Re: Calling StorageService.loadNewSSTables function results in deadlock with compaction background task.

[Jeff Jirsa <jj...@gmail.com>]

Can you open a JIRA with this info? 

-- 
Jeff Jirsa


> On Jan 10, 2018, at 2:34 AM, Desimpel, Ignace <Ig...@nuance.com> wrote:
> 
> Tested on version 2.2.11 (but seems like trunck 3.x is still the same for the related code path), using nodetool refresh for restoring a snapshot
> I guess the Cassandra committers can do something with this 😊.
> 
> Calling StorageService.loadNewSSTables function results in deadlock with compaction background task, 
> because  : 
> 
> From StorageService class , function public void loadNewSSTables(String ksName, String cfName)
> a call is made to ColumnFamilyStore class , function public static synchronized void loadNewSSTables(String ksName, String cfName)
> and then a call to Keyspace class, function public static Keyspace open(String keyspaceName)
> getting to the function private static Keyspace open(String keyspaceName, Schema schema, boolean loadSSTables)
> finally trying to get a lock by synchronized (Keyspace.class)
> 
> So inside the ColumnFamilyStore class lock, there is an attempt to get the lock on the Keyspace.class
> 
> Now at the same time I have the thread OptionalTasks executing the ColumnFamilyStore.getBackgroundCompactionTaskSubmitter() task.
> The thread task is also calling Keyspace.open function, already progressed as far as getting the lock on Keyspace class.
> But then the call also initializes the column families and thus is calling on class ColumnFamilyStore the public static synchronized ColumnFamilyStore createColumnFamilyStore ...
> 
> So function 1 locks A and then B
> And function 2 locks B and then A
> leading to deadlock
> 
> Regards,
> Ignace
> <Stack1.txt>
> 
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