Files
tidb/expression/function_traits.go
Jun-Seok Heo 0306bb0070 tidb: support a plan cache for prepared statements (#3956)
* tidb: support a plan cache for prepared statements
2017-10-24 00:55:51 -05:00

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1.5 KiB
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// Copyright 2017 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package expression
import (
"github.com/pingcap/tidb/ast"
)
// UnCacheableFunctions stores functions which can not be cached to plan cache.
var UnCacheableFunctions = map[string]struct{}{
ast.Now: {},
ast.CurrentTimestamp: {},
ast.UTCTime: {},
ast.Curtime: {},
ast.CurrentTime: {},
ast.UTCTimestamp: {},
ast.UnixTimestamp: {},
ast.Sysdate: {},
ast.Curdate: {},
ast.CurrentDate: {},
ast.UTCDate: {},
ast.Database: {},
ast.CurrentUser: {},
ast.User: {},
ast.ConnectionID: {},
ast.LastInsertId: {},
ast.Version: {},
}
// unFoldableFunctions stores functions which can not be folded duration constant folding stage.
var unFoldableFunctions = map[string]struct{}{
ast.FoundRows: {},
ast.Rand: {},
ast.UUID: {},
ast.Sleep: {},
ast.RowFunc: {},
ast.Values: {},
ast.SetVar: {},
ast.GetVar: {},
ast.GetParam: {},
}