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help / color / mirror / Atom feedFrom: Nathan Bossart <nathan@postgresql.org>
Subject: [PATCH v4 2/2] Bump transaction ID limit to warn at 100M.
Date: Fri, 12 Dec 2025 13:10:05 -0600
---
doc/src/sgml/maintenance.sgml | 8 ++++----
src/backend/access/transam/multixact.c | 6 +++---
src/backend/access/transam/varsup.c | 6 +++---
3 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index f146e14d3d6..75c22405a09 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -670,11 +670,11 @@ 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
-DETAIL: Approximately 1.86% of transaction IDs are available for use.
+WARNING: database "mydb" must be vacuumed within 99985967 transactions
+DETAIL: Approximately 4.66% of transaction IDs are available for use.
HINT: To avoid XID assignment failures, execute a database-wide VACUUM in that database.
</programlisting>
@@ -853,7 +853,7 @@ 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 9f5f8e692b8..978ade705e7 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -2092,16 +2092,16 @@ 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 2921148ceba..1441a051773 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;
--
2.50.1 (Apple Git-155)
--qmnHGfI3v6dYD6Bi--
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Cc: nathan@postgresql.org
Subject: Re: [PATCH v4 2/2] Bump transaction ID limit to warn at 100M.
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