You can use a text editor to set ONCONFIG parameters at any time. To change one of the configuration parameters that set shared-memory performance options, use the text editor to locate the parameter in the file, enter the new value or values, and rewrite the file to disk. The changes that you make do not take effect until you reinitialize shared memory.
Table 19 lists the ONCONFIG parameters that set shared-memory performance options. For more information, see the chapter on configuration parameters in the IBM Informix: Administrator's Reference.
| ONCONFIG
Parameter |
Purpose |
|---|---|
| CKPTINTVL | Specifies the maximum number of seconds that can elapse before the database server checks if a checkpoint is needed |
| CLEANERS | Specifies the number of page-cleaner threads that the database server is to run |
| LRU_MAX_DIRtY | Specifies the percentage of modified pages in the LRU queues that flags page cleaning to start |
| LRU_MIN_DIRTY | Specifies the percentage of modified pages in the LRU queues that flags page cleaning to stop |
| LRUS | Specifies the number of LRU queues for the shared-memory buffer pool |
| RA_PAGES | Specifies the number of disk pages that the database server should attempt to read ahead when it performs sequential scans of data or index records |
| RA_THRESHOLD | Specifies the number of unprocessed memory pages that, after they are read, cause the database server to read ahead on disk |
| IDX_RA_PAGES | Specifies the number of disk pages that the database server should attempt to read ahead when it performs sequential scans of index records |
| IDX_RA_THRESHOLD | Specifies the number of unprocessed memory pages that, after they are read, cause the database server to read ahead more index pages on disk |