[jira] [Commented] (COUCHDB-1893) Allow replication filters to meaningfully apply to deleted documents
[ https://issues.apache.org/jira/browse/COUCHDB-1893?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15932009#comment-15932009 ] ASF GitHub Bot commented on COUCHDB-1893: - Github user wohali closed the pull request at: https://github.com/apache/couchdb/pull/92 > Allow replication filters to meaningfully apply to deleted documents > > > Key: COUCHDB-1893 > URL: https://issues.apache.org/jira/browse/COUCHDB-1893 > Project: CouchDB > Issue Type: Improvement > Components: JavaScript View Server >Reporter: Stéphane Alnet > > A document that is deleted using the DELETE command will be presented to a > replication filter as an empty record with only a `_deleted:true` field. A > replication filter can then only use the document ID to decide whether or not > to propagate the deletion; in most cases this is not sufficient, and one may > have to pass along deletion documents for IDs that would not have been > replicated by the filter. > This might lead to document IDs being leaked to the target database, which > might be undesirable; more importantly if the goal of filtering was to build > a smaller subset of the source database (for example to replicate a very > large database to a device that has smaller storage space), those deletion > documents might overfill the database (they never get compacted). > I had somewhat documented this issue on the Wiki > (http://wiki.apache.org/couchdb/Replication#Filtered_Replication) a while > back but never got to add it to JIRA. > Dave Cottlehuber on the PouchDB list suggested to use PUT with a > `_deleted:true` field to work around the problem (the PUT body can then > contain data sufficient to enable the filter to work). However we're still > stuck in case DELETE was used instead. > My suggestion is to expand the replication filter API to add an optional > third argument > filter(doc,req,old_doc) > where old_doc if present references the version of the document that will get > deleted. It is then up to the filter to use the _deleted flag in `doc` and > the values in `old_doc`. > (It might be useful/meaningful/easier to add old_doc in all cases; at this > point I'm only suggesting to add it in the case doc contains a _deleted > field.) -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (COUCHDB-1893) Allow replication filters to meaningfully apply to deleted documents
[ https://issues.apache.org/jira/browse/COUCHDB-1893?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15932008#comment-15932008 ] ASF subversion and git services commented on COUCHDB-1893: -- Commit 67139cc96d4bffdd10d3e2cab02a86e569b220a2 in couchdb-documentation's branch refs/heads/master from [~wohali] [ https://git-wip-us.apache.org/repos/asf?p=couchdb-documentation.git;h=67139cc ] Document deletion approach when using filtered replication Addresses PR #92 and COUCHDB-1893. > Allow replication filters to meaningfully apply to deleted documents > > > Key: COUCHDB-1893 > URL: https://issues.apache.org/jira/browse/COUCHDB-1893 > Project: CouchDB > Issue Type: Improvement > Components: JavaScript View Server >Reporter: Stéphane Alnet > > A document that is deleted using the DELETE command will be presented to a > replication filter as an empty record with only a `_deleted:true` field. A > replication filter can then only use the document ID to decide whether or not > to propagate the deletion; in most cases this is not sufficient, and one may > have to pass along deletion documents for IDs that would not have been > replicated by the filter. > This might lead to document IDs being leaked to the target database, which > might be undesirable; more importantly if the goal of filtering was to build > a smaller subset of the source database (for example to replicate a very > large database to a device that has smaller storage space), those deletion > documents might overfill the database (they never get compacted). > I had somewhat documented this issue on the Wiki > (http://wiki.apache.org/couchdb/Replication#Filtered_Replication) a while > back but never got to add it to JIRA. > Dave Cottlehuber on the PouchDB list suggested to use PUT with a > `_deleted:true` field to work around the problem (the PUT body can then > contain data sufficient to enable the filter to work). However we're still > stuck in case DELETE was used instead. > My suggestion is to expand the replication filter API to add an optional > third argument > filter(doc,req,old_doc) > where old_doc if present references the version of the document that will get > deleted. It is then up to the filter to use the _deleted flag in `doc` and > the values in `old_doc`. > (It might be useful/meaningful/easier to add old_doc in all cases; at this > point I'm only suggesting to add it in the case doc contains a _deleted > field.) -- This message was sent by Atlassian JIRA (v6.3.15#6346)
