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planner: fix wrong prepare plan after isolation read changed (#16293)
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@lzmhhh123
lzmhhh123 authored Jun 1, 2020
1 parent bd586dc commit 64f0d4d
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Showing 4 changed files with 88 additions and 19 deletions.
49 changes: 49 additions & 0 deletions executor/prepared_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,14 @@
package executor_test

import (
"fmt"

. "github.com/pingcap/check"
"github.com/pingcap/parser/auth"
"github.com/pingcap/parser/model"
"github.com/pingcap/tidb/domain"
plannercore "github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/util"
"github.com/pingcap/tidb/util/testkit"
)

Expand Down Expand Up @@ -53,3 +60,45 @@ func (s *testSuite1) TestIgnorePlanCache(c *C) {
tk.MustExec("execute stmt using @ignore_plan_doma")
c.Assert(tk.Se.GetSessionVars().StmtCtx.UseCache, IsFalse)
}

func (s *testSuite1) TestPrepareStmtAfterIsolationReadChange(c *C) {
tk := testkit.NewTestKitWithInit(c, s.store)
tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "localhost", CurrentUser: true, AuthUsername: "root", AuthHostname: "%"}, nil, []byte("012345678901234567890"))

tk.MustExec("drop table if exists t")
tk.MustExec("create table t(a int)")
// create virtual tiflash replica.
dom := domain.GetDomain(tk.Se)
is := dom.InfoSchema()
db, exists := is.SchemaByName(model.NewCIStr("test"))
c.Assert(exists, IsTrue)
for _, tblInfo := range db.Tables {
if tblInfo.Name.L == "t" {
tblInfo.TiFlashReplica = &model.TiFlashReplicaInfo{
Count: 1,
Available: true,
}
}
}

tk.MustExec("set @@session.tidb_isolation_read_engines='tikv'")
tk.MustExec("prepare stmt from \"select * from t\"")
tk.MustQuery("execute stmt")
tkProcess := tk.Se.ShowProcess()
ps := []*util.ProcessInfo{tkProcess}
tk.Se.SetSessionManager(&mockSessionManager1{PS: ps})
rows := tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Rows()
c.Assert(rows[len(rows)-1][2], Equals, "cop[tikv]")

tk.MustExec("set @@session.tidb_isolation_read_engines='tiflash'")
tk.MustExec("execute stmt")
tkProcess = tk.Se.ShowProcess()
ps = []*util.ProcessInfo{tkProcess}
tk.Se.SetSessionManager(&mockSessionManager1{PS: ps})
rows = tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Rows()
c.Assert(rows[len(rows)-1][2], Equals, "cop[tiflash]")

c.Assert(len(tk.Se.GetSessionVars().PreparedStmts), Equals, 1)
c.Assert(tk.Se.GetSessionVars().PreparedStmts[1].(*plannercore.CachedPrepareStmt).NormalizedSQL, Equals, "select * from t")
c.Assert(tk.Se.GetSessionVars().PreparedStmts[1].(*plannercore.CachedPrepareStmt).NormalizedPlan, Equals, "")
}
54 changes: 37 additions & 17 deletions planner/core/cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ import (
"github.com/pingcap/parser/ast"
"github.com/pingcap/parser/model"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/codec"
Expand Down Expand Up @@ -63,13 +64,14 @@ func PreparedPlanCacheEnabled() bool {
}

type pstmtPlanCacheKey struct {
database string
connID uint64
pstmtID uint32
snapshot uint64
schemaVersion int64
sqlMode mysql.SQLMode
timezoneOffset int
database string
connID uint64
pstmtID uint32
snapshot uint64
schemaVersion int64
sqlMode mysql.SQLMode
timezoneOffset int
isolationReadEngines map[kv.StoreType]struct{}

hash []byte
}
Expand All @@ -79,7 +81,7 @@ func (key *pstmtPlanCacheKey) Hash() []byte {
if len(key.hash) == 0 {
var (
dbBytes = hack.Slice(key.database)
bufferSize = len(dbBytes) + 8*6
bufferSize = len(dbBytes) + 8*6 + 3*8
)
if key.hash == nil {
key.hash = make([]byte, 0, bufferSize)
Expand All @@ -91,19 +93,32 @@ func (key *pstmtPlanCacheKey) Hash() []byte {
key.hash = codec.EncodeInt(key.hash, key.schemaVersion)
key.hash = codec.EncodeInt(key.hash, int64(key.sqlMode))
key.hash = codec.EncodeInt(key.hash, int64(key.timezoneOffset))
if _, ok := key.isolationReadEngines[kv.TiDB]; ok {
key.hash = append(key.hash, kv.TiDB.Name()...)
}
if _, ok := key.isolationReadEngines[kv.TiKV]; ok {
key.hash = append(key.hash, kv.TiKV.Name()...)
}
if _, ok := key.isolationReadEngines[kv.TiFlash]; ok {
key.hash = append(key.hash, kv.TiFlash.Name()...)
}
}
return key.hash
}

// SetPstmtIDSchemaVersion implements PstmtCacheKeyMutator interface to change pstmtID and schemaVersion of cacheKey.
// so we can reuse Key instead of new every time.
func SetPstmtIDSchemaVersion(key kvcache.Key, pstmtID uint32, schemaVersion int64) {
func SetPstmtIDSchemaVersion(key kvcache.Key, pstmtID uint32, schemaVersion int64, isolationReadEngines map[kv.StoreType]struct{}) {
psStmtKey, isPsStmtKey := key.(*pstmtPlanCacheKey)
if !isPsStmtKey {
return
}
psStmtKey.pstmtID = pstmtID
psStmtKey.schemaVersion = schemaVersion
psStmtKey.isolationReadEngines = make(map[kv.StoreType]struct{})
for k, v := range isolationReadEngines {
psStmtKey.isolationReadEngines[k] = v
}
psStmtKey.hash = psStmtKey.hash[:0]
}

Expand All @@ -113,15 +128,20 @@ func NewPSTMTPlanCacheKey(sessionVars *variable.SessionVars, pstmtID uint32, sch
if sessionVars.TimeZone != nil {
_, timezoneOffset = time.Now().In(sessionVars.TimeZone).Zone()
}
return &pstmtPlanCacheKey{
database: sessionVars.CurrentDB,
connID: sessionVars.ConnectionID,
pstmtID: pstmtID,
snapshot: sessionVars.SnapshotTS,
schemaVersion: schemaVersion,
sqlMode: sessionVars.SQLMode,
timezoneOffset: timezoneOffset,
key := &pstmtPlanCacheKey{
database: sessionVars.CurrentDB,
connID: sessionVars.ConnectionID,
pstmtID: pstmtID,
snapshot: sessionVars.SnapshotTS,
schemaVersion: schemaVersion,
sqlMode: sessionVars.SQLMode,
timezoneOffset: timezoneOffset,
isolationReadEngines: make(map[kv.StoreType]struct{}),
}
for k, v := range sessionVars.IsolationReadEngines {
key.isolationReadEngines[k] = v
}
return key
}

// PSTMTPlanCacheValue stores the cached Statement and StmtNode.
Expand Down
2 changes: 1 addition & 1 deletion planner/core/cache_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -39,5 +39,5 @@ func (s *testCacheSuite) SetUpSuite(c *C) {
func (s *testCacheSuite) TestCacheKey(c *C) {
defer testleak.AfterTest(c)()
key := NewPSTMTPlanCacheKey(s.ctx.GetSessionVars(), 1, 1)
c.Assert(key.Hash(), DeepEquals, []byte{0x74, 0x65, 0x73, 0x74, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0})
c.Assert(key.Hash(), DeepEquals, []byte{0x74, 0x65, 0x73, 0x74, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x74, 0x69, 0x64, 0x62, 0x74, 0x69, 0x6b, 0x76, 0x74, 0x69, 0x66, 0x6c, 0x61, 0x73, 0x68})
}
2 changes: 1 addition & 1 deletion session/session.go
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Original file line number Diff line number Diff line change
Expand Up @@ -267,7 +267,7 @@ func (s *session) cleanRetryInfo() {
for i, stmtID := range retryInfo.DroppedPreparedStmtIDs {
if planCacheEnabled {
if i > 0 && preparedAst != nil {
plannercore.SetPstmtIDSchemaVersion(cacheKey, stmtID, preparedAst.SchemaVersion)
plannercore.SetPstmtIDSchemaVersion(cacheKey, stmtID, preparedAst.SchemaVersion, s.sessionVars.IsolationReadEngines)
}
s.PreparedPlanCache().Delete(cacheKey)
}
Expand Down

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