Github user franz1981 commented on the issue:
https://github.com/apache/activemq-artemis/pull/2478
@gaohoward The synchronized block will block any threads attempting to both
getting and creating a paging store, while a chm::get is lock-free ie won't
block any threads and chm::computeIfAbsent is locked on per-segment basis (that
means that depends on the number of segments and how the hashing of the keys
will distribute the entries into the segment.
Putting a synchronized like this will prevent any threads to do anything on
an hot-path, blocking each others: my advice is to keep chm::get lock-free (as
it is now) and into `newStore(storeName)` use chm::computeIfAbsent to avoid
duplicates creatings of `PagingStore` instances.
This should keep the scalability as it is now without allocating
unnecessary instances. wdyt?
---
