MB-9897: Add a stat that tracks number of dropped cursors

Change-Id: Id3fce7daab01ea162385ae3715f625715bcf5e60 Reviewed-on: http://review.couchbase.org/53626 Tested-by: buildbot <build@couchbase.com> Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
couchbase · Jul 23, 2015 · 893a937 · 893a937
1 parent b98fc82
commit 893a937
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diff --git a/docs/stats.org b/docs/stats.org
@@ -326,6 +326,8 @@ For introductory information on stats within Couchbase, start with the
 |                                    | dropping.                              |
 | ep_cursor_dropping_upper_threshold | Memory threshold above which checkpoint|
 |                                    | remover will start cursor dropping     |
+| ep_cursors_dropped                 | Number of cursors dropped by the       |
+|                                    | checkpoint remover                     |
 
 
 ** vBucket total stats

diff --git a/src/checkpoint_remover.cc b/src/checkpoint_remover.cc
@@ -120,6 +120,7 @@ void ClosedUnrefCheckpointRemoverTask::cursorDroppingIfNeeded(void) {
                     for (; itr != cursors.end(); ++itr) {
                         if (memoryCleared < amountOfMemoryToClear) {
                             engine->getDcpConnMap().closeSlowStream(vbid, *itr);
+                            ++stats.cursorsDropped;
                             memoryCleared +=
                                       vb->getChkMgrMemUsageOfUnrefCheckpoints();
                         } else {

diff --git a/src/ep_engine.cc b/src/ep_engine.cc
@@ -3538,6 +3538,8 @@ ENGINE_ERROR_CODE EventuallyPersistentEngine::doEngineStats(const void *cookie,
                     epstats.cursorDroppingLThreshold, add_stat, cookie);
     add_casted_stat("ep_cursor_dropping_upper_threshold",
                     epstats.cursorDroppingUThreshold, add_stat, cookie);
+    add_casted_stat("ep_cursors_dropped",
+                    epstats.cursorsDropped, add_stat, cookie);
 
     return ENGINE_SUCCESS;
 }

diff --git a/src/stats.h b/src/stats.h
@@ -79,6 +79,7 @@ class EPStats {
         mem_high_wat_percent(0),
         cursorDroppingLThreshold(0),
         cursorDroppingUThreshold(0),
+        cursorsDropped(0),
         pagerRuns(0),
         expiryPagerRuns(0),
         itemsRemovedFromCheckpoints(0),
@@ -267,6 +268,9 @@ class EPStats {
     AtomicValue<size_t> cursorDroppingLThreshold;
     AtomicValue<size_t> cursorDroppingUThreshold;
 
+    //! Number of cursors dropped by checkpoint remover
+    AtomicValue<size_t> cursorsDropped;
+
     //! Number of times we needed to kick in the pager
     AtomicValue<size_t> pagerRuns;
     //! Number of times the expiry pager runs for purging expired items