Hello, I'm running spark in local mode and seeing multiple threads showing like below, anybody knows why it's not using a concurrent hash map ?
--- "request-handler-dispatcher-19785" #107532 prio=5 os_prio=0 tid=0x00007fbd78036000 nid=0x4ebf runnable [0x00007fc6e83af000] java.lang.Thread.State: RUNNABLE at java.util.Collections$SynchronizedMap.get(Collections.java:2586) - locked <0x00007fc901c7d9f8> (a java.util.Collections$SynchronizedMap) at org.apache.spark.sql.internal.SQLConf.getConf(SQLConf.scala:3750) at org.apache.spark.sql.internal.SQLConf.constraintPropagationEnabled(SQLConf.scala:3346) "Executor task launch worker for task 23.0 in stage 279783.0 (TID 449746)" #107929 daemon prio=5 os_prio=0 tid=0x00007fbe2c005000 nid=0x55f6 waiting for monitor entry [0x00007fc6e4037000] java.lang.Thread.State: BLOCKED (on object monitor) at java.util.Collections$SynchronizedMap.get(Collections.java:2586) - waiting to lock <0x00007fc901c7d9f8> (a java.util.Collections$SynchronizedMap) at org.apache.spark.sql.internal.SQLConf.getConf(SQLConf.scala:3750) at org.apache.spark.sql.internal.SQLConf.methodSplitThreshold(SQLConf.scala:3330) "Executor task launch worker for task 16.0 in stage 279883.0 (TID 449728)" #107690 daemon prio=5 os_prio=0 tid=0x00007fbc60056800 nid=0x53c6 waiting for monitor entry [0x00007fc65a3a8000] java.lang.Thread.State: BLOCKED (on object monitor) at java.util.Collections$SynchronizedMap.get(Collections.java:2586) - waiting to lock <0x00007fc901c7d9f8> (a java.util.Collections$SynchronizedMap) at org.apache.spark.sql.internal.SQLConf.getConf(SQLConf.scala:3750) at org.apache.spark.sql.internal.SQLConf.planChangeLogLevel(SQLConf.scala:3160) at org.apache.spark.sql.catalyst.rules.PlanChangeLogger.<init>(RuleExecutor.scala:49) --- -- Kohki Nishio
