Is it possible to set a parameter even when there is no active config and consequently no child processes exist? (4330262)

Is it possible to set a parameter even when there is no active config and consequently no child processes exist?

Is it possible to set a parameter even when there is no active config and consequently no child processes exist?

General information. 

Yes, it is possible to do so.

The entry for the parameter will be created in the paramdb file but its effect will only kick in once the respective child process is spawned

The following illustrates the point:

My SharePlex instance does not have any config file active and only sp_cop and sp_cnc  (Cmd & Ctrl) exist:

sp_ctrl (alvsupl14:9111)> status

Brief Status for alvsupl14

Process          State                             PID     Running   Since

---------------  ------------------------------  --------  --------------------

Cop              Running                             5631  20-Apr-18 17:29:07

Cmd & Ctrl       Running                             5633  20-Apr-18 17:29:12

There are no active configuration files

I can still set a Capture parameter as below and it will show up in the output of “list param”:

sp_ctrl (alvsupl14:9111)> set param sp_oct_replicate_all_ddl 1

sp_ctrl (alvsupl14:9111)> list param modified capture

Oracle Capture parameters:

Parameter  Name                 Actual Value                           Units   Set At

------------------------------  ------------------------------------  -------  ---------------

SP_OCT_REPLICATE_ALL_DDL        1                                              Live

   Default   Value:     0

The value is also logged in the paramdb file under the /vardir/data directory even though no active config exists yet:

cat ../../var/data/paramdb

#

# User Parameter Database

#

# This file contains any parameter values which are different from

# their default values.  The customer may make changes to this file

# as they see fit.

.

.

SP_COP_TPORT 9111

SP_COP_UPORT 9111

SP_SYS_LIC_4473 nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn

SP_OCT_REPLICATE_ALL_DDL "1" # Replicate all ddl commands

Expectedly, the parameter will only take effect when the respective process is spawned.

If there were non-default settings in a SharePlex instance, then after running ora_cleansp, they will still show up if the command “list param modified” is issued. The reason for this is, the ora_cleansp does not remove the contents of the paramdb file which stores such non-default values used in tuning, etc. Hence, when SharePlex is restarted after running ora_cleansp, such values will show up if “list param modified” is issued, even though no child processes of SharePlex are present yet. But they will take effect soon after the SharePlex is restarted. Please refer to SharePlex Administrator Guide and SharePlex Refernce Guide for details on running ora_cleansp and details on the commands mentioned above.