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planner/core: derive StatsInfo lazily. (#8336)

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This commit is contained in:
Yiding Cui
2018-11-16 17:56:42 +08:00
committed by GitHub
parent b4746797fc
commit 89db1bab64
1 changed files with 50 additions and 15 deletions
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65
planner/core/stats.go
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@ -16,7 +16,6 @@ package core
import (
"math"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/planner/property"
log "github.com/sirupsen/logrus"
@ -27,6 +26,9 @@ func (p *basePhysicalPlan) StatsCount() float64 {
}
func (p *LogicalTableDual) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
profile := &property.StatsInfo{
RowCount: float64(p.RowCount),
Cardinality: make([]float64, p.Schema().Len()),
@ -39,6 +41,9 @@ func (p *LogicalTableDual) deriveStats() (*property.StatsInfo, error) {
}
func (p *baseLogicalPlan) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
if len(p.children) > 1 {
panic("LogicalPlans with more than one child should implement their own deriveStats().")
}
@ -46,7 +51,7 @@ func (p *baseLogicalPlan) deriveStats() (*property.StatsInfo, error) {
if len(p.children) == 1 {
var err error
p.stats, err = p.children[0].deriveStats()
return p.stats, errors.Trace(err)
return p.stats, err
}
profile := &property.StatsInfo{
@ -86,6 +91,9 @@ func (ds *DataSource) getStatsByFilter(conds expression.CNFExprs) *property.Stat
}
func (ds *DataSource) deriveStats() (*property.StatsInfo, error) {
if ds.stats != nil {
return ds.stats, nil
}
// PushDownNot here can convert query 'not (a != 1)' to 'a = 1'.
for i, expr := range ds.pushedDownConds {
ds.pushedDownConds[i] = expression.PushDownNot(nil, expr, false)
@ -95,7 +103,7 @@ func (ds *DataSource) deriveStats() (*property.StatsInfo, error) {
if path.isTablePath {
noIntervalRanges, err := ds.deriveTablePathStats(path)
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
// If we have point or empty range, just remove other possible paths.
if noIntervalRanges || len(path.ranges) == 0 {
@ -107,7 +115,7 @@ func (ds *DataSource) deriveStats() (*property.StatsInfo, error) {
}
noIntervalRanges, err := ds.deriveIndexPathStats(path)
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
// If we have empty range, or point range on unique index, just remove other possible paths.
if (noIntervalRanges && path.index.Unique) || len(path.ranges) == 0 {
@ -120,22 +128,28 @@ func (ds *DataSource) deriveStats() (*property.StatsInfo, error) {
}
func (p *LogicalSelection) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
childProfile, err := p.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
p.stats = childProfile.Scale(selectionFactor)
return p.stats, nil
}
func (p *LogicalUnionAll) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
p.stats = &property.StatsInfo{
Cardinality: make([]float64, p.Schema().Len()),
}
for _, child := range p.children {
childProfile, err := child.deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
p.stats.RowCount += childProfile.RowCount
for i := range p.stats.Cardinality {
@ -146,9 +160,12 @@ func (p *LogicalUnionAll) deriveStats() (*property.StatsInfo, error) {
}
func (p *LogicalLimit) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
childProfile, err := p.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
p.stats = &property.StatsInfo{
RowCount: math.Min(float64(p.Count), childProfile.RowCount),
@ -161,9 +178,12 @@ func (p *LogicalLimit) deriveStats() (*property.StatsInfo, error) {
}
func (lt *LogicalTopN) deriveStats() (*property.StatsInfo, error) {
if lt.stats != nil {
return lt.stats, nil
}
childProfile, err := lt.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
lt.stats = &property.StatsInfo{
RowCount: math.Min(float64(lt.Count), childProfile.RowCount),
@ -192,9 +212,12 @@ func getCardinality(cols []*expression.Column, schema *expression.Schema, profil
}
func (p *LogicalProjection) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
childProfile, err := p.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
p.stats = &property.StatsInfo{
RowCount: childProfile.RowCount,
@ -208,9 +231,12 @@ func (p *LogicalProjection) deriveStats() (*property.StatsInfo, error) {
}
func (la *LogicalAggregation) deriveStats() (*property.StatsInfo, error) {
if la.stats != nil {
return la.stats, nil
}
childProfile, err := la.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
gbyCols := make([]*expression.Column, 0, len(la.GroupByItems))
for _, gbyExpr := range la.GroupByItems {
@ -238,13 +264,16 @@ func (la *LogicalAggregation) deriveStats() (*property.StatsInfo, error) {
// This is a quite simple strategy: We assume every bucket of relation which will participate join has the same number of rows, and apply cross join for
// every matched bucket.
func (p *LogicalJoin) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
leftProfile, err := p.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
rightProfile, err := p.children[1].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
if p.JoinType == SemiJoin || p.JoinType == AntiSemiJoin {
p.stats = &property.StatsInfo{
@ -300,13 +329,16 @@ func (p *LogicalJoin) deriveStats() (*property.StatsInfo, error) {
}
func (la *LogicalApply) deriveStats() (*property.StatsInfo, error) {
if la.stats != nil {
return la.stats, nil
}
leftProfile, err := la.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
_, err = la.children[1].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
la.stats = &property.StatsInfo{
RowCount: leftProfile.RowCount,
@ -336,9 +368,12 @@ func getSingletonStats(len int) *property.StatsInfo {
}
func (p *LogicalMaxOneRow) deriveStats() (*property.StatsInfo, error) {
if p.stats != nil {
return p.stats, nil
}
_, err := p.children[0].deriveStats()
if err != nil {
return nil, errors.Trace(err)
return nil, err
}
p.stats = getSingletonStats(p.Schema().Len())
return p.stats, nil