[HBASE-5639] The logic used in waiting for region servers during startup is broken

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.94.0
• Hadoop Flags: Reviewed
• Assignee: Jean-Daniel Cryans
• Reporter: Jean-Daniel Cryans
• Created: 26/Mar/12 23:11
• Updated: 12/Oct/12 05:35
• Resolved: 27/Mar/12 20:41

Description

See the tail of HBASE-4993, which I'll report here:

Me:

I think a bug was introduced here. Here's the new waiting logic in waitForRegionServers:

the 'hbase.master.wait.on.regionservers.mintostart' is reached AND
there have been no new region server in for
'hbase.master.wait.on.regionservers.interval' time

And the code that verifies that:

!(lastCountChange+interval > now && count >= minToStart)

Nic:

It seems that changing the code to

(count < minToStart ||
lastCountChange+interval > now)

would make the code works as documented.
If you have 0 region servers that checked in and you are under the interval, you wait: (true or true) = true.
If you have 0 region servers but you are above the interval, you wait: (true or false) = true.
If you have 1 or more region servers that checked in and you are under the interval, you wait: (false or true) = true.