title: What do the mod_pagespeed statistics mean?
body: <p>Here's a dump of the stats provided my mod_pagespeed from one of my sites. </p>
  
  <pre><code>resource_url_domain_rejections: 6105
  rewrite_cached_output_missed_deadline: 4801
  rewrite_cached_output_hits: 116004
  rewrite_cached_output_misses: 934
  resource_404_count: 0
  slurp_404_count: 0
  total_page_load_ms: 0
  page_load_count: 0
  resource_fetches_cached: 0
  resource_fetch_construct_successes: 45
  resource_fetch_construct_failures: 0
  num_flushes: 947
  total_fetch_count: 0
  total_rewrite_count: 0
  cache_time_us: 572878
  cache_hits: 872
  cache_misses: 1345
  cache_expirations: 242
  cache_inserts: 1795
  cache_extensions: 50799
  not_cacheable: 0
  css_file_count_reduction: 0
  css_elements: 0
  domain_rewrites: 0
  google_analytics_page_load_count: 0
  google_analytics_rewritten_count: 0
  image_inline: 7567
  image_rewrite_saved_bytes: 208854
  image_rewrites: 34128
  image_ongoing_rewrites: 0
  image_webp_rewrites: 0
  image_rewrites_dropped_due_to_load: 0
  image_file_count_reduction: 0
  javascript_blocks_minified: 12438
  javascript_bytes_saved: 1173778
  javascript_minification_failures: 0
  javascript_total_blocks: 12439
  js_file_count_reduction: 0
  converted_meta_tags: 902
  url_trims: 54765
  url_trim_saved_bytes: 1651244
  css_filter_files_minified: 0
  css_filter_minified_bytes_saved: 0
  css_filter_parse_failures: 2
  css_image_rewrites: 0
  css_image_cache_extends: 0
  css_image_no_rewrite: 0
  css_imports_to_links: 0
  serf_fetch_request_count: 1412
  serf_fetch_bytes_count: 12809245
  serf_fetch_time_duration_ms: 28706
  serf_fetch_cancel_count: 0
  serf_fetch_active_count: 0
  serf_fetch_timeout_count: 0
  serf_fetch_failure_count: 0
  </code></pre>
  
  <p>Can someone please explain what all of the stats mean?</p>