You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "graham sanderson (JIRA)" <ji...@apache.org> on 2014/07/15 02:58:06 UTC
[jira] [Updated] (CASSANDRA-7545) Hints for a down node are written
to a single partition in system.hints on the coordinator leading to
contention
[ https://issues.apache.org/jira/browse/CASSANDRA-7545?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
graham sanderson updated CASSANDRA-7545:
----------------------------------------
Description:
The worst side effect is potentially orders of magnitude larger than suspected memory allocation due to a race condition updating the columns in the memtable (see CASSANDRA-7546)
That said, having so many hints in a single partition has other negative side effects (non linear growth of sorted tree data structure overhead in memtable, just plain large number of tombstones in a row etc.)
Ideally, the hints would be partitioned by both the nodeUUID, and a fixed number of (say 4) bits of a hash of the original rowmutation's partition key... even this small spreading of load has a significant improvement.
was:
The worst side effect is potentially orders of magnitude larger than suspected memory allocation due to a race condition updating the columns in the memtable.
That said, having so many hints in a single partition has other negative side effects (non linear growth of sorted tree data structure overhead in memtable, just plain large number of tombstones in a row etc.)
Ideally, the hints would be partitioned by both the nodeUUID, and a fixed number of (say 4) bits of a hash of the original rowmutation's partition key... even this small spreading of load has a significant improvement.
> Hints for a down node are written to a single partition in system.hints on the coordinator leading to contention
> ----------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-7545
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7545
> Project: Cassandra
> Issue Type: Bug
> Reporter: graham sanderson
>
> The worst side effect is potentially orders of magnitude larger than suspected memory allocation due to a race condition updating the columns in the memtable (see CASSANDRA-7546)
> That said, having so many hints in a single partition has other negative side effects (non linear growth of sorted tree data structure overhead in memtable, just plain large number of tombstones in a row etc.)
> Ideally, the hints would be partitioned by both the nodeUUID, and a fixed number of (say 4) bits of a hash of the original rowmutation's partition key... even this small spreading of load has a significant improvement.
--
This message was sent by Atlassian JIRA
(v6.2#6252)