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executor: fix data race in nullmap in hash join v2 #57451

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merged 1 commit into from
Nov 18, 2024
Merged

executor: fix data race in nullmap in hash join v2 #57451

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20 changes: 4 additions & 16 deletions pkg/executor/join/join_table_meta.go
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Original file line number Diff line number Diff line change
Expand Up @@ -211,14 +211,12 @@ func newTableMeta(buildKeyIndex []int, buildTypes, buildKeyTypes, probeKeyTypes
keyIndexMap := make(map[int]struct{})
meta.serializeModes = make([]codec.SerializeMode, 0, len(buildKeyIndex))
isAllKeyInteger := true
hasFixedSizeKeyColumn := false
varLengthKeyNumber := 0
for index, keyIndex := range buildKeyIndex {
keyType := buildKeyTypes[index]
prop := getKeyProp(keyType)
if prop.keyLength != chunk.VarElemLen {
meta.joinKeysLength += prop.keyLength
hasFixedSizeKeyColumn = true
} else {
meta.isJoinKeysFixedLength = false
varLengthKeyNumber++
Expand Down Expand Up @@ -327,20 +325,10 @@ func newTableMeta(buildKeyIndex []int, buildTypes, buildKeyTypes, probeKeyTypes
}
if needUsedFlag {
meta.colOffsetInNullMap = 1
// the total row length should be larger than 4 byte since the smallest unit of atomic.LoadXXX is UInt32
if len(columnsNeedToBeSaved) > 0 {
// the smallest length of a column is 4 byte, so the total row length is enough
meta.nullMapLength = (len(columnsNeedToBeSaved) + 1 + 7) / 8
} else {
// if no columns need to be converted to row format, then the key is not inlined
// 1. if any of the key columns is fixed length, then the row length is larger than 4 bytes(since the smallest length of a fixed length column is 4 bytes)
// 2. if all the key columns are variable length, there is no guarantee that the row length is larger than 4 byte, the nullmap should be 4 bytes alignment
if hasFixedSizeKeyColumn {
meta.nullMapLength = (len(columnsNeedToBeSaved) + 1 + 7) / 8
} else {
meta.nullMapLength = ((len(columnsNeedToBeSaved) + 1 + 31) / 32) * 4
}
}
// If needUsedFlag == true, during probe stage, the usedFlag will be accessed by both read/write operator,
// so atomic read/write is required. We want to keep this atomic operator inside the access of nullmap,
// then the nullMapLength should be 4 bytes alignment since the smallest unit of atomic.LoadUint32 is UInt32
meta.nullMapLength = ((len(columnsNeedToBeSaved) + 1 + 31) / 32) * 4
} else {
meta.colOffsetInNullMap = 0
meta.nullMapLength = (len(columnsNeedToBeSaved) + 7) / 8
Expand Down
14 changes: 6 additions & 8 deletions pkg/executor/join/join_table_meta_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -297,14 +297,12 @@ func TestJoinTableMetaNullMapLength(t *testing.T) {
// nullmap only used for columns that needed to be converted to rows
{[]int{0}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{}, false, 0},
{[]int{0}, []*types.FieldType{stringTp, intTp, intTp, intTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{}, false, 0},
// usedFlag is true
// the row length is at least 4 bytes, so nullmap is 1 byte alignment
{[]int{0}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, nil, true, 1},
{[]int{0}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{1}, true, 1},
{[]int{0}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{0}, true, 1},
{[]int{0, 1}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp, intTp}, []int{}, true, 1},
{[]int{0}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, []*types.FieldType{uintTp}, []int{}, true, 1},
// the row length is not guaranteed to be at least 4 bytes, nullmap is 4 bytes alignment
// usedFlag is true, nullmap is 4 byte alignment
{[]int{0}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, nil, true, 4},
{[]int{0}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{1}, true, 4},
{[]int{0}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{0}, true, 4},
{[]int{0, 1}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp, intTp}, []*types.FieldType{stringTp, intTp}, []int{}, true, 4},
{[]int{0}, []*types.FieldType{intTp}, []*types.FieldType{intTp}, []*types.FieldType{uintTp}, []int{}, true, 4},
{[]int{0}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []*types.FieldType{stringTp}, []int{}, true, 4},
{[]int{0, 1}, []*types.FieldType{stringTp, stringTp}, []*types.FieldType{stringTp, stringTp}, []*types.FieldType{stringTp, stringTp}, []int{}, true, 4},
}
Expand Down