On 12/7/2010 11:34 AM, Tom Polak wrote:
We are in the process of deciding on how to proceed on a database upgrade. We currently have MS SQL 2000 running on Windows 2003 (on my test server). I was shocked at the cost for MS SQL 2008 R2 for a new server (2 CPU license). I started comparing DB’s and came across postgresql. It seemed to be exactly what I was after. All of our programming is in ASP.net. Since I am running MSSQL 2000 I have no benefit for .Net integration, so it is not a concern. I ran a head to head test of MS SQL 2000 and Postgresql 9.0. Both are running on Windows 2003. What I found was quite surprising and I am wondering if anyone can point out what is going on here. Here is the test I ran. I created 2 tables, the main table had 5 fields with a serial ID field. The second table linked to table 1 for a state field. I had ASP.net via MSSQL create 1,000 records in the main table. Took 9.85 seconds to complete. Next I had ASP.net via Postgresql create 1,000 records. Took .65625 seconds. Postgresql smoked MS SQL server on that test.
did you play with the postgresql.conf file? Maybe turn off fsync? I'd guess the above is mssql is flushing to disk while PG isnt.
Next test is to use ASP.net and join all 1,000 rows with table 2 and then display the text out. MS SQL took 0.76 seconds to display select name,address,city,state,statename,stateid,other from pgtemp1 left join pgtemp2 on state=stateid Then I did the same test via Postgresql and it took 8.85 seconds! I tried it again as I thought I did something wrong. I did a few tweaks such as increasing the shared buffers. Still the best I could get it to was 7.5 seconds. This is insanely slow compared to MSSQL 2000. What am I missing. Here is my SQL statement for postgresql: select name,address,city,state,statename,stateid,other from pgtemp1 left join pgtemp2 on state=stateid Any ideas on why the Postgres server is soooo much slower on the joins? I am trying to understand what is going on here so please don’t flame me. Any advice is appreciated.
Did you create an index? That'd be my first guess. Also, can you run the sql from the command line client (psql) and see if it takes that long? While your in psql, stick a 'explain analyze' infront of your query, and let's see its output.
Also, as a fair warning: mssql doesn't really care about transactions, but PG really does. Make sure all your code is properly starting and commiting transactions.
-Andy -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
