This was an intersting Win32/linux comparison. I expected Linux to scale better, but I was surprised how poorly XP scaled. It reinforces our perception that Win32 is for low traffic servers. --------------------------------------------------------------------------- Merlin Moncure wrote: > Following is the promised writeup in performance related issues > comparing win32 with linux x86 and linux x86-64. Unfortunately, the 64 > bit portion of the test is not yet completed and won't be for a bit. > However there are some telling things about the win32/linux comparison. > If you are considering deploying postgres in a win32 environment read > on... > > First a description of the client app: > Our company develops an ERP/CRM written in cobol which we are porting to > run on PostgreSQL. Part of this porting effort was development of an > ISAM 'driver' for our app to allow it to store/fetch data from the > database in place of a traditional file system, which is complete. > > For those of you unfamiliar with COBOL/ISAM, applications written with > it have a 'one record at a time' mentality, such the application tends > to spam the server with queries of the select * from t where k = k1 > variety. Our driver creates stored procedures as necessary and uses > ExecParams wherever possible to cut down on server CPU time, which is a > precious resource in our case. Over time we plan to gradually redeploy > our application logic to make better use of the sql server's server side > power. Our application is very rarely i/o bound because we will make > sure our server has enough memory so that the data will be rarely, if > ever, *not* run from the cache. > > A good benchmark of our application performance is the time it takes to > read the entire bill of materials for a product. This is a recursive > read of about 2500 records in the typical case (2408 in the test case). > > Test platform: > Pentium 4 3.06 GHz/HT > 10k SATA Raptor > 1Gb memory > Windows XP Pro SP2/Redhat Fedora 3 (64 bit results coming soon) > > BOM traversal for product ***** (1 user): > win32: runtime: 3.34 sec avg cpu load: 60% > redhat: runtime: 3.46 sec avg cpu load: 20% > > Well, win32 wins this test. There is some variability in the results > meaning for a single user scenario there is basically no difference > between win32 and linux in execution time. However the cpu load is much > lower for linux which spells problems for win32 with multiple users: > > BOM traversal for product ***** (6 users): > win32: runtime (each): 7.29 sec avg cpu load: 100% > redhat: runtime (each): 4.56 sec avg cpu load: 90% > > Here, the win32 problems with cpu load start to manifest. The cpu meter > stays pegged at 100% while the redhat hand around 90%. The difference > in times is telling. > > The third and final test is what I call the query 'surprise' factor, IOW > surprise! your query takes forever! The test involves a combination of > the previous test with a query with a couple of joins that returns about > 15k records. On both redhat/win32, the query takes about .35 seconds to > execute on a unloaded server...remember that figure. > > > > Item List generation while 6 clients generating BOM for multiple > products: > Redhat: 2.5 seconds > Win32: 155 seconds (!) > > Here the win32 server is showing real problems. Also, the query > execution time is really variable, in some cases not returning until the > 6 workhorse processes completed their tasks. The linux server by > contrast ran slower but never ran over 4 seconds after multiple runs. > > Also, on the purely subjective side, the linux server 'feels' faster and > considerably more responsive under load, even under much higher load. > > Comments/Suggestions? > > Merlin > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@xxxxxxxxxxxxxx > -- Bruce Momjian | http://candle.pha.pa.us pgman@xxxxxxxxxxxxxxxx | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
