how to change ODS user running query schedule in OID to improve performance at high availability environment

Database statistics are updated automatically, OIDMON runs oidstats.sql for every configured number of updates to the database. By default, for every 5000 entries added OIDMON runs the oidstats.sql. This frequency can be changed using ldapmodify commad as shown below 

$ORACLE_HOME/bin/ldapmodify -p <oidPort> -h <oidHost> -D cn=orcladmin -w <adminPassword> << eof 
dn: cn=configset,cn=oidmon,cn=subconfigsubentry 
changetype: modify 
replace: orclstatsperiodicity 
orclstatsperiodicity: <desired_number> 




So to ensure that statistics will not be gathered except during a defined period (maintenance windows and the 3am oidstats), you should disable the supplemental oidmon statstics gathering and rely only on the once-daily oidstats database job and the autotask job. This is accomplished with ldapmodify to set the orclstatsperiodicity to 0: 

Example ldif to modify orclstatsperiodicity using ldapmodify: 
- - - 
dn: cn=configset,cn=oidmon,cn=subconfigsubentry 
changetype: modify 
replace: orclstatsperiodicity 
orclstatsperiodicity: 0