I'm using logstash 2.3.2(jdbc input/elasticsearch output) and elasticsearch 2.3.3 from CentOS7.
process status:
Name: java
State: S (sleeping)
Tgid: 4486
Ngid: 0
Pid: 4486
PPid: 4485
TracerPid: 0
Uid: 1000 1000 1000 1000
Gid: 1000 1000 1000 1000
FDSize: 256
Groups: 10 1000
VmPeak: 7406444 kB
VmSize: 7305992 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 697632 kB
VmRSS: 697632 kB
VmData: 7094780 kB
VmStk: 136 kB
VmExe: 4 kB
VmLib: 22752 kB
VmPTE: 2032 kB
VmSwap: 0 kB
Threads: 35
SigQ: 1/256556
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000001000
SigCgt: 2000000181004ccf
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 0000001fffffffff
Seccomp: 0
Cpus_allowed: fff
Cpus_allowed_list: 0-11
Mems_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001
Mems_allowed_list: 0
voluntary_ctxt_switches: 26
nonvoluntary_ctxt_switches: 5
my logstash log:
{:timestamp=>"2016-12-05T13:34:36.911000+0900", :message=>"closing output delegator", :klass=>LogStash::Outputs::Elasticsearch, :level=>:debug, :file=>"logstash/output_delegator.rb", :line=>"137", :method=>"do_close"}
{:timestamp=>"2016-12-05T13:34:36.911000+0900", :message=>"closing", :plugin=><LogStash::Outputs::Elasticsearch hosts=>["localhost:29200"], index=>"sz_20161205133401", document_type=>"%{type}", document_id=>"%{cs_sn}", routing=>"%{hb_sn}", parent=>"%{cs_sn}", codec=><LogStash::Codecs::Plain charset=>"UTF-8">, workers=>1, manage_template=>true, template_name=>"logstash", template_overwrite=>false, flush_size=>500, idle_flush_time=>1, doc_as_upsert=>false, max_retries=>3, script_type=>"inline", script_var_name=>"event", scripted_upsert=>false, retry_max_interval=>2, retry_max_items=>500, retry_on_conflict=>1, action=>"index", path=>"/", ssl_certificate_verification=>true, sniffing=>false, sniffing_delay=>5>, :level=>:debug, :file=>"logstash/plugin.rb", :line=>"35", :method=>"do_close"}
{:timestamp=>"2016-12-05T13:34:37.512000+0900", :message=>"Flushing buffer at interval", :instance=>"#<LogStash::Outputs::Elasticsearch::Buffer:0x22da17b4 @stopping=#Concurrent::AtomicBoolean:0x1c4a3c4c, @last_flush=2016-12-05 13:34:36 +0900, @flush_thread=#<Thread:0x1ecc9c39 run>, @max_size=500, @operations_lock=#Java::JavaUtilConcurrentLocks::ReentrantLock:0x5b71b74, @submit_proc=#Proc:0x11519466@/home/admin/logstash-2.3.2/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:57, @flush_interval=1, @logger=#<Cabin::Channel:0xeb56a28 @subscriber_lock=#Mutex:0x284c6fa3, @data={}, @metrics=#<Cabin::Metrics:0x32354b00 @channel=#<Cabin::Channel:0xeb56a28 ...>, @metrics={}, @metrics_lock=#Mutex:0xfc44c98>, @subscribers={12378=>#<Cabin::Subscriber:0x5a49781d @options={}, @output=#<Cabin::Outputs::IO:0x65edf5a0 @lock=#Mutex:0x69990fa7, @io=#<File:logstash_sz_start.out>>>}, @level=:debug>, @buffer=, @operations_mutex=#Mutex:0x3a6696fb>", :interval=>1, :level=>:debug, :file=>"logstash/outputs/elasticsearch/buffer.rb", :line=>"90", :method=>"interval_flush"}
{:timestamp=>"2016-12-05T13:34:37.512000+0900", :message=>"Flushing buffer at interval", :instance=>"#<LogStash::Outputs::Elasticsearch::Buffer:0x22da17b4 @stopping=#Concurrent::AtomicBoolean:0x1c4a3c4c, @last_flush=2016-12-05 13:34:36 +0900, @flush_thread=#<Thread:0x1ecc9c39 run>, @max_size=500, @operations_lock=#Java::JavaUtilConcurrentLocks::ReentrantLock:0x5b71b74, @submit_proc=#Proc:0x11519466@/home/admin/logstash-2.3.2/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:57, @flush_interval=1, @logger=#<Cabin::Channel:0xeb56a28 @subscriber_lock=#Mutex:0x284c6fa3, @data={}, @metrics=#<Cabin::Metrics:0x32354b00 @channel=#<Cabin::Channel:0xeb56a28 ...>, @metrics={}, @metrics_lock=#Mutex:0xfc44c98>, @subscribers={12378=>#<Cabin::Subscriber:0x5a49781d @options={}, @output=#<Cabin::Outputs::IO:0x65edf5a0 @lock=#Mutex:0x69990fa7, @io=#<File:logstash_sz_start.out>>>}, @level=:debug>, @buffer=, @operations_mutex=#Mutex:0x3a6696fb>", :interval=>1, :level=>:debug, :file=>"logstash/outputs/elasticsearch/buffer.rb", :line=>"90", :method=>"interval_flush"}
...
I wanna know why logstash is sleeping.