我们的Redis服务器在高负载下表现异常。调用Time（）命令时，它偶尔会返回一个空结果（不是Exception，只是空结果）。
这是服务器或网络过载时的预期行为吗？
修改：信息
# Server
redis_version:2.8.9
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:61e31fc3ea5bf6c
redis_mode:standalone
os:Linux 3.5.0-49-generic x86_64
arch_bits:64
multiplexing_api:epoll
gcc_version:4.6.3
process_id:31347
run_id:be2da8cf9660eebd9c70149e0eb6c6e75f424eb2
tcp_port:6379
uptime_in_seconds:7774141
uptime_in_days:89
hz:10
lru_clock:5927592
config_file:/etc/redis/6379.conf
# Clients
connected_clients:2471
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:64
# Memory
used_memory:3162944192
used_memory_human:2.95G
used_memory_rss:3483242496
used_memory_peak:16284341712
used_memory_peak_human:15.17G
used_memory_lua:797696
mem_fragmentation_ratio:1.10
mem_allocator:jemalloc-3.2.0
# Persistence
loading:0
rdb_changes_since_last_save:812647
rdb_bgsave_in_progress:0
rdb_last_save_time:1415213438
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:22
rdb_current_bgsave_time_sec:-1
aof_enabled:0
aof_rewrite_in_progress:0
aof_rewrite_scheduled:0
aof_last_rewrite_time_sec:-1
aof_current_rewrite_time_sec:-1
aof_last_bgrewrite_status:ok
aof_last_write_status:ok
# Stats
total_connections_received:84090665
total_commands_processed:15961550471
instantaneous_ops_per_sec:2032
rejected_connections:0
sync_full:0
sync_partial_ok:0
sync_partial_err:0
expired_keys:37013331
evicted_keys:0
keyspace_hits:3680528922
keyspace_misses:91889146
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:49438
# Replication
role:master
connected_slaves:0
master_repl_offset:0
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:0
repl_backlog_histlen:0
# CPU
used_cpu_sys:61983.57
used_cpu_user:925632.81
used_cpu_sys_children:9471.61
used_cpu_user_children:104999.56
# Keyspace
db0:keys=502,expires=187,avg_ttl=30590
db1:keys=47290,expires=0,avg_ttl=0