MySQL Bugs: #49617: Raise priority of thread handling heartbeating in NDB API

Bug #49617	Raise priority of thread handling heartbeating in NDB API
Submitted:	11 Dec 2009 10:53	Modified:	8 Feb 2010 13:35
Reporter:	Geert Vanderkelen	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Cluster: Cluster (NDB) storage engine	Severity:	S4 (Feature request)
Version:	mysql-cluster-6.3	OS:	Any
Assigned to:	Jonas Oreland	CPU Architecture:	Any

Description:
To help prevent heartbeat failure of NDB API applications, it would be good to raise the priority of the thread doing heartbeating in NDB API.

How to repeat:
(feature request)

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/99287

3099 Jonas Oreland	2010-02-04
      ndb - bug#49617 - allow setting of policy/prio for hb-thread in ndbapi/ndb_mgmd

pushed into drop6, 6.3.32 and 7.0.13

docs: there is a new variable settable on ndbapi/mysqld/ndb_mgmd
HeartbeatThreadPriority=[fifo | rr][,<prio>]

Which allows setting either SCHED_FIFO or SCHED_RR scheduling policy, and 
optionally a priority to (default 50 is HeartbeatThreadPriority is specified wo/ it)

Note:
1 - The ability to set scheduling policy is dependent on OS permissions.
2 - If code fails to parse setting an error will be given
3 - If code fails to set policy, and error will be printed to stderr,
    but otherwise the error is ignored

Documented in the NDB-6.3.32 and 7.0.13 changelogs as follows:

        A new configuration parameter HeartbeatThreadPriority makes 
        it possible to select between a 'first-in, first-out' or 
        'round-robin' scheduling policy for management node and API node 
        heartbeat threads, as well as to set the priority of these 
        threads. See 
        http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-ndbd-definition.html 
       or 
       http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-mgm-definition.html
       for more information.

Also updated Roadmap section and MGM/API configuration parameter tables.

Set NM, waiting for 7.1 merge.

it's also pushed to 7.1

Also documented bugfix in the NDB-7.1.2 changelog.

Closed.