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.
Controls
-
O90 Oracle9i
-
O10 Oracle 10g
-
ORA Oracle 11g
Syntax
|
1 |
MaxFetchBuffer=<span>buffersize</span> |
|
Parameter |
Description |
|---|---|
|
buffersize |
The number of bytes the fetch buffer |
Default
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
Block (ODBC, OLE DB, Oracle,
and SNC)