664 lines
22 KiB
Go
664 lines
22 KiB
Go
// Copyright 2017 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package core
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import (
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"context"
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"errors"
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"fmt"
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"math"
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"strings"
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"sync"
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"github.com/pingcap/tidb/pkg/expression"
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"github.com/pingcap/tidb/pkg/infoschema"
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"github.com/pingcap/tidb/pkg/kv"
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"github.com/pingcap/tidb/pkg/meta/model"
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"github.com/pingcap/tidb/pkg/parser/ast"
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"github.com/pingcap/tidb/pkg/parser/mysql"
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"github.com/pingcap/tidb/pkg/planner/core/base"
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core_metrics "github.com/pingcap/tidb/pkg/planner/core/metrics"
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"github.com/pingcap/tidb/pkg/planner/core/operator/physicalop"
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"github.com/pingcap/tidb/pkg/planner/util/fixcontrol"
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"github.com/pingcap/tidb/pkg/types"
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driver "github.com/pingcap/tidb/pkg/types/parser_driver"
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"github.com/pingcap/tidb/pkg/util/filter"
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"github.com/pingcap/tidb/pkg/util/intest"
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"github.com/pingcap/tidb/pkg/util/logutil"
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"go.uber.org/zap"
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)
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// Cacheable checks whether the input ast(query) is cacheable with empty session context, which is mainly for testing.
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// TODO: only for test, remove this function later on.
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func Cacheable(node ast.Node, is infoschema.InfoSchema) bool {
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c, _ := IsASTCacheable(nil, nil, node, is)
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return c
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}
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// CacheableWithCtx checks whether the input ast(query) is cacheable.
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// TODO: only for test, remove this function later on.
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func CacheableWithCtx(sctx base.PlanContext, node ast.Node, is infoschema.InfoSchema) (bool, string) {
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return IsASTCacheable(nil, sctx, node, is)
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}
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// IsASTCacheable checks whether the input ast(query) is cacheable.
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// Handle "ignore_plan_cache()" hint
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// If there are multiple hints, only one will take effect
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func IsASTCacheable(ctx context.Context, sctx base.PlanContext, node ast.Node, is infoschema.InfoSchema) (bool, string) {
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switch node.(type) {
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case *ast.SelectStmt, *ast.UpdateStmt, *ast.InsertStmt, *ast.DeleteStmt, *ast.SetOprStmt:
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default:
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return false, "not a SELECT/UPDATE/INSERT/DELETE/SET statement"
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}
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checker := cacheableChecker{
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ctx: ctx,
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sctx: sctx,
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cacheable: true,
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schema: is,
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sumInListLen: 0,
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maxNumParam: getMaxParamLimit(sctx),
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}
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node.Accept(&checker)
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return checker.cacheable, checker.reason
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}
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// cacheableChecker checks whether a query can be cached:
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type cacheableChecker struct {
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ctx context.Context
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sctx base.PlanContext
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cacheable bool
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schema infoschema.InfoSchema
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reason string // reason why cannot use plan-cache
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sumInListLen int // the accumulated number of elements in all in-lists
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maxNumParam int
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}
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// Enter implements Visitor interface.
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func (checker *cacheableChecker) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
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switch node := in.(type) {
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case *ast.InsertStmt:
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if node.Select == nil {
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nRows := len(node.Lists)
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nCols := 0
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if len(node.Lists) > 0 { // avoid index-out-of-range
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nCols = len(node.Lists[0])
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}
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if nRows*nCols > checker.maxNumParam { // to save memory
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checker.cacheable = false
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checker.reason = "too many values in the insert statement"
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return in, true
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}
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}
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case *ast.PatternInExpr:
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checker.sumInListLen += len(node.List)
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if checker.sumInListLen > checker.maxNumParam { // to save memory
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checker.cacheable = false
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checker.reason = "too many values in in-list"
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return in, true
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}
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case *ast.VariableExpr:
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checker.cacheable = false
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checker.reason = "query has user-defined variables is un-cacheable"
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return in, true
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case *ast.ExistsSubqueryExpr, *ast.SubqueryExpr:
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if !checker.sctx.GetSessionVars().EnablePlanCacheForSubquery {
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checker.cacheable = false
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checker.reason = "query has sub-queries is un-cacheable"
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return in, true
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}
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return in, false
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case *ast.FuncCallExpr:
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if _, found := expression.UnCacheableFunctions[node.FnName.L]; found {
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checker.cacheable = false
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checker.reason = fmt.Sprintf("query has '%v' is un-cacheable", node.FnName.L)
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return in, true
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}
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case *ast.OrderByClause:
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for _, item := range node.Items {
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if _, isParamMarker := item.Expr.(*driver.ParamMarkerExpr); isParamMarker {
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checker.cacheable = false
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checker.reason = "query has 'order by ?' is un-cacheable"
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return in, true
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}
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}
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case *ast.GroupByClause:
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for _, item := range node.Items {
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if _, isParamMarker := item.Expr.(*driver.ParamMarkerExpr); isParamMarker {
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checker.cacheable = false
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checker.reason = "query has 'group by ?' is un-cacheable"
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return in, true
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}
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}
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case *ast.Limit:
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if node.Count != nil {
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if _, isParamMarker := node.Count.(*driver.ParamMarkerExpr); isParamMarker && !checker.sctx.GetSessionVars().EnablePlanCacheForParamLimit {
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checker.cacheable = false
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checker.reason = "query has 'limit ?' is un-cacheable"
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return in, true
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}
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}
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if node.Offset != nil {
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if _, isParamMarker := node.Offset.(*driver.ParamMarkerExpr); isParamMarker && !checker.sctx.GetSessionVars().EnablePlanCacheForParamLimit {
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checker.cacheable = false
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checker.reason = "query has 'limit ?, 10' is un-cacheable"
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return in, true
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}
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}
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case *ast.FrameBound:
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if _, ok := node.Expr.(*driver.ParamMarkerExpr); ok {
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checker.cacheable = false
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checker.reason = "query has ? in window function frames is un-cacheable"
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return in, true
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}
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case *ast.TableName:
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if checker.schema != nil {
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checker.cacheable, checker.reason = checkTableCacheable(checker.ctx, checker.sctx, checker.schema, node, false)
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if !checker.cacheable {
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return in, true
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}
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}
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}
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return in, false
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}
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// Leave implements Visitor interface.
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func (checker *cacheableChecker) Leave(in ast.Node) (out ast.Node, ok bool) {
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return in, checker.cacheable
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}
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var nonPrepCacheCheckerPool = &sync.Pool{New: func() any { return &nonPreparedPlanCacheableChecker{} }}
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// NonPreparedPlanCacheableWithCtx checks whether this SQL is cacheable for non-prepared plan cache.
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func NonPreparedPlanCacheableWithCtx(sctx base.PlanContext, node ast.Node, is infoschema.InfoSchema) (ok bool, reason string) {
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selStmt, isSelect := node.(*ast.SelectStmt)
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if !sctx.GetSessionVars().EnableNonPreparedPlanCacheForDML &&
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(!isSelect || selStmt.LockInfo != nil) {
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return false, "not a SELECT statement"
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}
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maxNumParam := getMaxParamLimit(sctx)
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var tableNames []*ast.TableName
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switch x := node.(type) {
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case *ast.SelectStmt:
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tableNames, ok, reason = isSelectStmtNonPrepCacheableFastCheck(sctx, x)
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if !ok {
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return ok, reason
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}
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case *ast.UpdateStmt:
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if len(x.TableHints) > 0 {
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return false, "not support update statement with table hints"
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}
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if x.MultipleTable {
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return false, "not support multiple tables update statements"
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}
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tableNames, ok, reason = extractTableNames(x.TableRefs.TableRefs, tableNames)
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if !ok {
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return ok, reason
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}
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case *ast.InsertStmt:
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if len(x.TableHints) > 0 {
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return false, "not support insert statement with table hints"
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}
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if x.Select == nil { // `insert into t values (...)`
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nRows := len(x.Lists)
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nCols := 0
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if len(x.Lists) > 0 { // avoid index-out-of-range
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nCols = len(x.Lists[0])
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}
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if nRows*nCols > maxNumParam { // to save memory
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return false, "too many values in the insert statement"
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}
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tableNames, ok, reason = extractTableNames(x.Table.TableRefs, tableNames)
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if !ok {
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return ok, reason
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}
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} else { // `insert into t select ...`
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selectStmt, ok := x.Select.(*ast.SelectStmt)
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if !ok {
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return false, "not a select statement"
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}
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tableNames, ok, reason = isSelectStmtNonPrepCacheableFastCheck(sctx, selectStmt)
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if !ok {
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return ok, reason
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}
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tableNames, ok, reason = extractTableNames(x.Table.TableRefs, tableNames)
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if !ok {
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return ok, reason
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}
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}
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case *ast.DeleteStmt:
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if len(x.TableHints) > 0 {
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return false, "not support insert statement with table hints"
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}
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if x.IsMultiTable {
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return false, "not support multiple tables delete statements"
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}
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tableNames, ok, reason = extractTableNames(x.TableRefs.TableRefs, tableNames)
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if !ok {
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return ok, reason
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}
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default:
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return false, "not a SELECT/UPDATE/INSERT/DELETE statement"
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}
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// allocate and init the checker
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checker := nonPrepCacheCheckerPool.Get().(*nonPreparedPlanCacheableChecker)
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checker.reset(sctx, is, tableNames, maxNumParam)
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node.Accept(checker)
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cacheable, reason := checker.cacheable, checker.reason
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if !cacheable {
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// this metrics can measure the extra overhead of non-prep plan cache.
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core_metrics.GetNonPrepPlanCacheUnsupportedCounter().Inc()
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}
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// put the checker back
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nonPrepCacheCheckerPool.Put(checker)
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return cacheable, reason
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}
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// isSelectStmtNonPrepCacheableFastCheck checks whether the input select statement is cacheable for non-prepared plan cache.
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func isSelectStmtNonPrepCacheableFastCheck(sctx base.PlanContext, selectStmt *ast.SelectStmt) (names []*ast.TableName, ok bool, reason string) {
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if selectStmt.Kind != ast.SelectStmtKindSelect {
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return nil, false, "not a select statement"
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}
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if selectStmt.Having != nil { // having
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return nil, false, "queries with HAVING clauses are not supported"
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}
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if selectStmt.WindowSpecs != nil { // window function
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return nil, false, "queries using window-functions are not supported"
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}
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if selectStmt.Limit != nil && !sctx.GetSessionVars().EnablePlanCacheForParamLimit { // limit
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return nil, false, "queries with limit clauses are not supported"
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}
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if selectStmt.SelectIntoOpt != nil { // select-into statement
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return nil, false, "SELECT INTO queries are not supported"
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}
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from := selectStmt.From
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if from == nil || selectStmt.From.TableRefs == nil {
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return nil, false, "queries that have sub-queries are not supported"
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}
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tableRefs := from.TableRefs
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// match table names, currently only support 2 tables(2-way join) at most.
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tableNames, ok, reason := extractTableNames(tableRefs, nil)
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if !ok {
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return nil, false, reason
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}
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return tableNames, true, ""
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}
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// extractTableNames extracts table names from the input node.
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// Currently support 2 tables(2-way join) at most.
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func extractTableNames(node ast.ResultSetNode, names []*ast.TableName) ([]*ast.TableName, bool, string) {
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var ok bool
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var reason string
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switch x := node.(type) {
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case *ast.TableSource:
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name, isName := x.Source.(*ast.TableName)
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if isName {
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names = append(names, name)
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} else {
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if x.Source != nil {
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names, ok, reason = extractTableNames(x.Source, names)
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if !ok {
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return nil, ok, reason
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}
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}
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}
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case *ast.Join:
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if x.Left != nil {
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names, ok, reason = extractTableNames(x.Left, names)
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if !ok {
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return nil, ok, reason
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}
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}
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if x.Right != nil {
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names, ok, reason = extractTableNames(x.Right, names)
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if !ok {
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return nil, ok, reason
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}
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}
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default:
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return names, false, "queries that have sub-queries are not supported"
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}
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if len(names) > 2 {
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return names, false, "queries that have more than 2 tables are not supported"
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}
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return names, true, ""
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}
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// nonPreparedPlanCacheableChecker checks whether a query's plan can be cached for non-prepared plan cache.
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// NOTE: we can add more rules in the future.
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type nonPreparedPlanCacheableChecker struct {
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sctx base.PlanContext
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cacheable bool
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reason string // reason why this statement cannot hit the cache
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schema infoschema.InfoSchema
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tableNodes []*ast.TableName // only support 2-way joins currently
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constCnt int // the number of constants/parameters in this query
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filterCnt int // the number of filters in the current node
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maxNumberParam int // the maximum number of parameters for a query to be cached.
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}
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func (checker *nonPreparedPlanCacheableChecker) reset(sctx base.PlanContext, schema infoschema.InfoSchema, tableNodes []*ast.TableName, maxNumberParam int) {
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checker.sctx = sctx
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checker.cacheable = true
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checker.schema = schema
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checker.reason = ""
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checker.tableNodes = tableNodes
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checker.constCnt = 0
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checker.filterCnt = 0
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checker.maxNumberParam = maxNumberParam
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}
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// Enter implements Visitor interface.
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func (checker *nonPreparedPlanCacheableChecker) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
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if checker.isFilterNode(in) {
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checker.filterCnt++
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}
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switch node := in.(type) {
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case *ast.SelectStmt, *ast.FieldList, *ast.SelectField, *ast.TableRefsClause, *ast.Join, *ast.BetweenExpr, *ast.OnCondition,
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*ast.InsertStmt, *ast.DeleteStmt, *ast.UpdateStmt, *ast.Assignment, *ast.ParenthesesExpr, *ast.RowExpr,
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*ast.TableSource, *ast.ColumnNameExpr, *ast.PatternInExpr, *ast.BinaryOperationExpr, *ast.ByItem, *ast.AggregateFuncExpr,
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*ast.TableOptimizerHint:
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return in, !checker.cacheable // skip child if un-cacheable
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case *ast.Limit:
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if !checker.sctx.GetSessionVars().EnablePlanCacheForParamLimit {
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checker.cacheable = false
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checker.reason = "query has 'limit ?' is un-cacheable"
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}
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return in, !checker.cacheable
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case *ast.ColumnName:
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if checker.filterCnt > 0 {
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// this column is appearing some filters, e.g. `col = 1`
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colFound := false
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for _, tableNode := range checker.tableNodes {
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if tableNode == nil {
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continue
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}
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if colType, found := getColType(checker.schema, tableNode, node); found {
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colFound = found
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if colType == mysql.TypeJSON || colType == mysql.TypeEnum || colType == mysql.TypeSet || colType == mysql.TypeBit {
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checker.cacheable = false
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checker.reason = "query has some filters with JSON, Enum, Set or Bit columns"
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}
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}
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}
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if !colFound {
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checker.cacheable = false
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checker.reason = "some column is not found in table schema"
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}
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}
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return in, !checker.cacheable
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case *ast.FuncCallExpr:
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if _, found := expression.UnCacheableFunctions[node.FnName.L]; found {
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checker.cacheable = false
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checker.reason = "query has un-cacheable functions"
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}
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return in, !checker.cacheable
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case *driver.ValueExpr:
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if node.GetType().GetFlag()&mysql.UnderScoreCharsetFlag > 0 {
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// for safety, not support values with under-score charsets, e.g. select _latin1'abc' from t.
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checker.cacheable = false
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checker.reason = "query has values with under-score charset"
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}
|
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if node.Kind() == types.KindBinaryLiteral {
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// for safety, BIT / HEX literals are not supported.
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checker.cacheable = false
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checker.reason = "query has BIT / HEX literals are not supported"
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}
|
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if node.IsNull() {
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// for a condition like `not-null-col = null`, the planner will optimize it to `False` and generate a
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// table-dual plan, but if it is converted to `not-null-col = ?` here, then the planner cannot do this
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// optimization and a table-full-scan will be generated.
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checker.cacheable = false
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checker.reason = "query has null constants"
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}
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checker.constCnt++
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if checker.maxNumberParam > 0 && checker.constCnt > checker.maxNumberParam { // just for safety and reduce memory cost
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checker.cacheable = false
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checker.reason = "query has too many constants"
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}
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return in, !checker.cacheable
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case *ast.GroupByClause:
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for _, item := range node.Items {
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if _, isCol := item.Expr.(*ast.ColumnNameExpr); !isCol {
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checker.cacheable = false
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checker.reason = "only support group by {columns}'"
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return in, !checker.cacheable
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}
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}
|
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return in, !checker.cacheable
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case *ast.OrderByClause:
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for _, item := range node.Items {
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if _, isCol := item.Expr.(*ast.ColumnNameExpr); !isCol {
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checker.cacheable = false
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checker.reason = "only support order by {columns}'"
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return in, !checker.cacheable
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}
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}
|
|
return in, !checker.cacheable
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case *ast.TableName:
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if filter.IsSystemSchema(node.Schema.L) {
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checker.cacheable = false
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|
checker.reason = "access tables in system schema"
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return in, !checker.cacheable
|
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}
|
|
if checker.schema != nil {
|
|
checker.cacheable, checker.reason = checkTableCacheable(nil, checker.sctx, checker.schema, node, true)
|
|
}
|
|
return in, !checker.cacheable
|
|
}
|
|
|
|
checker.cacheable = false // unexpected cases
|
|
checker.reason = "query has some unsupported Node"
|
|
return in, !checker.cacheable
|
|
}
|
|
|
|
// Leave implements Visitor interface.
|
|
func (checker *nonPreparedPlanCacheableChecker) Leave(in ast.Node) (out ast.Node, ok bool) {
|
|
if checker.isFilterNode(in) {
|
|
checker.filterCnt--
|
|
}
|
|
return in, checker.cacheable
|
|
}
|
|
|
|
func (*nonPreparedPlanCacheableChecker) isFilterNode(node ast.Node) bool {
|
|
switch node.(type) {
|
|
case *ast.BetweenExpr, *ast.PatternInExpr, *ast.BinaryOperationExpr:
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
func getColType(schema infoschema.InfoSchema, tbl *ast.TableName, col *ast.ColumnName) (colType byte, found bool) {
|
|
if tbl == nil {
|
|
return 0, false
|
|
}
|
|
tb, err := schema.TableByName(context.Background(), tbl.Schema, tbl.Name)
|
|
if err != nil {
|
|
return 0, false
|
|
}
|
|
for _, c := range tb.Cols() {
|
|
if c.Name.L == col.Name.L {
|
|
return c.GetType(), true
|
|
}
|
|
}
|
|
return 0, false
|
|
}
|
|
|
|
// isPlanCacheable returns whether this plan is cacheable and the reason if not.
|
|
func isPlanCacheable(sctx base.PlanContext, p base.Plan, paramNum, limitParamNum int, hasSubQuery bool) (cacheable bool, reason string) {
|
|
var pp base.PhysicalPlan
|
|
switch x := p.(type) {
|
|
case *physicalop.Insert:
|
|
pp = x.SelectPlan
|
|
case *physicalop.Update:
|
|
pp = x.SelectPlan
|
|
case *physicalop.Delete:
|
|
pp = x.SelectPlan
|
|
case base.PhysicalPlan:
|
|
pp = x
|
|
default:
|
|
return false, fmt.Sprintf("unexpected un-cacheable plan %v", p.ExplainID().String())
|
|
}
|
|
if pp == nil { // simple DML statements
|
|
return true, ""
|
|
}
|
|
if limitParamNum != 0 && !sctx.GetSessionVars().EnablePlanCacheForParamLimit {
|
|
return false, "the switch 'tidb_enable_plan_cache_for_param_limit' is off"
|
|
}
|
|
if hasSubQuery && !sctx.GetSessionVars().EnablePlanCacheForSubquery {
|
|
return false, "the switch 'tidb_enable_plan_cache_for_subquery' is off"
|
|
}
|
|
if sctx.GetSessionVars().PlanCacheMaxPlanSize > 0 && uint64(pp.MemoryUsage()) > sctx.GetSessionVars().PlanCacheMaxPlanSize { // to save memory
|
|
return false, "plan is too large(decided by the variable @@tidb_plan_cache_max_plan_size)"
|
|
}
|
|
return isPhysicalPlanCacheable(sctx, pp, paramNum, limitParamNum, false)
|
|
}
|
|
|
|
// isPhysicalPlanCacheable returns whether this physical plan is cacheable and return the reason if not.
|
|
func isPhysicalPlanCacheable(sctx base.PlanContext, p base.PhysicalPlan, paramNum, limitParamNum int, underIndexMerge bool) (cacheable bool, reason string) {
|
|
var subPlans []base.PhysicalPlan
|
|
switch x := p.(type) {
|
|
case *physicalop.PhysicalTableDual:
|
|
if paramNum > 0 {
|
|
return false, "get a TableDual plan"
|
|
}
|
|
case *physicalop.PhysicalTableReader:
|
|
if x.StoreType == kv.TiFlash {
|
|
return false, "TiFlash plan is un-cacheable"
|
|
}
|
|
case *physicalop.PhysicalShuffle, *physicalop.PhysicalShuffleReceiverStub:
|
|
return false, "get a Shuffle plan"
|
|
case *physicalop.PhysicalMemTable:
|
|
return false, "PhysicalMemTable plan is un-cacheable"
|
|
case *physicalop.PhysicalIndexMergeReader:
|
|
if x.AccessMVIndex && !enablePlanCacheForGeneratedCols(sctx) {
|
|
return false, "the plan with IndexMerge accessing Multi-Valued Index is un-cacheable"
|
|
}
|
|
underIndexMerge = true
|
|
subPlans = append(subPlans, x.PartialPlansRaw...)
|
|
case *physicalop.PhysicalIndexScan:
|
|
if underIndexMerge && x.IsFullScan() {
|
|
return false, "IndexMerge plan with full-scan is un-cacheable"
|
|
}
|
|
case *physicalop.PhysicalTableScan:
|
|
if underIndexMerge && x.IsFullScan() {
|
|
return false, "IndexMerge plan with full-scan is un-cacheable"
|
|
}
|
|
case *physicalop.PhysicalApply:
|
|
return false, "PhysicalApply plan is un-cacheable"
|
|
}
|
|
|
|
subPlans = append(subPlans, p.Children()...)
|
|
for _, c := range subPlans {
|
|
if cacheable, reason = isPhysicalPlanCacheable(sctx, c, paramNum, limitParamNum, underIndexMerge); !cacheable {
|
|
return cacheable, reason
|
|
}
|
|
}
|
|
return true, ""
|
|
}
|
|
|
|
// getMaxParamLimit returns the maximum number of parameters for a query that can be cached in the Plan Cache.
|
|
func getMaxParamLimit(sctx base.PlanContext) int {
|
|
v := 200
|
|
if sctx == nil || sctx.GetSessionVars() == nil || sctx.GetSessionVars().OptimizerFixControl == nil {
|
|
return v
|
|
}
|
|
n := fixcontrol.GetIntWithDefault(sctx.GetSessionVars().GetOptimizerFixControlMap(), fixcontrol.Fix44823, int64(v))
|
|
if n == 0 {
|
|
v = math.MaxInt32 // no limitation
|
|
} else if n > 0 {
|
|
v = int(n)
|
|
}
|
|
|
|
return v
|
|
}
|
|
|
|
func enablePlanCacheForGeneratedCols(sctx base.PlanContext) bool {
|
|
// disable this by default since it's not well tested.
|
|
defaultVal := true
|
|
if sctx == nil || sctx.GetSessionVars() == nil || sctx.GetSessionVars().GetOptimizerFixControlMap() == nil {
|
|
return defaultVal
|
|
}
|
|
return fixcontrol.GetBoolWithDefault(sctx.GetSessionVars().GetOptimizerFixControlMap(), fixcontrol.Fix45798, defaultVal)
|
|
}
|
|
|
|
// checkTableCacheable checks whether a query accessing this table is cacheable.
|
|
func checkTableCacheable(ctx context.Context, sctx base.PlanContext, schema infoschema.InfoSchema, node *ast.TableName, isNonPrep bool) (cacheable bool, reason string) {
|
|
tableSchema := node.Schema
|
|
if tableSchema.L == "" {
|
|
tableSchema.O = sctx.GetSessionVars().CurrentDB
|
|
tableSchema.L = strings.ToLower(tableSchema.O)
|
|
}
|
|
tb, err := schema.TableByName(context.Background(), tableSchema, node.Name)
|
|
if intest.InTest && ctx != nil && ctx.Value(PlanCacheKeyTestIssue46760{}) != nil {
|
|
err = errors.New("mock error")
|
|
}
|
|
if err != nil {
|
|
sql := sctx.GetSessionVars().StmtCtx.OriginalSQL
|
|
if len(sql) > 256 {
|
|
sql = sql[:256]
|
|
}
|
|
logutil.BgLogger().Warn("find table failed", zap.Error(err), zap.String("sql", sql),
|
|
zap.String("table_schema", tableSchema.O), zap.String("table_name", node.Name.O))
|
|
return false, fmt.Sprintf("find table %s.%s failed: %s", tableSchema, node.Name, err.Error())
|
|
}
|
|
|
|
if tb.Meta().GetPartitionInfo() != nil {
|
|
if sctx == nil || !sctx.GetSessionVars().IsDynamicPartitionPruneEnabled() {
|
|
return false, "query accesses partitioned tables is un-cacheable if tidb_partition_pruning_mode = 'static'"
|
|
}
|
|
if fixcontrol.GetBoolWithDefault(sctx.GetSessionVars().OptimizerFixControl, fixcontrol.Fix33031, false) {
|
|
return false, "Fix33031 fix-control set and partitioned table"
|
|
}
|
|
}
|
|
|
|
if !enablePlanCacheForGeneratedCols(sctx) {
|
|
for _, col := range tb.Cols() {
|
|
if col.IsGenerated() {
|
|
return false, "query accesses generated columns is un-cacheable"
|
|
}
|
|
}
|
|
}
|
|
if tb.Meta().TempTableType != model.TempTableNone {
|
|
return false, "query accesses temporary tables is un-cacheable"
|
|
}
|
|
|
|
if isNonPrep { // non-prep plan cache is stricter
|
|
if tb.Meta().IsView() {
|
|
return false, "queries that access views are not supported"
|
|
}
|
|
if !tb.Type().IsNormalTable() {
|
|
return false, "queries that access in-memory tables"
|
|
}
|
|
}
|
|
|
|
return true, ""
|
|
}
|