No response from the backend

Hi
There are some questions when using progreSQL8.4.2. I don't sure this problem is bug.The detail is following:
I make a client program that communicate with progreSQL by ODBC on Windows7. After running serveral months, this client program is hung at 00:01 in 2011-11-26 , and become OK after 8 hours.When becoming OK, client program log message is following:

2011/11/26 08:38:05.527, : SQL ERROR: GetSelectRowNum: No response from the backend;
No response from the backend
2011/11/26 08:38:05.527, : SQL ERROR: GetSelectRowNum: State:42601,Native:26
2011/11/26 08:38:05.527, : SQL ERROR: GetSelectRowNum: Could not send Query(connection dead);
Could not send Query(connection dead)

I don't know how to solve this problem. Someone can explain this problem cause.Thanks

2011-12-07

feng.zhou