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Title
The command show scn results in error “No information to display” and “This command displays information gathered when SP_OPO_UPDATE_SCN is enabled” -
Description
The command “show scn” gives error as below:
sp_ctrl (alvsupl18:9111)> show scn
No information to display
This command displays information gathered when SP_OPO_UPDATE_SCN is enabled
Usage: show scn
[for datadest]
[on {host}] | [on {host}:{port}] |
[on {login}/{password}@{host}] |
[on {login}/{password}@{host}:{port}]
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Cause
The command will work when the parameter SP_OPO_UPDATE_SCN is enabled -
Resolution
The parameter SP_OPO_UPDATE_SCN needs to be set to 1 prior to issuing this command. After all Post will only track the SCN of the DML or other messages that are applied to the target if the parameter is set to 1. The following illustrates the way to set it:
sp_ctrl (alvsupl18:9111)> set param sp_opo_update_scn 1
sp_ctrl (alvsupl18:9111)> stop post
sp_ctrl (alvsupl18:9111)> show
Process Source Target State PID
---------- ------------------------------------ ---------------------- -------------------- ------
Post o.ORA11GR2-alvsupl14 o.ORA11GR2 Stopped by user
Import alvsupl14 alvsupl18 Idle
sp_ctrl (alvsupl18:9111)> start post
sp_ctrl (alvsupl18:9111)> show scn
For resume replication from ora11gr2
On source activate to scn=22047378680
reconcile queue alvsupl14 for o.ora11gr2-o.ORA11GR2 scn 22047419263
Here is the excerpt from Reference Guide for the parameter:
SP_OPO_UPDATE_SCN
This parameter controls the tracking of Oracle SCNs and allows SharePlex to recover quickly when operating in a high-availability cluster. When this parameter is enabled, SharePlex tracks SCNs in its internal transaction table. This enables SharePlex to activate to the lowest applied transaction and then reconcile to the correct transaction when there is a failover.
NOTE: Enabling this parameter disables the commit reduction feature of the Post Enhanced Performance feature. That feature is not supported when tracking SCNs.
Default: 0
Range of valid values: 0 (disabled) or 1 (enabled) Takes effect: when Post is restarted