[iotdb] 02/02: add java doc for cache, SGP, TsFileResource, query

[ja...@apache.org]

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jackietien pushed a commit to branch add-java-doc
in repository https://gitbox.apache.org/repos/asf/iotdb.git

commit a122d74d9015ff0da5b6bc28393226090030c090
Author: JackieTien97 <Ja...@foxmail.com>
AuthorDate: Wed Jun 9 11:43:20 2021 +0800

    add java doc for cache, SGP, TsFileResource, query
---
 .../iotdb/db/engine/cache/TimeSeriesMetadataCache.java | 14 ++++++++++++++
 .../db/engine/storagegroup/StorageGroupProcessor.java  |  4 ++++
 .../iotdb/db/engine/storagegroup/TsFileResource.java   |  4 ++++
 .../iotdb/db/qp/physical/crud/RawDataQueryPlan.java    | 18 ++++++++++++++++++
 4 files changed, 40 insertions(+)

diff --git a/server/src/main/java/org/apache/iotdb/db/engine/cache/TimeSeriesMetadataCache.java b/server/src/main/java/org/apache/iotdb/db/engine/cache/TimeSeriesMetadataCache.java
index 69d709b..889ba9e 100644
--- a/server/src/main/java/org/apache/iotdb/db/engine/cache/TimeSeriesMetadataCache.java
+++ b/server/src/main/java/org/apache/iotdb/db/engine/cache/TimeSeriesMetadataCache.java
@@ -303,6 +303,10 @@ public class TimeSeriesMetadataCache {
           try {
             timeSeriesMetadataList.forEach(
                 metadata -> {
+                  // for root.sg1.d1.vector1.s1, key.device of vector will only return root.sg1.d1
+                  // metadata.getMeasurementId() will return s1, the vector1 is saved in
+                  // key.measurement
+                  // so we should concat them to get the deviceId for root.sg1.d1.vector1.s1
                   TimeSeriesMetadataCacheKey k =
                       new TimeSeriesMetadataCacheKey(
                           key.filePath,
@@ -340,6 +344,16 @@ public class TimeSeriesMetadataCache {
     }
   }
 
+  /**
+   * !!!Attention!!!
+   *
+   * <p>For a vector, e.g. root.sg1.d1.vector1(s1, s2) TimeSeriesMetadataCacheKey for vector1 should
+   * be {filePath: ""./data/data/seq/......., device: root.sg1.d1.vector1, measurement: vector1},
+   * vector1 will be in both device and measurement TimeSeriesMetadataCacheKey for vector1.s1 should
+   * be {filePath: ""./data/data/seq/......., device: root.sg1.d1.vector1, measurement: s1}
+   * TimeSeriesMetadataCacheKey for vector1.s2 should be {filePath: ""./data/data/seq/.......,
+   * device: root.sg1.d1.vector1, measurement: s2}
+   */
   private void getVectorTimeSeriesMetadataListFromCache(
       TimeSeriesMetadataCacheKey key, List<String> subSensorList, List<TimeseriesMetadata> res) {
     lock.readLock().lock();
diff --git a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/StorageGroupProcessor.java b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/StorageGroupProcessor.java
index eb304e7..2b2185d 100755
--- a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/StorageGroupProcessor.java
+++ b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/StorageGroupProcessor.java
@@ -289,6 +289,10 @@ public class StorageGroupProcessor {
   // DEFAULT_POOL_TRIM_INTERVAL_MILLIS
   private long timeWhenPoolNotEmpty = Long.MAX_VALUE;
 
+  /**
+   * record the insertWriteLock in SG is being hold by which method, it will be empty string if on
+   * one holds the insertWriteLock
+   */
   private String insertWriteLockHolder = "";
 
   /** get the direct byte buffer from pool, each fetch contains two ByteBuffer */
diff --git a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileResource.java b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileResource.java
index 1d46900..9449437 100644
--- a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileResource.java
+++ b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileResource.java
@@ -217,6 +217,10 @@ public class TsFileResource {
     this.timeIndexType = 1;
   }
 
+  /**
+   * Because the unclosed tsfile don't have TimeSeriesMetadata and memtables in the memory don't
+   * have chunkMetadata, but query will use these, so we need to generate it for them.
+   */
   @SuppressWarnings("squid:S3776") // high Cognitive Complexity
   private void generateTimeSeriesMetadata() throws IOException {
     TimeseriesMetadata timeTimeSeriesMetadata = new TimeseriesMetadata();
diff --git a/server/src/main/java/org/apache/iotdb/db/qp/physical/crud/RawDataQueryPlan.java b/server/src/main/java/org/apache/iotdb/db/qp/physical/crud/RawDataQueryPlan.java
index 15d9b48..796acc3 100644
--- a/server/src/main/java/org/apache/iotdb/db/qp/physical/crud/RawDataQueryPlan.java
+++ b/server/src/main/java/org/apache/iotdb/db/qp/physical/crud/RawDataQueryPlan.java
@@ -46,7 +46,9 @@ public class RawDataQueryPlan extends QueryPlan {
   private IExpression expression = null;
   private Map<String, Set<String>> deviceToMeasurements = new HashMap<>();
 
+  /** used to group all the sub sensors of one vector into VectorPartialPath */
   private List<PartialPath> deduplicatedVectorPaths = new ArrayList<>();
+
   private List<TSDataType> deduplicatedVectorDataTypes = new ArrayList<>();
 
   public RawDataQueryPlan() {
@@ -93,9 +95,15 @@ public class RawDataQueryPlan extends QueryPlan {
       }
     }
 
+    // TODO Maybe we should get VectorPartialPath above from MTree
+    // Currently, the above processing will only produce PartialPath instead of VectorPartialPath
+    // even if the queried time series is vector
+    // So, we need to transform the PartialPath to VectorPartialPath if is is a vector.
     if (!isRawQuery()) {
       transformPaths(IoTDB.metaManager);
     } else {
+      // if it is a RawQueryWithoutValueFilter, we also need to group all the subSensors of one
+      // vector into one VectorPartialPath
       transformVectorPaths(physicalGenerator, columnForDisplaySet);
     }
   }
@@ -178,6 +186,12 @@ public class RawDataQueryPlan extends QueryPlan {
     }
   }
 
+  /**
+   * Group all the subSensors of one vector into one VectorPartialPath save the grouped
+   * VectorPartialPath in deduplicatedVectorPaths and deduplicatedVectorDataTypes instead of putting
+   * them directly into deduplicatedPaths and deduplicatedDataTypes, because we don't know whether
+   * the raw query has value filter here.
+   */
   public void transformVectorPaths(
       PhysicalGenerator physicalGenerator, Set<String> columnForDisplaySet)
       throws MetadataException {
@@ -214,6 +228,10 @@ public class RawDataQueryPlan extends QueryPlan {
     this.deduplicatedVectorDataTypes = deduplicatedVectorDataTypes;
   }
 
+  /**
+   * RawQueryWithoutValueFilter should call this method to use grouped vector partial path to
+   * replace the previous deduplicatedPaths and deduplicatedDataTypes
+   */
   public void transformToVector() {
     if (!this.deduplicatedVectorPaths.isEmpty()) {
       this.deduplicatedPaths = this.deduplicatedVectorPaths;