HDDS-9260. Optimize OmDbInsight API to avoid redundant recursive size calculations for deleted directories during data retrieval.

hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/OMDBInsightEndpoint.java

@@ -580,10 +580,22 @@ protected long fetchSizeForDeletedDirectory(long objectId)
     if (nsSummary == null) {
       return 0L;
     }
+    // Check if the deleted dir size is already computed and set previously.
+    if (nsSummary.getIsSizeOfDeletedDirectoryComputed()) {
+      return nsSummary.getSizeOfFiles();
+    }
+
+    // Initialize the total size
     long totalSize = nsSummary.getSizeOfFiles();
+
+    // Compute the size recursively
     for (long childId : nsSummary.getChildDir()) {
       totalSize += fetchSizeForDeletedDirectory(childId);
     }
+    // Update the size in the NSSummary and set sizeOfFilesSet to true to avoid
+    // re-computation the next time.
+    nsSummary.setSizeOfFiles(totalSize);
+    nsSummary.setIsSizeOfDeletedDirectoryComputed();
     return totalSize;
   }
 

hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/types/NSSummary.java

@@ -36,10 +36,13 @@ public class NSSummary {
   private int[] fileSizeBucket;
   private Set<Long> childDir;
   private String dirName;
+  private boolean isSizeOfDeletedDirectoryComputed;
 
   public NSSummary() {
     this(0, 0L, new int[ReconConstants.NUM_OF_FILE_SIZE_BINS],
          new HashSet<>(), "");
+    // Prevents redundant size computation for deleted directories.
+    isSizeOfDeletedDirectoryComputed = false;
   }
 
   public NSSummary(int numOfFiles,
@@ -82,6 +85,14 @@ public void setSizeOfFiles(long sizeOfFiles) {
     this.sizeOfFiles = sizeOfFiles;
   }
 
+  public boolean getIsSizeOfDeletedDirectoryComputed() {
+    return isSizeOfDeletedDirectoryComputed;
+  }
+
+  public void setIsSizeOfDeletedDirectoryComputed() {
+    this.isSizeOfDeletedDirectoryComputed = true;
+  }
+
   public void setFileSizeBucket(int[] fileSizeBucket) {
     this.fileSizeBucket = Arrays.copyOf(fileSizeBucket,
             ReconConstants.NUM_OF_FILE_SIZE_BINS);