How to: XDCR with same buckets but different scopes&collections / filters

Couchbase Server
1

We’re replicating buckets across different sites through XDCR.

We had 3 buckets replicating with different filters:

  • 2 buckets had the same “custom” filter expression;
  • 1 bucket had a “do not replicate DELETE operation” filter.

Then we moved the buckets into scopes&collections of a single parent bucket.

The replication from the source bucket to the target bucket can only be specified once.
The XDCR including all the 3 collections would apply the 2 filters to all of them.
The problem now is that the we need to keep different filters for the different scope&collections as described above, but that seems not possible.

As a workaround, we used a replication from the 3rd collection to a local staging bucket which was used to replicate with a filter in the same target bucket.

Is there a possibility to specify the “do not replicate DELETE operation” in a filter expression, in order to avoid the staging bucket and filter the DELETE operation only for the documents with specific values?

2

Any advice on this topic?

To better explain, we had the following XDCR Topology (only replicating _default scope/collection):
ClusterA.bucket1 → ClusterB.bucket1 - Filter 1
ClusterA.bucket2 → ClusterB.bucket2 - Filter 1
ClusterA.bucket3 → ClusterB.bucket3 - Filter 2

Then we moved “bucket2” and “bucket3” as scopes into the bucket1.
The following XDCR Topology is now present:
ClusterA.bucket1.scope1.collection1 → ClusterB.bucket1.scope1.collection1 - Filter 1
ClusterA.bucket1.scope2.collection2 → ClusterB.bucket1.scope2.collection2 - Filter 1

But I cannot create the following replication, since another filter is needed and I cannot specify same source/target buckets with different collections in another replication rule:
ClusterA.bucket1.scope3.collection3 → ClusterB.bucket1.scope3.collection3 - Filter 2

To avoid that I created a staging bucket and I’m using the local staging bucket as source for the new replication rule:
ClusterA.bucket1.scope3.collection3 → ClusterA.bucket1_staging.scope3.collection3
ClusterA.bucket1_staging.scope3.collection3 → ClusterB.bucket1.scope3.collection3 - Filter 2

So my question is: since Filter 2 is a “do not replicate DELETE operation”, can it be included in some way as a code in the Filter 1 expression?

4

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