SERVER-25180 make full histogram output optional

For full per-collection histograms, use the aggregation stage

    { $collStats: { latencyStats: { histograms: true } } }

For the full global histogram, invoke serverStatus with

    db.serverStatus( { opLatencies: { histograms: true } } )

1 files changed, 4 insertions, 18 deletions

diff --git a/src/mongo/db/stats/top.cpp b/src/mongo/db/stats/top.cpp
index 8bfe3431f6d..413c5f1c015 100644
--- a/src/mongo/db/stats/top.cpp
+++ b/src/mongo/db/stats/top.cpp
@@ -33,7 +33,6 @@
 
 #include "mongo/db/stats/top.h"
 
-#include "mongo/db/commands/server_status_metric.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/db/service_context.h"
 #include "mongo/util/log.h"
@@ -198,11 +197,11 @@ void Top::_appendStatsEntry(BSONObjBuilder& b, const char* statsName, const Usag
     bb.done();
 }
 
-void Top::appendLatencyStats(StringData ns, BSONObjBuilder* builder) {
+void Top::appendLatencyStats(StringData ns, bool includeHistograms, BSONObjBuilder* builder) {
     auto hashedNs = UsageMap::HashedKey(ns);
     stdx::lock_guard<SimpleMutex> lk(_lock);
     BSONObjBuilder latencyStatsBuilder;
-    _usage[hashedNs].opLatencyHistogram.append(&latencyStatsBuilder);
+    _usage[hashedNs].opLatencyHistogram.append(includeHistograms, &latencyStatsBuilder);
     builder->append("ns", ns);
     builder->append("latencyStats", latencyStatsBuilder.obj());
 }
@@ -214,9 +213,9 @@ void Top::incrementGlobalLatencyStats(OperationContext* txn,
     _incrementHistogram(txn, latency, &_globalHistogramStats, readWriteType);
 }
 
-void Top::appendGlobalLatencyStats(BSONObjBuilder* builder) {
+void Top::appendGlobalLatencyStats(bool includeHistograms, BSONObjBuilder* builder) {
     stdx::lock_guard<SimpleMutex> guard(_lock);
-    _globalHistogramStats.append(builder);
+    _globalHistogramStats.append(includeHistograms, builder);
 }
 
 void Top::_incrementHistogram(OperationContext* txn,
@@ -229,17 +228,4 @@ void Top::_incrementHistogram(OperationContext* txn,
         histogram->increment(latency, readWriteType);
     }
 }
-
-/**
- * Appends the global histogram to the server status.
- */
-class GlobalHistogramServerStatusMetric : public ServerStatusMetric {
-public:
-    GlobalHistogramServerStatusMetric() : ServerStatusMetric(".metrics.latency") {}
-    virtual void appendAtLeaf(BSONObjBuilder& builder) const {
-        BSONObjBuilder latencyBuilder;
-        Top::get(getGlobalServiceContext()).appendGlobalLatencyStats(&latencyBuilder);
-        builder.append("latency", latencyBuilder.obj());
-    }
-} globalHistogramServerStatusMetric;
 }  // namespace mongo