RE: Logical Standby Issues (cont.)

  • From: Bernard Polarski <bpolarsk@xxxxxxxxx>
  • To: ramick@xxxxxxxxxxx
  • Date: Thu, 27 Jul 2006 00:49:19 -0700 (PDT)

Logical Standby uses streams, and you refer a problem in apply process. I put 
some settings and explanations on streams settings, but only a few are related 
to apply process, maybe it is of some help:
 
 http://www.smenu.org/smenu_streams_set_parameters.html
 
 I am not aware that SGA size has a real influence on apply process, it has an 
indirect effect on capture process through percentage of SGA allocated to 
logminer. I know for sure that aq_tm_processes does makes a differences in 
apply process. However this influence is more on the speed to purge the queue 
tables and your issue seems to be related to single SQL.You may also consider 
the number of 'PARALLEL_MAX_SERVERS', what is its current value ? Having more 
apply process will help. Increasing the parallelism of the apply process will 
probably help the more in your case.
 
 But above all, since a bulk update in source DB is transformed in single 
statement, you 'd better check the statement explain plan for FS on a single 
update. For info, with redo of 100 meg on a sun450 4 cpu 8G ram, I got an avg 
of 3 min apply for bulk update on logical STDBY. So your 4 min for 10meg seems 
to underline another issue than raw perf.
 
 let us know what you find. It is interresting to compile evrything in the 
domain of the apply process parameters.
 
 B. Polarski
 http://www.smenu.org
 
 -----Original Message-----
 From: ramick [mailto:ramick@xxxxxxxxxxx] 
 Sent: Thursday, 27 July, 2006 4:41 AM
 To: strickland.mark@xxxxxxxxx; 'Ric Van Dyke'
 Cc: oracle-l@xxxxxxxxxxxxx
 Subject: RE: Logical Standby Issues (cont.)
 
 "some better settings for SQL Apply parameters"
 
 Would you please post these and the reasons for them?
 TIA

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