[GitHub] [incubator-iotdb] fanhualta commented on a change in pull request #935: Integrate data file version recording with time partitioning

[GitBox <gi...@apache.org>]

fanhualta commented on a change in pull request #935: Integrate data file version recording with time partitioning
URL: https://github.com/apache/incubator-iotdb/pull/935#discussion_r396863018
 
 

 ##########
 File path: server/src/main/java/org/apache/iotdb/db/engine/storagegroup/StorageGroupProcessor.java
 ##########
 @@ -1638,12 +1646,98 @@ public void loadNewTsFile(TsFileResource newTsFileResource)
     }
   }
 
+  /**
+   * Find the position of "newTsFileResource" in the sequence files if it can be inserted into them.
+   * @param newTsFileResource
+   * @return POS_ALREADY_EXIST(-2) if some file has the same name as the one to be inserted
+   *         POS_OVERLAP(-3) if some file overlaps the new file
+   *         an insertion position i >= -1 if the new file can be inserted between [i, i+1]
+   */
+  private int findInsertionPosition(TsFileResource newTsFileResource) {
+    File tsfileToBeInserted = newTsFileResource.getFile();
+    long newFilePartitionId = Long.parseLong(tsfileToBeInserted.getParent());
+    int insertPos = -1;
+
+    List<TsFileResource> sequenceList = new ArrayList<>(sequenceFileTreeSet);
+    // find the position where the new file should be inserted
+    for (int i = 0; i < sequenceList.size(); i++) {
+      TsFileResource localFile = sequenceList.get(i);
+      if (localFile.getFile().getName().equals(tsfileToBeInserted.getName())) {
+        return POS_ALREADY_EXIST;
+      }
+      long localPartitionId = Long.parseLong(localFile.getFile().getParent());
+      if (i == sequenceList.size() - 1 && localFile.getEndTimeMap().isEmpty()
+          || newFilePartitionId != localPartitionId) {
+        // skip files that are not in the partition as the new file and the last empty file
+        continue;
+      }
+
+      int fileComparison = compareTsFileDevices(newTsFileResource, localFile);
+      switch (fileComparison) {
+        case 0:
+          // some devices are newer but some devices are older, the two files overlap in general
+          return POS_OVERLAP;
+        case -1:
+          // all devices in the local file are newer than the new file, the new file can be
+          // inserted before the new file
+          return i - 1;
+        default:
+          // all devices in the local file are older than the new file, proceed to the next file
+          insertPos = i;
+      }
+    }
+    return insertPos;
+  }
+
+  /**
+   * Compare each device in the two files to find the time relation of them.
+   * @param fileA
+   * @param fileB
+   * @return -1 if fileA is totally older than fileB (A < B)
+   *          0 if fileA is partially older than fileB and partially newer than fileB (A X B)
+   *          1 if fileA is totally newer than fileB (B < A)
+   */
+  private int compareTsFileDevices(TsFileResource fileA, TsFileResource fileB) {
+    boolean hasPre = false, hasSubsequence = false;
+    for (String device : fileA.getStartTimeMap().keySet()) {
+      if (!fileB.getStartTimeMap().containsKey(device)) {
+        continue;
+      }
+      long startTimeA = fileA.getStartTimeMap().get(device);
+      long endTimeA = fileA.getEndTimeMap().get(device);
+      long startTimeB = fileB.getStartTimeMap().get(device);
+      long endTimeB = fileB.getEndTimeMap().get(device);
+      if (startTimeA > endTimeB) {
+        // A's data of the device is later than to the B's data
+        hasSubsequence = true;
+      } else if (startTimeB > endTimeA) {
+        // A's data of the device is previous to the B's data
+        hasPre = true;
+      } else {
+        // the two files overlap in the device
+        return 0;
+      }
+    }
+    if (hasPre && hasSubsequence) {
+      // some devices are newer but some devices are older, the two files overlap in general
+      return 0;
+    }
+    if (!hasPre && hasSubsequence) {
+      // all devices in B are newer than those in A
 
 Review comment:
   All devices in A are newer than those in B.

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