Files
tidb/pkg/distsql/distsql.go

281 lines
10 KiB
Go

// Copyright 2017 PingCAP, Inc.
//
// 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 distsql
import (
"context"
"fmt"
"strconv"
"unsafe"
"github.com/pingcap/errors"
"github.com/pingcap/failpoint"
"github.com/pingcap/tidb/pkg/config"
distsqlctx "github.com/pingcap/tidb/pkg/distsql/context"
"github.com/pingcap/tidb/pkg/executor/join/joinversion"
"github.com/pingcap/tidb/pkg/kv"
"github.com/pingcap/tidb/pkg/metrics"
"github.com/pingcap/tidb/pkg/sessionctx/vardef"
"github.com/pingcap/tidb/pkg/types"
"github.com/pingcap/tidb/pkg/util/logutil"
"github.com/pingcap/tidb/pkg/util/topsql/stmtstats"
"github.com/pingcap/tidb/pkg/util/tracing"
"github.com/pingcap/tidb/pkg/util/trxevents"
"github.com/pingcap/tipb/go-tipb"
"github.com/tikv/client-go/v2/tikvrpc/interceptor"
"go.uber.org/zap"
"google.golang.org/grpc/metadata"
)
// GenSelectResultFromMPPResponse generates an iterator from response.
func GenSelectResultFromMPPResponse(dctx *distsqlctx.DistSQLContext, fieldTypes []*types.FieldType, planIDs []int, rootID int, resp kv.Response) SelectResult {
// TODO: Add metric label and set open tracing.
return &selectResult{
label: "mpp",
resp: resp,
rowLen: len(fieldTypes),
fieldTypes: fieldTypes,
ctx: dctx,
copPlanIDs: planIDs,
rootPlanID: rootID,
storeType: kv.TiFlash,
}
}
// Select sends a DAG request, returns SelectResult.
// In kvReq, KeyRanges is required, Concurrency/KeepOrder/Desc/IsolationLevel/Priority are optional.
func Select(ctx context.Context, dctx *distsqlctx.DistSQLContext, kvReq *kv.Request, fieldTypes []*types.FieldType) (SelectResult, error) {
r, ctx := tracing.StartRegionEx(ctx, "distsql.Select")
defer r.End()
// For testing purpose.
if hook := ctx.Value("CheckSelectRequestHook"); hook != nil {
hook.(func(*kv.Request))(kvReq)
}
enabledRateLimitAction := dctx.EnabledRateLimitAction
originalSQL := dctx.OriginalSQL
eventCb := func(event trxevents.TransactionEvent) {
// Note: Do not assume this callback will be invoked within the same goroutine.
if copMeetLock := event.GetCopMeetLock(); copMeetLock != nil {
logutil.Logger(ctx).Debug("coprocessor encounters lock",
zap.Uint64("startTS", kvReq.StartTs),
zap.Stringer("lock", copMeetLock.LockInfo),
zap.String("stmt", originalSQL))
}
}
ctx = WithSQLKvExecCounterInterceptor(ctx, dctx.KvExecCounter)
option := &kv.ClientSendOption{
SessionMemTracker: dctx.SessionMemTracker,
EnabledRateLimitAction: enabledRateLimitAction,
EventCb: eventCb,
EnableCollectExecutionInfo: config.GetGlobalConfig().Instance.EnableCollectExecutionInfo.Load(),
TryCopLiteWorker: &dctx.TryCopLiteWorker,
}
// Force the CopLiteWorker to be used or not used for testing purposes
failpoint.Inject("TryCopLiteWorker", func(val failpoint.Value) {
n, ok := val.(int)
if !ok {
panic(fmt.Sprintf("TryCopLiteWorker: expected int, got %T (%v)", val, val))
}
option.TryCopLiteWorker.Store(uint32(n))
logutil.Logger(ctx).Info("setting TryCopLiteWorker for test",
zap.String("value", option.TryCopLiteWorker.String()),
)
})
if kvReq.StoreType == kv.TiFlash {
ctx = SetTiFlashConfVarsInContext(ctx, dctx)
option.TiFlashReplicaRead = dctx.TiFlashReplicaRead
option.AppendWarning = dctx.AppendWarning
}
resp := dctx.Client.Send(ctx, kvReq, dctx.KVVars, option)
if resp == nil {
return nil, errors.New("client returns nil response")
}
label := metrics.LblGeneral
if dctx.InRestrictedSQL {
label = metrics.LblInternal
}
// kvReq.MemTracker is used to trace and control memory usage in DistSQL layer;
// for selectResult, we just use the kvReq.MemTracker prepared for co-processor
// instead of creating a new one for simplification.
return &selectResult{
label: "dag",
resp: resp,
rowLen: len(fieldTypes),
fieldTypes: fieldTypes,
ctx: dctx,
sqlType: label,
memTracker: kvReq.MemTracker,
storeType: kvReq.StoreType,
paging: kvReq.Paging.Enable,
distSQLConcurrency: kvReq.Concurrency,
}, nil
}
// SetTiFlashConfVarsInContext set some TiFlash config variables in context.
func SetTiFlashConfVarsInContext(ctx context.Context, dctx *distsqlctx.DistSQLContext) context.Context {
if dctx.TiFlashMaxThreads != -1 {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiDBMaxTiFlashThreads, strconv.FormatInt(dctx.TiFlashMaxThreads, 10))
}
if dctx.TiFlashMaxBytesBeforeExternalJoin != -1 {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiDBMaxBytesBeforeTiFlashExternalJoin, strconv.FormatInt(dctx.TiFlashMaxBytesBeforeExternalJoin, 10))
}
if dctx.TiFlashMaxBytesBeforeExternalGroupBy != -1 {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiDBMaxBytesBeforeTiFlashExternalGroupBy, strconv.FormatInt(dctx.TiFlashMaxBytesBeforeExternalGroupBy, 10))
}
if dctx.TiFlashMaxBytesBeforeExternalSort != -1 {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiDBMaxBytesBeforeTiFlashExternalSort, strconv.FormatInt(dctx.TiFlashMaxBytesBeforeExternalSort, 10))
}
if dctx.TiFlashMaxQueryMemoryPerNode <= 0 {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiFlashMemQuotaQueryPerNode, "0")
} else {
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiFlashMemQuotaQueryPerNode, strconv.FormatInt(dctx.TiFlashMaxQueryMemoryPerNode, 10))
}
ctx = metadata.AppendToOutgoingContext(ctx, vardef.TiFlashQuerySpillRatio, strconv.FormatFloat(dctx.TiFlashQuerySpillRatio, 'f', -1, 64))
ctx = metadata.AppendToOutgoingContext(ctx, "tiflash_use_hash_join_v2", strconv.FormatBool(joinversion.IsOptimizedVersion(dctx.TiFlashHashJoinVersion)))
return ctx
}
// SelectWithRuntimeStats sends a DAG request, returns SelectResult.
// The difference from Select is that SelectWithRuntimeStats will set copPlanIDs into selectResult,
// which can help selectResult to collect runtime stats.
func SelectWithRuntimeStats(ctx context.Context, dctx *distsqlctx.DistSQLContext, kvReq *kv.Request,
fieldTypes []*types.FieldType, copPlanIDs []int, rootPlanID int) (SelectResult, error) {
sr, err := Select(ctx, dctx, kvReq, fieldTypes)
if err != nil {
return nil, err
}
if selectResult, ok := sr.(*selectResult); ok {
selectResult.copPlanIDs = copPlanIDs
selectResult.rootPlanID = rootPlanID
}
return sr, nil
}
// Analyze do a analyze request.
func Analyze(ctx context.Context, client kv.Client, kvReq *kv.Request, vars any,
isRestrict bool, dctx *distsqlctx.DistSQLContext) (SelectResult, error) {
ctx = WithSQLKvExecCounterInterceptor(ctx, dctx.KvExecCounter)
kvReq.RequestSource.RequestSourceInternal = true
kvReq.RequestSource.RequestSourceType = kv.InternalTxnStats
resp := client.Send(ctx, kvReq, vars, &kv.ClientSendOption{})
if resp == nil {
return nil, errors.New("client returns nil response")
}
label := metrics.LblGeneral
if isRestrict {
label = metrics.LblInternal
}
result := &selectResult{
label: "analyze",
resp: resp,
sqlType: label,
storeType: kvReq.StoreType,
}
return result, nil
}
// Checksum sends a checksum request.
func Checksum(ctx context.Context, client kv.Client, kvReq *kv.Request, vars any) (SelectResult, error) {
// FIXME: As BR have dependency of `Checksum` and TiDB also introduced BR as dependency, Currently we can't edit
// Checksum function signature. The two-way dependence should be removed in the future.
resp := client.Send(ctx, kvReq, vars, &kv.ClientSendOption{})
if resp == nil {
return nil, errors.New("client returns nil response")
}
result := &selectResult{
label: "checksum",
resp: resp,
sqlType: metrics.LblGeneral,
storeType: kvReq.StoreType,
}
return result, nil
}
// SetEncodeType sets the encoding method for the DAGRequest. The supported encoding
// methods are:
// 1. TypeChunk: the result is encoded using the Chunk format, refer util/chunk/chunk.go
// 2. TypeDefault: the result is encoded row by row
func SetEncodeType(ctx *distsqlctx.DistSQLContext, dagReq *tipb.DAGRequest) {
if canUseChunkRPC(ctx) {
dagReq.EncodeType = tipb.EncodeType_TypeChunk
setChunkMemoryLayout(dagReq)
} else {
dagReq.EncodeType = tipb.EncodeType_TypeDefault
}
}
func canUseChunkRPC(ctx *distsqlctx.DistSQLContext) bool {
if !ctx.EnableChunkRPC {
return false
}
if !checkAlignment() {
return false
}
return true
}
var supportedAlignment = unsafe.Sizeof(types.MyDecimal{}) == 40
// checkAlignment checks the alignment in current system environment.
// The alignment is influenced by system, machine and Golang version.
// Using this function can guarantee the alignment is we want.
func checkAlignment() bool {
return supportedAlignment
}
var systemEndian tipb.Endian
// setChunkMemoryLayout sets the chunk memory layout for the DAGRequest.
func setChunkMemoryLayout(dagReq *tipb.DAGRequest) {
dagReq.ChunkMemoryLayout = &tipb.ChunkMemoryLayout{Endian: GetSystemEndian()}
}
// GetSystemEndian gets the system endian.
func GetSystemEndian() tipb.Endian {
return systemEndian
}
func init() {
i := 0x0100
ptr := unsafe.Pointer(&i)
if 0x01 == *(*byte)(ptr) {
systemEndian = tipb.Endian_BigEndian
} else {
systemEndian = tipb.Endian_LittleEndian
}
}
// WithSQLKvExecCounterInterceptor binds an interceptor for client-go to count the
// number of SQL executions of each TiKV (if any).
func WithSQLKvExecCounterInterceptor(ctx context.Context, counter *stmtstats.KvExecCounter) context.Context {
if counter != nil {
// Unlike calling Transaction or Snapshot interface, in distsql package we directly
// face tikv Request. So we need to manually bind RPCInterceptor to ctx. Instead of
// calling SetRPCInterceptor on Transaction or Snapshot.
return interceptor.WithRPCInterceptor(ctx, counter.RPCInterceptor())
}
return ctx
}