thetumbled opened a new pull request, #23582:
URL: https://github.com/apache/pulsar/pull/23582
### Motivation
**Delayed message feature** need to retain the message id and timestamp info
in the memory. Delayed message queue need to retain such info in broker side,
**Negative ack feature** need to retain such info in the consumer client side,
both of these two cases could lead to great memory consumption.
This PR aim to replace the `HashMap` with the inner map implementation
`ConcurrentLongLongPairHashMap` to reduce the memory consumption. Though
`HashMap` is faster than the inner map implementation
`ConcurrentLongLongPairHashMap` in some cases, but the most important issue in
this case is memory consumption instead of the speed.
Some test data list as follows:
```
public static void main(String[] args) throws IOException {
ConcurrentLongLongPairHashMap map1 =
ConcurrentLongLongPairHashMap.newBuilder()
.autoShrink(true)
.concurrencyLevel(16)
.build();
HashMap<MessageId, Long> map2 = new HashMap<>();
long numMessages = 5000000;
long ledgerId, entryId, partitionIndex, timestamp;
for (long i = 0; i < numMessages; i++) {
ledgerId = 10000+i;
entryId = i;
partitionIndex = 0;
timestamp = System.currentTimeMillis();
map1.put(ledgerId, entryId, partitionIndex, timestamp);
map2.put(new MessageIdImpl(ledgerId, entryId,
(int)partitionIndex), timestamp);
}
System.out.println("map1 size: " + map1.size());
System.out.println("map2 size: " + map2.size());
try {
Thread.sleep(10000000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
```
- 100w entry
HashMap：178Mb
ConcurrentLongLongPairHashMap：64Mb
- 500w entry
HashMap：566Mb
ConcurrentLongLongPairHashMap：256Mb
- 1000w entry
HashMap：1132MB
**Approximately each entry consume 1132MB/10000000=118byte.**
ConcurrentLongLongPairHashMap：512MB
**Approximately each entry consume 512MB/10000000=53byte.**
With this improvement, we can reduce 50% of the memory consumption!
### Modifications
Replace `HashMap` with `ConcurrentLongLongPairHashMap` in Negative Ack
Tracker.
### Verifying this change
- [ ] Make sure that the change passes the CI checks.
*(Please pick either of the following options)*
This change is already covered by existing tests, such as *(please describe
tests)*.
### Does this pull request potentially affect one of the following parts:
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*If the box was checked, please highlight the changes*
- [ ] Dependencies (add or upgrade a dependency)
- [ ] The public API
- [ ] The schema
- [ ] The default values of configurations
- [ ] The threading model
- [ ] The binary protocol
- [ ] The REST endpoints
- [ ] The admin CLI options
- [ ] The metrics
- [ ] Anything that affects deployment
### Documentation
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- [ ] `doc` <!-- Your PR contains doc changes. -->
- [ ] `doc-required` <!-- Your PR changes impact docs and you will update
later -->
- [ ] `doc-not-needed` <!-- Your PR changes do not impact docs -->
- [ ] `doc-complete` <!-- Docs have been already added -->
### Matching PR in forked repository
PR in forked repository:
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