jvarenina commented on a change in pull request #7145:
URL: https://github.com/apache/geode/pull/7145#discussion_r760941193
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File path: geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java
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@@ -5942,6 +5943,8 @@ void cleanupAfterCompaction(boolean compactFailed) {
if (!compactFailed) {
// all data has been copied forward to new oplog so no live entries
remain
getTotalLiveCount().set(0);
+ // No need for regionMap as there are no more live entries and .crf will
be deleted
+ regionMap.set(new ConcurrentHashMap<>());
Review comment:
@upthewaterspout thank you for the review!
What you are proposing was actually our first solution to this problem and
that we later changed to this current one. When instantiated, the regionMap
HashMap will be created with initial capacity of 16. This is really small value
and it doesn't add a lot to the heap memory. The problem is that this HashMap
can grow a lot from it's initial size during lifetime of the Oplog. It could
contain hundreds or even more then thousand of elements. In order to consume
that many elements the HashMap have to be rehashed to the bigger capacity. The
problem is that new (bigger) capacity remain even after we clear the regionMap
HashMap, and even it is empty, it is consuming not negligible amount of memory.
We now know that it is possible for server to collect a lot of orphaned .drf
files during the lifetime, and that difference between initial capacity of 16
and 1024 is huge in terms of memory consumption. So this is why we decided to
use atomic reference and just reinitialize regionMap with new object of initial
size 16.
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