Fix: Crash when creating a new cublet for a single cube (#149)

* fix: NullPointerException when a new cublet is created

* fix: wrong data chunk offset due to not resetting after cublet change

* refactor: new data chunk instead of inplace setting

* fix: formatting

---------

Co-authored-by: hugy718 <[email protected]>

cool-core/src/main/java/com/nus/cool/core/io/readstore/CubletRS.java

@@ -31,6 +31,8 @@
 import java.util.List;
 import lombok.Getter;
 import lombok.Setter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Read cublet store
@@ -50,6 +52,8 @@
  */
 public class CubletRS implements Input {
 
+  static final Logger logger = LoggerFactory.getLogger(CubletRS.class);
+
   /**
    * MetaChunk for this cublet.
    */
@@ -82,6 +86,8 @@ public CubletRS(TableSchema schema) {
    */
   @Override
   public void readFrom(ByteBuffer buffer) {
+    logger.debug("readFrom: buffer.limit()=" + buffer.limit());
+
     // Read header offset
     int end = buffer.limit();
     this.limit = end;
@@ -105,12 +111,15 @@ public void readFrom(ByteBuffer buffer) {
       }
     }
 
+    logger.debug("headOffset=" + headOffset);
+
     // Get #chunk and chunk offsets
     buffer.position(headOffset);
     int chunks = buffer.getInt();
     int[] chunkOffsets = new int[chunks];
     for (int i = 0; i < chunks; i++) {
       chunkOffsets[i] = buffer.getInt();
+      logger.debug("chunkOffsets[" + i + "]=" + chunkOffsets[i]);
     }
 
     // read the metaChunk, which is the last one in #chunks
@@ -124,6 +133,7 @@ public void readFrom(ByteBuffer buffer) {
     for (int i = 0; i < chunks - 1; i++) {
       buffer.position(chunkOffsets[i]);
       chunkHeadOffset = buffer.getInt();
+      logger.debug("chunkHeadOffset[" + i + "]=" + chunkHeadOffset);
       buffer.position(chunkHeadOffset);
       ChunkRS chunk = new ChunkRS(this.schema, this.metaChunk);
       chunk.readFrom(buffer);

cool-core/src/main/java/com/nus/cool/core/io/writestore/MetaUserFieldWS.java

@@ -1,5 +1,6 @@
 package com.nus.cool.core.io.writestore;
 
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.nus.cool.core.field.FieldValue;
 import com.nus.cool.core.field.HashField;
@@ -14,6 +15,7 @@
 import java.io.DataOutput;
 import java.io.IOException;
 import java.nio.charset.Charset;
+import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -38,7 +40,12 @@ public class MetaUserFieldWS extends MetaHashFieldWS {
   public MetaUserFieldWS(FieldType type, Charset charset, MetaChunkWS metaChunkWS) {
     super(type, charset);
     this.metaChunkWS = metaChunkWS;
-    for (int invariantIdx : metaChunkWS.getTableSchema().getInvariantFieldIdxs()) {
+    this.resetInvariantIdxToValueList();
+  }
+
+  private void resetInvariantIdxToValueList() {
+    this.invariantIdxToValueList.clear();
+    for (int invariantIdx : this.metaChunkWS.getTableSchema().getInvariantFieldIdxs()) {
       this.invariantIdxToValueList.put(invariantIdx, new LinkedList<>());
     }
   }
@@ -47,7 +54,7 @@ public MetaUserFieldWS(FieldType type, Charset charset, MetaChunkWS metaChunkWS)
   public void put(FieldValue[] tuple, int idx) throws IllegalArgumentException {
     if (!(tuple[idx] instanceof HashField)) {
       throw new IllegalArgumentException(
-        "Illegal argument for MetaUserFieldWS (HashField required).");
+          "Illegal argument for MetaUserFieldWS (HashField required).");
     }
     HashField user = (HashField) tuple[idx];
     int hashKey = user.getInt();
@@ -89,15 +96,12 @@ public int count() {
 
   @Override
   public void cleanForNextCublet() {
-    this.fingerToGid.clear();
-    this.invariantIdxToValueList.clear();
-    this.valueList.clear();
-    this.nextGid = 0; // a field can have different id across cublet.
+    super.cleanForNextCublet();
+    this.resetInvariantIdxToValueList();
   }
 
   @Override
   public int writeTo(DataOutput out) throws IOException {
-
     int bytesWritten = writeFingersAndGids(out);
 
     TableSchema tableSchema = this.metaChunkWS.getTableSchema();
@@ -121,13 +125,13 @@ public int writeTo(DataOutput out) throws IOException {
           .numOfValues(values.size())
           .build();
       bytesWritten += OutputCompressor.writeTo(CompressType.Value, hist,
-        values, out);
+          values, out);
     }
 
     // Write value
     bytesWritten += OutputCompressor.writeTo(CompressType.KeyString,
-    Histogram.builder().charset(charset).build(),
-    valueList, out);
+        Histogram.builder().charset(charset).build(),
+        valueList, out);
 
     return bytesWritten;
   }

cool-core/src/main/java/com/nus/cool/core/util/writer/NativeDataWriter.java

@@ -13,13 +13,17 @@
 import java.util.List;
 import javax.validation.constraints.NotNull;
 import lombok.RequiredArgsConstructor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Native data writer writes a set of records in cool storage format.
  */
 @RequiredArgsConstructor
 public class NativeDataWriter implements DataWriter {
 
+  static final Logger logger = LoggerFactory.getLogger(NativeDataWriter.class);
+
   @NotNull
   private final TableSchema tableSchema;
 
@@ -107,6 +111,7 @@ private boolean maybeSwitchChunk(FieldValue curUser) throws IOException {
     }
     finishChunk();
     // create a new data chunk, init tuple Count
+    logger.debug("newDataChunk: offset=" + offset);
     dataChunk = DataChunkWS.newDataChunk(tableSchema, metaChunk.getMetaFields(), offset);
     tupleCount = 0;
     return true;
@@ -134,6 +139,8 @@ private void finishCublet() throws IOException {
     // 4. flush after writing whole Cublet.
     out.flush();
     out.close();
+
+    this.offset = 0;
   }
 
   /**
@@ -146,20 +153,23 @@ private DataOutputStream newCublet() throws IOException {
     System.out.println("[*] A new cublet " + fileName + " is created!");
     File cublet = new File(outputDir, fileName);
     DataOutputStream out = new DataOutputStream(new FileOutputStream(cublet));
-    offset = 0;
     chunkHeaderOffsets.clear();
     return out;
   }
 
   /**
    * Switch a new cublet File once meet 1GB.
    */
-  private void maybeSwitchCublet() throws IOException {
+  private boolean maybeSwitchCublet() throws IOException {
     if (offset < cubletSize) {
-      return;
+      return false;
     }
     finishCublet();
+    logger.debug("switching cublet...");
+
     out = newCublet();
+
+    return true;
   }
 
   @Override
@@ -170,7 +180,11 @@ public boolean add(FieldValue[] tuple) throws IOException {
     }
     // start a new chunk
     if (maybeSwitchChunk(curUser)) {
-      maybeSwitchCublet();
+      if (maybeSwitchCublet()) {
+        // create a new data chunk with offset 0
+        this.dataChunk = DataChunkWS.newDataChunk(
+          this.tableSchema, this.metaChunk.getMetaFields(), 0);
+      }
     }
     lastUser = curUser;
     // update metachunk / metafield

cool-core/src/main/java/com/nus/cool/model/CoolModel.java

@@ -143,12 +143,20 @@ public synchronized void reload(String cube) throws IOException {
     CubeRS cubeRS = new CubeRS(schema);
 
     File[] cubletFiles = currentVersion.listFiles((file, s) -> s.endsWith(".dz"));
+    Arrays.sort(cubletFiles);
+
     logger.info("Cube " + cube + ", Use version: " + currentVersion.getName());
     storePath.put(cube, currentVersion);
 
+    logger.debug("cublet files: ");
+    for (int i = 0; i < cubletFiles.length; i++) {
+      logger.debug(cubletFiles[i].getPath());
+    }
+
     // Load all cubes under latest version
     checkNotNull(cubletFiles);
     for (File cubletFile : cubletFiles) {
+      logger.debug("loading cublet file: " + cubletFile);
       cubeRS.addCublet(cubletFile);
     }