Re: [Postgres-xc-developers] A question on DBT1 performance

[Koichi S. <ko...@in...>]

Hi,

I compared your result with ours and I found your environment consumes
more system CPU (in our case, with 90% workload, system CPU is around 18
to 19%) and also your result idle % (14% and 17%) is a bit higher than
your case.   In our case, user CPU is around 70%, system around 19% and
the idle around was 10% (we put a workload so that 90% of the server CPU
resource is used).  We can reduce the idle to a few % by charging much
more workload.

Idle time shows you've not put a transaction workload to fully use
coordinator/datanode CPUs.

Please take a look at loader's situation (number of transactions per
sec, etc).  I suppose there could be another thing to put DBT-1
transactions equally to all the coordinators.

Kind Regards;
-----------
Koichi Suzuki

(2010年11月25日 14:25), xiong wang wrote:
> Dears,
> I am really appreciated your response.
> 
> Here is the basic information about my test.
> My configure on DBT1 as follows:
> [appServer]
> #dbconnection-connection from 1 dbdriver to 1 backend, with 4 loaders, 
> each of the 5 coords receives 40 connections
> 10
> #transaction_queue_size
> 1500
> #transaction_array_size
> 1500
> 
> [dbdriver]
> #items
> 1000
> #customers
> 28800
> #eu
> 1500
> #eu/min
> 1000
> #mean think_time
> 0.1
> #run_duration in seconds
> 1200
> #access mode access with access_direct or access_appServer
> access_appServer
> #access clean of order table with access_clean if cleanup, by default 
> disactivated if let empty
> access_clean
> The results by sar as follows:
> Method1:
> 
> *coordinator/datanode 1:*
> 
> CPU %user %nice %system %iowait %steal %idle
> 
> Average: all 58.90 0.00 23.61 0.81 0.00 16.69**
> 
> *coordinator/datanode 2:*
> 
> CPU %user %nice %system %iowait %steal %idle
> 
> Average: all 64.19 0.00 28.67 0.55 0.00 6.58
> 
> Method2:
> 
> *coordinator/datanode 1:*
> 
> CPU %user %nice %system %iowait %steal %idle
> 
> Average: all 59.35 0.00 25.39 0.47 0.00 14.79
> 
> *coordinator/datanode 2:*
> 
> CPU %user %nice %system %iowait %steal %idle
> 
> Average: all 57.71 0.00 24.56 0.55 0.00 17.18
> 
> The average results by DBT1 as follows:
> 
> Method1:
> 
> *loader 1:*
> 
> 1356.6 bogotransactions per second**
> 
> *loader 2:*
> 
> 1843.7 bogotransactions per second
> 
> Method2:
> 
> *loader 1:*
> 
> 757.4 bogotransactions per second**
> 
> *loader 2:*
> 
> 779.3 bogotransactions per second
> 
> It's obvious that there is a big difference between Method1 and Method2. 
> I am courious about why.
> 
> Thanks again.
> 
> Regards,
> 
> Benny
> 
> 
> 2010/11/24 Koichi Suzuki <ko...@in... 
> <mailto:ko...@in...>>
> 
>     Hi, Xiong;
> 
>     Could you tell me CPU and I/O usage you can measure by sar? I'm
>     afraid load balance is not good in Method 2. How many backend did
>     you use in each coordinator? Did you have any warning that
>     connection overflew in data nodes? 
> 
>     Also, how long warm-up did you have?
> 
>     I'll let you know our configuration (sorry please let me have a bit).
> 
>     Regards;
>     ---
>     Koichi Suzuki
> 
> 
>     (2010年11月24日 14:40), xiong wang wrote:
> 
>         Hi Mason,
>         I tested it by 5 PCs.
>         The enviroment as follows:
>         2 PCs, one datanode and one coordinator together on each of them,
>         GTM is on another PC,
>         2 Loaders are on other 2 PCs.
>         Network 1G.
>         I tested Postgres-XC in two methods as follows:
>         Method 1.
>         loader -------- coordinator & datanode
>         \
>         GTM
>         /
>         loader -------- coordinator & datanode
>         Method 2.
>         loader-------- coordinator & datanode
>         \ / \
>         \ / \
>         /\ GTM
>         / \ /
>         / \ /
>         loader -------- coordinator & datanode
>         The DBT1 test results in these two methods are very different.
>         Method 1
>         is much better than Method 2. I don't know why.
>         If I test Postgres-XC in Method 1, the DBT1 performance is close
>         to what
>         the document declares. If I test it in Method 2, the result is much
>         worse than what the document writes. Could you tell me why the two
>         methods have so much effect on the DBT1 performace.
>         Thanks,
>         Regards,
>         Benny
>          >How much worse?
>          >How many physical servers are in each configuration? How is
>         each server
>          >configured in each, with how many data nodes? What kind of
>         network?
>          >Gigabit?
>          >Or was everything on one system? With virtual machines or
>         without and
>          >just using different ports?
>          >Are there errors in the log file (connection limits hit)?
>          >Regards,
>          >Mason
> 
> 
> 
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