Streams Performance Tuning Steps

We have been working, with the help of Taiwan, on several Streams optimizations with long latency network links and we have achieved a significant improvement going from 400 LCR/s to more than 3000 LCR/s in the case of Taiwan as target database. We should now introduce these optimizations to all the sites and compare the results. So I would like to ask you to implement the following changes:

TCP tuning

Apply the following changes to /etc/sysctl.conf and run sysctl -p to activate the changes (for all the RAC nodes):

   # increase TCP max buffer size
   net.core.rmem_max = 16777216
   net.core.wmem_max = 16777216
   # increase Linux autotuning TCP buffer limits # min, default, and max 
   # number of bytes to use 
   net.ipv4.tcp_rmem = 4096 87380 16777216 
   net.ipv4.tcp_wmem = 4096 65536 16777216 

Apply performance

   alter table sys.streams$_apply_progress initrans 16 pctfree 10;
   
   -- event to reduce the acknowledge time/frequency: 
   -- on each running instance (once per instance):
   alter system set events '26749 trace name context forever, level 2';

   -- on one RAC instance: 
   alter system set event='26749 trace name context forever, level 2' scope=spfile sid='*';

Network tuning

DEFAULT_SDU_SIZE=32767
RECV_BUF_SIZE=
SEND_BUF_SIZE=

The last 2 parameters must be calculated in base of the bandwidth of the link and the network Round Trip time. I have calculated the value for each site:

• RAL: 7125000
• GridKa: 4500000
• CNAF: 4500000
• IN2P3: 6000000
• BNL: 54750000
• Triumf: 63375000
• Taiwan: 117000000
• SARA: 6375000
• NDGF: 14400000
• PIC: 14400000