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

[yubiao]

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


The following commit(s) were added to refs/heads/master by this push:
     new cc7b3816ce1 [fix] [ml] incorrect non-durable cursor's backlog due to 
concurrently trimming ledger and non-durable cursor creation (#23951)
cc7b3816ce1 is described below

commit cc7b3816ce14a2ddff18dbf04216769fdb8751db
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>
---
 .../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 f9a0ff26208..7426059e576 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
@@ -1152,16 +1152,17 @@ public class ManagedLedgerImpl implements 
ManagedLedger, CreateCallback {
             return cachedCursor;
         }
 
-        NonDurableCursorImpl cursor = new NonDurableCursorImpl(bookKeeper, 
this, cursorName,
-                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,
+                    startCursorPosition, initialPosition, isReadCompacted);
+            cursor.setActive();
+            log.info("[{}] Opened new cursor: {}", name, cursor);
             addCursor(cursor);
+            return cursor;
         }
-
-        return cursor;
     }
 
     @Override