store: Add status variables for tikv statistics (#22286)

pingcap · Mar 10, 2021 · 5f1e205 · 5f1e205
1 parent bdfcaf8
commit 5f1e205
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Showing 2 changed files with 55 additions and 0 deletions.
diff --git a/store/gcworker/gc_worker.go b/store/gcworker/gc_worker.go
@@ -42,6 +42,7 @@ import (
 	"github.com/pingcap/tidb/metrics"
 	"github.com/pingcap/tidb/privilege"
 	"github.com/pingcap/tidb/session"
+	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/store/tikv"
 	"github.com/pingcap/tidb/store/tikv/logutil"
 	"github.com/pingcap/tidb/store/tikv/oracle"
@@ -93,6 +94,7 @@ func NewGCWorker(store kv.Storage, pdClient pd.Client) (*GCWorker, error) {
 		lastFinish:  time.Now(),
 		done:        make(chan error),
 	}
+	variable.RegisterStatistics(worker)
 	return worker, nil
 }
 
@@ -155,6 +157,13 @@ const (
 	gcDefaultAutoConcurrency = true
 
 	gcWorkerServiceSafePointID = "gc_worker"
+
+	// Status var names start with tidb_%
+	tidbGCLastRunTime = "tidb_gc_last_run_time"
+	tidbGCLeaderDesc  = "tidb_gc_leader_desc"
+	tidbGCLeaderLease = "tidb_gc_leader_lease"
+	tidbGCLeaderUUID  = "tidb_gc_leader_uuid"
+	tidbGCSafePoint   = "tidb_gc_safe_point"
 )
 
 var gcSafePointCacheInterval = tikv.GcSafePointCacheInterval
@@ -223,6 +232,32 @@ func createSession(store kv.Storage) session.Session {
 	}
 }
 
+// GetScope gets the status variables scope.
+func (w *GCWorker) GetScope(status string) variable.ScopeFlag {
+	return variable.DefaultStatusVarScopeFlag
+}
+
+// Stats returns the server statistics.
+func (w *GCWorker) Stats(vars *variable.SessionVars) (map[string]interface{}, error) {
+	m := make(map[string]interface{})
+	if v, err := w.loadValueFromSysTable(gcLeaderUUIDKey); err == nil {
+		m[tidbGCLeaderUUID] = v
+	}
+	if v, err := w.loadValueFromSysTable(gcLeaderDescKey); err == nil {
+		m[tidbGCLeaderDesc] = v
+	}
+	if v, err := w.loadValueFromSysTable(gcLeaderLeaseKey); err == nil {
+		m[tidbGCLeaderLease] = v
+	}
+	if v, err := w.loadValueFromSysTable(gcLastRunTimeKey); err == nil {
+		m[tidbGCLastRunTime] = v
+	}
+	if v, err := w.loadValueFromSysTable(gcSafePointKey); err == nil {
+		m[tidbGCSafePoint] = v
+	}
+	return m, nil
+}
+
 func (w *GCWorker) tick(ctx context.Context) {
 	isLeader, err := w.checkLeader()
 	if err != nil {

diff --git a/store/gcworker/gc_worker_test.go b/store/gcworker/gc_worker_test.go
@@ -390,6 +390,26 @@ func (s *testGCWorkerSuite) TestPrepareGC(c *C) {
 	c.Assert(safepoint, Equals, uint64(0))
 }
 
+func (s *testGCWorkerSuite) TestStatusVars(c *C) {
+	// Status variables should now exist for:
+	// tidb_gc_safe_point, tidb_gc_last_run_time
+	se := createSession(s.gcWorker.store)
+	defer se.Close()
+
+	safePoint, err := s.gcWorker.loadValueFromSysTable(gcSafePointKey)
+	c.Assert(err, IsNil)
+	lastRunTime, err := s.gcWorker.loadValueFromSysTable(gcLastRunTimeKey)
+	c.Assert(err, IsNil)
+
+	statusVars, _ := s.gcWorker.Stats(se.GetSessionVars())
+	val, ok := statusVars[tidbGCSafePoint]
+	c.Assert(ok, IsTrue)
+	c.Assert(val, Equals, safePoint)
+	val, ok = statusVars[tidbGCLastRunTime]
+	c.Assert(ok, IsTrue)
+	c.Assert(val, Equals, lastRunTime)
+}
+
 func (s *testGCWorkerSuite) TestDoGCForOneRegion(c *C) {
 	ctx := context.Background()
 	bo := tikv.NewBackofferWithVars(ctx, tikv.GcOneRegionMaxBackoff, nil)