UPDATABLE_SECONDARY configuration parameter

Use the UPDATABLE_SECONDARY configuration parameter to set the number of connections to establish between the primary and secondary servers. Setting this configuration parameter enables client applications to perform update, insert, and delete operations on a high-availability secondary server.

onconfig.std value
Any number from zero (the default value) up to twice the number of CPU VPs. Setting the value to 0 configures the secondary server as read-only. Setting the value from 1 through twice the number of CPU VPs makes the secondary server updatable and configures connection threads.
Number of network connections between a given secondary server and its primary server
takes effect
After you edit your onconfig file and restart the database server.

Isolation Levels for Secondary Data Replication Servers

If the UPDATABLE_SECONDARY configuration parameter is not set or is set to zero, a secondary data replication server is read-only. In this case, only the DIRTY READ or READ UNCOMMITTED transaction isolation levels are available on secondary servers.

If the UPDATABLE_SECONDARY parameter is set to a valid number of connections greater than zero, a secondary data replication server can support the COMMITTED READ , COMMITTED READ LAST COMMITTED, or COMMITTED READ transaction isolation level, or the USELASTCOMMITTED session environment variable. Only SQL DML statements, such as INSERT, UPDATE, MERGE, and DELETE, and the dbexport utility, can support write operations on an updatable secondary server. (Besides UPDATABLE_SECONDARY, the STOP_APPLY and USELASTCOMMITTED configuration parameters must also be set to enable write operations by dbexport on a secondary data replication server.)

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