**980+ threads** were blocked at OgnlRuntime.invokeMethod with the state BLOCKED (on object monitor), waiting to lock java.lang.reflect.Method objects.

[fanzhongwei]

About the Bug...

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of MyBatis.

• I have confirmed this bug reproduces without 3rd party extensions (e.g. mybatis-plus).

Database Version

OceanBase

JDBC Driver Version

oceanbase-client-2.4.11

Issue Description

Fix: Reduce thread blocking by double null check instead of synchronizing on Method object #521

We observed severe thread blocking issues in production: 980+ threads were blocked at OgnlRuntime.invokeMethod with the state BLOCKED (on object monitor), waiting to lock java.lang.reflect.Method objects.

# 980 threads blocked
"default-17571" #91915 prio=5 os_prio=0 tid=0x00007f7b7c05d800 nid=0x167f9 waiting for monitor entry [0x00007f757f772000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at org.apache.ibatis.ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:1151)
	- waiting to lock <0x00000004a55aaf48> (a java.lang.reflect.Method)
	at org.apache.ibatis.ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:2146)
	at org.apache.ibatis.ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:66)
	at org.apache.ibatis.ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:160)
	at org.apache.ibatis.ognl.OgnlRuntime.getProperty(OgnlRuntime.java:3356)
	...

# got method lock thread
"HSFBizProcessor-DEFAULT-6-thread-5179" #90650 daemon prio=10 os_prio=0 tid=0x00007f794c319000 nid=0x16214 waiting for monitor entry [0x00007f758366e000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at org.apache.ibatis.ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:1151)
	- locked <0x00000004a55aaf48> (a java.lang.reflect.Method)
	at org.apache.ibatis.ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:2146)
	at org.apache.ibatis.ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:66)
	at org.apache.ibatis.ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:160)
	at org.apache.ibatis.ognl.OgnlRuntime.getProperty(OgnlRuntime.java:3356)
	...

Root cause:

• Direct synchronization on Method objects leads to heavy thread contention — all threads competing to execute method access checks must wait for the same Method monitor, which severely degrades system concurrency and performance.

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[harawata]

Hello @fanzhongwei ,

Thank you for the report.
I didn't look into the source ONGL issue, but the problem should be fixed in the latest 3.5.0-SNAPSHOT (via #3590).
Could you verify the fix on your end?

Thank you!