Memory use: large amounts of memory used for Env content in CallEnv implementations about groovy-cps

[svanoort]

Sample heap histogram from one particular user:

1: 3225619 1883930096 [B
2: 13087693 1414354160 [C
3: 26803765 1286580720 java.util.HashMap
4: 2553146 612125480 [I
5: 5234200 428849536 [Ljava.util.HashMap$Node;
6: 6397241 326882112 [Ljava.lang.Object;
7: 7396770 236696640 java.util.HashMap$Node
8: 8773568 210565632 java.lang.String
9: 8227045 197449080 com.cloudbees.groovy.cps.impl.BlockScopeEnv
10: 1307970 192596624 [S
11: 4113772 164550880 com.cloudbees.groovy.cps.impl.FunctionCallEnv

Now, obviously it's hard to tell exactly what's doing what, but since each BlockScopeEnv and FunctionCallEnv has 2 HashMaps (types and locals), that adds up to: 24681634 HashMaps out of 26803765.

Yes, those two classes hold 92% of all of 'em.

[svanoort]

7396770 236696640 java.util.HashMap$Node means... uh, those maps are largely empty 😢

Yes, that's an average of 1 actual map entry for roughly every 4 maps.

[svanoort]

Resolved by released fix.