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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL Informix® database servers.
Administrator's ReferenceThe includes comprehensive descriptions of HCL Informix® configuration parameters, the system-monitoring interface (SMI) tables in the sysmaster database, the syntax of database server utilities such as onmode and onstat, logical-log records, disk structures, event alarms, and unnumbered error messages.
Administrative Utilities
The onstat utilityThe onstat utility reads shared-memory structures and provides statistics about the database server at the time that the command runs.
onstat -g monitoring optionsThe options that you can use with onstat -g command are used for support and debugging only. You can include only one of these options in the onstat -g command.
onstat -g rah command: Print read-ahead request statisticsUse the onstat -g rah command to display information about read-ahead requests.
onstat -g rah command: Section 4 Recovery ReadAhead StatisticsThis section displays information about read-aheads occuring during a logical recovery.

onstat -g rah command: Section 4 Recovery ReadAhead Statistics

This section displays information about read-aheads occuring during a logical recovery.

Figure 4. onstat -g rah command output, section 4
Recovery ReadAhead Statistics
                             To Do Free 
# pages # done # ios # alrdy QLen  QLen ra_req
26439   26421  0     26515   0     12   0x53090d40

Output description

# pages: Number of pages requested for read-ahead during recovery.
# done: Number of pages that have been read by the RA daemon.
# ios: Number of I/Os required to read '# done' pages.
# alrdy: Number of duplicate page requests. Many log records may modify a relatively small set of pages.
To Do QLen: Number of requested pages remaining in the list to be read ahead.
Free QLen: Number of items in the free page list. This free list helps make inserting and deleting RA page requests more efficient.
ra_req: The memory address of the read-ahead request associated with these stats.

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