tidb index 代码
文件路径：/table/index.go
/ Copyright 2016 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,
/ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/ See the License for the specific language governing permissions and
/ limitations under the License.
package table
import (
"context"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/parser/model"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/types"
)
/ IndexIterator is the interface for iterator of index data on KV store.
type IndexIterator interface {
Next() (k []types.Datum, h kv.Handle, err error)
Close()
}
/ CreateIdxOpt contains the options will be used when creating an index.
type CreateIdxOpt struct {
Ctx context.Context
Untouched bool / If true, the index key/value is no need to commit.
IgnoreAssertion bool
FromBackFill bool
}
/ CreateIdxOptFunc is defined for the Create() method of Index interface.
/ Here is a blog post about how to use this pattern:
/ https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
type CreateIdxOptFunc func(*CreateIdxOpt)
/ IndexIsUntouched uses to indicate the index kv is untouched.
var IndexIsUntouched CreateIdxOptFunc = func(opt *CreateIdxOpt) {
opt.Untouched = true
}
/ WithIgnoreAssertion uses to indicate the process can ignore assertion.
var WithIgnoreAssertion = func(opt *CreateIdxOpt) {
opt.IgnoreAssertion = true
}
/ FromBackfill indicates that the index is created by DDL backfill worker.
/ In the backfill-merge process, the index KVs from DML will be redirected to
/ the temp index. On the other hand, the index KVs from DDL backfill worker should
/ never be redirected to the temp index.
var FromBackfill = func(opt *CreateIdxOpt) {
opt.FromBackFill = true
}
/ WithCtx returns a CreateIdxFunc.
/ This option is used to pass context.Context.
func WithCtx(ctx context.Context) CreateIdxOptFunc {
return func(opt *CreateIdxOpt) {
opt.Ctx = ctx
}
}
/ Index is the interface for index data on KV store.
type Index interface {
/ Meta returns IndexInfo.
Meta() *model.IndexInfo
/ Create supports insert into statement.
Create(ctx sessionctx.Context, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle, handleRestoreData []types.Datum, opts ...CreateIdxOptFunc) (kv.Handle, error)
/ Delete supports delete from statement.
Delete(sc *stmtctx.StatementContext, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle) error
/ Exist supports check index exists or not.
Exist(sc *stmtctx.StatementContext, txn kv.Transaction, indexedValues []types.Datum, h kv.Handle) (bool, kv.Handle, error)
/ GenIndexKey generates an index key.
GenIndexKey(sc *stmtctx.StatementContext, indexedValues []types.Datum, h kv.Handle, buf []byte) (key []byte, distinct bool, err error)
/ GenIndexValue generates an index value.
GenIndexValue(sc *stmtctx.StatementContext, distinct bool, indexedValues []types.Datum, h kv.Handle, restoredData []types.Datum) ([]byte, error)
/ FetchValues fetched index column values in a row.
/ Param columns is a reused buffer, if it is not nil, FetchValues will fill the index values in it,
/ and return the buffer, if it is nil, FetchValues will allocate the buffer instead.
FetchValues(row []types.Datum, columns []types.Datum) ([]types.Datum, error)
}