private void updateChunkingAndSizeMetricsOnSuccessfulGet() {
      routerMetrics.getBlobSizeBytes.update(bytesWritten.get());
      routerMetrics.getBlobChunkCount.update(numChunksTotal);
      if (options != null) {
        if (options.getBlobOptions.getRange() != null) {
          routerMetrics.getBlobWithRangeSizeBytes.update(bytesWritten.get());
          routerMetrics.getBlobWithRangeTotalBlobSizeBytes.update(totalSize);
        }
        if (options.getBlobOptions.hasBlobSegmentIdx()) {
          routerMetrics.getBlobWithSegmentSizeBytes.update(bytesWritten.get());
          routerMetrics.getBlobWithSegmentTotalBlobSizeBytes.update(totalSize);
        }
      }
      if (!options.getBlobOptions.isRawMode()) {
        if (numChunksTotal == 1) {
          routerMetrics.simpleBlobGetCount.inc();
        } else {
          routerMetrics.compositeBlobGetCount.inc();
        }
      } else {
        routerMetrics.rawBlobGetCount.inc();
      }
    }
Update chunking and size related metrics - blob size, chunk count, and whether the blob is simple or composite.
ambry-router/src/main/java/com/github/ambry/router/GetBlobOperation.java