Re: Error with "Read Backup"

[Jeff Steele]

I have some basic questions to help clarify what is going on when "READ_BACKUP" is used:

1) I have two data nodes in one node group with NoOfReplicas set to 2. I assumed that this means that each node has a full copy of the data. Is that correct?

2) I assume that "READ_BACKUP" only works if there is a full copy of the data stored locally. Otherwise, the local sql node will still have to go to the other data node to get the data. Is that correct?

3) If I am wrong about (1) but right about (2), does READ_BACKUP cause the table to be copied so that all that table's data is on both nodes?

4) you identified a discrepancy between my NoOfFragmentLogParts and MaxNoOfExecutionThreads settings. My data node servers have 12 threads (6 cores with 2 threads each). Should I set MaxNoOfExecutionThreads to 12 or do I need to leave cores free for other things (an sql node is on the same server)?

5) If I leave MaxNoOfExecutionThreads set to 8 as it is now, should I change NoOfFragmentLogParts to 4?

6) My IndexMemory usage is currently 54% so I would have to do an initial restart if I change either NoOfFragmentLogParts or MaxNoOfExecutionThreads. If I do that, do I simply do a rolling restart using "--initial" for each ndb_mgmd and ndbmtd? Will my data be safe if I do that?

Thanks much for all of your help which has been lighting fast and very impressive.