Stefan Egli created OAK-3398:
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Summary: make lease update more robust
Key: OAK-3398
URL: https://issues.apache.org/jira/browse/OAK-3398
Project: Jackrabbit Oak
Issue Type: Improvement
Components: core
Affects Versions: 1.3.6
Reporter: Stefan Egli
Assignee: Stefan Egli
Fix For: 1.3.7
With the lease check introduced in OAK-2739 (and refined to do a oak-core stop
in OAK-3397) it becomes more critical that the lease is always properly updated
(to avoid an unnecessary oak-core stop). The following issues exist atm:
* currently the lease is valid 60sec by default, updated every 20sec, the lease
check fails with a margin of 20sec *before* it times out. this means if the
lease update thread is not operating for 20sec it will cause a stop. that's
quite a low figure probably
** the suggestion is to increase the lease timeout to 120sec from 60sec -
update it as soon as 10sec has been eaten off it, and leave the 20sec safety
margin at the end. This would result in 90sec 'idle equals faulty'
* on a machine with heavy load it seems likely that the lease-update-thread
doesn't get scheduled timely enough - as it races for cpu against all the other
busy threads
** the suggestion is to increase the thread priority of the lease update thread
- so if the VM supports thread priorities, that would help reduce lease failure
'just because the cpu is too busy'
* the ClusterNodeInfo, when renewing the lease, doesn't check if the lease has
been marked as timed-out/recovering by another instance. it just overwrites
whatever is there.
** It should, however, only update the lease when it has not yet been marked as
timed out.
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