How can you optimize a test plan for lower memory use in a soak test?

Remove or disable memory-heavy listeners entirely from the test plan used for the actual soak run, especially View Results Tree, since these accumulate stored sample data over time and a long-duration soak test is exactly the scenario where that accumulation compounds into a serious memory problem rather than staying small.

Configure result-file writers to save only the specific fields actually needed for later analysis, rather than the full default set including response data, since storing complete response bodies for every sample across a many-hour soak test can produce enormous result files and proportional memory pressure while writing them.

Watch for unbounded variable growth in scripted elements (JSR223 Pre/Post-Processors) - a script that appends to a shared list or map without ever clearing it across thousands of iterations over a long soak test will leak memory within the JMeter process itself, independent of anything happening on the system under test.

Periodically restart long-running remote engines if a soak test is expected to run for many hours or days, since even a well-optimized test plan can accumulate some JVM-level memory fragmentation over very long uptimes, and a planned restart between test phases can be cheaper than troubleshooting a slow memory creep hours into an already-long run.

Increase the JVM heap allocated to JMeter appropriately for the expected sample volume, but treat this as a complement to the above practices, not a substitute for them, since a larger heap alone doesn't fix an actual memory leak in the test plan itself - it just delays when that leak becomes visible as an out-of-memory failure.