When MultiNodeQueryHandler send multiple sql statements to mysql, if the middle part failed to execute, frontend session will hang

[tankilo]

• dble version：
• preconditions ：
  no
• configs：

schema.xml

<table name="xa_test" dataNode="dn1,dn2" rule="sharding-by-mod2" primaryKey="ID"/>

rule.xml

<tableRule name="sharding-by-mod2">
       <rule>
           <columns>id</columns>
           <algorithm>hashmod2</algorithm>
       </rule>
</tableRule>
<function name="hashmod2" class="Hash">
       <property name="partitionCount">2</property>
       <property name="partitionLength">1</property>
</function>

server.xml

• steps：
  step1. edit com.actiontech.dble.backend.mysql.nio.MySQLConnection#synAndDoExecuteMultiNode
  
  add following code

xaCmd = xaCmd.replace("'", "\\'");
xaCmd = "MOCK ERROR '" + xaCmd + "'";

step2. execute sql

set xa = 1;
delete from xa_test;

• expect result：

  1. sql execution returns the exepcted syntax error response

• real result：

  1. cmd hang!!!
     

• supplements：
  1.

/label ~BUG

[tankilo]

[tankilo]

In the above, i repalce xa start with syntax error and get wrong result, this is because mysql mix the third sql and the fourth sql. So there was only three response.

But when i replace xa start with [delete nonexistent table], the above problem did happen again, session still hang.

And in QQ group, someone has already asked the same question.

[PanternBao]

So the problem is known, we are going to find a good way to fix it.

[tankilo]

So the problem is known, we are going to find a good way to fix it.

I have searched through issues yesterday and didn't find any related information. You should record problem in time next time.

[PanternBao]

OK, thx for issue and pr. The problem is also related to #1176.