executor: refactoring the 'replace' implementation, remove its depend…

…ency of batch checker (pingcap#12319)

executor/replace.go

@@ -18,7 +18,9 @@ import (
 	"fmt"
 
 	"github.com/opentracing/opentracing-go"
+	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/mysql"
+	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/table/tables"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/types"
@@ -53,13 +55,19 @@ func (e *ReplaceExec) Open(ctx context.Context) error {
 
 // removeRow removes the duplicate row and cleanup its keys in the key-value map,
 // but if the to-be-removed row equals to the to-be-added row, no remove or add things to do.
-func (e *ReplaceExec) removeRow(handle int64, r toBeCheckedRow) (bool, error) {
+func (e *ReplaceExec) removeRow(ctx context.Context, txn kv.Transaction, handle int64, r toBeCheckedRow) (bool, error) {
 	newRow := r.row
-	oldRow, err := e.batchChecker.getOldRow(e.ctx, r.t, handle, e.GenExprs)
+	oldRow, err := getOldRow(ctx, e.ctx, txn, r.t, handle, e.GenExprs)
 	if err != nil {
-		logutil.Logger(context.Background()).Error("get old row failed when replace", zap.Int64("handle", handle), zap.String("toBeInsertedRow", types.DatumsToStrNoErr(r.row)))
+		logutil.Logger(context.Background()).Error("get old row failed when replace",
+			zap.Int64("handle", handle),
+			zap.String("toBeInsertedRow", types.DatumsToStrNoErr(r.row)))
+		if kv.IsErrNotFound(err) {
+			err = errors.NotFoundf("can not be duplicated row, due to old row not found. handle %d", handle)
+		}
 		return false, err
 	}
+
 	rowUnchanged, err := types.EqualDatums(e.ctx.GetSessionVars().StmtCtx, oldRow, newRow)
 	if err != nil {
 		return false, err
@@ -74,36 +82,40 @@ func (e *ReplaceExec) removeRow(handle int64, r toBeCheckedRow) (bool, error) {
 		return false, err
 	}
 	e.ctx.GetSessionVars().StmtCtx.AddAffectedRows(1)
-
-	// Cleanup keys map, because the record was removed.
-	err = e.deleteDupKeys(e.ctx, r.t, [][]types.Datum{oldRow})
-	if err != nil {
-		return false, err
-	}
 	return false, nil
 }
 
 // replaceRow removes all duplicate rows for one row, then inserts it.
-func (e *ReplaceExec) replaceRow(r toBeCheckedRow) error {
+func (e *ReplaceExec) replaceRow(ctx context.Context, r toBeCheckedRow) error {
+	txn, err := e.ctx.Txn(true)
+	if err != nil {
+		return err
+	}
+
 	if r.handleKey != nil {
-		if _, found := e.dupKVs[string(r.handleKey.newKV.key)]; found {
-			handle, err := tablecodec.DecodeRowKey(r.handleKey.newKV.key)
-			if err != nil {
-				return err
-			}
-			rowUnchanged, err := e.removeRow(handle, r)
+		handle, err := tablecodec.DecodeRowKey(r.handleKey.newKV.key)
+		if err != nil {
+			return err
+		}
+
+		if _, err := txn.Get(r.handleKey.newKV.key); err == nil {
+			rowUnchanged, err := e.removeRow(ctx, txn, handle, r)
 			if err != nil {
 				return err
 			}
 			if rowUnchanged {
 				return nil
 			}
+		} else {
+			if !kv.IsErrNotFound(err) {
+				return err
+			}
 		}
 	}
 
 	// Keep on removing duplicated rows.
 	for {
-		rowUnchanged, foundDupKey, err := e.removeIndexRow(r)
+		rowUnchanged, foundDupKey, err := e.removeIndexRow(ctx, txn, r)
 		if err != nil {
 			return err
 		}
@@ -117,11 +129,10 @@ func (e *ReplaceExec) replaceRow(r toBeCheckedRow) error {
 	}
 
 	// No duplicated rows now, insert the row.
-	newHandle, err := e.addRecord(r.row)
+	_, err = e.addRecord(r.row)
 	if err != nil {
 		return err
 	}
-	e.fillBackKeys(r.t, r, newHandle)
 	return nil
 }
 
@@ -131,19 +142,25 @@ func (e *ReplaceExec) replaceRow(r toBeCheckedRow) error {
 //     2. bool: true when found the duplicated key. This only means that duplicated key was found,
 //              and the row was removed.
 //     3. error: the error.
-func (e *ReplaceExec) removeIndexRow(r toBeCheckedRow) (bool, bool, error) {
+func (e *ReplaceExec) removeIndexRow(ctx context.Context, txn kv.Transaction, r toBeCheckedRow) (bool, bool, error) {
 	for _, uk := range r.uniqueKeys {
-		if val, found := e.dupKVs[string(uk.newKV.key)]; found {
-			handle, err := tables.DecodeHandle(val)
-			if err != nil {
-				return false, found, err
-			}
-			rowUnchanged, err := e.removeRow(handle, r)
-			if err != nil {
-				return false, found, err
+		val, err := txn.Get(uk.newKV.key)
+		if err != nil {
+			if kv.IsErrNotFound(err) {
+				continue
 			}
-			return rowUnchanged, found, nil
+			return false, false, err
+		}
+
+		handle, err := tables.DecodeHandle(val)
+		if err != nil {
+			return false, true, err
+		}
+		rowUnchanged, err := e.removeRow(ctx, txn, handle, r)
+		if err != nil {
+			return false, true, err
 		}
+		return rowUnchanged, true, nil
 	}
 	return false, false, nil
 }
@@ -161,19 +178,27 @@ func (e *ReplaceExec) exec(ctx context.Context, newRows [][]types.Datum) error {
 	 * because in this case, one row was inserted after the duplicate was deleted.
 	 * See http://dev.mysql.com/doc/refman/5.7/en/mysql-affected-rows.html
 	 */
-	err := e.batchGetInsertKeys(e.ctx, e.Table, newRows)
+
+	// Get keys need to be checked.
+	toBeCheckedRows, err := e.getKeysNeedCheck(e.ctx, e.Table, newRows)
 	if err != nil {
 		return err
 	}
 
-	// Batch get the to-be-replaced rows in storage.
-	err = e.initDupOldRowValue(e.ctx, e.Table, newRows)
+	txn, err := e.ctx.Txn(true)
 	if err != nil {
 		return err
 	}
+
+	// Use BatchGet to fill cache.
+	// It's an optimization and could be removed without affecting correctness.
+	if err = prefetchDataCache(ctx, txn, toBeCheckedRows); err != nil {
+		return err
+	}
+
 	e.ctx.GetSessionVars().StmtCtx.AddRecordRows(uint64(len(newRows)))
-	for _, r := range e.toBeCheckedRows {
-		err = e.replaceRow(r)
+	for _, r := range toBeCheckedRows {
+		err = e.replaceRow(ctx, r)
 		if err != nil {
 			return err
 		}

go.sum

@@ -192,6 +192,7 @@ github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d h1:GoAlyOgbOEIFd
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/remyoudompheng/bigfft v0.0.0-20190512091148-babf20351dd7 h1:FUL3b97ZY2EPqg2NbXKuMHs5pXJB9hjj1fDHnF2vl28=
 github.com/remyoudompheng/bigfft v0.0.0-20190512091148-babf20351dd7/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+github.com/sergi/go-diff v1.0.1-0.20180205163309-da645544ed44 h1:tB9NOR21++IjLyVx3/PCPhWMwqGNCMQEH96A6dMZ/gc=
 github.com/sergi/go-diff v1.0.1-0.20180205163309-da645544ed44/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/shirou/gopsutil v2.18.10+incompatible h1:cy84jW6EVRPa5g9HAHrlbxMSIjBhDSX0OFYyMYminYs=
 github.com/shirou/gopsutil v2.18.10+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=