Re: executeQuery and busy waiting

It's about as simple a JDBC program as you can get. Source included
below, minus company info ofcourse.

public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
Class.forName("org.postgresql.Driver");
conn = DriverManager.getConnection("jdbc:postgresql://server_ip/db_name", "user", "password");
stmt = conn.createStatement();
rs = stmt.executeQuery("select myFunction(2)");
if(rs.next()){
System.out.println("Function Execution Successfull.");
}
} catch (Exception e){
e.printStackTrace();
} finally {
try{ rs.close(); } catch (Exception e){}
try{ stmt.close(); } catch (Exception e){}
try{ conn.close(); } catch (Exception e){}
}
}

Garick Dasbach

On Fri, 2003-06-27 at 13:53, Dave Cramer wrote:
> Garrick,
>
> It would help if you posted a small program to replicate the problem.
>
> Dave
> On Fri, 2003-06-27 at 14:44, Garrick Dasbach wrote:
> > I'm working on a project with Postgresql and I'm running into a strange
> > problem.
> >
> > I have a Java Program running on the Database server that periodicly
> > connects to the Database and runs a pl/pgsql function. This function
> > should run fairly fast, but could take several minutes based on the load
> > of the server and amount of information it needs to process.
> >
> > Running the function from psql takes 40 seconds under no load and
> > minimal data, but when I run the function from java using JDBC it takes
> > 20-30 minutes.
> >
> > Checking top, this is a Linux system, I see that the java program takes
> > up 99% of the CPU when it's running this function through executeQuery.
> > Is executeQuery() doing a busy wait for the data from postgres? It
> > seems a bit absurd that the executeQuery method would hijack 99% of the
> > CPU waiting for results and slowing everything else on the system down.
> >
> > The second problem I am noticing is that if I move the java program to
> > another machine, to keep java from stealing all the CPU cycles, the
> > function still takes 20-30 minutes to run through java, but only takes
> > 40 seconds to run through psql. What's the deal?
> >
> > Any help would be appreciated.
> >
> > Garrick Dasbach
> >
> > Software Developer
> > MusicRebellion.com, Inc.
> > Garrick(at)musicrebellion(dot)com
> >
> >
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> >
> --
> Dave Cramer <Dave(at)micro-automation(dot)net>
>
>
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