]
Will Burns updated ISPN-11679:
------------------------------
Status: Resolved (was: Pull Request Sent)
Resolution: Done
Bad uneven segment distributions can happen after the rebalancing
with SyncConsistentHashFactory
------------------------------------------------------------------------------------------------
Key: ISPN-11679
URL:
https://issues.redhat.com/browse/ISPN-11679
Project: Infinispan
Issue Type: Bug
Components: Core
Affects Versions: 9.4.19.Final, 10.1.6.Final
Reporter: Masafumi Miura
Assignee: Dan Berindei
Priority: Major
Fix For: 11.0.0.Final
Uneven segment distribution can happen after rebalancing with SyncConsistentHashFactory.
Even if a larger number of segments than "20 * number of nodes" is configured,
some nodes have only around 50-60% number of segments than other nodes after the rebalance
in the worst case.
I understand the documentation (like the following) states about the possibility of
slight uneven distribution as a potential drawback of SyncConsistentHashFactory.
[Infinispan 10 configuration
guide|https://infinispan.org/docs/stable/titles/configuring/configuring.h...]
says:
{quote}
This implementation does have some negative points in that the load distribution is
slightly uneven. It also moves more segments than strictly necessary on a join or leave.
{quote}
[JDG 7 Developer
Guide|https://access.redhat.com/documentation/en-us/red_hat_data_grid/7.2...]
says:
{quote}
It has a potential drawback in that it can move a greater number of segments than
necessary during re-balancing. This can be mitigated by using a larger number of
segments.
Another potential drawback is that the segments are not distributed as evenly as
possible, and actually using a very large number of segments can make the distribution of
segments worse.
{quote}
However, only half segments than others is not a slight uneven.