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Object documentation CLEANERS (Informix)  Locate the document in its SAP Library structure

Definition

The CLEANERS parameter in the Informix ONCONFIG file determines how many threads are started to manage I/O operations. For example, cleaner threads verify that a page has been written to the physical log before it is modified. The cleaner threads run on CPU virtual processors (VPs).

Use

For up-to-date recommendations, see SAP Note 41360.

To monitor the activity of the page cleaners, use the command onstat –F .

Example

This is an example of the output from onstat –F :

Fg Writes

LRU Writes

Chunk Writes

0

263094

73191

address

flusher

state

data

d3292450

0

I

0

0X0

d3292888

1

I

0

0X0

d3292cc0

2

I

0

0X0

d32930f8

3

I

0

0X0

d3293530

4

I

0

0X0

d3293968

5

I

0

0X0

d3293da0

6

I

=

0X0

states: Exit Idle Chunk Lru

If the value for Fg Writes is not 0, this means that there are no more unchanged pages available in the buffer. In this case a direct write to disk is necessary. This should be avoided for performance reason. Therefore, increase the number of CLEANERS or decrease the value for the LRU_MAX_DIRTY parameter.

For more information, see Monitoring the I/O Subsystem (Informix).

 

See also:

Cleaners (Informix)

LRU_MAX_DIRTY, LRU_MIN_DIRTY (Informix)