[SPARK-20386][SPARK CORE] modify the log info if the block exists on the slave already

## What changes were proposed in this pull request?
Modify the added memory size to memSize-originalMemSize if the  block exists on the slave already
since if the  block exists, the added memory size should be memSize-originalMemSize; if originalMemSize is bigger than memSize ,then the log info should be Removed memory, removed size should be originalMemSize-memSize

## How was this patch tested?
Multiple runs on existing unit tests

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: eatoncys <[email protected]>

Closes apache#17683 from eatoncys/SPARK-20386.

Author: eatoncys

core/src/main/scala/org/apache/spark/storage/BlockManagerMasterEndpoint.scala

@@ -497,11 +497,17 @@ private[spark] class BlockManagerInfo(
 
     updateLastSeenMs()
 
-    if (_blocks.containsKey(blockId)) {
+    val blockExists = _blocks.containsKey(blockId)
+    var originalMemSize: Long = 0
+    var originalDiskSize: Long = 0
+    var originalLevel: StorageLevel = StorageLevel.NONE
+
+    if (blockExists) {
       // The block exists on the slave already.
       val blockStatus: BlockStatus = _blocks.get(blockId)
-      val originalLevel: StorageLevel = blockStatus.storageLevel
-      val originalMemSize: Long = blockStatus.memSize
+      originalLevel = blockStatus.storageLevel
+      originalMemSize = blockStatus.memSize
+      originalDiskSize = blockStatus.diskSize
 
       if (originalLevel.useMemory) {
         _remainingMem += originalMemSize
@@ -520,32 +526,44 @@ private[spark] class BlockManagerInfo(
         blockStatus = BlockStatus(storageLevel, memSize = memSize, diskSize = 0)
         _blocks.put(blockId, blockStatus)
         _remainingMem -= memSize
-        logInfo("Added %s in memory on %s (size: %s, free: %s)".format(
-          blockId, blockManagerId.hostPort, Utils.bytesToString(memSize),
-          Utils.bytesToString(_remainingMem)))
+        if (blockExists) {
+          logInfo(s"Updated $blockId in memory on ${blockManagerId.hostPort}" +
+            s" (current size: ${Utils.bytesToString(memSize)}," +
+            s" original size: ${Utils.bytesToString(originalMemSize)}," +
+            s" free: ${Utils.bytesToString(_remainingMem)})")
+        } else {
+          logInfo(s"Added $blockId in memory on ${blockManagerId.hostPort}" +
+            s" (size: ${Utils.bytesToString(memSize)}," +
+            s" free: ${Utils.bytesToString(_remainingMem)})")
+        }
       }
       if (storageLevel.useDisk) {
         blockStatus = BlockStatus(storageLevel, memSize = 0, diskSize = diskSize)
         _blocks.put(blockId, blockStatus)
-        logInfo("Added %s on disk on %s (size: %s)".format(
-          blockId, blockManagerId.hostPort, Utils.bytesToString(diskSize)))
+        if (blockExists) {
+          logInfo(s"Updated $blockId on disk on ${blockManagerId.hostPort}" +
+            s" (current size: ${Utils.bytesToString(diskSize)}," +
+            s" original size: ${Utils.bytesToString(originalDiskSize)})")
+        } else {
+          logInfo(s"Added $blockId on disk on ${blockManagerId.hostPort}" +
+            s" (size: ${Utils.bytesToString(diskSize)})")
+        }
       }
       if (!blockId.isBroadcast && blockStatus.isCached) {
         _cachedBlocks += blockId
       }
-    } else if (_blocks.containsKey(blockId)) {
+    } else if (blockExists) {
       // If isValid is not true, drop the block.
-      val blockStatus: BlockStatus = _blocks.get(blockId)
       _blocks.remove(blockId)
       _cachedBlocks -= blockId
-      if (blockStatus.storageLevel.useMemory) {
-        logInfo("Removed %s on %s in memory (size: %s, free: %s)".format(
-          blockId, blockManagerId.hostPort, Utils.bytesToString(blockStatus.memSize),
-          Utils.bytesToString(_remainingMem)))
+      if (originalLevel.useMemory) {
+        logInfo(s"Removed $blockId on ${blockManagerId.hostPort} in memory" +
+          s" (size: ${Utils.bytesToString(originalMemSize)}," +
+          s" free: ${Utils.bytesToString(_remainingMem)})")
       }
-      if (blockStatus.storageLevel.useDisk) {
-        logInfo("Removed %s on %s on disk (size: %s)".format(
-          blockId, blockManagerId.hostPort, Utils.bytesToString(blockStatus.diskSize)))
+      if (originalLevel.useDisk) {
+        logInfo(s"Removed $blockId on ${blockManagerId.hostPort} on disk" +
+          s" (size: ${Utils.bytesToString(originalDiskSize)})")
       }
     }
   }