diff options
| -rw-r--r-- | graphx/src/main/scala/org/apache/spark/graphx/Pregel.scala | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/graphx/src/main/scala/org/apache/spark/graphx/Pregel.scala b/graphx/src/main/scala/org/apache/spark/graphx/Pregel.scala index cfcf7244ea..2ca60d51f8 100644 --- a/graphx/src/main/scala/org/apache/spark/graphx/Pregel.scala +++ b/graphx/src/main/scala/org/apache/spark/graphx/Pregel.scala @@ -127,28 +127,25 @@ object Pregel extends Logging { var prevG: Graph[VD, ED] = null var i = 0 while (activeMessages > 0 && i < maxIterations) { - // Receive the messages. Vertices that didn't get any messages do not appear in newVerts. - val newVerts = g.vertices.innerJoin(messages)(vprog).cache() - // Update the graph with the new vertices. + // Receive the messages and update the vertices. prevG = g - g = g.outerJoinVertices(newVerts) { (vid, old, newOpt) => newOpt.getOrElse(old) } - g.cache() + g = g.joinVertices(messages)(vprog).cache() val oldMessages = messages - // Send new messages. Vertices that didn't get any messages don't appear in newVerts, so don't - // get to send messages. We must cache messages so it can be materialized on the next line, - // allowing us to uncache the previous iteration. - messages = g.mapReduceTriplets(sendMsg, mergeMsg, Some((newVerts, activeDirection))).cache() - // The call to count() materializes `messages`, `newVerts`, and the vertices of `g`. This - // hides oldMessages (depended on by newVerts), newVerts (depended on by messages), and the - // vertices of prevG (depended on by newVerts, oldMessages, and the vertices of g). + // Send new messages, skipping edges where neither side received a message. We must cache + // messages so it can be materialized on the next line, allowing us to uncache the previous + // iteration. + messages = g.mapReduceTriplets( + sendMsg, mergeMsg, Some((oldMessages, activeDirection))).cache() + // The call to count() materializes `messages` and the vertices of `g`. This hides oldMessages + // (depended on by the vertices of g) and the vertices of prevG (depended on by oldMessages + // and the vertices of g). activeMessages = messages.count() logInfo("Pregel finished iteration " + i) // Unpersist the RDDs hidden by newly-materialized RDDs oldMessages.unpersist(blocking = false) - newVerts.unpersist(blocking = false) prevG.unpersistVertices(blocking = false) prevG.edges.unpersist(blocking = false) // count the iteration |