[feat](cloud) Expose approximate rowset metric

be/src/cloud/cloud_tablet_mgr.cpp

@@ -555,11 +555,13 @@ void CloudTabletMgr::build_all_report_tablets_info(std::map<TTabletId, TTablet>*
     VLOG_NOTICE << "begin to build all report cloud tablets info";
 
     HistogramStat tablet_version_num_hist;
+    HistogramStat tablet_approximate_num_rowsets_hist;
 
     auto handler = [&](const std::weak_ptr<CloudTablet>& tablet_wk) {
         auto tablet = tablet_wk.lock();
         if (!tablet) return;
         (*tablet_num)++;
+        tablet_approximate_num_rowsets_hist.add(tablet->fetch_add_approximate_num_rowsets(0));
         TTabletInfo tablet_info;
         tablet->build_tablet_report_info(&tablet_info);
         using namespace std::chrono;
@@ -581,6 +583,8 @@ void CloudTabletMgr::build_all_report_tablets_info(std::map<TTabletId, TTablet>*
 
     DorisMetrics::instance()->tablet_version_num_distribution->set_histogram(
             tablet_version_num_hist);
+    DorisMetrics::instance()->tablet_approximate_num_rowsets_distribution->set_histogram(
+            tablet_approximate_num_rowsets_hist);
     LOG(INFO) << "success to build all cloud report tablets info. all_tablet_count=" << *tablet_num
               << " exceed drop time limit count=" << tablets_info->size();
 }

be/src/common/metrics/doris_metrics.cpp

@@ -207,6 +207,8 @@ DEFINE_GAUGE_METRIC_PROTOTYPE_2ARG(compaction_used_permits, MetricUnit::NOUNIT);
 DEFINE_GAUGE_METRIC_PROTOTYPE_2ARG(compaction_waitting_permits, MetricUnit::NOUNIT);
 
 DEFINE_HISTOGRAM_METRIC_PROTOTYPE_2ARG(tablet_version_num_distribution, MetricUnit::NOUNIT);
+DEFINE_HISTOGRAM_METRIC_PROTOTYPE_2ARG(tablet_approximate_num_rowsets_distribution,
+                                       MetricUnit::NOUNIT);
 
 DEFINE_GAUGE_CORE_METRIC_PROTOTYPE_2ARG(query_scan_bytes_per_second, MetricUnit::BYTES);
 
@@ -406,6 +408,7 @@ DorisMetrics::DorisMetrics() : _metric_registry(_s_registry_name) {
     INT_GAUGE_METRIC_REGISTER(_server_metric_entity, compaction_waitting_permits);
 
     HISTOGRAM_METRIC_REGISTER(_server_metric_entity, tablet_version_num_distribution);
+    HISTOGRAM_METRIC_REGISTER(_server_metric_entity, tablet_approximate_num_rowsets_distribution);
 
     INT_GAUGE_METRIC_REGISTER(_server_metric_entity, query_scan_bytes_per_second);
 

be/src/common/metrics/doris_metrics.h

@@ -182,6 +182,7 @@ class DorisMetrics {
     IntGauge* compaction_waitting_permits = nullptr;
 
     HistogramMetric* tablet_version_num_distribution = nullptr;
+    HistogramMetric* tablet_approximate_num_rowsets_distribution = nullptr;
 
     // The following metrics will be calculated
     // by metric calculator

be/test/cloud/cloud_tablet_mgr_test.cpp

@@ -28,6 +28,8 @@
 #include <thread>
 
 #include "cloud/cloud_storage_engine.h"
+#include "cloud/cloud_tablet.h"
+#include "common/metrics/doris_metrics.h"
 #include "cpp/sync_point.h"
 #include "storage/tablet/tablet_meta.h"
 #include "util/uid_util.h"
@@ -210,4 +212,29 @@ TEST_F(CloudTabletMgrTest, TestGetTabletIfCachedOnlyReturnsCachedTablet) {
     sp->clear_all_call_backs();
 }
 
+TEST_F(CloudTabletMgrTest, TestApproximateRowsetsMetricIncludesActiveTablets) {
+    const uint64_t previous_inactive_duration = g_tablet_report_inactive_duration_ms;
+    g_tablet_report_inactive_duration_ms = 1000;
+    CloudTabletMgr mgr(_engine);
+    auto tablet = std::make_shared<CloudTablet>(_engine, _tablet_meta);
+    auto* metric = DorisMetrics::instance()->tablet_approximate_num_rowsets_distribution;
+    metric->clear();
+    tablet->reset_approximate_stats(0, 0, 0, 0);
+    tablet->fetch_add_approximate_num_rowsets(8);
+    tablet->last_access_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
+                                          std::chrono::system_clock::now().time_since_epoch())
+                                          .count();
+    mgr.put_tablet_for_UT(tablet);
+
+    std::map<TTabletId, TTablet> tablets_info;
+    uint64_t tablet_num = 0;
+    mgr.build_all_report_tablets_info(&tablets_info, &tablet_num);
+
+    EXPECT_EQ(1, tablet_num);
+    EXPECT_TRUE(tablets_info.empty());
+    EXPECT_EQ(1, metric->num());
+    EXPECT_EQ(8, metric->max());
+    g_tablet_report_inactive_duration_ms = previous_inactive_duration;
+}
+
 } // namespace doris