dbexpoda.dll slow via VPN LAN2LAN

medalex · Post by **medalex** » Fri 09 Mar 2012 10:12

Hi,

we have a problem with application written in Delphi 7 which using dbexpoda.dll and TSQLConnection (old version of 2003 year) to connect to Oracle 9 database. Application request-response time is much slower via LAN2LAN. If application is used in the local network where is the database the speed is ok. Could it be connected with the driver verion or it is the network settings problem?

Thank you in advance.
Alexandr

AlexP · Post by **AlexP** » Mon 12 Mar 2012 12:41

Hello,

Please specify the mode you use for connection to the server - Direct or OCI.
Speed loss is possible at VPN connection when working with large amounts of BLOB data, therefore, if you work with such data, you should read them on the client only if necessary.
Since you use very old version of our driver, try downloading the latest version and check the performance on it when working with VPN.

medalex · Post by **medalex** » Mon 12 Mar 2012 13:10

Thank you for the answer.

Where can I see the connection type? We do not use much BLOB in our application so I do not think they are the reason of the problem. I have these connection parameters
BlobSize=-1
DataBase=10.11.5.6:1521:devel
DriverName=Oracle Net (Core Lab)
ErrorResourceFile=
LocaleCode=0000
Password=
Oracle TransIsolation=ReadCommited
User_Name=
RoleName=Normal
LongStrings=True
EnableBCD=True

InternalName=
UseQuoteChar=False
FetchAll=False
CharLength=0
Charset=

I will try to install new version and try.

Thank you in advance.

AlexP · Post by **AlexP** » Mon 12 Mar 2012 15:03

Hello,

You are using the Direct (Net) mode that doesn't require Oracle Client presence. Try to check perfomane using the OCI mode.

DataBase= Database_name // from the tnsnames.ora file
DriverName=Oracle (Core Lab)

medalex · Post by **medalex** » Mon 26 Mar 2012 07:05

Thank you for the answer. I will try that.
I have one more question. Is it possible to set packet's size used in communication between application and Oracle database? For example application sends 300 requests to database and Wireshark shows that 12000 packets were sent during this process. Is it possible to reduce the number of sent packets by increasing their size in dbExpress or it could be only set in the network settings out of the dbExpress?

Thank you in advance.

AlexP · Post by **AlexP** » Mon 26 Mar 2012 07:58

Hello,

You cannot change packages size directly when working with our driver, however, if you have dbExpress Driver for Oracle Edition with Source Code, you can rebuild the driver specifying the need packagws size. There are two global variables in the OraNet module - SDU and TDU - with values 2048 and 32767 respectively on default. Guidelines on changing these values can be found in the Oracle documentation. The values of these variables must be set before connection, therefore we cannot create options for setting these variables as driver parameters in Delphi versions earlier than Delphi 2007

medalex · Post by **medalex** » Mon 26 Mar 2012 08:45

Hello,

Thank you very much for the answer. If I set the package's size in driver's source code does I need to change some OS or/and Oracle database settings?

AlexP · Post by **AlexP** » Mon 26 Mar 2012 10:18

Hello,

You don't need to make changes on the server side and OS when changing these parameters in our driver. Changing of these parameters in the driver for Direct mode is similar to assigning these values in the sqlnet.ora or tnsnames.ora files for OCI mode.