Loop Prevention

Owned by Clive Otten (Unlicensed)
Jan 21, 2020
1 min read

Description

This article explains about the loop prevention parameter which is very useful when complex replication setup is used and enables the data to replicate to our requirements.

Solution

  • Valid values for 

    • _LOOP_PREVENTION

     parameters are YES and NO.

  • In the basic one-way replication 

    • _LOOP_PREVENTION

     parameters are not required by Dbvisit Replicate at all.

  • In two-way replication where no change should be propagated further once applied, MINE loop prevention is used whereas APPLY loop prevention does not get invoked.

  • In advanced configurations such as cascading destinations (A -> B -> C), APPLY loop prevention is used and MINE loop prevention is disabled.

APPLY loop prevention can be used in all cases but the disadvantage is that MINE and APPLY have to do more work by processing changes that eventually get skipped later. Therefore, MINE loop prevention is used in some scenarios (i.e two-way) to achieve good replication performance.

Setup wizard sets correct values for 

  • _LOOP_PREVENTION

 parameters for advance replication automatically. However, for some complex configurations, such as A -> B <=>C <- D where multiple set-up wizards are used, manual setting of 

  • _LOOP_PREVENTION

 is required. This prevents propagating DMLs further once applied.

Donna Zehl November 04, 2014 03:53