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generatedexpr: reuse parser to improve performance #59304

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Merged
merged 1 commit into from
Feb 7, 2025
Merged

generatedexpr: reuse parser to improve performance #59304

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7 changes: 6 additions & 1 deletion pkg/util/generatedexpr/generated_expr.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package generatedexpr

import (
"fmt"
"sync"

"github.com/pingcap/errors"
"github.com/pingcap/tidb/pkg/meta/model"
Expand Down Expand Up @@ -53,14 +54,18 @@ func (nr *nameResolver) Leave(inNode ast.Node) (node ast.Node, ok bool) {
return inNode, true
}

var parserPool = &sync.Pool{New: func() any { return parser.New() }}

// ParseExpression parses an ExprNode from a string.
// When TiDB loads infoschema from TiKV, `GeneratedExprString`
// of `ColumnInfo` is a string field, so we need to parse
// it into ast.ExprNode. This function is for that.
func ParseExpression(expr string) (node ast.ExprNode, err error) {
expr = fmt.Sprintf("select %s", expr)
charset, collation := charset.GetDefaultCharsetAndCollate()
stmts, _, err := parser.New().ParseSQL(expr,
parse := parserPool.Get().(*parser.Parser)
defer parserPool.Put(parse)
stmts, _, err := parse.ParseSQL(expr,
parser.CharsetConnection(charset),
parser.CollationConnection(collation))
if err == nil {
Expand Down