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From Chien Le <Chien...@ds-iq.com>
Subject RE: Bolt slow down the emit speed of spout
Date Tue, 18 Oct 2016 21:38:28 GMT
dstat -d is measuring your disk throughput, yes? Did you mean dstat -n?

Otherwise, dstat -d showing 300MB/s doesn't eliminate disk as your bottleneck. I would try
using iostat -x 1 and see what your %util and svc times are to truly eliminate disk as the
bottleneck.

-Chien

From: Chen Junfeng [mailto:k-2feng@hotmail.com]
Sent: Monday, October 17, 2016 11:30 PM
To: user@storm.apache.org
Subject: Bolt slow down the emit speed of spout


I found a tough but interesting issue about Storm 1.0.2 to share with you.
Firstly I introduce my system structure. My topology has 471 workers, 6 kafka topic and some
processor bolt. Backpressure has been disabled in topology by

conf.put(Config.TOPOLOGY_BACKPRESSURE_ENABLE, false);

If I submit KafkaSpout only, the statistic data from Storm UI is as below:
Topology stats

Window

Emitted

Transferred

Complete latency (ms)

Acked

Failed

10m 0s

875161429

0

0

875141691

3h 0m 0s

927117120

0

0

927117320

1d 0h 0m 0s

927117120

0

0

927117320

All time

927117120

0

0

927117320

Spouts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Complete latency (ms)

Acked

Failed

Spout_JSCTGW_144

2

2

128701261

0

0

128702858

0

Spout_JSCTGW_145

2

2

162347454

0

0

162347639

0

Spout_JSCTGW_146

2

2

135598494

0

0

135598608

0

Spout_JSCTGW_147

2

2

128307822

0

0

128306102

0

Spout_JSCTGW_148

2

2

160369513

0

0

160360423

0

Spout_JSCTGW_149

2

2

159836885

0

0

159826061

0



In 10 minutes time, 6 kafkaSpout read more than 800 million tuple from kafka cluster.
Then I submit the topology with a simple PrintBolt, the 10min stat data is as following:
Spouts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Complete latency (ms)

Acked

Failed

Error Host

Error Port

Spout_JSCTGW_144

2

2

113599789

113599789

0

113513630

0

Spout_JSCTGW_145

2

2

122501522

122501575

0

122659659

0

Spout_JSCTGW_146

2

2

91308915

91308915

0

91308652

0

Spout_JSCTGW_147

2

2

105029568

105029568

0

104968275

0

Spout_JSCTGW_148

2

2

115889172

115889178

0

115890165

0

Spout_JSCTGW_149

2

2

115185591

115185591

0

115185638

0

Showing 1 to 6 of 6 entries

663526019

Bolts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Capacity (last 10m)

Execute latency (ms)

Executed

Process latency (ms)

Acked

PrintBolt

240

240

0

0

0.241

0.041

665063824

0

665,036,902


The printbolt contains nothing but a simple log.info method, but the total number of emitted
tuple of spout decrease to about 600 million. All of machines have 32 cores but the system
average load never exceed 15. Also I have checked the network load. My network adapter has
10Gb bandwidth and the dstat -d command shows the max rec or send speed is 300MB/s at most
, which doesn’t reach the limit of network adapter. The total number of executors is less
than that of total workers, so performance should not be problem.

Then I do some more test,
Only one kafkaspout reading on topic

Spouts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Complete latency (ms)

Acked

Failed

Spout_JSCTGW_145

2

2

148918096

0

0

148917805

0


One kafkaspout and one data processing bolt

Spouts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Complete latency (ms)

Acked

Failed

Spout_JSCTGW_145

2

2

106481751

106481751

0

106367801

0

Showing 1 to 1 of 1 entries

Bolts (10m 0s)

Search:

Id

Executors

Tasks

Emitted

Transferred

Capacity (last 10m)

Execute latency (ms)

Executed

AtomPluginBolt

1000

1000

132752203

0

0.019

0.067

106519630



Even I only read one kafka topic, the emit speed is also slowed down.

Does anyone meet the same problem?

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