Comments on: Pop Quiz: MySQL Cluster

By: Log Buffer #89: a Carnival of the Vanities for DBAs

Log Buffer #89: a Carnival of the Vanities for DBAs — Fri, 21 Mar 2008 16:55:11 +0000

[…] the MySQL world, Sheeri Cabral challenges anyone who thinks they know MySQL to a pop-quiz. She asks, “If you have a 12-server MySQL Cluster with: 1 Management Node, 3 SQL Nodes, 2 […]

By: Artem Russakovskii

Artem Russakovskii — Thu, 20 Mar 2008 00:16:49 +0000

Hehe, it looks as if I just copied the answer above mine, but in reality it’s because none of the comments were visible at the time :-]

By: Sheeri Cabral

Sheeri Cabral — Wed, 19 Mar 2008 03:49:05 +0000

Matic — nope, that’s not it. See the other 2 comments before yours for the correct answer, and why.

By: Matic

Matic — Sun, 16 Mar 2008 08:52:04 +0000

4GB. Data is stored in data nodes (8 nodes total). Each node has 1/2 of memory dedicated to live dataset and the other half to redundant dataset.

By: Artem Russakovskii

Artem Russakovskii — Sun, 16 Mar 2008 06:14:07 +0000

2GB? Each node group would have 1GB of memory since they share the same data and there’s 2 of them?

[[Artem — you are correct!]]

By: Matthew Montgomery

Matthew Montgomery — Sat, 15 Mar 2008 20:43:03 +0000

Slightly less than 2GB of usable DataMemory+IndexMemory

All nodes in a node group will be identical replicas. So each node group will only hold 1GB. Your usable memory is limited by the number of node groups you have. You will also use some memory for operation records and log buffers (MaxNoOfConcurrentOperations, RedoBuffer, UndoDataBuffer, etc…)

p.s. 4 nodes per node group is not so thoroughly tested and just plain silly.

[[Matthew — you’re right! BTW, I only used 4 nodes per node group so I could have a 2,3,4 pattern — easier to understand if it’s something multiplied or divided by 2, 3 or 4 then it relates to that. I could have said 4 node groups with 2 nodes in each group instead.]]