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rule_partition_processor.go
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/
rule_partition_processor.go
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// Copyright 2018 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package core
import (
"context"
"fmt"
gomath "math"
"sort"
"strings"
"github.com/pingcap/errors"
"github.com/pingcap/parser/ast"
"github.com/pingcap/parser/model"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/ddl"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/table"
"github.com/pingcap/tidb/table/tables"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/math"
"github.com/pingcap/tidb/util/plancodec"
"github.com/pingcap/tidb/util/ranger"
"github.com/pingcap/tidb/util/set"
)
// FullRange represent used all partitions.
const FullRange = -1
// partitionProcessor rewrites the ast for table partition.
//
// create table t (id int) partition by range (id)
// (partition p1 values less than (10),
// partition p2 values less than (20),
// partition p3 values less than (30))
//
// select * from t is equal to
// select * from (union all
// select * from p1 where id < 10
// select * from p2 where id < 20
// select * from p3 where id < 30)
//
// partitionProcessor is here because it's easier to prune partition after predicate push down.
type partitionProcessor struct{}
func (s *partitionProcessor) optimize(ctx context.Context, lp LogicalPlan) (LogicalPlan, error) {
return s.rewriteDataSource(lp)
}
func (s *partitionProcessor) rewriteDataSource(lp LogicalPlan) (LogicalPlan, error) {
// Assert there will not be sel -> sel in the ast.
switch p := lp.(type) {
case *DataSource:
return s.prune(p)
case *LogicalUnionScan:
ds := p.Children()[0]
ds, err := s.prune(ds.(*DataSource))
if err != nil {
return nil, err
}
if ua, ok := ds.(*LogicalPartitionUnionAll); ok {
// Adjust the UnionScan->Union->DataSource1, DataSource2 ... to
// Union->(UnionScan->DataSource1), (UnionScan->DataSource2)
children := make([]LogicalPlan, 0, len(ua.Children()))
for _, child := range ua.Children() {
us := LogicalUnionScan{
conditions: p.conditions,
handleCols: p.handleCols,
}.Init(ua.ctx, ua.blockOffset)
us.SetChildren(child)
children = append(children, us)
}
ua.SetChildren(children...)
return ua, nil
}
// Only one partition, no union all.
p.SetChildren(ds)
return p, nil
default:
children := lp.Children()
for i, child := range children {
newChild, err := s.rewriteDataSource(child)
if err != nil {
return nil, err
}
children[i] = newChild
}
}
return lp, nil
}
// partitionTable is for those tables which implement partition.
type partitionTable interface {
PartitionExpr() (*tables.PartitionExpr, error)
}
func generateHashPartitionExpr(ctx sessionctx.Context, pi *model.PartitionInfo, columns []*expression.Column, names types.NameSlice) (expression.Expression, error) {
schema := expression.NewSchema(columns...)
exprs, err := expression.ParseSimpleExprsWithNames(ctx, pi.Expr, schema, names)
if err != nil {
return nil, err
}
exprs[0].HashCode(ctx.GetSessionVars().StmtCtx)
return exprs[0], nil
}
func (s *partitionProcessor) findUsedPartitions(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
conds []expression.Expression, columns []*expression.Column, names types.NameSlice) ([]int, []expression.Expression, error) {
pi := tbl.Meta().Partition
pe, err := generateHashPartitionExpr(ctx, pi, columns, names)
if err != nil {
return nil, nil, err
}
partIdx := expression.ExtractColumns(pe)
colLen := make([]int, 0, len(partIdx))
for i := 0; i < len(partIdx); i++ {
partIdx[i].Index = i
colLen = append(colLen, types.UnspecifiedLength)
}
detachedResult, err := ranger.DetachCondAndBuildRangeForPartition(ctx, conds, partIdx, colLen)
if err != nil {
return nil, nil, err
}
ranges := detachedResult.Ranges
used := make([]int, 0, len(ranges))
for _, r := range ranges {
if r.IsPointNullable(ctx.GetSessionVars().StmtCtx) {
if !r.HighVal[0].IsNull() {
if len(r.HighVal) != len(partIdx) {
used = []int{-1}
break
}
}
highLowVals := make([]types.Datum, 0, len(r.HighVal)+len(r.LowVal))
highLowVals = append(highLowVals, r.HighVal...)
highLowVals = append(highLowVals, r.LowVal...)
pos, isNull, err := pe.EvalInt(ctx, chunk.MutRowFromDatums(highLowVals).ToRow())
if err != nil {
return nil, nil, err
}
if isNull {
pos = 0
}
idx := math.Abs(pos % int64(pi.Num))
if len(partitionNames) > 0 && !s.findByName(partitionNames, pi.Definitions[idx].Name.L) {
continue
}
used = append(used, int(idx))
} else {
// processing hash partition pruning. eg:
// create table t2 (a int, b bigint, index (a), index (b)) partition by hash(a) partitions 10;
// desc select * from t2 where t2.a between 10 and 15;
// determine whether the partition key is int
if col, ok := pe.(*expression.Column); ok && col.RetType.EvalType() == types.ETInt {
numPartitions := len(pi.Definitions)
posHigh, highIsNull, err := pe.EvalInt(ctx, chunk.MutRowFromDatums(r.HighVal).ToRow())
if err != nil {
return nil, nil, err
}
posLow, lowIsNull, err := pe.EvalInt(ctx, chunk.MutRowFromDatums(r.LowVal).ToRow())
if err != nil {
return nil, nil, err
}
// consider whether the range is closed or open
if r.LowExclude {
posLow++
}
if r.HighExclude {
posHigh--
}
var rangeScalar float64
if mysql.HasUnsignedFlag(col.RetType.Flag) {
rangeScalar = float64(uint64(posHigh)) - float64(uint64(posLow)) // use float64 to avoid integer overflow
} else {
rangeScalar = float64(posHigh) - float64(posLow) // use float64 to avoid integer overflow
}
// if range is less than the number of partitions, there will be unused partitions we can prune out.
if rangeScalar < float64(numPartitions) && !highIsNull && !lowIsNull {
for i := posLow; i <= posHigh; i++ {
idx := math.Abs(i % int64(pi.Num))
if len(partitionNames) > 0 && !s.findByName(partitionNames, pi.Definitions[idx].Name.L) {
continue
}
used = append(used, int(idx))
}
continue
}
// issue:#22619
if col.RetType.Tp == mysql.TypeBit {
// maximum number of partitions is 8192
if col.RetType.Flen > 0 && col.RetType.Flen < int(gomath.Log2(ddl.PartitionCountLimit)) {
// all possible hash values
maxUsedPartitions := 1 << col.RetType.Flen
if maxUsedPartitions < numPartitions {
for i := 0; i < maxUsedPartitions; i++ {
used = append(used, i)
}
continue
}
}
}
}
used = []int{FullRange}
break
}
}
if len(partitionNames) > 0 && len(used) == 1 && used[0] == FullRange {
or := partitionRangeOR{partitionRange{0, len(pi.Definitions)}}
return s.convertToIntSlice(or, pi, partitionNames), nil, nil
}
sort.Ints(used)
ret := used[:0]
for i := 0; i < len(used); i++ {
if i == 0 || used[i] != used[i-1] {
ret = append(ret, used[i])
}
}
return ret, detachedResult.RemainedConds, nil
}
func (s *partitionProcessor) convertToIntSlice(or partitionRangeOR, pi *model.PartitionInfo, partitionNames []model.CIStr) []int {
if len(or) == 1 && or[0].start == 0 && or[0].end == len(pi.Definitions) {
if len(partitionNames) == 0 {
return []int{FullRange}
}
}
ret := make([]int, 0, len(or))
for i := 0; i < len(or); i++ {
for pos := or[i].start; pos < or[i].end; pos++ {
if len(partitionNames) > 0 && !s.findByName(partitionNames, pi.Definitions[pos].Name.L) {
continue
}
ret = append(ret, pos)
}
}
return ret
}
func convertToRangeOr(used []int, pi *model.PartitionInfo) partitionRangeOR {
if len(used) == 1 && used[0] == -1 {
return fullRange(len(pi.Definitions))
}
ret := make(partitionRangeOR, 0, len(used))
for _, i := range used {
ret = append(ret, partitionRange{i, i + 1})
}
return ret
}
func (s *partitionProcessor) pruneHashPartition(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
conds []expression.Expression, columns []*expression.Column, names types.NameSlice) ([]int, error) {
used, _, err := s.findUsedPartitions(ctx, tbl, partitionNames, conds, columns, names)
if err != nil {
return nil, err
}
return used, nil
}
// reconstructTableColNames reconstructs FieldsNames according to ds.TblCols.
// ds.names may not match ds.TblCols since ds.names is pruned while ds.TblCols contains all original columns.
// please see https://github.com/pingcap/tidb/issues/22635 for more details.
func (s *partitionProcessor) reconstructTableColNames(ds *DataSource) ([]*types.FieldName, error) {
names := make([]*types.FieldName, 0, len(ds.TblCols))
colsInfo := ds.table.FullHiddenColsAndVisibleCols()
colsInfoMap := make(map[int64]*table.Column, len(colsInfo))
for _, c := range colsInfo {
colsInfoMap[c.ID] = c
}
for _, colExpr := range ds.TblCols {
if colExpr.ID == model.ExtraHandleID {
names = append(names, &types.FieldName{
DBName: ds.DBName,
TblName: ds.tableInfo.Name,
ColName: model.ExtraHandleName,
OrigColName: model.ExtraHandleName,
})
continue
}
if colExpr.ID == model.ExtraPidColID {
names = append(names, &types.FieldName{
DBName: ds.DBName,
TblName: ds.tableInfo.Name,
ColName: model.ExtraPartitionIdName,
OrigColName: model.ExtraPartitionIdName,
})
continue
}
if colInfo, found := colsInfoMap[colExpr.ID]; found {
names = append(names, &types.FieldName{
DBName: ds.DBName,
TblName: ds.tableInfo.Name,
ColName: colInfo.Name,
OrigTblName: ds.tableInfo.Name,
OrigColName: colInfo.Name,
})
continue
}
return nil, errors.Trace(fmt.Errorf("information of column %v is not found", colExpr.String()))
}
return names, nil
}
func (s *partitionProcessor) processHashPartition(ds *DataSource, pi *model.PartitionInfo) (LogicalPlan, error) {
names, err := s.reconstructTableColNames(ds)
if err != nil {
return nil, err
}
used, err := s.pruneHashPartition(ds.SCtx(), ds.table, ds.partitionNames, ds.allConds, ds.TblCols, names)
if err != nil {
return nil, err
}
if used != nil {
return s.makeUnionAllChildren(ds, pi, convertToRangeOr(used, pi))
}
tableDual := LogicalTableDual{RowCount: 0}.Init(ds.SCtx(), ds.blockOffset)
tableDual.schema = ds.Schema()
return tableDual, nil
}
// listPartitionPruner uses to prune partition for list partition.
type listPartitionPruner struct {
*partitionProcessor
ctx sessionctx.Context
pi *model.PartitionInfo
partitionNames []model.CIStr
colIDToUniqueID map[int64]int64
fullRange map[int]struct{}
listPrune *tables.ForListPruning
}
func newListPartitionPruner(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
s *partitionProcessor, conds []expression.Expression, pruneList *tables.ForListPruning) *listPartitionPruner {
colIDToUniqueID := make(map[int64]int64)
for _, cond := range conds {
condCols := expression.ExtractColumns(cond)
for _, c := range condCols {
colIDToUniqueID[c.ID] = c.UniqueID
}
}
fullRange := make(map[int]struct{})
fullRange[FullRange] = struct{}{}
return &listPartitionPruner{
partitionProcessor: s,
ctx: ctx,
pi: tbl.Meta().Partition,
partitionNames: partitionNames,
colIDToUniqueID: colIDToUniqueID,
fullRange: fullRange,
listPrune: pruneList,
}
}
func (l *listPartitionPruner) locatePartition(cond expression.Expression) (tables.ListPartitionLocation, bool, error) {
switch sf := cond.(type) {
case *expression.Constant:
b, err := sf.Value.ToBool(l.ctx.GetSessionVars().StmtCtx)
if err == nil && b == 0 {
// A constant false expression.
return nil, false, nil
}
case *expression.ScalarFunction:
switch sf.FuncName.L {
case ast.LogicOr:
dnfItems := expression.FlattenDNFConditions(sf)
return l.locatePartitionByDNFCondition(dnfItems)
case ast.LogicAnd:
cnfItems := expression.FlattenCNFConditions(sf)
return l.locatePartitionByCNFCondition(cnfItems)
}
return l.locatePartitionByColumn(sf)
}
return nil, true, nil
}
func (l *listPartitionPruner) locatePartitionByCNFCondition(conds []expression.Expression) (tables.ListPartitionLocation, bool, error) {
if len(conds) == 0 {
return nil, true, nil
}
countFull := 0
helper := tables.NewListPartitionLocationHelper()
for _, cond := range conds {
cnfLoc, isFull, err := l.locatePartition(cond)
if err != nil {
return nil, false, err
}
if isFull {
countFull++
continue
}
if cnfLoc.IsEmpty() {
// No partition for intersection, just return 0 partition.
return nil, false, nil
}
if !helper.Intersect(cnfLoc) {
return nil, false, nil
}
}
if countFull == len(conds) {
return nil, true, nil
}
return helper.GetLocation(), false, nil
}
func (l *listPartitionPruner) locatePartitionByDNFCondition(conds []expression.Expression) (tables.ListPartitionLocation, bool, error) {
if len(conds) == 0 {
return nil, true, nil
}
helper := tables.NewListPartitionLocationHelper()
for _, cond := range conds {
dnfLoc, isFull, err := l.locatePartition(cond)
if err != nil || isFull {
return nil, isFull, err
}
helper.Union(dnfLoc)
}
return helper.GetLocation(), false, nil
}
// locatePartitionByColumn uses to locate partition by the one of the list columns value.
// Such as: partition by list columns(a,b) (partition p0 values in ((1,1),(2,2)), partition p1 values in ((6,6),(7,7)));
// and if the condition is `a=1`, then we can use `a=1` and the expression `(a in (1,2))` to locate partition `p0`.
func (l *listPartitionPruner) locatePartitionByColumn(cond *expression.ScalarFunction) (tables.ListPartitionLocation, bool, error) {
condCols := expression.ExtractColumns(cond)
if len(condCols) != 1 {
return nil, true, nil
}
var colPrune *tables.ForListColumnPruning
for _, cp := range l.listPrune.ColPrunes {
if cp.ExprCol.ID == condCols[0].ID {
colPrune = cp
}
}
if colPrune == nil {
return nil, true, nil
}
return l.locateColumnPartitionsByCondition(cond, colPrune)
}
func (l *listPartitionPruner) locateColumnPartitionsByCondition(cond expression.Expression, colPrune *tables.ForListColumnPruning) (tables.ListPartitionLocation, bool, error) {
ranges, err := l.detachCondAndBuildRange([]expression.Expression{cond}, colPrune.ExprCol)
if err != nil {
return nil, false, err
}
sc := l.ctx.GetSessionVars().StmtCtx
helper := tables.NewListPartitionLocationHelper()
for _, r := range ranges {
if len(r.LowVal) != 1 || len(r.HighVal) != 1 {
return nil, true, nil
}
var locations []tables.ListPartitionLocation
if r.IsPointNullable(sc) {
location, err := colPrune.LocatePartition(sc, r.HighVal[0])
if err != nil {
return nil, false, err
}
locations = []tables.ListPartitionLocation{location}
} else {
locations, err = colPrune.LocateRanges(sc, r)
if err != nil {
return nil, false, nil
}
}
for _, location := range locations {
if len(l.partitionNames) > 0 {
for _, pg := range location {
if l.findByName(l.partitionNames, l.pi.Definitions[pg.PartIdx].Name.L) {
helper.UnionPartitionGroup(pg)
}
}
} else {
helper.Union(location)
}
}
}
return helper.GetLocation(), false, nil
}
func (l *listPartitionPruner) detachCondAndBuildRange(conds []expression.Expression, exprCols ...*expression.Column) ([]*ranger.Range, error) {
cols := make([]*expression.Column, 0, len(exprCols))
colLen := make([]int, 0, len(exprCols))
for _, c := range exprCols {
c = c.Clone().(*expression.Column)
if uniqueID, ok := l.colIDToUniqueID[c.ID]; ok {
c.UniqueID = uniqueID
}
cols = append(cols, c)
colLen = append(colLen, types.UnspecifiedLength)
}
detachedResult, err := ranger.DetachCondAndBuildRangeForPartition(l.ctx, conds, cols, colLen)
if err != nil {
return nil, err
}
return detachedResult.Ranges, nil
}
func (l *listPartitionPruner) findUsedListColumnsPartitions(conds []expression.Expression) (map[int]struct{}, error) {
if len(conds) == 0 {
return l.fullRange, nil
}
location, isFull, err := l.locatePartitionByCNFCondition(conds)
if err != nil {
return nil, err
}
if isFull {
return l.fullRange, nil
}
used := make(map[int]struct{}, len(location))
for _, pg := range location {
used[pg.PartIdx] = struct{}{}
}
return used, nil
}
func (l *listPartitionPruner) findUsedListPartitions(conds []expression.Expression) (map[int]struct{}, error) {
if len(conds) == 0 {
return l.fullRange, nil
}
exprCols := l.listPrune.PruneExprCols
pruneExpr := l.listPrune.PruneExpr
ranges, err := l.detachCondAndBuildRange(conds, exprCols...)
if err != nil {
return nil, err
}
used := make(map[int]struct{}, len(ranges))
for _, r := range ranges {
if r.IsPointNullable(l.ctx.GetSessionVars().StmtCtx) {
if len(r.HighVal) != len(exprCols) && !r.HighVal[0].IsNull() {
// For the list partition, if the first argument is null,
// then the list partition expression should also be null.
return l.fullRange, nil
}
value, isNull, err := pruneExpr.EvalInt(l.ctx, chunk.MutRowFromDatums(r.HighVal).ToRow())
if err != nil {
return nil, err
}
partitionIdx := l.listPrune.LocatePartition(value, isNull)
if partitionIdx == -1 {
continue
}
if len(l.partitionNames) > 0 && !l.findByName(l.partitionNames, l.pi.Definitions[partitionIdx].Name.L) {
continue
}
used[partitionIdx] = struct{}{}
} else {
return l.fullRange, nil
}
}
return used, nil
}
func (s *partitionProcessor) findUsedListPartitions(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
conds []expression.Expression) ([]int, error) {
pi := tbl.Meta().Partition
partExpr, err := tbl.(partitionTable).PartitionExpr()
if err != nil {
return nil, err
}
listPruner := newListPartitionPruner(ctx, tbl, partitionNames, s, conds, partExpr.ForListPruning)
var used map[int]struct{}
if partExpr.ForListPruning.ColPrunes == nil {
used, err = listPruner.findUsedListPartitions(conds)
} else {
used, err = listPruner.findUsedListColumnsPartitions(conds)
}
if err != nil {
return nil, err
}
if _, ok := used[FullRange]; ok {
or := partitionRangeOR{partitionRange{0, len(pi.Definitions)}}
return s.convertToIntSlice(or, pi, partitionNames), nil
}
ret := make([]int, 0, len(used))
for k := range used {
ret = append(ret, k)
}
sort.Ints(ret)
return ret, nil
}
func (s *partitionProcessor) pruneListPartition(ctx sessionctx.Context, tbl table.Table, partitionNames []model.CIStr,
conds []expression.Expression) ([]int, error) {
used, err := s.findUsedListPartitions(ctx, tbl, partitionNames, conds)
if err != nil {
return nil, err
}
return used, nil
}
func (s *partitionProcessor) prune(ds *DataSource) (LogicalPlan, error) {
pi := ds.tableInfo.GetPartitionInfo()
if pi == nil {
return ds, nil
}
// PushDownNot here can convert condition 'not (a != 1)' to 'a = 1'. When we build range from ds.allConds, the condition
// like 'not (a != 1)' would not be handled so we need to convert it to 'a = 1', which can be handled when building range.
// TODO: there may be a better way to push down Not once for all.
for i, cond := range ds.allConds {
ds.allConds[i] = expression.PushDownNot(ds.ctx, cond)
}
// Try to locate partition directly for hash partition.
switch pi.Type {
case model.PartitionTypeRange:
return s.processRangePartition(ds, pi)
case model.PartitionTypeHash:
return s.processHashPartition(ds, pi)
case model.PartitionTypeList:
return s.processListPartition(ds, pi)
}
// We haven't implement partition by list and so on.
return s.makeUnionAllChildren(ds, pi, fullRange(len(pi.Definitions)))
}
// findByName checks whether object name exists in list.
func (s *partitionProcessor) findByName(partitionNames []model.CIStr, partitionName string) bool {
for _, s := range partitionNames {
if s.L == partitionName {
return true
}
}
return false
}
func (*partitionProcessor) name() string {
return "partition_processor"
}
type lessThanDataInt struct {
data []int64
maxvalue bool
}
func (lt *lessThanDataInt) length() int {
return len(lt.data)
}
func compareUnsigned(v1, v2 int64) int {
switch {
case uint64(v1) > uint64(v2):
return 1
case uint64(v1) == uint64(v2):
return 0
}
return -1
}
func (lt *lessThanDataInt) compare(ith int, v int64, unsigned bool) int {
if ith == len(lt.data)-1 {
if lt.maxvalue {
return 1
}
}
if unsigned {
return compareUnsigned(lt.data[ith], v)
}
switch {
case lt.data[ith] > v:
return 1
case lt.data[ith] == v:
return 0
}
return -1
}
// partitionRange represents [start, range)
type partitionRange struct {
start int
end int
}
// partitionRangeOR represents OR(range1, range2, ...)
type partitionRangeOR []partitionRange
func fullRange(end int) partitionRangeOR {
var reduceAllocation [3]partitionRange
reduceAllocation[0] = partitionRange{0, end}
return reduceAllocation[:1]
}
func (or partitionRangeOR) intersectionRange(start, end int) partitionRangeOR {
// Let M = intersection, U = union, then
// a M (b U c) == (a M b) U (a M c)
ret := or[:0]
for _, r1 := range or {
newStart, newEnd := intersectionRange(r1.start, r1.end, start, end)
// Exclude the empty one.
if newEnd > newStart {
ret = append(ret, partitionRange{newStart, newEnd})
}
}
return ret
}
func (or partitionRangeOR) Len() int {
return len(or)
}
func (or partitionRangeOR) Less(i, j int) bool {
return or[i].start < or[j].start
}
func (or partitionRangeOR) Swap(i, j int) {
or[i], or[j] = or[j], or[i]
}
func (or partitionRangeOR) union(x partitionRangeOR) partitionRangeOR {
or = append(or, x...)
return or.simplify()
}
func (or partitionRangeOR) simplify() partitionRangeOR {
// if the length of the `or` is zero. We should return early.
if len(or) == 0 {
return or
}
// Make the ranges order by start.
sort.Sort(or)
sorted := or
// Iterate the sorted ranges, merge the adjacent two when their range overlap.
// For example, [0, 1), [2, 7), [3, 5), ... => [0, 1), [2, 7) ...
res := sorted[:1]
for _, curr := range sorted[1:] {
last := &res[len(res)-1]
if curr.start > last.end {
res = append(res, curr)
} else {
// Merge two.
if curr.end > last.end {
last.end = curr.end
}
}
}
return res
}
func (or partitionRangeOR) intersection(x partitionRangeOR) partitionRangeOR {
if or.Len() == 1 {
return x.intersectionRange(or[0].start, or[0].end)
}
if x.Len() == 1 {
return or.intersectionRange(x[0].start, x[0].end)
}
// Rename to x, y where len(x) > len(y)
var y partitionRangeOR
if or.Len() > x.Len() {
x, y = or, x
} else {
y = or
}
// (a U b) M (c U d) => (x M c) U (x M d), x = (a U b)
res := make(partitionRangeOR, 0, len(y))
for _, r := range y {
// As intersectionRange modify the raw data, we have to make a copy.
tmp := make(partitionRangeOR, len(x))
copy(tmp, x)
tmp = tmp.intersectionRange(r.start, r.end)
res = append(res, tmp...)
}
return res.simplify()
}
// intersectionRange calculate the intersection of [start, end) and [newStart, newEnd)
func intersectionRange(start, end, newStart, newEnd int) (int, int) {
var s, e int
if start > newStart {
s = start
} else {
s = newStart
}
if end < newEnd {
e = end
} else {
e = newEnd
}
return s, e
}
func (s *partitionProcessor) pruneRangePartition(ctx sessionctx.Context, pi *model.PartitionInfo, tbl table.PartitionedTable, conds []expression.Expression,
columns []*expression.Column, names types.NameSlice, condsToBePruned *[]expression.Expression) (partitionRangeOR, []expression.Expression, error) {
partExpr, err := tbl.(partitionTable).PartitionExpr()
if err != nil {
return nil, nil, err
}
// Partition by range columns.
if len(pi.Columns) > 0 {
result, err := s.pruneRangeColumnsPartition(ctx, conds, pi, partExpr, columns, names)
return result, nil, err
}
// Partition by range.
col, fn, mono, err := makePartitionByFnCol(ctx, columns, names, pi.Expr)
if err != nil {
return nil, nil, err
}
result := fullRange(len(pi.Definitions))
if col == nil {
return result, nil, nil
}
// Extract the partition column, if the column is not null, it's possible to prune.
pruner := rangePruner{
lessThan: lessThanDataInt{
data: partExpr.ForRangePruning.LessThan,
maxvalue: partExpr.ForRangePruning.MaxValue,
},
col: col,
partFn: fn,
monotonous: mono,
}
result = partitionRangeForCNFExpr(ctx, conds, &pruner, result)
if condsToBePruned == nil {
return result, nil, nil
}
// remove useless predicates after partition pruning
newConds := make([]expression.Expression, 0, len(*condsToBePruned))
for _, cond := range *condsToBePruned {
if dataForPrune, ok := pruner.extractDataForPrune(ctx, cond); ok {
switch dataForPrune.op {
case ast.EQ:
unsigned := mysql.HasUnsignedFlag(pruner.col.RetType.Flag)
start, _ := pruneUseBinarySearch(pruner.lessThan, dataForPrune, unsigned)
// if the type of partition key is Int
if pk, ok := partExpr.Expr.(*expression.Column); ok && pk.RetType.EvalType() == types.ETInt {
// see if can be removed
// see issue #22079: https://github.com/pingcap/tidb/issues/22079 for details
if start > 0 && pruner.lessThan.data[start-1] == dataForPrune.c && (pruner.lessThan.data[start]-1) == dataForPrune.c {
continue
}
}
}
}
newConds = append(newConds, cond)
}
return result, newConds, nil
}
func (s *partitionProcessor) processRangePartition(ds *DataSource, pi *model.PartitionInfo) (LogicalPlan, error) {
used, prunedConds, err := s.pruneRangePartition(ds.ctx, pi, ds.table.(table.PartitionedTable), ds.allConds, ds.TblCols, ds.names, &ds.pushedDownConds)
if err != nil {
return nil, err
}
if prunedConds != nil {
ds.pushedDownConds = prunedConds
}
return s.makeUnionAllChildren(ds, pi, used)
}
func (s *partitionProcessor) processListPartition(ds *DataSource, pi *model.PartitionInfo) (LogicalPlan, error) {
used, err := s.pruneListPartition(ds.SCtx(), ds.table, ds.partitionNames, ds.allConds)
if err != nil {
return nil, err
}
if used != nil {
return s.makeUnionAllChildren(ds, pi, convertToRangeOr(used, pi))
}
tableDual := LogicalTableDual{RowCount: 0}.Init(ds.SCtx(), ds.blockOffset)
tableDual.schema = ds.Schema()
return tableDual, nil
}
// makePartitionByFnCol extracts the column and function information in 'partition by ... fn(col)'.
func makePartitionByFnCol(sctx sessionctx.Context, columns []*expression.Column, names types.NameSlice, partitionExpr string) (*expression.Column, *expression.ScalarFunction, monotoneMode, error) {
monotonous := monotoneModeInvalid
schema := expression.NewSchema(columns...)
tmp, err := expression.ParseSimpleExprsWithNames(sctx, partitionExpr, schema, names)
if err != nil {
return nil, nil, monotonous, err
}
partExpr := tmp[0]
var col *expression.Column
var fn *expression.ScalarFunction
switch raw := partExpr.(type) {
case *expression.ScalarFunction:
args := raw.GetArgs()
// Special handle for floor(unix_timestamp(ts)) as partition expression.
// This pattern is so common for timestamp(3) column as partition expression that it deserve an optimization.
if raw.FuncName.L == ast.Floor {
if ut, ok := args[0].(*expression.ScalarFunction); ok && ut.FuncName.L == ast.UnixTimestamp {
args1 := ut.GetArgs()
if len(args1) == 1 {
if c, ok1 := args1[0].(*expression.Column); ok1 {
return c, raw, monotoneModeNonStrict, nil
}
}
}
}
fn = raw
monotonous = getMonotoneMode(raw.FuncName.L)
// Check the partitionExpr is in the form: fn(col, ...)
// There should be only one column argument, and it should be the first parameter.
if expression.ExtractColumnSet(args).Len() == 1 {
if col1, ok := args[0].(*expression.Column); ok {
col = col1
}
}
case *expression.Column:
col = raw
}
return col, fn, monotonous, nil
}
func partitionRangeForCNFExpr(sctx sessionctx.Context, exprs []expression.Expression,
pruner partitionRangePruner, result partitionRangeOR) partitionRangeOR {
for i := 0; i < len(exprs); i++ {
result = partitionRangeForExpr(sctx, exprs[i], pruner, result)
}
return result
}
// partitionRangeForExpr calculate the partitions for the expression.
func partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression,
pruner partitionRangePruner, result partitionRangeOR) partitionRangeOR {
// Handle AND, OR respectively.
if op, ok := expr.(*expression.ScalarFunction); ok {
if op.FuncName.L == ast.LogicAnd {
return partitionRangeForCNFExpr(sctx, op.GetArgs(), pruner, result)
} else if op.FuncName.L == ast.LogicOr {
args := op.GetArgs()
newRange := partitionRangeForOrExpr(sctx, args[0], args[1], pruner)
return result.intersection(newRange)
} else if op.FuncName.L == ast.In {
if p, ok := pruner.(*rangePruner); ok {
newRange := partitionRangeForInExpr(sctx, op.GetArgs(), p)
return result.intersection(newRange)
}
return result
}
}
// Handle a single expression.
start, end, ok := pruner.partitionRangeForExpr(sctx, expr)
if !ok {
// Can't prune, return the whole range.
return result
}
return result.intersectionRange(start, end)
}
type partitionRangePruner interface {
partitionRangeForExpr(sessionctx.Context, expression.Expression) (start, end int, succ bool)
fullRange() partitionRangeOR
}
var _ partitionRangePruner = &rangePruner{}
// rangePruner is used by 'partition by range'.
type rangePruner struct {
lessThan lessThanDataInt
col *expression.Column
partFn *expression.ScalarFunction
// If partFn is not nil, monotonous indicates partFn is monotonous or not.
monotonous monotoneMode
}
func (p *rangePruner) partitionRangeForExpr(sctx sessionctx.Context, expr expression.Expression) (int, int, bool) {
if constExpr, ok := expr.(*expression.Constant); ok {
if b, err := constExpr.Value.ToBool(sctx.GetSessionVars().StmtCtx); err == nil && b == 0 {
// A constant false expression.
return 0, 0, true
}
}
dataForPrune, ok := p.extractDataForPrune(sctx, expr)
if !ok {
return 0, 0, false
}
unsigned := mysql.HasUnsignedFlag(p.col.RetType.Flag)
start, end := pruneUseBinarySearch(p.lessThan, dataForPrune, unsigned)