support Threads_connected and Threads_running status variables (#2432)

Author: jycor

enginetest/enginetests.go

@@ -3942,17 +3942,6 @@ func TestVariables(t *testing.T, harness Harness) {
 	}
 }
 
-func TestStatusVariables(t *testing.T, harness Harness) {
-	e := mustNewEngine(t, harness)
-	if IsServerEngine(e) {
-		t.Skip("prepare statements cause status variables to incorrectly increment twice")
-	}
-	for _, script := range queries.StatusVariableScripts {
-		variables.InitStatusVariables()
-		TestScript(t, harness, script)
-	}
-}
-
 func TestPreparedInsert(t *testing.T, harness Harness) {
 	harness.Setup(setup.MydbData, setup.MytableData)
 	e := mustNewEngine(t, harness)

enginetest/memory_engine_test.go

@@ -927,10 +927,6 @@ func TestTransactions(t *testing.T) {
 	enginetest.TestTransactionScripts(t, enginetest.NewSkippingMemoryHarness())
 }
 
-func TestStatusVariables(t *testing.T) {
-	enginetest.TestStatusVariables(t, enginetest.NewDefaultMemoryHarness())
-}
-
 func mergableIndexDriver(dbs []sql.Database) sql.IndexDriver {
 	return memory.NewIndexDriver("mydb", map[string][]sql.DriverIndex{
 		"mytable": {

enginetest/queries/variable_queries.go

@@ -18,7 +18,6 @@ import (
 	"math"
 
 	"github.com/dolthub/go-mysql-server/sql"
-	"github.com/dolthub/go-mysql-server/sql/plan"
 	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
@@ -661,267 +660,3 @@ var VariableErrorTests = []QueryErrorTest{
 		ExpectedErr: sql.ErrSyntaxError,
 	},
 }
-
-var StatusVariableScripts = []ScriptTest{
-	{
-		Name: "Com_delete",
-		SetUpScript: []string{
-			"create table t (i int primary key)",
-			"insert into t values (1), (2), (3)",
-		},
-		Assertions: []ScriptTestAssertion{
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(0)},
-				},
-			},
-			{
-				// syntax errors do not trigger the status variable
-				Query:          "delete abc",
-				ExpectedErrStr: "syntax error at position 11 near 'abc'",
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(0)},
-				},
-			},
-
-			{
-				// delete 1 row
-				Query: "delete from t where i = 1",
-				Expected: []sql.Row{
-					{types.NewOkResult(1)},
-				},
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(1)},
-				},
-			},
-
-			{
-				// delete 2 rows
-				Query: "delete from t where i > 0",
-				Expected: []sql.Row{
-					{types.NewOkResult(2)},
-				},
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(2)},
-				},
-			},
-
-			{
-				// delete 0 rows
-				Query: "delete from t where false",
-				Expected: []sql.Row{
-					{types.NewOkResult(0)},
-				},
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(3)},
-				},
-			},
-
-			{
-				Query:       "delete from t where notarealcolumn > 0",
-				ExpectedErr: sql.ErrColumnNotFound,
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(4)},
-				},
-			},
-
-			{
-				Query:       "delete from notarealtable",
-				ExpectedErr: sql.ErrTableNotFound,
-			},
-			{
-				Query: "show status like 'Com_delete'",
-				Expected: []sql.Row{
-					{"Com_delete", uint64(5)},
-				},
-			},
-		},
-	},
-	{
-		Name: "Com_insert",
-		SetUpScript: []string{
-			"create table t (i int primary key)",
-		},
-		Assertions: []ScriptTestAssertion{
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(0)},
-				},
-			},
-
-			{
-				Query:          "insert syntax error",
-				ExpectedErrStr: "syntax error at position 20 near 'error'",
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(0)},
-				},
-			},
-
-			{
-				Query: "insert into t values (1)",
-				Expected: []sql.Row{
-					{types.NewOkResult(1)},
-				},
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(1)},
-				},
-			},
-
-			{
-				Query: "insert into t values (2), (3)",
-				Expected: []sql.Row{
-					{types.NewOkResult(2)},
-				},
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(2)},
-				},
-			},
-
-			{
-				Query:       "insert into faketable values (2), (3)",
-				ExpectedErr: sql.ErrTableNotFound,
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(3)},
-				},
-			},
-
-			{
-				Query:       "insert into t values (1)",
-				ExpectedErr: sql.ErrPrimaryKeyViolation,
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(4)},
-				},
-			},
-
-			{
-				Query:       "insert into t(bad) values (1)",
-				ExpectedErr: sql.ErrUnknownColumn,
-			},
-			{
-				Query: "show status like 'Com_insert'",
-				Expected: []sql.Row{
-					{"Com_insert", uint64(5)},
-				},
-			},
-		},
-	},
-	{
-		Name: "Com_update",
-		SetUpScript: []string{
-			"create table t (i int primary key)",
-			"insert into t values (1), (2), (3)",
-		},
-		Assertions: []ScriptTestAssertion{
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(0)},
-				},
-			},
-
-			{
-				Query:          "update t abc",
-				ExpectedErrStr: "syntax error at position 13 near 'abc'",
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(0)},
-				},
-			},
-
-			{
-				Query: "update t set i = 10 where i = 1",
-				Expected: []sql.Row{
-					{types.OkResult{RowsAffected: 1, Info: plan.UpdateInfo{Matched: 1, Updated: 1}}},
-				},
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(1)},
-				},
-			},
-
-			{
-				Query: "update t set i = i * 10 where i < 10",
-				Expected: []sql.Row{
-					{types.OkResult{RowsAffected: 2, Info: plan.UpdateInfo{Matched: 2, Updated: 2}}},
-				},
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(2)},
-				},
-			},
-
-			{
-				Query: "update t set i = 1000 where false",
-				Expected: []sql.Row{
-					{types.OkResult{Info: plan.UpdateInfo{}}},
-				},
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(3)},
-				},
-			},
-
-			{
-				Query:       "update badtbl set i = 1000",
-				ExpectedErr: sql.ErrTableNotFound,
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(4)},
-				},
-			},
-
-			{
-				Query:       "update t set badcol = 1000",
-				ExpectedErr: sql.ErrColumnNotFound,
-			},
-			{
-				Query: "show status like 'Com_update'",
-				Expected: []sql.Row{
-					{"Com_update", uint64(5)},
-				},
-			},
-		},
-	},
-}

processlist.go

@@ -71,6 +71,9 @@ func (pl *ProcessList) Processes() []sql.Process {
 func (pl *ProcessList) AddConnection(id uint32, addr string) {
 	pl.mu.Lock()
 	defer pl.mu.Unlock()
+	go func() {
+		sql.StatusVariables.IncrementGlobal("Threads_connected", 1)
+	}()
 	pl.procs[id] = &sql.Process{
 		Connection: id,
 		Command:    sql.ProcessCommandConnect,
@@ -98,6 +101,9 @@ func (pl *ProcessList) RemoveConnection(connID uint32) {
 	defer pl.mu.Unlock()
 	p := pl.procs[connID]
 	if p != nil {
+		go func() {
+			sql.StatusVariables.IncrementGlobal("Threads_connected", -1)
+		}()
 		if p.Kill != nil {
 			p.Kill()
 		}
@@ -112,6 +118,9 @@ func (pl *ProcessList) BeginQuery(
 ) (*sql.Context, error) {
 	pl.mu.Lock()
 	defer pl.mu.Unlock()
+
+	sql.IncrementStatusVariable(ctx, "Threads_running", 1)
+
 	id := ctx.Session.ID()
 	pid := ctx.Pid()
 	p := pl.procs[id]
@@ -145,6 +154,7 @@ func (pl *ProcessList) EndQuery(ctx *sql.Context) {
 	delete(pl.byQueryPid, pid)
 	p := pl.procs[id]
 	if p != nil && p.QueryPid == pid {
+		sql.IncrementStatusVariable(ctx, "Threads_running", -1)
 		p.Command = sql.ProcessCommandSleep
 		p.Query = ""
 		p.StartedAt = time.Now()