franz1981 commented on a change in pull request #2730: ARTEMIS-2399 Fix
performance degradation when there are a lot of subscribers
URL: https://github.com/apache/activemq-artemis/pull/2730#discussion_r296809409
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File path:
artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/cursor/impl/PageCursorProviderImpl.java
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@@ -74,6 +75,8 @@
private final SoftValueLongObjectHashMap<PageCache> softCache;
+ private final LongObjectHashMap<PageCache> indexCacheMap;
Review comment:
@clebertsuconic They have implemented a specialized `PageCache` that just
hold the offset into the page file to read the data (kafka does something
similar), not the "full fat" `PageCache` we are used to reference with Soft
references, but I agree with Clebert that it has some GC costs (both due to the
TreeMap and the Integer usage).
I think this could improved by using something primitive or (even better) by
storing the offset in the page file in some paged message reference instead,
wdyt?
https://github.com/apache/activemq-artemis/blob/79465f7f88e32ca477655bb3f7fc6d261511ebae/artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/Page.java#L284
on
```java
message.setFileOffset((int)file.size());
file.writeDirect(buffer, false);
```
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