Negative caching only applies to small number of errors

[mlibbey]

https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-negative-caching-enabled
says, "The following negative responses are cached by Traffic Server:" followed by a list of specific status codes. This is incorrect.

• the list doesn't completely match the code:

  trafficserver/proxy/http/HttpTransact.cc

  Lines 243 to 254 in 469ccb4

  	case HTTP_STATUS_NO_CONTENT:
  	case HTTP_STATUS_USE_PROXY:
  	case HTTP_STATUS_BAD_REQUEST:
  	case HTTP_STATUS_FORBIDDEN:
  	case HTTP_STATUS_NOT_FOUND:
  	case HTTP_STATUS_METHOD_NOT_ALLOWED:
  	case HTTP_STATUS_REQUEST_URI_TOO_LONG:
  	case HTTP_STATUS_INTERNAL_SERVER_ERROR:
  	case HTTP_STATUS_NOT_IMPLEMENTED:
  	case HTTP_STATUS_BAD_GATEWAY:
  	case HTTP_STATUS_SERVICE_UNAVAILABLE:
  	case HTTP_STATUS_GATEWAY_TIMEOUT:

  For instance, case HTTP_STATUS_REQUEST_URI_TOO_LONG is status code 414. which isn't listed
• non-listed 4xx errors are cached based on proxy.config.http.cache.heuristic_min_lifetime, which defaults to 1hour.

(remap.config maps http://httpbin.org to a local instance of httpbin)

$ traffic_ctl config get proxy.config.http.negative_caching_lifetime
proxy.config.http.negative_caching_lifetime: 10
$ for status in `seq 400 499`; do 
echo "####status code=$status####"; 
for retry in `seq 3`; do 
  result=$(curl -sD- -o/dev/null -x 127.0.0.1:80 "http://httpbin.org/status/$status" | egrep "(Age|X-Cache)"); 
  if [[ $retry < 3 ]]; then 
    sleep 6; 
  else if [[ "$result" == *"Age: 0"* ]]; then 
      echo "$status code works"; 
    else 
      echo "$status is cached too long"; 
    fi;
  fi; 
  done; 
done
####status code=400####
400 code works
####status code=401####
401 code works
####status code=402####
402 is cached too long
####status code=403####
403 is cached too long
####status code=404####
404 code works
####status code=405####
405 code works
####status code=406####
406 is cached too long
####status code=407####
407 is cached too long
####status code=408####
408 is cached too long
####status code=409####
409 is cached too long
####status code=410####
410 is cached too long
####status code=411####
411 is cached too long
####status code=412####
412 is cached too long
####status code=413####
413 is cached too long
####status code=414####
414 code works
####status code=415####
415 is cached too long
####status code=416####
416 code works
####status code=417####
417 is cached too long
####status code=418####
418 is cached too long
####status code=419####
419 is cached too long
####status code=420####
420 is cached too long
####status code=421####
421 is cached too long
####status code=422####
422 is cached too long
####status code=423####
423 is cached too long
####status code=424####
424 is cached too long
####status code=425####
425 is cached too long
####status code=426####
426 is cached too long
####status code=427####
427 is cached too long
####status code=428####
428 is cached too long
####status code=429####
429 is cached too long
####status code=430####
430 is cached too long
####status code=431####
431 is cached too long
####status code=432####
432 is cached too long
####status code=433####
433 is cached too long
####status code=434####
434 is cached too long
####status code=435####
435 is cached too long
####status code=436####
436 is cached too long
####status code=437####
437 is cached too long
####status code=438####
438 is cached too long
####status code=439####
439 is cached too long
####status code=440####
440 is cached too long
####status code=441####
441 is cached too long
####status code=442####
442 is cached too long
####status code=443####
443 is cached too long
####status code=444####
444 is cached too long
####status code=445####
445 is cached too long
####status code=446####
446 is cached too long
####status code=447####
447 is cached too long
####status code=448####
448 is cached too long
####status code=449####
449 is cached too long
####status code=450####
450 is cached too long
####status code=451####
451 is cached too long
####status code=452####
452 is cached too long
####status code=453####
453 is cached too long
####status code=454####
454 is cached too long
####status code=455####
455 is cached too long
####status code=456####
456 is cached too long
####status code=457####
457 is cached too long
####status code=458####
458 is cached too long
####status code=459####
459 is cached too long
####status code=460####
460 is cached too long
####status code=461####
461 is cached too long
####status code=462####
462 is cached too long
####status code=463####
463 is cached too long
####status code=464####
464 is cached too long
####status code=465####
465 is cached too long
####status code=466####
466 is cached too long
####status code=467####
467 is cached too long
####status code=468####
468 is cached too long
####status code=469####
469 is cached too long
####status code=470####
470 is cached too long
####status code=471####
471 is cached too long
####status code=472####
472 is cached too long
####status code=473####
473 is cached too long
####status code=474####
474 is cached too long
####status code=475####
475 is cached too long
####status code=476####
476 is cached too long
####status code=477####
477 is cached too long
####status code=478####
478 is cached too long
####status code=479####
479 is cached too long
####status code=480####
480 is cached too long
####status code=481####
481 is cached too long
####status code=482####
482 is cached too long
####status code=483####
483 is cached too long
####status code=484####
484 is cached too long
####status code=485####
485 is cached too long
####status code=486####
486 is cached too long
####status code=487####
487 is cached too long
####status code=488####
488 is cached too long
####status code=489####
489 is cached too long
####status code=490####
490 is cached too long
####status code=491####
491 is cached too long
####status code=492####
492 is cached too long
####status code=493####
493 is cached too long
####status code=494####
494 is cached too long
####status code=495####
495 is cached too long
####status code=496####
496 is cached too long
####status code=497####
497 is cached too long
####status code=498####
498 is cached too long
####status code=499####
499 is cached too long

[zwoop]

What's even stranger is that we have our setting set to require a Expires / CC: max-age header, so it really shouldn't be using the heuristics settings IMO.

[mlibbey]

Update... modified the script to show that the heuristic is taking over, even though its "off" (
proxy.config.http.cache.required_headers: 2)

neg=$(sudo traffic_ctl config get proxy.config.http.negative_caching_lifetime);
h=$(sudo traffic_ctl config get proxy.config.http.cache.heuristic_min_lifetime);
s=0;
if [[ $neg != *"3"* ]]; then sudo traffic_ctl config set proxy.config.http.negative_caching_lifetime 3; s=1;fi;
if [[ $h != *"5"* ]]; then sudo traffic_ctl config set proxy.config.http.cache.heuristic_min_lifetime 5; s=1;fi;
if [[ $s == 1 ]]; then sleep 15; fi;
for status in `seq 400 430`; do
echo "####status code=$status####";
for retry in `seq 4`; do
  result=$(curl -sD- -o/dev/null -x 127.0.0.1:80 -H "X-Debug: X-Cache" "http://httpbin.org/status/$status" | egrep "(X-Cache:)");
  echo $result;
  if [[ $retry < 3 ]]; then
    echo "do nothing" > /dev/null;
  elif [[ "$result" != *"hit-fresh"* ]]; then # cache miss
    if [[ $retry == 3 ]]; then
      echo "$status cached by negative_caching_lifetime";
      break;
    else echo "$status cached by heuristic_min_lifetime";
    fi;
  fi;
  sleep 2;
done;
done;

####status code=400####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
400 cached by negative_caching_lifetime
####status code=401####
X-Cache: miss
X-Cache: miss
X-Cache: miss
401 cached by negative_caching_lifetime
####status code=402####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
402 cached by heuristic_min_lifetime
####status code=403####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
403 cached by negative_caching_lifetime
####status code=404####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
404 cached by negative_caching_lifetime
####status code=405####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
405 cached by negative_caching_lifetime
####status code=406####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
406 cached by heuristic_min_lifetime
####status code=407####
X-Cache: miss
X-Cache: miss
X-Cache: miss
407 cached by negative_caching_lifetime
####status code=408####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
408 cached by heuristic_min_lifetime
####status code=409####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
409 cached by heuristic_min_lifetime
####status code=410####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
410 cached by heuristic_min_lifetime
####status code=411####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
411 cached by heuristic_min_lifetime
####status code=412####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
412 cached by heuristic_min_lifetime
####status code=413####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
413 cached by heuristic_min_lifetime
####status code=414####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
414 cached by negative_caching_lifetime
####status code=415####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
415 cached by heuristic_min_lifetime
####status code=416####
X-Cache: miss
X-Cache: miss
X-Cache: miss
416 cached by negative_caching_lifetime
####status code=417####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
417 cached by heuristic_min_lifetime
####status code=418####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
418 cached by heuristic_min_lifetime
####status code=419####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
419 cached by heuristic_min_lifetime
####status code=420####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
420 cached by heuristic_min_lifetime
####status code=421####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
421 cached by heuristic_min_lifetime
####status code=422####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
422 cached by heuristic_min_lifetime
####status code=423####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
423 cached by heuristic_min_lifetime
####status code=424####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
424 cached by heuristic_min_lifetime
####status code=425####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
425 cached by negative_caching_lifetime
####status code=426####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
426 cached by heuristic_min_lifetime
####status code=427####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
427 cached by heuristic_min_lifetime
####status code=428####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
428 cached by heuristic_min_lifetime
####status code=429####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
429 cached by heuristic_min_lifetime
####status code=430####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
430 cached by heuristic_min_lifetime
####status code=431####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
431 cached by heuristic_min_lifetime
####status code=432####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
432 cached by heuristic_min_lifetime
####status code=433####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
433 cached by heuristic_min_lifetime
####status code=434####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
434 cached by heuristic_min_lifetime
####status code=435####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
435 cached by heuristic_min_lifetime
####status code=436####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
436 cached by heuristic_min_lifetime
####status code=437####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
437 cached by heuristic_min_lifetime
####status code=438####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
438 cached by heuristic_min_lifetime
####status code=439####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
439 cached by heuristic_min_lifetime
####status code=440####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
440 cached by heuristic_min_lifetime
####status code=441####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
441 cached by heuristic_min_lifetime
####status code=442####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
442 cached by heuristic_min_lifetime
####status code=443####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
443 cached by heuristic_min_lifetime
####status code=444####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
444 cached by heuristic_min_lifetime
####status code=445####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
445 cached by heuristic_min_lifetime
####status code=446####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
446 cached by negative_caching_lifetime
####status code=447####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
447 cached by heuristic_min_lifetime
####status code=448####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
448 cached by heuristic_min_lifetime
####status code=449####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
449 cached by heuristic_min_lifetime
####status code=450####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
450 cached by heuristic_min_lifetime
####status code=451####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
451 cached by heuristic_min_lifetime
####status code=452####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
452 cached by heuristic_min_lifetime
####status code=453####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
453 cached by heuristic_min_lifetime
####status code=454####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
454 cached by negative_caching_lifetime
####status code=455####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
455 cached by heuristic_min_lifetime
####status code=456####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
456 cached by heuristic_min_lifetime
####status code=457####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
457 cached by heuristic_min_lifetime
####status code=458####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
458 cached by heuristic_min_lifetime
####status code=459####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
459 cached by heuristic_min_lifetime
####status code=460####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
460 cached by heuristic_min_lifetime
####status code=461####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
461 cached by heuristic_min_lifetime
####status code=462####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
462 cached by negative_caching_lifetime
####status code=463####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
463 cached by heuristic_min_lifetime
####status code=464####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
464 cached by heuristic_min_lifetime
####status code=465####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
465 cached by heuristic_min_lifetime
####status code=466####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
466 cached by heuristic_min_lifetime
####status code=467####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
467 cached by heuristic_min_lifetime
####status code=468####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
468 cached by heuristic_min_lifetime
####status code=469####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
469 cached by heuristic_min_lifetime
####status code=470####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
470 cached by heuristic_min_lifetime
####status code=471####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
471 cached by heuristic_min_lifetime
####status code=472####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
472 cached by heuristic_min_lifetime
####status code=473####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
473 cached by heuristic_min_lifetime
####status code=474####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
474 cached by heuristic_min_lifetime
####status code=475####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
475 cached by heuristic_min_lifetime
####status code=476####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
476 cached by heuristic_min_lifetime
####status code=477####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
477 cached by heuristic_min_lifetime
####status code=478####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
478 cached by heuristic_min_lifetime
####status code=479####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
479 cached by heuristic_min_lifetime
####status code=480####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
480 cached by heuristic_min_lifetime
####status code=481####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
481 cached by heuristic_min_lifetime
####status code=482####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
482 cached by heuristic_min_lifetime
####status code=483####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
483 cached by heuristic_min_lifetime
####status code=484####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
484 cached by heuristic_min_lifetime
####status code=485####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
485 cached by negative_caching_lifetime
####status code=486####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
486 cached by heuristic_min_lifetime
####status code=487####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
487 cached by heuristic_min_lifetime
####status code=488####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
488 cached by heuristic_min_lifetime
####status code=489####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
489 cached by heuristic_min_lifetime
####status code=490####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
490 cached by heuristic_min_lifetime
####status code=491####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
491 cached by heuristic_min_lifetime
####status code=492####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
492 cached by heuristic_min_lifetime
####status code=493####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
493 cached by heuristic_min_lifetime
####status code=494####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
494 cached by heuristic_min_lifetime
####status code=495####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
495 cached by heuristic_min_lifetime
####status code=496####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
496 cached by heuristic_min_lifetime
####status code=497####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
497 cached by heuristic_min_lifetime
####status code=498####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
498 cached by heuristic_min_lifetime
####status code=499####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
499 cached by heuristic_min_lifetime
####status code=500####
X-Cache: hit-stale
X-Cache: hit-fresh
X-Cache: hit-stale
500 cached by negative_caching_lifetime
####status code=501####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
501 cached by negative_caching_lifetime
####status code=502####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
502 cached by negative_caching_lifetime
####status code=503####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
503 cached by negative_caching_lifetime
####status code=504####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
504 cached by negative_caching_lifetime
####status code=505####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
505 cached by negative_caching_lifetime
####status code=506####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
506 cached by heuristic_min_lifetime
####status code=507####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
507 cached by heuristic_min_lifetime
####status code=508####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
508 cached by heuristic_min_lifetime
####status code=509####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
509 cached by heuristic_min_lifetime
####status code=510####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
510 cached by heuristic_min_lifetime
####status code=511####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
511 cached by heuristic_min_lifetime
####status code=512####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
512 cached by heuristic_min_lifetime
####status code=513####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
513 cached by heuristic_min_lifetime
####status code=514####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
514 cached by heuristic_min_lifetime
####status code=515####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
515 cached by heuristic_min_lifetime
####status code=516####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
516 cached by heuristic_min_lifetime
####status code=517####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
517 cached by heuristic_min_lifetime
####status code=518####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
518 cached by heuristic_min_lifetime
####status code=519####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
519 cached by heuristic_min_lifetime
####status code=520####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
520 cached by heuristic_min_lifetime
####status code=521####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
521 cached by heuristic_min_lifetime
####status code=522####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
522 cached by heuristic_min_lifetime
####status code=523####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
523 cached by heuristic_min_lifetime
####status code=524####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
524 cached by heuristic_min_lifetime
####status code=525####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
525 cached by heuristic_min_lifetime
####status code=526####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
526 cached by heuristic_min_lifetime
####status code=527####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
527 cached by negative_caching_lifetime
####status code=528####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
528 cached by heuristic_min_lifetime
####status code=529####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
529 cached by heuristic_min_lifetime
####status code=530####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
530 cached by heuristic_min_lifetime
####status code=531####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
531 cached by heuristic_min_lifetime
####status code=532####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
532 cached by heuristic_min_lifetime
####status code=533####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
533 cached by heuristic_min_lifetime
####status code=534####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
534 cached by heuristic_min_lifetime
####status code=535####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
535 cached by heuristic_min_lifetime
####status code=536####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
536 cached by heuristic_min_lifetime
####status code=537####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
537 cached by heuristic_min_lifetime
####status code=538####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
538 cached by heuristic_min_lifetime
####status code=539####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
539 cached by heuristic_min_lifetime
####status code=540####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
540 cached by heuristic_min_lifetime
####status code=541####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
541 cached by heuristic_min_lifetime
####status code=542####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
542 cached by heuristic_min_lifetime
####status code=543####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
543 cached by heuristic_min_lifetime
####status code=544####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
544 cached by heuristic_min_lifetime
####status code=545####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
545 cached by heuristic_min_lifetime
####status code=546####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
546 cached by heuristic_min_lifetime
####status code=547####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
547 cached by negative_caching_lifetime
####status code=548####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
548 cached by heuristic_min_lifetime
####status code=549####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
549 cached by heuristic_min_lifetime
####status code=550####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
550 cached by heuristic_min_lifetime
####status code=551####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
551 cached by heuristic_min_lifetime
####status code=552####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
552 cached by negative_caching_lifetime
####status code=553####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
553 cached by heuristic_min_lifetime
####status code=554####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
554 cached by heuristic_min_lifetime
####status code=555####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
555 cached by heuristic_min_lifetime
####status code=556####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
556 cached by heuristic_min_lifetime
####status code=557####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
557 cached by negative_caching_lifetime
####status code=558####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
558 cached by heuristic_min_lifetime
####status code=559####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
559 cached by heuristic_min_lifetime
####status code=560####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
560 cached by heuristic_min_lifetime
####status code=561####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
561 cached by heuristic_min_lifetime
####status code=562####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
562 cached by heuristic_min_lifetime
####status code=563####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
563 cached by heuristic_min_lifetime
####status code=564####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
564 cached by heuristic_min_lifetime
####status code=565####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
565 cached by heuristic_min_lifetime
####status code=566####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
566 cached by heuristic_min_lifetime
####status code=567####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
567 cached by heuristic_min_lifetime
####status code=568####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
568 cached by heuristic_min_lifetime
####status code=569####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
569 cached by heuristic_min_lifetime
####status code=570####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
570 cached by heuristic_min_lifetime
####status code=571####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
571 cached by heuristic_min_lifetime
####status code=572####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
572 cached by heuristic_min_lifetime
####status code=573####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
573 cached by heuristic_min_lifetime
####status code=574####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
574 cached by heuristic_min_lifetime
####status code=575####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
575 cached by heuristic_min_lifetime
####status code=576####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
576 cached by heuristic_min_lifetime
####status code=577####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
577 cached by heuristic_min_lifetime
####status code=578####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
578 cached by heuristic_min_lifetime
####status code=579####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
579 cached by heuristic_min_lifetime
####status code=580####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
580 cached by heuristic_min_lifetime
####status code=581####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
581 cached by heuristic_min_lifetime
####status code=582####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
582 cached by heuristic_min_lifetime
####status code=583####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-stale
583 cached by negative_caching_lifetime
####status code=584####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
584 cached by heuristic_min_lifetime
####status code=585####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
585 cached by heuristic_min_lifetime
####status code=586####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
586 cached by heuristic_min_lifetime
####status code=587####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
587 cached by heuristic_min_lifetime
####status code=588####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
588 cached by heuristic_min_lifetime
####status code=589####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
589 cached by heuristic_min_lifetime
####status code=590####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
590 cached by heuristic_min_lifetime
####status code=591####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
591 cached by heuristic_min_lifetime
####status code=592####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
592 cached by heuristic_min_lifetime
####status code=593####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
593 cached by heuristic_min_lifetime
####status code=594####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
594 cached by heuristic_min_lifetime
####status code=595####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
595 cached by heuristic_min_lifetime
####status code=596####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
596 cached by heuristic_min_lifetime
####status code=597####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
597 cached by heuristic_min_lifetime
####status code=598####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
598 cached by heuristic_min_lifetime
####status code=599####
X-Cache: miss
X-Cache: hit-fresh
X-Cache: hit-fresh
X-Cache: hit-stale
599 cached by heuristic_min_lifetime

[SolidWallOfCode]

I thought we had a patch that enabled listing the status codes to which negative caching applied, but I can't find it now. Will look around some more.

[SolidWallOfCode]

It was #2031 - it was closed and never brought back. I need to fix that.

[nqyy]

Fixed in commit 4c34cbc.