MaxFetchBuffer
database parameter
Description
Sets the maximum size of the buffer into which theDataWindow
object can fetch rows from the database. Using the MaxFetchBuffer
parameter with the Block parameter can improve performance when
accessing a database in PowerBuilder.
Applies to
O90 Oracle9i
O10 Oracle 10g
ORA Oracle (for 11g and later)
Syntax
|
1 |
MaxFetchBuffer=buffersize |
|
Parameter |
Description |
|---|---|
|
buffersize |
The number of bytes the fetch buffer can |
Default value
5000000 (bytes)
Using the default buffer size
You should not have to set a non-default value for
MaxFetchBuffer. In most cases, the default buffer size should meet
your needs.
Usage
You can use the MaxFetchBuffer database parameter in conjunction
with the Block database parameter to improve performance when the size
of a row is very large.
The size of the actual fetch buffer is the product of the value of
the blocking factor and the size of the row. If the fetch buffer
required by the blocking factor and the row size is greater than the
value of MaxFetchBuffer, the value of the blocking factor is adjusted so
that the buffer is not exceeded.
For example, if block=500 and the row size is 10KB, the fetch
buffer is 5000KB, which equals the default maximum buffer size.
You can set Block and MaxFetchBuffer dynamically in code after
connecting to the database. MaxFetchBuffer cannot be set in the Database
Profile Setup dialog box.
Examples
The following example sets the maximum fetch buffer size to 6000KB
and the blocking factor to 500:
|
1 |
SQLCA.DBParm = "MaxFetchBuffer=6000000,block=500" |
See also