fix: emit QueryExecutionsByTable for success cases only

go/test/endtoend/vtgate/misc_test.go

@@ -1008,6 +1008,38 @@ func TestQueryProcessedMetric(t *testing.T) {
 	}
 }
 
+// TestQueryProcessedMetric verifies that query metrics are correctly published.
+func TestMetricForExplain(t *testing.T) {
+	conn, closer := start(t)
+	defer closer()
+
+	initialQP := getQPMetric(t, "QueryExecutions")
+	initialQT := getQPMetric(t, "QueryExecutionsByTable")
+	t.Run("explain t1", func(t *testing.T) {
+		utils.Exec(t, conn, "explain t1")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValuesf(t, 1, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"), "queryExecutions metric: %s", "explain")
+		assert.EqualValuesf(t, 1, getValue(updatedQT, "EXPLAIN.ks_t1")-getValue(initialQT, "EXPLAIN.ks_t1"), "queryExecutionsByTable metric: %s", "asdasd")
+	})
+
+	t.Run("explain `select id1, id2 from t1`", func(t *testing.T) {
+		utils.ExecAllowError(t, conn, "explain `select id1, id2 from t1`")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValuesf(t, 1, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"), "queryExecutions metric: %s", "explain")
+		assert.EqualValuesf(t, 1, getValue(updatedQT, "EXPLAIN.ks_t1")-getValue(initialQT, "EXPLAIN.ks_t1"), "queryExecutionsByTable metric: %s", "asdasd")
+	})
+
+	t.Run("explain select id1, id2 from t1", func(t *testing.T) {
+		utils.Exec(t, conn, "explain select id1, id2 from t1")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValuesf(t, 2, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"), "queryExecutions metric: %s", "explain")
+		assert.EqualValuesf(t, 2, getValue(updatedQT, "EXPLAIN.ks_t1")-getValue(initialQT, "EXPLAIN.ks_t1"), "queryExecutionsByTable metric: %s", "asdasd")
+	})
+}
+
 func getQPMetric(t *testing.T, metric string) map[string]any {
 	t.Helper()
 

go/test/endtoend/vtgate/unsharded/main_test.go

@@ -459,3 +459,70 @@ func execMulti(t *testing.T, conn *mysql.Conn, query string) []*sqltypes.Result
 	}
 	return res
 }
+
+// TestMetricForExplain verifies that query metrics are correctly published for explain queries.
+func TestMetricForExplain(t *testing.T) {
+	ctx := context.Background()
+	conn, err := mysql.Connect(ctx, &vtParams)
+	require.NoError(t, err)
+	defer conn.Close()
+
+	initialQP := getQPMetric(t, "QueryExecutions")
+	initialQT := getQPMetric(t, "QueryExecutionsByTable")
+
+	t.Run("explain t1", func(t *testing.T) {
+		utils.Exec(t, conn, "explain t1")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValues(t, 1, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"))
+		assert.EqualValues(t, 1, getValue(updatedQT, "EXPLAIN.customer_t1")-getValue(initialQT, "EXPLAIN.customer_t1"))
+	})
+
+	t.Run("explain `select c1, c2 from t1`", func(t *testing.T) {
+		utils.ExecAllowError(t, conn, "explain `select c1, c2 from t1`")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValues(t, 2, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"))
+		assert.EqualValues(t, 1, getValue(updatedQT, "EXPLAIN.customer_t1")-getValue(initialQT, "EXPLAIN.customer_t1"))
+	})
+
+	t.Run("explain select c1, c2 from t1", func(t *testing.T) {
+		utils.Exec(t, conn, "explain select c1, c2 from t1")
+		updatedQP := getQPMetric(t, "QueryExecutions")
+		updatedQT := getQPMetric(t, "QueryExecutionsByTable")
+		assert.EqualValues(t, 3, getValue(updatedQP, "EXPLAIN.Passthrough.PRIMARY")-getValue(initialQP, "EXPLAIN.Passthrough.PRIMARY"))
+		assert.EqualValues(t, 2, getValue(updatedQT, "EXPLAIN.customer_t1")-getValue(initialQT, "EXPLAIN.customer_t1"))
+	})
+}
+
+func getQPMetric(t *testing.T, metric string) map[string]any {
+	t.Helper()
+
+	vars := clusterInstance.VtgateProcess.GetVars()
+	require.NotNil(t, vars)
+
+	qpVars, exists := vars[metric]
+	if !exists {
+		return nil
+	}
+
+	qpMap, ok := qpVars.(map[string]any)
+	require.True(t, ok, "query queryMetric vars is not a map")
+
+	return qpMap
+}
+
+func getValue(m map[string]any, key string) float64 {
+	if m == nil {
+		return 0
+	}
+	val, exists := m[key]
+	if !exists {
+		return 0
+	}
+	f, ok := val.(float64)
+	if !ok {
+		return 0
+	}
+	return f
+}

go/vt/vtgate/executor_stats_test.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2025 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package vtgate
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"vitess.io/vitess/go/sqltypes"
+	vtgatepb "vitess.io/vitess/go/vt/proto/vtgate"
+	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
+	econtext "vitess.io/vitess/go/vt/vtgate/executorcontext"
+)
+
+// TestQueryExecutionsByTable_OnError verifies that queryExecutionsByTable counters
+// are incremented on successful execution but NOT incremented on execution failure.
+func TestQueryExecutionsByTable_OnError(t *testing.T) {
+	executor, sbc1, _, _, ctx := createExecutorEnv(t)
+
+	// Set up successful result first
+	sbc1.SetResults([]*sqltypes.Result{sqltypes.MakeTestResult(sqltypes.MakeTestFields("id", "int64"), "1")})
+
+	// Get initial counter values
+	initialCounts := getCurrentQueryExecutionsByTableCounts()
+
+	// Execute a query successfully first
+	session := econtext.NewSafeSession(&vtgatepb.Session{TargetString: KsTestSharded})
+	result, err := executorExecSession(ctx, executor, session, "select id from user where id = 1", nil)
+
+	// Verify successful execution
+	assert.NoError(t, err, "Expected query execution to succeed")
+	assert.NotNil(t, result, "Expected valid result")
+
+	// Get counter values after successful execution
+	successCounts := getCurrentQueryExecutionsByTableCounts()
+
+	// Check the specific counter that should be incremented for SELECT on user table
+	selectUserKey := "SELECT.TestExecutor_user"
+	initialUserCount := initialCounts[selectUserKey]
+	successUserCount := successCounts[selectUserKey]
+
+	// Verify counter was incremented on successful execution
+	assert.Equal(t, initialUserCount+1, successUserCount,
+		"queryExecutionsByTable counter should be incremented on successful execution")
+
+	// Now set up the sandbox connection to return an error on next execution
+	sbc1.MustFailCodes[vtrpcpb.Code_INTERNAL] = 1
+
+	// Execute the same query again, but this time it should fail
+	_, err = executorExecSession(ctx, executor, session, "select id from user where id = 1", nil)
+
+	// Verify that the execution failed
+	assert.Error(t, err, "Expected query execution to fail")
+
+	// Get counter values after failed execution
+	finalCounts := getCurrentQueryExecutionsByTableCounts()
+
+	// Verify that queryExecutionsByTable counter was NOT incremented on execution error
+	// The counter should remain the same as after the successful execution
+	finalUserCount := finalCounts[selectUserKey]
+	assert.Equal(t, successUserCount, finalUserCount,
+		"queryExecutionsByTable counter should not be incremented on execution error")
+}
+
+// getCurrentQueryExecutionsByTableCounts returns the current values of all queryExecutionsByTable counters
+func getCurrentQueryExecutionsByTableCounts() map[string]int64 {
+	// queryExecutionsByTable is a global variable, so we can use its Counts() method
+	// to get all counter values. The keys are already formatted as "query.table"
+	return queryExecutionsByTable.Counts()
+}

go/vt/vtgate/plan_execute.go

@@ -409,7 +409,6 @@ func (e *Executor) rollbackPartialExec(ctx context.Context, safeSession *econtex
 func (e *Executor) setLogStats(logStats *logstats.LogStats, plan *engine.Plan, vcursor *econtext.VCursorImpl, execStart time.Time, err error, qr *sqltypes.Result) {
 	logStats.StmtType = plan.QueryType.String()
 	logStats.ActiveKeyspace = vcursor.GetKeyspace()
-	logStats.TablesUsed = plan.TablesUsed
 	logStats.TabletType = vcursor.TabletType().String()
 	errCount := e.logExecutionEnd(logStats, execStart, plan, vcursor, err, qr)
 	plan.AddStats(1, time.Since(logStats.StartTime), logStats.ShardQueries, logStats.RowsAffected, logStats.RowsReturned, errCount)
@@ -418,16 +417,19 @@ func (e *Executor) setLogStats(logStats *logstats.LogStats, plan *engine.Plan, v
 func (e *Executor) logExecutionEnd(logStats *logstats.LogStats, execStart time.Time, plan *engine.Plan, vcursor *econtext.VCursorImpl, err error, qr *sqltypes.Result) uint64 {
 	logStats.ExecuteTime = time.Since(execStart)
 
-	e.updateQueryStats(plan.QueryType.String(), plan.Type.String(), vcursor.TabletType().String(), int64(logStats.ShardQueries), plan.TablesUsed)
-
 	var errCount uint64
 	if err != nil {
 		logStats.Error = err
 		errCount = 1
 	} else {
 		logStats.RowsAffected = qr.RowsAffected
 		logStats.RowsReturned = uint64(len(qr.Rows))
+		// log the tables used in the plan for successful query execution.
+		logStats.TablesUsed = plan.TablesUsed
 	}
+
+	e.updateQueryStats(plan.QueryType.String(), plan.Type.String(), vcursor.TabletType().String(), int64(logStats.ShardQueries), logStats.TablesUsed)
+
 	return errCount
 }