(pulsar) branch branch-3.3 updated: [fix] [ml] incorrect non-durable cursor's backlog due to concurrently trimming ledger and non-durable cursor creation (#23951)

[yubiao]

This is an automated email from the ASF dual-hosted git repository.

yubiao pushed a commit to branch branch-3.3
in repository https://gitbox.apache.org/repos/asf/pulsar.git


The following commit(s) were added to refs/heads/branch-3.3 by this push:
     new 3ef5a860a35 [fix] [ml] incorrect non-durable cursor's backlog due to 
concurrently trimming ledger and non-durable cursor creation (#23951)
3ef5a860a35 is described below

commit 3ef5a860a350f748b639c204420cd1f7480b1a10
Author: fengyubiao <yubiao.f...@streamnative.io>
AuthorDate: Tue Feb 11 11:03:39 2025 +0800

    [fix] [ml] incorrect non-durable cursor's backlog due to concurrently 
trimming ledger and non-durable cursor creation (#23951)
    
    Co-authored-by: Yunze Xu <xyzinfern...@163.com>
    (cherry picked from commit cc7b3816ce14a2ddff18dbf04216769fdb8751db)
---
 .../apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git 
a/managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java
 
b/managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java
index 6cfc5ec46ab..517af781ad3 100644
--- 
a/managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java
+++ 
b/managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java
@@ -1135,16 +1135,17 @@ public class ManagedLedgerImpl implements 
ManagedLedger, CreateCallback {
             return cachedCursor;
         }
 
-        NonDurableCursorImpl cursor = new NonDurableCursorImpl(bookKeeper, 
this, cursorName,
-                (PositionImpl) startCursorPosition, initialPosition, 
isReadCompacted);
-        cursor.setActive();
-
-        log.info("[{}] Opened new cursor: {}", name, cursor);
+        // The backlog of a non-durable cursor could be incorrect if the 
cursor is created before `internalTrimLedgers`
+        // and added to the managed ledger after `internalTrimLedgers`.
+        // For more details, see https://github.com/apache/pulsar/pull/23951.
         synchronized (this) {
+            NonDurableCursorImpl cursor = new NonDurableCursorImpl(bookKeeper, 
this, cursorName,
+                    (PositionImpl) startCursorPosition, initialPosition, 
isReadCompacted);
+            cursor.setActive();
+            log.info("[{}] Opened new cursor: {}", name, cursor);
             addCursor(cursor);
+            return cursor;
         }
-
-        return cursor;
     }
 
     @Override