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78 lines
2.0 KiB
78 lines
2.0 KiB
// Copyright 2017 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 aggregation
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import (
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"github.com/pingcap/tidb/sessionctx/stmtctx"
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"github.com/pingcap/tidb/types"
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"github.com/pingcap/tidb/util/chunk"
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)
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type countFunction struct {
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aggFunction
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}
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// Update implements Aggregation interface.
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func (cf *countFunction) Update(evalCtx *AggEvaluateContext, sc *stmtctx.StatementContext, row chunk.Row) error {
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var datumBuf []types.Datum
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if cf.HasDistinct {
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datumBuf = make([]types.Datum, 0, len(cf.Args))
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}
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for _, a := range cf.Args {
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value, err := a.Eval(row)
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if err != nil {
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return err
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}
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if value.IsNull() {
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return nil
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}
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if cf.Mode == FinalMode || cf.Mode == Partial2Mode {
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evalCtx.Count += value.GetInt64()
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}
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if cf.HasDistinct {
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datumBuf = append(datumBuf, value)
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}
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}
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if cf.HasDistinct {
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d, err := evalCtx.DistinctChecker.Check(datumBuf)
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if err != nil {
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return err
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}
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if !d {
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return nil
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}
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}
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if cf.Mode == CompleteMode || cf.Mode == Partial1Mode {
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evalCtx.Count++
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}
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return nil
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}
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func (cf *countFunction) ResetContext(sc *stmtctx.StatementContext, evalCtx *AggEvaluateContext) {
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if cf.HasDistinct {
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evalCtx.DistinctChecker = createDistinctChecker(sc)
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}
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evalCtx.Count = 0
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}
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// GetResult implements Aggregation interface.
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func (cf *countFunction) GetResult(evalCtx *AggEvaluateContext) (d types.Datum) {
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d.SetInt64(evalCtx.Count)
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return d
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}
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// GetPartialResult implements Aggregation interface.
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func (cf *countFunction) GetPartialResult(evalCtx *AggEvaluateContext) []types.Datum {
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return []types.Datum{cf.GetResult(evalCtx)}
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}
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