404 lines
12 KiB
Go
404 lines
12 KiB
Go
// Copyright 2016 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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package tables
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import (
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"context"
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"io"
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"sync"
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"time"
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"github.com/opentracing/opentracing-go"
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"github.com/pingcap/errors"
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"github.com/pingcap/parser/model"
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"github.com/pingcap/parser/mysql"
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"github.com/pingcap/tidb/kv"
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"github.com/pingcap/tidb/sessionctx"
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"github.com/pingcap/tidb/sessionctx/stmtctx"
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"github.com/pingcap/tidb/table"
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"github.com/pingcap/tidb/tablecodec"
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"github.com/pingcap/tidb/types"
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"github.com/pingcap/tidb/util/rowcodec"
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)
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// indexIter is for KV store index iterator.
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type indexIter struct {
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it kv.Iterator
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idx *index
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prefix kv.Key
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colInfos []rowcodec.ColInfo
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tps []*types.FieldType
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}
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// Close does the clean up works when KV store index iterator is closed.
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func (c *indexIter) Close() {
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if c.it != nil {
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c.it.Close()
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c.it = nil
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}
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}
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// Next returns current key and moves iterator to the next step.
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func (c *indexIter) Next() (indexData []types.Datum, h kv.Handle, err error) {
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if !c.it.Valid() {
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return nil, nil, errors.Trace(io.EOF)
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}
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if !c.it.Key().HasPrefix(c.prefix) {
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return nil, nil, errors.Trace(io.EOF)
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}
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vals, err := tablecodec.DecodeIndexKV(c.it.Key(), c.it.Value(), len(c.colInfos), tablecodec.HandleNotNeeded, c.colInfos)
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if err != nil {
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return nil, nil, errors.Trace(err)
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}
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handle, err := tablecodec.DecodeIndexHandle(c.it.Key(), c.it.Value(), len(c.colInfos))
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if err != nil {
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return nil, nil, errors.Trace(err)
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}
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for i, v := range vals {
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d, err := tablecodec.DecodeColumnValue(v, c.tps[i], time.Local)
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if err != nil {
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return nil, nil, errors.Trace(err)
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}
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indexData = append(indexData, d)
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}
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// update new iter to next
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err = c.it.Next()
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if err != nil {
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return nil, nil, err
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}
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return indexData, handle, nil
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}
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// index is the data structure for index data in the KV store.
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type index struct {
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idxInfo *model.IndexInfo
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tblInfo *model.TableInfo
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prefix kv.Key
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phyTblID int64
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// initNeedRestoreData is used to initialize `needRestoredData` in `index.Create()`.
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// This routine cannot be done in `NewIndex()` because `needRestoreData` relies on `NewCollationEnabled()` and
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// the collation global variable is initialized *after* `NewIndex()`.
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initNeedRestoreData sync.Once
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needRestoredData bool
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}
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// NeedRestoredData checks whether the index columns needs restored data.
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func NeedRestoredData(idxCols []*model.IndexColumn, colInfos []*model.ColumnInfo) bool {
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for _, idxCol := range idxCols {
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col := colInfos[idxCol.Offset]
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if types.NeedRestoredData(&col.FieldType) {
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return true
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}
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}
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return false
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}
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// NewIndex builds a new Index object.
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func NewIndex(physicalID int64, tblInfo *model.TableInfo, indexInfo *model.IndexInfo) table.Index {
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// The prefix can't encode from tblInfo.ID, because table partition may change the id to partition id.
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var prefix kv.Key
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if indexInfo.Global {
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// In glabal index of partition table, prefix start with tblInfo.ID.
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prefix = tablecodec.EncodeTableIndexPrefix(tblInfo.ID, indexInfo.ID)
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} else {
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// Otherwise, start with physicalID.
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prefix = tablecodec.EncodeTableIndexPrefix(physicalID, indexInfo.ID)
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}
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index := &index{
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idxInfo: indexInfo,
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tblInfo: tblInfo,
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prefix: prefix,
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phyTblID: physicalID,
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}
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return index
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}
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// Meta returns index info.
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func (c *index) Meta() *model.IndexInfo {
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return c.idxInfo
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}
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// GenIndexKey generates storage key for index values. Returned distinct indicates whether the
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// indexed values should be distinct in storage (i.e. whether handle is encoded in the key).
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func (c *index) GenIndexKey(sc *stmtctx.StatementContext, indexedValues []types.Datum, h kv.Handle, buf []byte) (key []byte, distinct bool, err error) {
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idxTblID := c.phyTblID
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if c.idxInfo.Global {
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idxTblID = c.tblInfo.ID
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}
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return tablecodec.GenIndexKey(sc, c.tblInfo, c.idxInfo, idxTblID, indexedValues, h, buf)
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}
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// Create creates a new entry in the kvIndex data.
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// If the index is unique and there is an existing entry with the same key,
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// Create will return the existing entry's handle as the first return value, ErrKeyExists as the second return value.
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func (c *index) Create(sctx sessionctx.Context, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle, handleRestoreData []types.Datum, opts ...table.CreateIdxOptFunc) (kv.Handle, error) {
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if c.Meta().Unique {
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txn.CacheTableInfo(c.phyTblID, c.tblInfo)
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}
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var opt table.CreateIdxOpt
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for _, fn := range opts {
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fn(&opt)
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}
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vars := sctx.GetSessionVars()
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writeBufs := vars.GetWriteStmtBufs()
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skipCheck := vars.StmtCtx.BatchCheck
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key, distinct, err := c.GenIndexKey(vars.StmtCtx, indexedValues, h, writeBufs.IndexKeyBuf)
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if err != nil {
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return nil, err
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}
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ctx := opt.Ctx
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if opt.Untouched {
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txn, err1 := sctx.Txn(true)
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if err1 != nil {
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return nil, err1
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}
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// If the index kv was untouched(unchanged), and the key/value already exists in mem-buffer,
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// should not overwrite the key with un-commit flag.
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// So if the key exists, just do nothing and return.
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v, err := txn.GetMemBuffer().Get(ctx, key)
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if err == nil && len(v) != 0 {
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return nil, nil
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}
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}
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// save the key buffer to reuse.
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writeBufs.IndexKeyBuf = key
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c.initNeedRestoreData.Do(func() {
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c.needRestoredData = NeedRestoredData(c.idxInfo.Columns, c.tblInfo.Columns)
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})
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idxVal, err := tablecodec.GenIndexValuePortal(sctx.GetSessionVars().StmtCtx, c.tblInfo, c.idxInfo, c.needRestoredData, distinct, opt.Untouched, indexedValues, h, c.phyTblID, handleRestoreData)
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if err != nil {
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return nil, err
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}
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if !distinct || skipCheck || opt.Untouched {
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err = txn.GetMemBuffer().Set(key, idxVal)
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return nil, err
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}
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if ctx != nil {
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if span := opentracing.SpanFromContext(ctx); span != nil && span.Tracer() != nil {
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span1 := span.Tracer().StartSpan("index.Create", opentracing.ChildOf(span.Context()))
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defer span1.Finish()
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ctx = opentracing.ContextWithSpan(ctx, span1)
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}
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} else {
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ctx = context.TODO()
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}
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var value []byte
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if sctx.GetSessionVars().LazyCheckKeyNotExists() {
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value, err = txn.GetMemBuffer().Get(ctx, key)
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} else {
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value, err = txn.Get(ctx, key)
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}
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if err != nil && !kv.IsErrNotFound(err) {
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return nil, err
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}
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if err != nil || len(value) == 0 {
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if sctx.GetSessionVars().LazyCheckKeyNotExists() && err != nil {
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err = txn.GetMemBuffer().SetWithFlags(key, idxVal, kv.SetPresumeKeyNotExists)
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} else {
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err = txn.GetMemBuffer().Set(key, idxVal)
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}
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return nil, err
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}
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handle, err := tablecodec.DecodeHandleInUniqueIndexValue(value, c.tblInfo.IsCommonHandle)
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if err != nil {
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return nil, err
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}
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return handle, kv.ErrKeyExists
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}
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// Delete removes the entry for handle h and indexedValues from KV index.
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func (c *index) Delete(sc *stmtctx.StatementContext, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle) error {
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key, distinct, err := c.GenIndexKey(sc, indexedValues, h, nil)
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if err != nil {
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return err
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}
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if distinct {
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err = txn.GetMemBuffer().DeleteWithFlags(key, kv.SetNeedLocked)
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} else {
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err = txn.GetMemBuffer().Delete(key)
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}
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return err
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}
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// Drop removes the KV index from store.
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func (c *index) Drop(txn kv.Transaction) error {
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it, err := txn.Iter(c.prefix, c.prefix.PrefixNext())
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if err != nil {
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return err
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}
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defer it.Close()
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// remove all indices
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for it.Valid() {
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if !it.Key().HasPrefix(c.prefix) {
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break
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}
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err := txn.GetMemBuffer().Delete(it.Key())
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if err != nil {
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return err
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}
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err = it.Next()
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Seek searches KV index for the entry with indexedValues.
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func (c *index) Seek(sc *stmtctx.StatementContext, r kv.Retriever, indexedValues []types.Datum) (iter table.IndexIterator, hit bool, err error) {
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key, _, err := c.GenIndexKey(sc, indexedValues, nil, nil)
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if err != nil {
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return nil, false, err
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}
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upperBound := c.prefix.PrefixNext()
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it, err := r.Iter(key, upperBound)
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if err != nil {
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return nil, false, err
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}
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// check if hit
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hit = false
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if it.Valid() && it.Key().Cmp(key) == 0 {
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hit = true
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}
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colInfos := BuildRowcodecColInfoForIndexColumns(c.idxInfo, c.tblInfo)
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tps := BuildFieldTypesForIndexColumns(c.idxInfo, c.tblInfo)
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return &indexIter{it: it, idx: c, prefix: c.prefix, colInfos: colInfos, tps: tps}, hit, nil
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}
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// SeekFirst returns an iterator which points to the first entry of the KV index.
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func (c *index) SeekFirst(r kv.Retriever) (iter table.IndexIterator, err error) {
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upperBound := c.prefix.PrefixNext()
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it, err := r.Iter(c.prefix, upperBound)
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if err != nil {
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return nil, err
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}
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colInfos := BuildRowcodecColInfoForIndexColumns(c.idxInfo, c.tblInfo)
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tps := BuildFieldTypesForIndexColumns(c.idxInfo, c.tblInfo)
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return &indexIter{it: it, idx: c, prefix: c.prefix, colInfos: colInfos, tps: tps}, nil
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}
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func (c *index) Exist(sc *stmtctx.StatementContext, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle) (bool, kv.Handle, error) {
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key, distinct, err := c.GenIndexKey(sc, indexedValues, h, nil)
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if err != nil {
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return false, nil, err
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}
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value, err := txn.Get(context.TODO(), key)
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if kv.IsErrNotFound(err) {
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return false, nil, nil
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}
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if err != nil {
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return false, nil, err
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}
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// For distinct index, the value of key is handle.
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if distinct {
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var handle kv.Handle
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handle, err := tablecodec.DecodeHandleInUniqueIndexValue(value, c.tblInfo.IsCommonHandle)
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if err != nil {
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return false, nil, err
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}
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if !handle.Equal(h) {
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return true, handle, kv.ErrKeyExists
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}
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return true, handle, nil
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}
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return true, h, nil
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}
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func (c *index) FetchValues(r []types.Datum, vals []types.Datum) ([]types.Datum, error) {
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needLength := len(c.idxInfo.Columns)
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if vals == nil || cap(vals) < needLength {
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vals = make([]types.Datum, needLength)
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}
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vals = vals[:needLength]
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for i, ic := range c.idxInfo.Columns {
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if ic.Offset < 0 || ic.Offset >= len(r) {
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return nil, table.ErrIndexOutBound.GenWithStackByArgs(ic.Name, ic.Offset, r)
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}
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vals[i] = r[ic.Offset]
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}
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return vals, nil
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}
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// FindChangingCol finds the changing column in idxInfo.
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func FindChangingCol(cols []*table.Column, idxInfo *model.IndexInfo) *table.Column {
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for _, ic := range idxInfo.Columns {
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if col := cols[ic.Offset]; col.ChangeStateInfo != nil {
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return col
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}
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}
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return nil
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}
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// IsIndexWritable check whether the index is writable.
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func IsIndexWritable(idx table.Index) bool {
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s := idx.Meta().State
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if s != model.StateDeleteOnly && s != model.StateDeleteReorganization {
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return true
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}
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return false
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}
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// BuildRowcodecColInfoForIndexColumns builds []rowcodec.ColInfo for the given index.
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// The result can be used for decoding index key-values.
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func BuildRowcodecColInfoForIndexColumns(idxInfo *model.IndexInfo, tblInfo *model.TableInfo) []rowcodec.ColInfo {
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colInfo := make([]rowcodec.ColInfo, 0, len(idxInfo.Columns))
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for _, idxCol := range idxInfo.Columns {
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col := tblInfo.Columns[idxCol.Offset]
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colInfo = append(colInfo, rowcodec.ColInfo{
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ID: col.ID,
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IsPKHandle: tblInfo.PKIsHandle && mysql.HasPriKeyFlag(col.Flag),
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Ft: rowcodec.FieldTypeFromModelColumn(col),
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})
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}
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return colInfo
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}
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// BuildFieldTypesForIndexColumns builds the index columns field types.
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func BuildFieldTypesForIndexColumns(idxInfo *model.IndexInfo, tblInfo *model.TableInfo) []*types.FieldType {
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tps := make([]*types.FieldType, 0, len(idxInfo.Columns))
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for _, idxCol := range idxInfo.Columns {
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col := tblInfo.Columns[idxCol.Offset]
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tps = append(tps, rowcodec.FieldTypeFromModelColumn(col))
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}
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return tps
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}
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// TryAppendCommonHandleRowcodecColInfos tries to append common handle columns to `colInfo`.
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func TryAppendCommonHandleRowcodecColInfos(colInfo []rowcodec.ColInfo, tblInfo *model.TableInfo) []rowcodec.ColInfo {
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if !tblInfo.IsCommonHandle || tblInfo.CommonHandleVersion == 0 {
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return colInfo
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}
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if pkIdx := FindPrimaryIndex(tblInfo); pkIdx != nil {
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for _, idxCol := range pkIdx.Columns {
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col := tblInfo.Columns[idxCol.Offset]
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colInfo = append(colInfo, rowcodec.ColInfo{
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ID: col.ID,
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Ft: rowcodec.FieldTypeFromModelColumn(col),
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})
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}
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}
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return colInfo
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}
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