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*: add preparedStmt metric and add limit to max prepareStmt (#8405)

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This commit is contained in:
lysu
2018-11-28 20:37:50 +08:00
committed by Zhang Jian
parent d301c16e0e
commit e7e31fae3f
9 changed files with 153 additions and 29 deletions
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5
executor/prepared.go
View File

@ -177,8 +177,7 @@ func (e *PrepareExec) Next(ctx context.Context, chk *chunk.Chunk) error {
if e.name != "" {
vars.PreparedStmtNameToID[e.name] = e.ID
}
vars.PreparedStmts[e.ID] = prepared
return nil
return vars.AddPreparedStmt(e.ID, prepared)
}
// ExecuteExec represents an EXECUTE executor.
@ -242,7 +241,7 @@ func (e *DeallocateExec) Next(ctx context.Context, chk *chunk.Chunk) error {
vars, id, vars.PreparedStmts[id].SchemaVersion,
))
}
delete(vars.PreparedStmts, id)
vars.RemovePreparedStmt(id)
return nil
}

1
metrics/metrics.go
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@ -56,6 +56,7 @@ func RegisterMetrics() {
prometheus.MustRegister(BatchAddIdxHistogram)
prometheus.MustRegister(CampaignOwnerCounter)
prometheus.MustRegister(ConnGauge)
prometheus.MustRegister(PreparedStmtGauge)
prometheus.MustRegister(CriticalErrorCounter)
prometheus.MustRegister(DDLCounter)
prometheus.MustRegister(DDLWorkerHistogram)

7
metrics/server.go
View File

@ -48,6 +48,13 @@ var (
Help: "Number of connections.",
})
PreparedStmtGauge = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: "tidb",
Subsystem: "server",
Name: "prepared_stmts",
Help: "number of prepared statements.",
})
ExecuteErrorCounter = prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: "tidb",

61
planner/core/prepare_test.go
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@ -14,16 +14,20 @@
package core_test
import (
"strconv"
"time"
. "github.com/pingcap/check"
"github.com/pingcap/parser/terror"
"github.com/pingcap/tidb/executor"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/util/memory"
"github.com/pingcap/tidb/util/testkit"
"github.com/pingcap/tidb/util/testleak"
"github.com/prometheus/client_golang/prometheus"
dto "github.com/prometheus/client_model/go"
)
@ -217,3 +221,60 @@ func (s *testPrepareSuite) TestPrepareCacheNow(c *C) {
rs = tk.MustQuery("execute stmt4").Rows()
c.Assert(rs[0][0].(string), Equals, rs[0][2].(string))
}
func (s *testPrepareSuite) TestPrepareOverMaxPreparedStmtCount(c *C) {
defer testleak.AfterTest(c)()
store, dom, err := newStoreWithBootstrap()
c.Assert(err, IsNil)
tk := testkit.NewTestKit(c, store)
defer func() {
dom.Close()
store.Close()
}()
tk.MustExec("use test")
// test prepare and deallocate.
prePrepared := readGaugeInt(metrics.PreparedStmtGauge)
tk.MustExec(`prepare stmt1 from "select 1"`)
onePrepared := readGaugeInt(metrics.PreparedStmtGauge)
c.Assert(prePrepared+1, Equals, onePrepared)
tk.MustExec(`deallocate prepare stmt1`)
deallocPrepared := readGaugeInt(metrics.PreparedStmtGauge)
c.Assert(prePrepared, Equals, deallocPrepared)
// test change global limit and make it affected in test session.
tk.MustQuery("select @@max_prepared_stmt_count").Check(testkit.Rows("-1"))
tk.MustExec("set @@global.max_prepared_stmt_count = 2")
tk.MustQuery("select @@global.max_prepared_stmt_count").Check(testkit.Rows("2"))
time.Sleep(3 * time.Second) // renew a session after 2 sec
// test close session to give up all prepared stmt
tk.MustExec(`prepare stmt2 from "select 1"`)
prePrepared = readGaugeInt(metrics.PreparedStmtGauge)
tk.Se.Close()
drawPrepared := readGaugeInt(metrics.PreparedStmtGauge)
c.Assert(prePrepared-1, Equals, drawPrepared)
// test meet max limit.
tk.Se = nil
tk.MustQuery("select @@max_prepared_stmt_count").Check(testkit.Rows("2"))
for i := 1; ; i++ {
prePrepared = readGaugeInt(metrics.PreparedStmtGauge)
if prePrepared >= 2 {
_, err = tk.Exec(`prepare stmt` + strconv.Itoa(i) + ` from "select 1"`)
c.Assert(terror.ErrorEqual(err, variable.ErrMaxPreparedStmtCountReached), IsTrue)
break
} else {
tk.Exec(`prepare stmt` + strconv.Itoa(i) + ` from "select 1"`)
}
}
}
func readGaugeInt(g prometheus.Gauge) int {
ch := make(chan prometheus.Metric, 1)
g.Collect(ch)
m := <-ch
mm := &dto.Metric{}
m.Write(mm)
return int(mm.GetGauge().GetValue())
}

6
session/session.go
View File

@ -189,7 +189,7 @@ func (s *session) cleanRetryInfo() {
}
s.PreparedPlanCache().Delete(cacheKey)
}
delete(s.sessionVars.PreparedStmts, stmtID)
s.sessionVars.RemovePreparedStmt(stmtID)
}
}
@ -1097,6 +1097,9 @@ func (s *session) Close() {
if err := s.RollbackTxn(ctx); err != nil {
log.Error("session Close error:", errors.ErrorStack(err))
}
if s.sessionVars != nil {
s.sessionVars.WithdrawAllPreparedStmt()
}
}
// GetSessionVars implements the context.Context interface.
@ -1381,6 +1384,7 @@ const loadCommonGlobalVarsSQL = "select HIGH_PRIORITY * from mysql.global_variab
variable.TimeZone + quoteCommaQuote +
variable.BlockEncryptionMode + quoteCommaQuote +
variable.WaitTimeout + quoteCommaQuote +
variable.MaxPreparedStmtCount + quoteCommaQuote +
/* TiDB specific global variables: */
variable.TiDBSkipUTF8Check + quoteCommaQuote +
variable.TiDBIndexJoinBatchSize + quoteCommaQuote +

44
sessionctx/variable/session.go
View File

@ -16,6 +16,7 @@ package variable
import (
"crypto/tls"
"fmt"
"strconv"
"strings"
"sync"
"sync/atomic"
@ -31,6 +32,7 @@ import (
"github.com/pingcap/tidb/config"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/meta/autoid"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
@ -44,6 +46,8 @@ const (
codeSnapshotTooOld terror.ErrCode = 3
)
var preparedStmtCount int64
// Error instances.
var (
errCantGetValidID = terror.ClassVariable.New(codeCantGetValidID, "cannot get valid auto-increment id in retry")
@ -531,6 +535,46 @@ func (s *SessionVars) setDDLReorgPriority(val string) {
}
}
// AddPreparedStmt adds prepareStmt to current session and count in global.
func (s *SessionVars) AddPreparedStmt(stmtID uint32, stmt *ast.Prepared) error {
if _, exists := s.PreparedStmts[stmtID]; !exists {
valStr, _ := s.GetSystemVar(MaxPreparedStmtCount)
maxPreparedStmtCount, err := strconv.ParseInt(valStr, 10, 64)
if err != nil {
maxPreparedStmtCount = DefMaxPreparedStmtCount
}
newPreparedStmtCount := atomic.AddInt64(&preparedStmtCount, 1)
if maxPreparedStmtCount >= 0 && newPreparedStmtCount > maxPreparedStmtCount {
atomic.AddInt64(&preparedStmtCount, -1)
return ErrMaxPreparedStmtCountReached.GenWithStackByArgs(maxPreparedStmtCount)
}
metrics.PreparedStmtGauge.Set(float64(newPreparedStmtCount))
}
s.PreparedStmts[stmtID] = stmt
return nil
}
// RemovePreparedStmt removes preparedStmt from current session and decrease count in global.
func (s *SessionVars) RemovePreparedStmt(stmtID uint32) {
_, exists := s.PreparedStmts[stmtID]
if !exists {
return
}
delete(s.PreparedStmts, stmtID)
afterMinus := atomic.AddInt64(&preparedStmtCount, -1)
metrics.PreparedStmtGauge.Set(float64(afterMinus))
}
// WithdrawAllPreparedStmt remove all preparedStmt in current session and decrease count in global.
func (s *SessionVars) WithdrawAllPreparedStmt() {
psCount := len(s.PreparedStmts)
if psCount == 0 {
return
}
afterMinus := atomic.AddInt64(&preparedStmtCount, -int64(psCount))
metrics.PreparedStmtGauge.Set(float64(afterMinus))
}
// SetSystemVar sets the value of a system variable.
func (s *SessionVars) SetSystemVar(name string, val string) error {
switch name {

55
sessionctx/variable/sysvar.go
View File

@ -59,27 +59,29 @@ func GetSysVar(name string) *SysVar {
// Variable error codes.
const (
CodeUnknownStatusVar terror.ErrCode = 1
CodeUnknownSystemVar terror.ErrCode = mysql.ErrUnknownSystemVariable
CodeIncorrectScope terror.ErrCode = mysql.ErrIncorrectGlobalLocalVar
CodeUnknownTimeZone terror.ErrCode = mysql.ErrUnknownTimeZone
CodeReadOnly terror.ErrCode = mysql.ErrVariableIsReadonly
CodeWrongValueForVar terror.ErrCode = mysql.ErrWrongValueForVar
CodeWrongTypeForVar terror.ErrCode = mysql.ErrWrongTypeForVar
CodeTruncatedWrongValue terror.ErrCode = mysql.ErrTruncatedWrongValue
CodeUnknownStatusVar terror.ErrCode = 1
CodeUnknownSystemVar terror.ErrCode = mysql.ErrUnknownSystemVariable
CodeIncorrectScope terror.ErrCode = mysql.ErrIncorrectGlobalLocalVar
CodeUnknownTimeZone terror.ErrCode = mysql.ErrUnknownTimeZone
CodeReadOnly terror.ErrCode = mysql.ErrVariableIsReadonly
CodeWrongValueForVar terror.ErrCode = mysql.ErrWrongValueForVar
CodeWrongTypeForVar terror.ErrCode = mysql.ErrWrongTypeForVar
CodeTruncatedWrongValue terror.ErrCode = mysql.ErrTruncatedWrongValue
CodeMaxPreparedStmtCountReached terror.ErrCode = mysql.ErrMaxPreparedStmtCountReached
)
// Variable errors
var (
UnknownStatusVar = terror.ClassVariable.New(CodeUnknownStatusVar, "unknown status variable")
UnknownSystemVar = terror.ClassVariable.New(CodeUnknownSystemVar, mysql.MySQLErrName[mysql.ErrUnknownSystemVariable])
ErrIncorrectScope = terror.ClassVariable.New(CodeIncorrectScope, mysql.MySQLErrName[mysql.ErrIncorrectGlobalLocalVar])
ErrUnknownTimeZone = terror.ClassVariable.New(CodeUnknownTimeZone, mysql.MySQLErrName[mysql.ErrUnknownTimeZone])
ErrReadOnly = terror.ClassVariable.New(CodeReadOnly, "variable is read only")
ErrWrongValueForVar = terror.ClassVariable.New(CodeWrongValueForVar, mysql.MySQLErrName[mysql.ErrWrongValueForVar])
ErrWrongTypeForVar = terror.ClassVariable.New(CodeWrongTypeForVar, mysql.MySQLErrName[mysql.ErrWrongTypeForVar])
ErrTruncatedWrongValue = terror.ClassVariable.New(CodeTruncatedWrongValue, mysql.MySQLErrName[mysql.ErrTruncatedWrongValue])
ErrUnsupportedValueForVar = terror.ClassVariable.New(CodeUnknownStatusVar, "variable '%s' does not yet support value: %s")
UnknownStatusVar = terror.ClassVariable.New(CodeUnknownStatusVar, "unknown status variable")
UnknownSystemVar = terror.ClassVariable.New(CodeUnknownSystemVar, mysql.MySQLErrName[mysql.ErrUnknownSystemVariable])
ErrIncorrectScope = terror.ClassVariable.New(CodeIncorrectScope, mysql.MySQLErrName[mysql.ErrIncorrectGlobalLocalVar])
ErrUnknownTimeZone = terror.ClassVariable.New(CodeUnknownTimeZone, mysql.MySQLErrName[mysql.ErrUnknownTimeZone])
ErrReadOnly = terror.ClassVariable.New(CodeReadOnly, "variable is read only")
ErrWrongValueForVar = terror.ClassVariable.New(CodeWrongValueForVar, mysql.MySQLErrName[mysql.ErrWrongValueForVar])
ErrWrongTypeForVar = terror.ClassVariable.New(CodeWrongTypeForVar, mysql.MySQLErrName[mysql.ErrWrongTypeForVar])
ErrTruncatedWrongValue = terror.ClassVariable.New(CodeTruncatedWrongValue, mysql.MySQLErrName[mysql.ErrTruncatedWrongValue])
ErrMaxPreparedStmtCountReached = terror.ClassVariable.New(CodeMaxPreparedStmtCountReached, mysql.MySQLErrName[mysql.ErrMaxPreparedStmtCountReached])
ErrUnsupportedValueForVar = terror.ClassVariable.New(CodeUnknownStatusVar, "variable '%s' does not yet support value: %s")
)
func init() {
@ -91,13 +93,14 @@ func init() {
// Register terror to mysql error map.
mySQLErrCodes := map[terror.ErrCode]uint16{
CodeUnknownSystemVar: mysql.ErrUnknownSystemVariable,
CodeIncorrectScope: mysql.ErrIncorrectGlobalLocalVar,
CodeUnknownTimeZone: mysql.ErrUnknownTimeZone,
CodeReadOnly: mysql.ErrVariableIsReadonly,
CodeWrongValueForVar: mysql.ErrWrongValueForVar,
CodeWrongTypeForVar: mysql.ErrWrongTypeForVar,
CodeTruncatedWrongValue: mysql.ErrTruncatedWrongValue,
CodeUnknownSystemVar: mysql.ErrUnknownSystemVariable,
CodeIncorrectScope: mysql.ErrIncorrectGlobalLocalVar,
CodeUnknownTimeZone: mysql.ErrUnknownTimeZone,
CodeReadOnly: mysql.ErrVariableIsReadonly,
CodeWrongValueForVar: mysql.ErrWrongValueForVar,
CodeWrongTypeForVar: mysql.ErrWrongTypeForVar,
CodeTruncatedWrongValue: mysql.ErrTruncatedWrongValue,
CodeMaxPreparedStmtCountReached: mysql.ErrMaxPreparedStmtCountReached,
}
terror.ErrClassToMySQLCodes[terror.ClassVariable] = mySQLErrCodes
}
@ -516,7 +519,7 @@ var defaultSysVars = []*SysVar{
{ScopeSession, "innodb_create_intrinsic", ""},
{ScopeGlobal, "gtid_executed_compression_period", ""},
{ScopeGlobal, "ndb_log_empty_epochs", ""},
{ScopeGlobal, "max_prepared_stmt_count", "16382"},
{ScopeGlobal, MaxPreparedStmtCount, strconv.FormatInt(DefMaxPreparedStmtCount, 10)},
{ScopeNone, "have_geometry", "YES"},
{ScopeGlobal | ScopeSession, "optimizer_trace_max_mem_size", "16384"},
{ScopeGlobal | ScopeSession, "net_retry_count", "10"},
@ -706,6 +709,8 @@ const (
GeneralLog = "general_log"
// AvoidTemporalUpgrade is the name for 'avoid_temporal_upgrade' system variable.
AvoidTemporalUpgrade = "avoid_temporal_upgrade"
// MaxPreparedStmtCount is the name for 'max_prepared_stmt_count' system variable.
MaxPreparedStmtCount = "max_prepared_stmt_count"
// BigTables is the name for 'big_tables' system variable.
BigTables = "big_tables"
// CheckProxyUsers is the name for 'check_proxy_users' system variable.

1
sessionctx/variable/tidb_vars.go
View File

@ -240,6 +240,7 @@ const (
DefCurretTS = 0
DefMaxChunkSize = 32
DefDMLBatchSize = 20000
DefMaxPreparedStmtCount = -1
DefWaitTimeout = 28800
DefTiDBMemQuotaHashJoin = 32 << 30 // 32GB.
DefTiDBMemQuotaMergeJoin = 32 << 30 // 32GB.

2
sessionctx/variable/varsutil.go
View File

@ -292,6 +292,8 @@ func ValidateSetSystemVar(vars *SessionVars, name string, value string) (string,
return checkUInt64SystemVar(name, value, 1024, math.MaxUint64, vars)
case WaitTimeout:
return checkUInt64SystemVar(name, value, 1, 31536000, vars)
case MaxPreparedStmtCount:
return checkInt64SystemVar(name, value, -1, 1048576, vars)
case TimeZone:
if strings.EqualFold(value, "SYSTEM") {
return "SYSTEM", nil