Github user aarondav commented on a diff in the pull request:
https://github.com/apache/spark/pull/887#discussion_r13062338
--- Diff: core/src/main/scala/org/apache/spark/storage/BlockManager.scala
---
@@ -772,7 +772,7 @@ private[spark] class BlockManager(
/**
* Replicate block to another node.
*/
- var cachedPeers: Seq[BlockManagerId] = null
+ @volatile var cachedPeers: Seq[BlockManagerId] = null
--- End diff --
@rxin Looking at this code, is this right? When we create this (5 lines
down), we seem to give it a specific `level.replication`, so we'll only end up
with a certain number of peers, which we will then **cache**. It seems to me
that every block thereafter will be forcibly stored at the same replication
level as the first.
This bug may be possible, because it would only show up if you're using 2
separate replication levels above 1, which is probably uncommon. Am I missing
something, though?
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