[Date Prev][Date Next] [Chronological] [Thread] [Top]

Re: consistency expectations for 3 node multimaster deltasyncrepl



Zach Hanson  Hart wrote:
> Hello list,
> 
> TL;DR
> 
> With multimaster deltasyncrepl, when the cluster is partitioned (no replication) and conflicting values are added to an entry for a single-valued attribute,
> after the nodes are reconnected and replication commences, is it expected for all nodes to end up with the same value for the attribute, or is it expected that
> they may be inconsistent?

All nodes should end up with the same value.
 
> 
> The long version:
> 
> I'm following test063-delta-multimaster in a local test cluster, with 3 master nodes, and I wanted to confirm that I'm not misunderstanding before moving forward.
> 
> The test test063-delta-multimaster breaks replication and does conflicting adds of a single-valued attribute (employeeNumber) with different values on the two
> nodes.  It then restores replication, gives it a bit to replicate, and then confirms that the "filtered" ldif is the same.  My confusion is about this filtering. 
> 
> In the test, it does
> $LDIFFILTER -s a < $TESTDIR/server$n.out > $TESTDIR/server$n.flt
> and then compares the filtered files. 
> 
> Does this simply sort the attributes and values, or does it strip values?  Essentially, is this testing that the value of the employeeNumber is the same on both
> nodes, or is it simply testing that the employeeNumber is present on both nodes? 

You can read the definition of LDIFFILTER in scripts/defines.h. All it does is strip comments and sort attributes.
The employeeNumber will be the same on all nodes.

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/