Specifying lightweight I/O for smart large objects
To specify the use of lightweight I/O when creating the sbspace, use the BUFFERING tag of the -Df option in the onspaces -c -S command.
The default value for BUFFERING is ON, which means
to use the buffer pool. The buffering mode that you specify (or the
default, if you do not specify) in the onspaces command is
the default buffering mode for all smart large objects stored within
the sbspace.
Important: In general,
if read and write operations to the smart large objects are less than
8080 bytes, do not specify a buffering mode when you create the sbspace.
If you are reading or writing short blocks of data, such as 2 kilobytes
or 4 kilobytes, leave the default of “buffering=ON” to obtain better
performance.
Programmers can override the default buffering mode when they create,
open, or alter a smart-large-object instance with DataBlade
API and
the Informix®
ESQL/C functions.
The DataBlade
API and
the Informix
ESQL/C application
programming interface provide the LO_NOBUFFER flag to allow lightweight
I/O for smart large objects.
Important: Use
the LO_NOBUFFER flag only when you read or write smart large objects
in operations greater than 8080 bytes and you seldom access them.
That is, if you have infrequent read or write function calls that
read large amounts of data in a single function invocation, lightweight
I/O can improve I/O performance.