Flaky MemtableSizeTest

Error Message

Expected heap usage close to 50.085MiB, got 41.294MiB.

Stacktrace

junit.framework.AssertionFailedError: Expected heap usage close to 50.085MiB, got 41.294MiB.

	at org.apache.cassandra.cql3.MemtableSizeTest.testSize(MemtableSizeTest.java:121)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

Standard Output

INFO  [main] 2021-05-18 22:08:42,837 YamlConfigurationLoader.java:93 - Configuration location: file:////home/cassandra/cassandra/build/test/cassandra.compressed.yaml
DEBUG [main] 2021-05-18 22:08:42,840 YamlConfigurationLoader.java:112 - Loading settings from file:////home/cassandra/cassandra/build/test/cassandra.compressed.yaml
DEBUG [main] 2021-05-18 22:08:42,934 InternalLoggerFactory.java:63 - Using SLF4J as the default logging framework
DEBUG [main] 2021-05-18 22:08:42,956 PlatformDependent0
...[truncated 86028 chars]...
hed transaction log, deleting /home/cassandra/cassandra/build/test/cassandra/data/system_schema/keyspaces-abac5682dea631c5b535b3d6cffd0fb6/nb_txn_flush_a3253f00-b825-11eb-b0ec-cd4f0218a6b5.log 
DEBUG [MemtableFlushWriter:2] 2021-05-18 22:08:55,552 ColumnFamilyStore.java:1197 - Flushed to [BigTableReader(path='/home/cassandra/cassandra/build/test/cassandra/data/system_schema/keyspaces-abac5682dea631c5b535b3d6cffd0fb6/nb-6-big-Data.db')] (1 sstables, 4.894KiB), biggest 4.894KiB, smallest 4.894KiB