[incubator-iotdb] 01/03: add javaDocs for mlog

[hx...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

hxd pushed a commit to branch feature/pathid
in repository https://gitbox.apache.org/repos/asf/incubator-iotdb.git

commit 08a07a622808c79968452d7fd7496d63c6525933
Author: xiangdong huang <sa...@gmail.com>
AuthorDate: Wed May 27 12:21:23 2020 +0800

    add javaDocs for mlog
---
 .../3-SchemaManager/1-SchemaManager.md             |  2 +-
 .../3-SchemaManager/1-SchemaManager.md             |  2 +-
 .../metadata/{IDGenerator.java => IDManager.java}  |  2 +-
 .../org/apache/iotdb/db/metadata/MLogWriter.java   | 23 ++++++++++++++++++++++
 .../{IDGeneratorTest.java => IDManagerTest.java}   | 10 +++++-----
 5 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/docs/SystemDesign/3-SchemaManager/1-SchemaManager.md b/docs/SystemDesign/3-SchemaManager/1-SchemaManager.md
index cec2c86..2556117 100644
--- a/docs/SystemDesign/3-SchemaManager/1-SchemaManager.md
+++ b/docs/SystemDesign/3-SchemaManager/1-SchemaManager.md
@@ -222,7 +222,7 @@ sql examples and the corresponding mlog record:
 ## TLog
 * org.apache.iotdb.db.metadata.TagLogFile
 
-All timeseries tag/attribute information will be saved in the tag file, which defaults to data/system/schema/mlog.txt.
+All timeseries tag/attribute information will be saved in the tag file, which defaults to data/system/schema/tlog.txt.
 
 * Total number of bytes of persistence for tags and attributes of each time series is L, which can be configured in the iotdb-engine.properties
 
diff --git a/docs/zh/SystemDesign/3-SchemaManager/1-SchemaManager.md b/docs/zh/SystemDesign/3-SchemaManager/1-SchemaManager.md
index 8a4cba2..112f0db 100644
--- a/docs/zh/SystemDesign/3-SchemaManager/1-SchemaManager.md
+++ b/docs/zh/SystemDesign/3-SchemaManager/1-SchemaManager.md
@@ -220,7 +220,7 @@ IoTDB 的元数据管理采用目录树的形式，倒数第二层为设备层
 * org.apache.iotdb.db.metadata.TagLogFile
 
 
-所有时间序列的标签/属性信息都会保存在标签文件中，此文件默认为 data/system/schema/mlog.txt。
+所有时间序列的标签/属性信息都会保存在标签文件中，此文件默认为 data/system/schema/tlog.txt。
 
 * 每条时间序列的 tags 和 attributes 持久化总字节数为 L，在 iotdb-engine.properties 中配置。
 
diff --git a/server/src/main/java/org/apache/iotdb/db/metadata/IDGenerator.java b/server/src/main/java/org/apache/iotdb/db/metadata/IDManager.java
similarity index 99%
rename from server/src/main/java/org/apache/iotdb/db/metadata/IDGenerator.java
rename to server/src/main/java/org/apache/iotdb/db/metadata/IDManager.java
index d8caf65..187c925 100644
--- a/server/src/main/java/org/apache/iotdb/db/metadata/IDGenerator.java
+++ b/server/src/main/java/org/apache/iotdb/db/metadata/IDManager.java
@@ -24,7 +24,7 @@ import org.apache.iotdb.db.exception.metadata.MetadataException;
 /**
  * ID generator for storage groups, devices, and measurements
  */
-public class IDGenerator {
+public class IDManager {
 
   private static int storageGroupIDLength = 16; //16 bits, must be not greater than 32
   private static int deviceIDLength = 32; //32 bits, must be not greater than 32
diff --git a/server/src/main/java/org/apache/iotdb/db/metadata/MLogWriter.java b/server/src/main/java/org/apache/iotdb/db/metadata/MLogWriter.java
index c61a1bf..1956605 100644
--- a/server/src/main/java/org/apache/iotdb/db/metadata/MLogWriter.java
+++ b/server/src/main/java/org/apache/iotdb/db/metadata/MLogWriter.java
@@ -31,6 +31,29 @@ import org.apache.iotdb.tsfile.fileSystem.FSFactoryProducer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * MLogWriter is for serializing Schema on disk.
+ * The format:
+ * Storage Group:
+ * - Create:
+ * MetadataOperationType(2), fullPath
+ * - Delete:
+ * MetadataOperationType(1), fullPath
+ *
+ * Series:
+ * - Create:
+ * MetadataOperationType(0), fullPath, DataType, Encoding Type, Compression Type,
+ * PropKey=PropValue&PropKey=PropValue&...., Alias, Offset
+ * - Delete:
+ * MetadataOperationType(1), fullPath,
+ * - SET TTL:
+ * MetadataOperationType(10), fullPath, long TTL
+ * - ChangeOffset:
+ * MetadataOperationType(12), fullPath, new offset
+ *
+ * Here, the offset means the offset of this time series in the tagFile.
+ *
+ */
 public class MLogWriter {
 
   private static final Logger logger = LoggerFactory.getLogger(MLogWriter.class);
diff --git a/server/src/test/java/org/apache/iotdb/db/metadata/IDGeneratorTest.java b/server/src/test/java/org/apache/iotdb/db/metadata/IDManagerTest.java
similarity index 80%
rename from server/src/test/java/org/apache/iotdb/db/metadata/IDGeneratorTest.java
rename to server/src/test/java/org/apache/iotdb/db/metadata/IDManagerTest.java
index 783f690..8bba51d 100644
--- a/server/src/test/java/org/apache/iotdb/db/metadata/IDGeneratorTest.java
+++ b/server/src/test/java/org/apache/iotdb/db/metadata/IDManagerTest.java
@@ -22,15 +22,15 @@ import org.apache.iotdb.db.exception.metadata.MetadataException;
 import org.junit.Assert;
 import org.junit.Test;
 
-public class IDGeneratorTest {
+public class IDManagerTest {
 
   @Test
   public void testNewGenerator() throws MetadataException {
-    Assert.assertEquals(1, IDGenerator.newSGNumber());
-    Assert.assertEquals(1, IDGenerator.newDeviceNumber());
-    Assert.assertEquals(1, IDGenerator.newMeasurementNumber());
+    Assert.assertEquals(1, IDManager.newSGNumber());
+    Assert.assertEquals(1, IDManager.newDeviceNumber());
+    Assert.assertEquals(1, IDManager.newMeasurementNumber());
     //0000 0000 0000 0010 0000 0000 0000 0000 0000 0000 0000 0010 0000 0000 0000 0010
-    Assert.assertEquals(0x0002000000020002L, IDGenerator.newID());
+    Assert.assertEquals(0x0002000000020002L, IDManager.newID());
   }
 
 }