[rabbitmq-discuss] Pika from master branch - All messages arrive in 1 shot

Wed Sep 21 10:43:14 BST 2011

Hi everyone,

When I'm running the demo_receive / demo_send example with pika from the
master branch (pre0.9.6 i think), I'm getting a strange behaviour.

It seems that demo_send sends its 10 messages before demo_receive actually
receive everything in one shot. It results in a tcp backpressure problem.

In pika 0.9.5 example, demo_receive consumes a message 1 by 1, as it
arrives, and acks it, this is what I expect.

Here's the output from both scripts (I added a 0.5sec sleep after sending a
message to see what's happening) :

demo_receive:
> demo_receive: Connected to RabbitMQ
> demo_receive: Received our Channel
> demo_receive: Queue Declared
> Basic.Deliver text/plain delivery-tag 1: Hello World #0:
> 1316597081.62437701
> Basic.Deliver text/plain delivery-tag 2: Hello World #1:
> 1316597082.62570310
> Basic.Deliver text/plain delivery-tag 3: Hello World #2:
> 1316597083.62713790
> Basic.Deliver text/plain delivery-tag 4: Hello World #3:
> 1316597084.62860394
> Basic.Deliver text/plain delivery-tag 5: Hello World #4:
> 1316597085.63100100
> Basic.Deliver text/plain delivery-tag 6: Hello World #5:
> 1316597086.63265109
> Basic.Deliver text/plain delivery-tag 7: Hello World #6:
> 1316597087.63385701
> Basic.Deliver text/plain delivery-tag 8: Hello World #7:
> 1316597088.63560796
> Basic.Deliver text/plain delivery-tag 9: Hello World #8:
> 1316597089.63728094
> Basic.Deliver text/plain delivery-tag 10: Hello World #9:
> 1316597090.63895893

>

demo_send:
> INFO:pika:Connecting to 127.0.0.1:5672
> demo_send: Connected to RabbitMQ
> demo_send: Received our Channel
> demo_send: Queue Declared
> demo_send: Sent Hello World #0: 1316597081.62437701
> demo_send: Sent Hello World #1: 1316597082.62570310
> demo_send: Sent Hello World #2: 1316597083.62713790
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 500 bytes and an estimated 10 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #3: 1316597084.62860394
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 521 bytes and an estimated 11 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 582 bytes and an estimated 12 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 625 bytes and an estimated 13 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #4: 1316597085.63100100
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 646 bytes and an estimated 14 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 707 bytes and an estimated 15 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 750 bytes and an estimated 16 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #5: 1316597086.63265109
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 771 bytes and an estimated 17 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 832 bytes and an estimated 18 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 875 bytes and an estimated 19 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #6: 1316597087.63385701
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 896 bytes and an estimated 20 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 957 bytes and an estimated 21 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1000 bytes and an estimated 22 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #7: 1316597088.63560796
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1021 bytes and an estimated 23 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1082 bytes and an estimated 24 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1125 bytes and an estimated 25 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #8: 1316597089.63728094
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1146 bytes and an estimated 26 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1207 bytes and an estimated 27 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1250 bytes and an estimated 28 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> demo_send: Sent Hello World #9: 1316597090.63895893
> demo_send: Closing
> INFO:pika:Closing connection: 200 - Normal shutdown
> ../pika/connection.py:756: UserWarning: Pika: Write buffer exceeded warning
> threshold at 1284 bytes and an estimated 29 frames behind
>   warn(message % (self.outbound_buffer.size, est_frames_behind))
> INFO:pika:Disconnected from RabbitMQ at 127.0.0.1:5672

My question is :  why all 10 messages arrive in one shot ?
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