eDBA Services - Oracle & MySQL

The client load balancing feature enables clients to randomize connection requests among the listeners. Tnsnames Parameter: LOAD_BALANCE

The connect-time failover enables clients to connect to another listener if the initial connection to the first listener fails. The number of listener protocol addresses determines how many listeners are tried. Without connect-time failover, Oracle Net attempts a connection with only one listener. The default is on. Tnsnames Parameter: FAILOVER

The listener connection load balancing feature improves connection performance by balancing the number of active connections among multiple dispatchers and instances. In a single-instance environment, the listener selects the least loaded dispatcher to handle the incoming client requests. In an Oracle Real Application Clusters (RAC) environment, connection load balancing also has the capability to balance the number of active connections among multiple instances. 1. Least-loaded node 2. Least-loaded instance 3. Least-loaded dispatcher for that instance (in case of Shared server configuration)

Doc ID: 263599.1

1. Turn on block checking

2. Turn on block tracking when using RMAN backups (if running 10g)

3. Duplex log groups and members and have more than one archive log dest

Doc ID: 578524.1

Note: It is very important to use entire address string in order to configure dispatchers on RAC and host name used in it should be a VIP hostname, otherwise connection may suffer intermittent ORA-12545 errors. Refer metalink note <333159.1>

alter system set dispatchers='(address=(protocol=tcp)(host=node1-vip))(dispatchers=2)' scope=both   sid='racdb1';

PARALLEL PROCESSING Ensure the system has enough shared memory. GoldenGate runs as an Oracle process. Each Extract or Replicat process requires upwards of 25-50 MB of system shared memory. This means less memory for the Oracle DBMS, especially the SGA. Use parallel Replicat groups on the target system to reduce latency thru parallelism. Consider parallel Extract groups for tables that are fetch intensive (e.g., those that trigger SQL procedures). Group tables that have R.I. to each other in the same Extract-Replicat pair. Pair each Replicat with its own trail and corresponding Extract process. When using parallel Replicats, configure each one to process a different portion of the overall data.

PASSTHRU PARAMETER Consider using this parameter if there is no filtering, conversion or mapping required and you’re using DATAPUMP. In pass-through mode, the Extract process does not look up table definitions, either from the database or from a data definitions file. Pass-through mode increases the throughput of the data pump, because all of the functionality that looks up object definitions is bypassed. This saves database fetches to improve performance.

INSERTAPPEND A new GoldenGate 10.4 feature. Use for large transactions . Puts records at end of table rather than doing a more costly insert into other areas of table.