SERVER-7646 - track how many docs TTL deletes

jstests/slowNightly/ttl1.js

@@ -38,6 +38,8 @@ assert.soon(
 assert.eq( 0 , t.find( { x : { $lt : new Date( now - 20000000 ) } } ).count() );
 assert.eq( 12 , t.count() );
 
+assert.lte( 18, db.serverStatus().metrics.ttl.deletedDocuments );
+
 // Part 2
 t.ensureIndex( { y : 1 } , { expireAfterSeconds : 10000 } );
 
@@ -48,4 +50,4 @@ assert.soon(
 );
 
 assert.eq( 0 , t.find( { y : { $lt : new Date( now - 10000000 ) } } ).count() );
-assert.eq( 9 , t.count() );
+assert.eq( 9 , t.count() );

src/mongo/base/counter.h

@@ -19,13 +19,14 @@
 #pragma once
 
 #include "mongo/platform/atomic_word.h"
+#include "mongo/platform/cstdint.h"
 
 namespace mongo {
 
     class Counter64 {
     public:
         
-        void increment() { _counter.addAndFetch(1); }
+        void increment( uint64_t n = 1 ) { _counter.addAndFetch(n); }
         
         long long get() const { return _counter.load(); }
         

src/mongo/db/ttl.cpp

@@ -18,15 +18,26 @@
 
 #include "pch.h"
 
-#include "mongo/db/commands/fsync.h"
 #include "mongo/db/ttl.h"
+
+#include "mongo/base/counter.h"
+#include "mongo/db/commands/fsync.h"
+#include "mongo/db/commands/server_status.h"
 #include "mongo/db/databaseholder.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/ops/delete.h"
-#include "mongo/util/background.h"
 #include "mongo/db/replutil.h"
+#include "mongo/util/background.h"
 
 namespace mongo {
+
+    Counter64 ttlPasses;
+    Counter64 ttlDocDeletes;
+
+    ServerStatusMetricField<Counter64> ttlPassesDisplay( "ttl.passes", false, &ttlPasses );
+    ServerStatusMetricField<Counter64> ttlDocDeletesDisplay( "ttl.deletedDocuments", false, &ttlDocDeletes );
+
+
     
     class TTLMonitor : public BackgroundJob {
     public:
@@ -94,6 +105,7 @@ namespace mongo {
                     }
 
                     n = deleteObjects( ns.c_str() , query , false , true );
+                    ttlDocDeletes.increment( n );
                 }
 
                 LOG(1) << "\tTTL deleted: " << n << endl;
@@ -127,6 +139,8 @@ namespace mongo {
                     dbHolder().getAllShortNames( dbs );
                 }
                 
+                ttlPasses.increment();
+
                 for ( set<string>::const_iterator i=dbs.begin(); i!=dbs.end(); ++i ) {
                     string db = *i;
                     try {