As the OpenLink MT and ST drivers are middleware software, it is
important to note that its performance can be influenced by the
Client and Server configurations in use. This means, lack of system
memory, kernel configurations, disk space, sql queries, coding
techniques, un-indexed tables, network can all play a major part in
the performance of the driver. Notwithstanding, we have outlined
below ways in which you can increase the performance of the
- Use OpenLink Single-Tier drivers where possible.
- It is always recommended that, OpenLink's latest drivers are
used where possible as these contain patches that might alleviate
any performance bottlenecks you are facing. Only use OpenLink 4.2
drivers where we do not have a driver available. If you request
this driver, please contact a Product Support consultant who will
liaise with your Account Manager.
- Establish 3-Tier Multi-Tier connections when Single-Tier
connectivity is not possible.
- Establish shared memory connections to databases that provide
sockets and shared memory alternatives.
- Check your DSN's "Defer fetching of long data" check box, when
your result-sets contain binary data.
- Locate the Row Buffer Size box that appears on your DSN setup
dialog. Set this value to 1. Test. Next, set Row Buffer Size to 99.
Test. Do you see a difference? If the first test is faster, your
performance problems may stem from the makeup of your result-sets.
If the second test is faster, your performance problems may stem
from network latency. This awareness will help you set your Row
Buffer Size in a manner that is beneficial to your situation.
- Test a variety of client and server cursor modalities. Choose
the modality that suits your application needs and provides the
- If you are using the Multi-Tier Drivers, you can also increase
the Send & Receive sizes. These might have an adverse effect on
the network if you increase it sharply. Please consult your Product
Support consultant if you want more information on this. If you
increase this value, please ensure the Client (Send size) matches
the Server (Receive size) and vice versa. Typically, this value is
only increase when sending data from the Server to the client
- If using the Multi-Tier drivers, please ensure your Reuse Rule
is set in a manner that is appropriate for your system. If you
anticipate long and complex queries, it is recommended that you do
not reuse the agent. Alternatively, if you are in an environment
that utilizes short, sharp bursts at the system, it might be
conducive if you share agents, this means less system processes and
resources will be instantiated on your system.
- In OpenLink 5.x Multi-Tier, we have introduced the Linger
Timeout. This creates a Connection Pooling environment on the
server when handling connections. This means dormant connections
can be reused.