Replication Server configuration parameter: sqm_recover_segs
sqm_recover_segs specifies the number of stable queue segments Replication Server allocates before updating the RSSD with recovery QID information.
If sqm_recover_segs is set low, more RSSD updates are performed, possibly slowing performance. If sqm_recover_segs is set high, fewer RSSD updates are performed, possibly improving performance at the expense of longer recovery times.
Monitor how often an SQM Writer makes updates to the rs_oqids table by reviewing counter 6036 – UpdsRsoqid. Typically, increasing the value of sqm_recover_segs improves performance by reducing the amount of time and system resources necessary to allocate segments. However, queue startup and restart take longer as the SQM Writer must scan more of the queue to determine the last message successfully written for each origin. Each segment requires 1MB of queue space; determine the value of sqm_recover_segs by calculating the number of megabytes the SQM Writer can afford to scan at startup or restart. For example, if the SQM Writer can scan 50MB of queue without slowing Replication Server startup or restart, set sqm_recover_segs to 50.
