Cardano API memory leak/growth example programs

This repository contains two example programs that demonstrate that Cardano API is leaking memory when interacting via the client2node protocol with a (local) Cardano node .

As example-interaction and to keep things comparable, both programs query the mempool capacity and log it to the console. Both programs do this within a forever loop, however there are subtle differences in both implementations, which in the Leaky case lead to an ever-growing memory size of the application; where the NonLeaky case does not and tops out at a moderate memory allocation.

Requirements to build and run the examples:

• GHC 9.2.5
• Cabal 3.6+
• A socket to some running cardano node

Specs of the machine that was used to test it:

• CPU: 12th Gen Intel® Core™ i9-12900K × 24
• Memory: 32.0 GiB DDR5
• OS: Ubuntu 22.04

Leaky

This application uses the Cardano API function queryTxMonitoringLocal to query the information from the mempool. Usage: cardano run -- cardano-api-leaky NETWORK_ID SOCKET_PATH

NonLeaky

This appliation is using the local node client protocol that is also used by Cardano API, to do the same as the Leaky abstraction however with the essential difference that it does call connectToLocalNode only once and then re-uses the localTxMonitoringClient to make calls.

Usage: cardano run -- cardano-api-nonleaky NETWORK_ID SOCKET_PATH

Memory/Performance Analysis

• Leaky: the application memory grows unbounded reaching 680MiB after 10 minutes (application was terminated manually then) according to Ubuntu 22.04 System Monitor.

• NonLeaky: the application memory consumption tops out at ~131MiB on local machine according to the Ubuntu 22.04 System Monitor.

When running Leaky with profiling: True and "-with-rtsopts=-N -T -s -i1.0 -hc -l-agu -p" then we get the following memory consumptions via eventlog2html: TODO: this was not able to run because when compiling with profiling on then the folloing ghc panic happened:

[41 of 52] Compiling Ouroboros.Consensus.Shelley.Node.TPraos ( src/shelley/Ouroboros/Consensus/Shelley/Node/TPraos.hs, dist/build/Ouroboros/Consensus/Shelley/Node/TPraos.p_o )
ghc: panic! (the 'impossible' happened)
  (GHC version 9.2.5:
        expectOnly: cgLit:Rubbish