When workload affecting captured source tables is very low the latency between source update and target apply may be slower than under normal workload levels. Two optional parms can be used to control the wait interval following an "all caught up" scenario. The two parameters, with their corresponding default values are --small-stall=250 (ms) and --large-stall=1000 (ms). Both values represent fixed wait intervals, that is to say they are not incremental and do not produce longer and longer waits.
The new parms may only be used with sqdconf modify and become effective immediately following sqdconf stop and sqdconf start sequence. NOapply is required.
The --small-stall parm value applies to the first "wait" after capture is caught up. If after the --small-stall wait, the next request also returns no changed data the --large-stall parm value is used for subsequent "waits" until logminer once again returns data to the capture.
The effectiveness or efficiency of the wait interval is solely dependent on transaction patterns which are hard if not impossible to analyze. These two parameters are "tuning" values. Precisely recommends all implementations begin with the defaults and then tune for your environment. If --small-stall is too short there is an increased potential for wasting CPU performing logminer calls, current LSN queries and other factors.
The sqdconf display shows current values ONLY if you have overridden the defaults.
SQDF803I Instance (Version) : orcl19c (19.0.0.0.0)
SQDF800I Display as of: 2021-01-04 15:11:03 -00:00
SQDF901I Configuration file : /home/sqdata/oracdc/oracdc.cab
SQDF902I Status : MOUNTED,STARTED,STALLED
SQDF903I Configuration key : cab_033B41F7447D5EDA
SQDF904I Allocated entries : 31
SQDF905I Used entries : 5
SQDF906I Active Database : localhost/orcl19c
SQDF907I Start Log Point : 25915451
SQDF908I Last Log Point : 26667017
SQDF940I Last Log Timestamp : 2021-01-04-15.11.03
SQDF981I Safe Restart Point : 26667014
SQDF986I Safe Remine Point : 26637169
SQDF910I Active User : SQDATA
SQDF913I Fix Flags : RETRY,DICT_FROM_LOG
SQDF914I Retry Interval : 30
SQDF919I Active Flags : CDCSTORE,RAW LOG
SQDF980I Pending Flags : CDCSTORE,RAW LOG
SQDF915I Active store name : /home/sqdata/oracdc/oracdc_store.cab
SQDF916I Active store id : cab_061EA9E047296655
SQDF957I small stall (ms) : 50
SQDF958I large stall (ms) : 150
SQDF920I Source Entry : # 0
SQDF930I Key : SQD.ADDRESS
SQDF923I Active Flags : ACTIVE
SQDF928I Last Log Point : 22388290
SQDF950I session # insert : 0
SQDF951I session # delete : 0
SQDF952I session # update : 0
SQDF960I cumul # of insert : 1389
SQDF961I cumul # of delete : 1200
SQDF962I cumul # of update : 72
SQDF925I Active Datastore : cdc:///ORATOKAF