Cascade Historian™ : Version 6.4
	Commands

`bufsize`

bufsize — sets the history buffer size.

Syntax

(bufsize history [numvalues])

Parameters

history: The name of a history defined by the history command.
numvalues: The size of the buffer, in number of data values. The default is 100. If no value is supplied, or is zero, the command behaves like a query and the buffer size is not modified.

Returns

The size of the buffer, as an integer, in the format:

(bufsize history numvalues)

if successful, otherwise

(error "History history does not exist")

Description

This command sets the number of data values that will be buffered for the specified history. (There are actually up to twice this number stored at any time, as the Cascade Historian double-buffers its data storage.) When a buffer is full, the data is flushed to disk, as long as an associated file has been assigned (with filebase or HI_FileBase). A larger buffer will retain more data in memory and increase the speed of queries on that data if it is within the range of the data in the buffer.

The history data is flushed to disk whenever this command is called. Until this command is used, the history buffer size is set to the initial default value (100).

This command corresponds to the Cogent C API function HI_Bufsize and the hist_bufsize dynamic library function.

Example

Hist> (bufsize p3)
(bufsize p3 100)
Hist> (bufsize p3 800)
(bufsize p3 800)
Hist> (bufsize p3)
(bufsize p3 800)


bufferIdLength		count