# Regarding CDB Data

**URL:** <https://dmap-community.ductus.global/t/regarding-cdb-data/2646>\
**Category:** CDB and CDB API\
**Created:** [August 21, 2019, 6:04am UTC](https://dmap-community.ductus.global/t/regarding-cdb-data/2646 "2019-08-21T06:04:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sourasen](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@sourasen](https://dmap-community.ductus.global/u/sourasen)\
**Post date:** [August 21, 2019, 6:04am UTC](https://dmap-community.ductus.global/t/regarding-cdb-data/2646/1 "2019-08-21T06:04:44Z")

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Hi,

As per my my understanding, CDB config data is preserved across Confd restarts by saving them and retrieving them from XML files. My intention is to utilize transaction and set-hooks to trigger a south-bound message from the application and this configuration is stored in CDB.

My question is two-fold:

1. I was wondering if there was any way to invoke the same transaction or set-hook callbacks that were utilized to trigger the sound-bound message when CDB is restored with the configuration data from the XML files upon a restart?

2. Is it possible to fetch a CDB element’s value(read operation) during the commit phase of a transaction for example in the create callback’s execution?

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**Author:** ![mvf](https://yyz2.discourse-cdn.com/flex010/user_avatar/dmap-community.ductus.global/mvf/32/182_2.png) [@mvf](https://dmap-community.ductus.global/u/mvf)\
**Post date:** [September 2, 2019, 11:14am UTC](https://dmap-community.ductus.global/t/regarding-cdb-data/2646/2 "2019-09-02T11:14:26Z")

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1. sounds like a use case for `cdb_trigger_subscription` (or `confd_cmd -c trigger_subscriptions`, if you prefer to call it from a shell). But that would not invoke set-hook callbacks, only the CDB subscribers (I assume this is what you mean by “south-bound message”). I am not aware of any simple way to re-trigger data-provider callbacks.

2. Yes, you can open a CDB session while processing the callback. Just be careful, the callbacks are supposed to react quickly.