dnsdist: Stop reporting timeouts in `topSlow()`, add `topTimeouts()`

Until this commit `topSlow()` returned queries that timed out, which
is not very helpful. This was happening because timeouts are internally
recorded with a very high response time.
With this change, `topSlow()` now ignores queries that timed out, and
a new command is added to look into these: `topTimeouts()`.

(cherry picked from commit 49243aa47ffc4162a44d2badfdcbad3f6c5c8fd7)

diff --git a/pdns/dnsdist-console.cc b/pdns/dnsdist-console.cc
index 3e92b566e9eb7bafbd7b987c1e77a2c0039ac529..cb53413f3ca980371c7db4aa33930523513e40b2 100644 (file)
--- a/pdns/dnsdist-console.cc
+++ b/pdns/dnsdist-console.cc
@@ -831,7 +831,8 @@ const std::vector<ConsoleKeyword> g_consoleKeywords{
   { "topResponseRules", true, "[top][, vars]", "show `top` response rules" },
   { "topRules", true, "[top][, vars]", "show `top` rules" },
   { "topSelfAnsweredResponseRules", true, "[top][, vars]", "show `top` self-answered response rules" },
-  { "topSlow", true, "[top][, limit][, labels]", "show `top` queries slower than `limit` milliseconds, grouped by last `labels` labels" },
+  {"topSlow", true, "[top][, limit][, labels]", "show `top` queries slower than `limit` milliseconds (timeouts excepted), grouped by last `labels` labels"},
+  {"topTimeouts", true, "[top][, labels]", "show `top` queries that timed out, grouped by last `labels` labels"},
   { "TrailingDataRule", true, "", "Matches if the query has trailing data" },
   { "truncateTC", true, "bool", "if set (defaults to no starting with dnsdist 1.2.0) truncate TC=1 answers so they are actually empty. Fixes an issue for PowerDNS Authoritative Server 2.9.22. Note: turning this on breaks compatibility with RFC 6891." },
   { "unregisterDynBPFFilter", true, "DynBPFFilter", "unregister this dynamic BPF filter" },

diff --git a/pdns/dnsdist-lua-inspection.cc b/pdns/dnsdist-lua-inspection.cc
index ba7dfdb92d624dee66026c5294701cc2fc6ce58b..d347ae204b0cd8f3ee68b8dd2dfdc4d605d9f0c1 100644 (file)
--- a/pdns/dnsdist-lua-inspection.cc
+++ b/pdns/dnsdist-lua-inspection.cc
@@ -378,12 +378,18 @@ void setupLuaInspection(LuaContext& luaCtx)
   luaCtx.executeCode(R"(function topResponses(top, kind, labels) top = top or 10; kind = kind or 0; for k,v in ipairs(getTopResponses(top, kind, labels)) do show(string.format("%4d  %-40s %4d %4.1f%%",k,v[1],v[2],v[3])) end end)");
 
 
-  luaCtx.writeFunction("getSlowResponses", [](uint64_t top, uint64_t msec, boost::optional<int> labels) {
-      return getGenResponses(top, labels, [msec](const Rings::Response& r) { return r.usec > msec*1000; });
+  luaCtx.writeFunction("getSlowResponses", [](uint64_t top, uint64_t msec, boost::optional<int> labels, boost::optional<bool> timeouts) {
+    return getGenResponses(top, labels, [msec, timeouts](const Rings::Response& resp) {
+      if (timeouts && *timeouts) {
+        return resp.usec == std::numeric_limits<unsigned int>::max();
+      }
+      return resp.usec > msec * 1000 && resp.usec != std::numeric_limits<unsigned int>::max();
     });
+  });
 
+  luaCtx.executeCode(R"(function topSlow(top, msec, labels) top = top or 10; msec = msec or 500; for k,v in ipairs(getSlowResponses(top, msec, labels, false)) do show(string.format("%4d  %-40s %4d %4.1f%%",k,v[1],v[2],v[3])) end end)");
 
-  luaCtx.executeCode(R"(function topSlow(top, msec, labels) top = top or 10; msec = msec or 500; for k,v in ipairs(getSlowResponses(top, msec, labels)) do show(string.format("%4d  %-40s %4d %4.1f%%",k,v[1],v[2],v[3])) end end)");
+  luaCtx.executeCode(R"(function topTimeouts(top, labels) top = top or 10; for k,v in ipairs(getSlowResponses(top, 0, labels, true)) do show(string.format("%4d  %-40s %4d %4.1f%%",k,v[1],v[2],v[3])) end end)");
 
   luaCtx.writeFunction("getTopBandwidth", [](uint64_t top) {
       setLuaNoSideEffect();

diff --git a/pdns/dnsdistdist/docs/reference/config.rst b/pdns/dnsdistdist/docs/reference/config.rst
index d62622b3ea032b3d0abf91c2a1f1249caa1d5d31..b6d9bcf86e7b1cd4987d16711397156eded0d8f7 100644 (file)
--- a/pdns/dnsdistdist/docs/reference/config.rst
+++ b/pdns/dnsdistdist/docs/reference/config.rst
@@ -1498,6 +1498,9 @@ Status, Statistics and More
 
 .. function:: topSlow([num[, limit[, labels]]])
 
+  .. versionchanged:: 1.9.7
+    queries that timed out are no longer reported by ``topSlow``, see :func:`topTimeouts` instead
+
   Print the ``num`` slowest queries that are slower than ``limit`` milliseconds.
   Optionally grouped by the rightmost ``labels`` DNS labels.
 
@@ -1505,6 +1508,16 @@ Status, Statistics and More
   :param int limit: Show queries slower than this amount of milliseconds, defaults to 2000
   :param int label: Number of labels to cut down to
 
+.. function:: topTimeouts([num[, labels]])
+
+  .. versionadded:: 1.9.7
+
+  Print the ``num`` queries that timed out the most.
+  Optionally grouped by the rightmost ``labels`` DNS labels.
+
+  :param int num: Number to show, defaults to 10
+  :param int label: Number of labels to cut down to
+
 .. _dynblocksref:
 
 Dynamic Blocks