From 853a95e0b365f21191baf90955fd01b1886032df Mon Sep 17 00:00:00 2001
From: Edd Robinson <me@edd.io>
Date: Tue, 24 May 2016 12:25:01 +0100
Subject: [PATCH] Reduce allocations on Query's io.Stringer implementation
A query's String method is called multiple times per query. This commit
ensures all calls to query.String share use of a strings.NewReplacer.
This approximately halves the number of allocations for the benchmarked
query.
---
CHANGELOG.md | 1 +
influxql/ast_test.go | 8 ++++++++
influxql/parser.go | 11 +++++++----
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ffc55cd13..fc05849749 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@
- [#6655](https://github.com/influxdata/influxdb/issues/6655): Add HTTP(s) based subscriptions.
- [#5906](https://github.com/influxdata/influxdb/issues/5906): Dynamically update the documentation link in the admin UI.
- [#6686](https://github.com/influxdata/influxdb/pull/6686): Optimize timestamp run-length decoding
+- [#6713](https://github.com/influxdata/influxdb/pull/6713): Reduce allocations during query parsing.
### Bugfixes
diff --git a/influxql/ast_test.go b/influxql/ast_test.go
index 34cc07f8f3..7a95fbabcf 100644
--- a/influxql/ast_test.go
+++ b/influxql/ast_test.go
@@ -10,6 +10,14 @@ import (
"github.com/influxdata/influxdb/influxql"
)
+func BenchmarkQuery_String(b *testing.B) {
+ p := influxql.NewParser(strings.NewReader(`SELECT foo AS zoo, a AS b FROM bar WHERE value > 10 AND q = 'hello'`))
+ q, _ := p.ParseStatement()
+ for i := 0; i < b.N; i++ {
+ _ = q.String()
+ }
+}
+
// Ensure a value's data type can be retrieved.
func TestInspectDataType(t *testing.T) {
for i, tt := range []struct {
diff --git a/influxql/parser.go b/influxql/parser.go
index e8272bb928..7c4c28fd22 100644
--- a/influxql/parser.go
+++ b/influxql/parser.go
@@ -2680,15 +2680,18 @@ func (p *Parser) parseTokenMaybe(expected Token) bool {
return true
}
+var (
+ qsReplacer = strings.NewReplacer("\n", `\n`, `\`, `\\`, `'`, `\'`)
+ qiReplacer = strings.NewReplacer("\n", `\n`, `\`, `\\`, `"`, `\"`)
+)
+
// QuoteString returns a quoted string.
func QuoteString(s string) string {
- return `'` + strings.NewReplacer("\n", `\n`, `\`, `\\`, `'`, `\'`).Replace(s) + `'`
+ return `'` + qsReplacer.Replace(s) + `'`
}
// QuoteIdent returns a quoted identifier from multiple bare identifiers.
func QuoteIdent(segments ...string) string {
- r := strings.NewReplacer("\n", `\n`, `\`, `\\`, `"`, `\"`)
-
var buf bytes.Buffer
for i, segment := range segments {
needQuote := IdentNeedsQuotes(segment) ||
@@ -2698,7 +2701,7 @@ func QuoteIdent(segments ...string) string {
_ = buf.WriteByte('"')
}
- _, _ = buf.WriteString(r.Replace(segment))
+ _, _ = buf.WriteString(qiReplacer.Replace(segment))
if needQuote {
_ = buf.WriteByte('"')