错误报告：
这两天跑一个程序的时候，有好几次程序就直接hang住了，刚才打了strace如下：
Thread 100 (Thread 0x7f3503906700 (LWP 10985)):
#0 0x0000003d8e2e14f3 in select () from /lib64/libc.so.6
#1 0x000000000045e8bf in _ossSocket::recv(char*, int, int&, int, int, int) ()
#2 0x0000000000435b57 in sdbclient::_sdbImpl::_recv(char**, int*) ()
#3 0x0000000000435e78 in sdbclient::_sdbImpl::_recvExtract(char**, int*, long long&, int&) ()
#4 0x000000000043f063 in sdbclient::_sdbCollectionImpl::query(sdbclient::_sdbCursor**, bson::BSONObj const&, bson::BSONObj const&, bson::BSONObj const&, bson::BSONObj const&, long long, long long, int) ()
#5 0x0000000000426f2b in sdbclient::sdbCollection::query(sdbclient::sdbCursor&, bson::BSONObj const&, bson::BSONObj const&, bson::BSONObj const&, bson::BSONObj const&, long long, long long, int) ()
#6 0x000000000041fa9e in UgcSdb::_increaseId(sdbclient::sdbCollectionSpace&, int) ()
