin to emit warning messages when the database's oldest
MXIDs reach one hundred
million transactions from the wraparound point. And, just as in the XID
case, if these
warnings are ignored, the system will refuse to generate new MXIDs once
there are fewer
than three million left until wraparound.
diff --git a/src/backend/access/transam/multixact.c
b/src/backend/access/transam/multixact.c
index 39e5b691573..27a0baab8c7 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -2040,16 +2040,16 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
multiStopLimit -= FirstMultiXactId;
/*
- * We'll start complaining loudly when we get within 40M multis of data
+ * We'll start complaining loudly when we get within 100M multis of data
* loss. This is kind of arbitrary, but if you let your gas gauge get
- * down to 2% of full, would you be looking for the next gas station?
We
+ * down to 5% of full, would you be looking for the next gas station?
We
* need to be fairly liberal about this number because there are lots of
* scenarios where most transactions are done by automatic clients that
* won't pay attention to warnings. (No, we're not gonna make this
* configurable. If you know enough to configure it, you know enough to
* not get in this kind of trouble in the first place.)
*/
- multiWarnLimit = multiWrapLimit - 40000000;
+ multiWarnLimit = multiWrapLimit - 100000000;
if (multiWarnLimit < FirstMultiXactId)
multiWarnLimit -= FirstMultiXactId;
diff --git a/src/backend/access/transam/varsup.c
b/src/backend/access/transam/varsup.c
index 32961b9acab..98aeea96e8a 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -411,16 +411,16 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
xidStopLimit -= FirstNormalTransactionId;
/*
- * We'll start complaining loudly when we get within 40M transactions of
+ * We'll start complaining loudly when we get within 100M transactions
of
* data loss. This is kind of arbitrary, but if you let your gas gauge
- * get down to 2% of full, would you be looking for the next gas
station?
+ * get down to 5% of full, would you be looking for the next gas
station?
* We need to be fairly liberal about this number because there are lots
* of scenarios where most transactions are done by automatic clients
that
* won't pay attention to warnings. (No, we're not gonna make this
* configurable. If you know enough to configure it, you know enough to
* not get in this kind of trouble in the first place.)
*/
- xidWarnLimit = xidWrapLimit - 40000000;
+ xidWarnLimit = xidWrapLimit - 100000000;
if (xidWarnLimit < FirstNormalTransactionId)
xidWarnLimit -= FirstNormalTransactionId;
--
2.39.5 (Apple Git-154)
>From 2ca1da92e081f767f756f93b3c091cdf6d084a50 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <[email protected]>
Date: Fri, 12 Dec 2025 13:13:55 -0600
Subject: [PATCH v3 3/3] Periodically emit server logs when fewer than 500M
remaining transaction IDs.
---
src/backend/access/transam/multixact.c | 40 +++++++++++++++++++++++---
src/backend/access/transam/varsup.c | 40 +++++++++++++++++++++++---
src/include/access/transam.h | 5 ++--
3 files changed, 75 insertions(+), 10 deletions(-)
diff --git a/src/backend/access/transam/multixact.c
b/src/backend/access/transam/multixact.c
index 27a0baab8c7..abd89c3a73d 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -153,6 +153,7 @@ typedef struct MultiXactStateData
/* support for anti-wraparound measures */
MultiXactId multiVacLimit;
+ MultiXactId multiLogLimit;
MultiXactId multiWarnLimit;
MultiXactId multiStopLimit;
MultiXactId multiWrapLimit;
@@ -947,6 +948,7 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
* If we're past multiVacLimit or the safe threshold for member storage
* space, or we don't know what the safe threshold for member storage
is,
* start trying to force autovacuum cycles.
+ * If we're past multiLogLimit, start issuing logs periodically.
* If we're past multiWarnLimit, start issuing warnings.
* If we're past multiStopLimit, refuse to create new MultiXactIds.
*
@@ -962,6 +964,7 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
* possibility of deadlock while doing get_database_name().
First,
* copy all the shared values we'll need in this path.
*/
+ MultiXactId multiLogLimit = MultiXactState->multiLogLimit;
MultiXactId multiWarnLimit = MultiXactState->multiWarnLimit;
MultiXactId multiStopLimit = MultiXactState->multiStopLimit;
MultiXactId multiWrapLimit = MultiXactState->multiWrapLimit;
@@ -1005,13 +1008,27 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
if (IsUnderPostmaster && ((result % 65536) == 0 || result ==
FirstMultiXactId))
SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER);
- if (!MultiXactIdPrecedes(result, multiWarnLimit))
+ if (!MultiXactIdPrecedes(result, multiWarnLimit) ||
+ (!MultiXactIdPrecedes(result, multiLogLimit) &&
+ result % 1000000 == 0))
{
char *oldest_datname =
get_database_name(oldest_datoid);
+ int elevel;
+
+ /*
+ * We only send the periodic warnings to the server log
in an
+ * attempt to avoid confusion from clients (since the
WARNING will
+ * disappear for 1M multis at a time). Once the
warning limit is
+ * reached, we emit a proper WARNING every time.
+ */
+ if (!MultiXactIdPrecedes(result, multiWarnLimit))
+ elevel = WARNING;
+ else
+ elevel = LOG_SERVER_ONLY;
/* complain even if that DB has disappeared */
if (oldest_datname)
- ereport(WARNING,
+ ereport(elevel,
(errmsg_plural("database \"%s\"
must be vacuumed before %u more MultiXactId is used",
"database \"%s\" must be vacuumed before %u more MultiXactIds are used",
multiWrapLimit - result,
@@ -1022,7 +1039,7 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
errhint("Execute a
database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
else
- ereport(WARNING,
+ ereport(elevel,
(errmsg_plural("database with
OID %u must be vacuumed before %u more MultiXactId is used",
"database with OID %u must be vacuumed before %u more MultiXactIds are used",
multiWrapLimit - result,
@@ -2015,6 +2032,7 @@ void
SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid oldest_datoid)
{
MultiXactId multiVacLimit;
+ MultiXactId multiLogLimit;
MultiXactId multiWarnLimit;
MultiXactId multiStopLimit;
MultiXactId multiWrapLimit;
@@ -2053,6 +2071,15 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
if (multiWarnLimit < FirstMultiXactId)
multiWarnLimit -= FirstMultiXactId;
+ /*
+ * We'll start complaining every 1M multis when we get within 500M
multis
+ * of data loss. The idea is to provide an early warning system that is
+ * less noisy than multiWarnLimit but provides ample time to react.
+ */
+ multiLogLimit = multiWrapLimit - 500000000;
+ if (multiLogLimit < FirstMultiXactId)
+ multiLogLimit -= FirstMultiXactId;
+
/*
* We'll start trying to force autovacuums when oldest_datminmxid gets
to
* be more than autovacuum_multixact_freeze_max_age mxids old.
@@ -2070,6 +2097,7 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
MultiXactState->oldestMultiXactId = oldest_datminmxid;
MultiXactState->oldestMultiXactDB = oldest_datoid;
MultiXactState->multiVacLimit = multiVacLimit;
+ MultiXactState->multiLogLimit = multiLogLimit;
MultiXactState->multiWarnLimit = multiWarnLimit;
MultiXactState->multiStopLimit = multiStopLimit;
MultiXactState->multiWrapLimit = multiWrapLimit;
@@ -2112,7 +2140,11 @@ SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid
oldest_datoid)
if (MultiXactIdPrecedes(multiVacLimit, curMulti) && IsUnderPostmaster)
SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER);
- /* Give an immediate warning if past the wrap warn point */
+ /*
+ * Give an immediate warning if past the wrap warn point. We don't
bother
+ * with multiLogLimit here, as it's unlikely to apply. We leave that
part
+ * to GetNewMultiXactId() instead.
+ */
if (MultiXactIdPrecedes(multiWarnLimit, curMulti))
{
char *oldest_datname;
diff --git a/src/backend/access/transam/varsup.c
b/src/backend/access/transam/varsup.c
index 98aeea96e8a..0f633cc0e14 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -112,6 +112,7 @@ GetNewTransactionId(bool isSubXact)
* catastrophic data loss due to XID wraparound. The basic rules are:
*
* If we're past xidVacLimit, start trying to force autovacuum cycles.
+ * If we're past xidLogLimit, start issuing logs periodically.
* If we're past xidWarnLimit, start issuing warnings.
* If we're past xidStopLimit, refuse to execute transactions, unless
* we are running in single-user mode (which gives an escape hatch
@@ -129,6 +130,7 @@ GetNewTransactionId(bool isSubXact)
* possibility of deadlock while doing get_database_name().
First,
* copy all the shared values we'll need in this path.
*/
+ TransactionId xidLogLimit = TransamVariables->xidLogLimit;
TransactionId xidWarnLimit = TransamVariables->xidWarnLimit;
TransactionId xidStopLimit = TransamVariables->xidStopLimit;
TransactionId xidWrapLimit = TransamVariables->xidWrapLimit;
@@ -165,13 +167,27 @@ GetNewTransactionId(bool isSubXact)
errhint("Execute a
database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
}
- else if (TransactionIdFollowsOrEquals(xid, xidWarnLimit))
+ else if (TransactionIdFollowsOrEquals(xid, xidWarnLimit) ||
+ (TransactionIdFollowsOrEquals(xid,
xidLogLimit) &&
+ xid % 1000000 == 0))
{
char *oldest_datname =
get_database_name(oldest_datoid);
+ int elevel;
+
+ /*
+ * We only send the periodic warnings to the server log
in an
+ * attempt to avoid confusion from clients (since the
WARNING will
+ * disappear for 1M transactions at a time). Once the
warning
+ * limit is reached, we emit a proper WARNING every
time.
+ */
+ if (TransactionIdFollowsOrEquals(xid, xidWarnLimit))
+ elevel = WARNING;
+ else
+ elevel = LOG_SERVER_ONLY;
/* complain even if that DB has disappeared */
if (oldest_datname)
- ereport(WARNING,
+ ereport(elevel,
(errmsg("database \"%s\" must
be vacuumed within %u transactions",
oldest_datname,
xidWrapLimit -
xid),
@@ -180,7 +196,7 @@ GetNewTransactionId(bool isSubXact)
errhint("To avoid transaction
ID assignment failures, execute a database-wide VACUUM in that database.\n"
"You might
also need to commit or roll back old prepared transactions, or drop stale
replication slots.")));
else
- ereport(WARNING,
+ ereport(elevel,
(errmsg("database with OID %u
must be vacuumed within %u transactions",
oldest_datoid,
xidWrapLimit -
xid),
@@ -376,6 +392,7 @@ void
SetTransactionIdLimit(TransactionId oldest_datfrozenxid, Oid oldest_datoid)
{
TransactionId xidVacLimit;
+ TransactionId xidLogLimit;
TransactionId xidWarnLimit;
TransactionId xidStopLimit;
TransactionId xidWrapLimit;
@@ -424,6 +441,16 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
if (xidWarnLimit < FirstNormalTransactionId)
xidWarnLimit -= FirstNormalTransactionId;
+ /*
+ * We'll start complaining every 1M transactions when we get within 500M
+ * transactions of data loss. The idea is to provide an early warning
+ * system that is less noisy than xidWarnLimit but provides ample time
to
+ * react.
+ */
+ xidLogLimit = xidWrapLimit - 500000000;
+ if (xidLogLimit < FirstNormalTransactionId)
+ xidLogLimit -= FirstNormalTransactionId;
+
/*
* We'll start trying to force autovacuums when oldest_datfrozenxid gets
* to be more than autovacuum_freeze_max_age transactions old.
@@ -447,6 +474,7 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
LWLockAcquire(XidGenLock, LW_EXCLUSIVE);
TransamVariables->oldestXid = oldest_datfrozenxid;
TransamVariables->xidVacLimit = xidVacLimit;
+ TransamVariables->xidLogLimit = xidLogLimit;
TransamVariables->xidWarnLimit = xidWarnLimit;
TransamVariables->xidStopLimit = xidStopLimit;
TransamVariables->xidWrapLimit = xidWrapLimit;
@@ -470,7 +498,11 @@ SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid)
IsUnderPostmaster && !InRecovery)
SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER);
- /* Give an immediate warning if past the wrap warn point */
+ /*
+ * Give an immediate warning if past the wrap warn point. We don't
bother
+ * with xidLogLimit here, as it's unlikely to apply. We leave that part
+ * to GetNewTransactionId() instead.
+ */
if (TransactionIdFollowsOrEquals(curXid, xidWarnLimit) && !InRecovery)
{
char *oldest_datname;
diff --git a/src/include/access/transam.h b/src/include/access/transam.h
index c9e20418275..a1bd4259f86 100644
--- a/src/include/access/transam.h
+++ b/src/include/access/transam.h
@@ -203,8 +203,8 @@ FullTransactionIdAdvance(FullTransactionId *dest)
* LWLocks.
*
* Note: xidWrapLimit and oldestXidDB are not "active" values, but are
- * used just to generate useful messages when xidWarnLimit or xidStopLimit
- * are exceeded.
+ * used just to generate useful messages when xidLogLimit, xidWarnLimit, or
+ * xidStopLimit are exceeded.
*/
typedef struct TransamVariablesData
{
@@ -221,6 +221,7 @@ typedef struct TransamVariablesData
TransactionId oldestXid; /* cluster-wide minimum datfrozenxid */
TransactionId xidVacLimit; /* start forcing autovacuums here */
+ TransactionId xidLogLimit; /* start logging periodically here */
TransactionId xidWarnLimit; /* start complaining here */
TransactionId xidStopLimit; /* refuse to advance nextXid beyond here */
TransactionId xidWrapLimit; /* where the world ends */
--
2.39.5 (Apple Git-154)
