Error in OverFlow Mode

[FLOW4215]

When I was using benchmark to test iotdb,I found an error in overflow mode.
I used almost same 'config.properties' files in two tests.
Just set
1st : "IS_OVERFLOW=false";
2nd : "IS_OVERFLOW=true",
then I got an error when benchmark working on overflow mode:

In the same config with no overflow :

Plesae help us to check this issue.Thanks
B.R

[liuruiyiyang]

Fixed in PR #93