RE: SAPDB performance?

I too experience that problem. Any query hitting the same tables at the same
time will cause a performance lag, sometimes very significant lag. For
instance, if 1 user sends a vague search query that will return a
significant listing that query will block out another user that sends a
prikey search that returns a single record.

These queries should not hinder each other in any way when connecting in
dirty_read mode. Please keep me informed if you get any information that
helps your performance.

Kevin

-----Original Message-----
From: José Rómulo Elías Contreras [mailto:romulo@xxxxxxxxxxxxxxxxxxxx]
Sent: Thursday, February 17, 2005 9:11 AM
To: maxdb@xxxxxxxxxxxxxxx
Subject: SAPDB performance?


Hello:

I test the performance of SAPDB in two tomcat servers connecting to the 
same database. Each tomcat server open 10 
sessions with the next parameters:

DriverManager.getConnection(databaseUrl + databaseName + "?user=" + 
databaseUser + "&password=" + databasePassword + "&timeout=0&isolation=" 
+ java.sql.Connection.TRANSACTION_READ_UNCOMMITTED);

   I open 4 differents browser sessions connected 2 to each tomcat 
server. If I request the same information in each different browser 
session at the same time the performance go down. The first session 
connected to tomcatServer1 takes 9 seconds to execute the query, the 
second session connected to tomcatServer1 takes 12 seconds to execute 
the query, the third session connected to tomcatServer2 takes 14 seconds 
to execute the query and the fourth session connected to tomcatServer2 
takes 16 seconds to execute the query aproximately. If I open only one 
browser session to execute the query, then the query takes only 3 seconds.

   I measured the time before calling the execute method of the 
statement, and afterwards:

   // Before execute statement save time (time1)
   ResultSet rs = statement.executeQuery( sql );
   // After execute statement save time (time2)
   // differenceTime = time2 - time1

Why does the performance go down?
How can I correct it?


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