poorbarcode commented on code in PR #20935:
URL: https://github.com/apache/pulsar/pull/20935#discussion_r1289518684
##########
managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedCursorImpl.java:
##########
@@ -2151,7 +2151,13 @@ public void operationFailed(ManagedLedgerException
exception) {
mdEntry.triggerFailed(exception);
}
- });
+ };
+
+ if (State.NoLedger.equals(STATE_UPDATER.get(this))) {
+ persistPositionMetaStore(mdEntry, cb);
Review Comment:
> If the BookKeeper cluster runs into read-only mode and millions of
consumers keep acknowledging the mark-delete position to brokers, we will
persist the mark-delete position to the meta store without any throttle policy,
will it bring high pressure or risk for the meta store? especially when we use
Zookeeper as the Pulsar cluster's meta store service.
Some users may want to set BK to read-only, and stop sending messages but
consume messages.
However, pulsar does not support this yet, because even if only the message
is consumed, there is still some BK write operations, here are some examples:
- If a transaction is used when consuming a message, a transaction log is
also written
- Compaction tasks are still written to BK
- Topic policies depend on BK write
- https://github.com/apache/pulsar/issues/16691
- https://github.com/apache/pulsar/issues/16763
- https://github.com/apache/pulsar/issues/16042
- ... and so on
If we want to support the above scenario "Make BK read-only and only consume
messages", we should need a large design.
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