openstack/deb-python-kafka
Code Issues Proposed changes

Add comment for round robin partitioner with different subscriptions

Browse Source
This commit is contained in:
Dana Powers
2016-08-20 16:34:51 -07:00
parent e5c64874b4
commit e50d4dde3c
1 changed files with 15 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
kafka/coordinator/assignors/roundrobin.py
View File

@@ -29,6 +29,21 @@ class RoundRobinPartitionAssignor(AbstractPartitionAssignor):
The assignment will be: The assignment will be:
C0: [t0p0, t0p2, t1p1] C0: [t0p0, t0p2, t1p1]
C1: [t0p1, t1p0, t1p2] C1: [t0p1, t1p0, t1p2]
When subscriptions differ across consumer instances, the assignment process
still considers each consumer instance in round robin fashion but skips
over an instance if it is not subscribed to the topic. Unlike the case when
subscriptions are identical, this can result in imbalanced assignments.
For example, suppose we have three consumers C0, C1, C2, and three topics
t0, t1, t2, with unbalanced partitions t0p0, t1p0, t1p1, t2p0, t2p1, t2p2,
where C0 is subscribed to t0; C1 is subscribed to t0, t1; and C2 is
subscribed to t0, t1, t2.
The assignment will be:
C0: [t0p0]
C1: [t1p0]
C2: [t1p1, t2p0, t2p1, t2p2]
""" """
name = 'roundrobin' name = 'roundrobin'
version = 0 version = 0