Description

akarnokd

opened on Oct 2, 2025

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⚠️ Due to the unexpectedly long time this issue was up, we require you to target 4.x first and we'll see if it is worth backporting it to an earlier version.

The current implementations of the various cache and replay operators and hot sources can hold onto effectively unreachable elements longer than necessary, causing GC pressure with certain collectors.

The following operators need to be checked and updated.

• ObservableCache
• FlowableCache
• ObservableReplay
• FlowableReplay
• ReplaySubject
• ReplayProcessor

Activity

1. akarnokd

   added this to the 3.1-support milestone on Oct 2, 2025
2. akarnokd

   added

   Enhancement

   3.x

   on Oct 2, 2025
3. akarnokd commented on Oct 2, 2025

   

   akarnokd

   on Oct 2, 2025

   MemberAuthor

   More actions

   ObservableCache - #7911
4. akarnokd

   added

   4.x

   on Mar 18, 2026
5. akarnokd

   added the

   Task

   issue type on Mar 19, 2026
6. DragonFSKY commented on Jul 27, 2026

   

   DragonFSKY

   on Jul 27, 2026

   Contributor

   More actions

   I'd like to work on the FlowableCache item in #7912, using the ownership split from ObservableCache #7911 while preserving Flowable's per-subscriber request, cancellation, and serialized replay semantics. I'll add the same focused MemoryMXBean/System.gc regression test. Please let me know if someone is already working on this item.

   Reacted by David Karnok
7. akarnokd commented on Jul 27, 2026

   

   akarnokd

   on Jul 27, 2026

   MemberAuthor

   More actions

   No one is working on these currently so go ahead 👍
8. akarnokd

   removed

   3.x

   on Jul 27, 2026
9. akarnokd

   changed the title [-]Cache/Replay operators to be more GC friendly[/-] [+]4.x: Cache/Replay operators to be more GC friendly[/+] on Jul 27, 2026
10. akarnokd

    added a commit that references this issue on Oct 5, 2026

    Release cancelled replay consumers from their buffers (#8317)

    452b30c

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