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[#1010319] Concurrency problems

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Date:
2008-03-16 17:05
Priority:
3
State:
Open
Submitted by:
Nicolas Cornu (ncornu)
Assigned to:
Nobody (None)
Npgsql Version:
2.0
Category:
Group:
Resolution:
None
Summary:
Concurrency problems

Detailed description
I made a small version of my webiste. only one page that call the datalayer library. I did not get errors on windows (IIS/.NET Framework) or with XSP2 1.9 (Mono). I installed this website on my linux server (Centos 5) and did some test. was not getting errors.

I did a stress test with apache benchmark and i get errors with concurrency:

------------------------------------------------
ab2 -c 2 -n 10 -t 120 http://forums.syndica.fr/Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7

This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/

Benchmarking forums.syndica.fr (be patient)
Finished 61 requests


Server Software: Apache/2.2.3
Server Hostname: forums.syndica.fr
Server Port: 80

Document Path: /Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7
Document Length: 6568 bytes

Concurrency Level: 2
Time taken for tests: 120.29281 seconds
Complete requests: 61
Failed requests: 53
(Connect: 0, Length: 53, Exceptions: 0)
Write errors: 0
Non-2xx responses: 24
Total transferred: 490400 bytes
HTML transferred: 474072 bytes
Requests per second: 0.51 [#/sec] (mean)
Time per request: 3935.386 [ms] (mean)
Time per request: 1967.693 [ms] (mean, across all concurrent requests)
Transfer rate: 3.98 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.5 0 4
Processing: 76 3768 3314.6 2459 16562
Waiting: 75 3767 3314.5 2458 16561
Total: 76 3768 3314.6 2459 16562

Percentage of the requests served within a certain time (ms)
50% 2422
66% 4467
75% 6367
80% 6753
90% 7988
95% 9798
98% 11604
99% 16562
100% 16562 (longest request)
------------------------------------------------

I have less errors without concurrency:
------------------------------------------------
ab2 -n 10 -t 120 http://forums.syndica.fr/Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7

This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/

Benchmarking forums.syndica.fr (be patient)
Finished 28 requests


Server Software: Apache/2.2.3
Server Hostname: forums.syndica.fr
Server Port: 80

Document Path: /Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7
Document Length: 8632 bytes

Concurrency Level: 1
Time taken for tests: 124.961307 seconds
Complete requests: 28
Failed requests: 2
(Connect: 0, Length: 2, Exceptions: 0)
Write errors: 0
Non-2xx responses: 2
Total transferred: 245603 bytes
HTML transferred: 238141 bytes
Requests per second: 0.22 [#/sec] (mean)
Time per request: 4462.904 [ms] (mean)
Time per request: 4462.904 [ms] (mean, across all concurrent requests)
Transfer rate: 1.91 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.0 0 0
Processing: 165 4215 4064.5 2139 16958
Waiting: 164 4214 4064.6 2138 16958
Total: 165 4215 4064.5 2139 16958

Percentage of the requests served within a certain time (ms)
50% 2139
66% 3885
75% 6656
80% 6854
90% 11818
95% 12339
98% 16958
99% 16958
100% 16958 (longest request)
***************************************
ab2 -n 10 -t 120 http://forums.syndica.fr/Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/

Benchmarking forums.syndica.fr (be patient)
Finished 33 requests


Server Software: Apache/2.2.3
Server Hostname: forums.syndica.fr
Server Port: 80

Document Path: /Default.aspx?articleid=7c6084e755c272f47b0874feae13aeb7
Document Length: 8632 bytes

Concurrency Level: 1
Time taken for tests: 126.286629 seconds
Complete requests: 33
Failed requests: 0
Write errors: 0
Total transferred: 294752 bytes
HTML transferred: 286048 bytes
Requests per second: 0.26 [#/sec] (mean)
Time per request: 3826.868 [ms] (mean)
Time per request: 3826.868 [ms] (mean, across all concurrent requests)
Transfer rate: 2.27 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.0 0 0
Processing: 1548 3599 2701.5 1708 11580
Waiting: 1547 3598 2701.5 1707 11579
Total: 1548 3599 2701.5 1708 11580

Percentage of the requests served within a certain time (ms)
50% 1702
66% 4408
75% 6617
80% 6624
90% 6654
95% 6929
98% 11580
99% 11580
100% 11580 (longest request)
-------------------------------------------------

I will attach the example website.

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Attached Files:

Attachments:
postgres-test.rar

Changes:

Field Old Value Date By
File Added325: postgres-test.rar2008-03-16 17:05ncornu
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