Improved the performance of CopyIn and CopyInSchema and added BufferQ…

conn.go

@@ -2,6 +2,7 @@ package pq
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"crypto/md5"
 	"crypto/sha256"
@@ -1631,10 +1632,10 @@ func (rs *rows) NextResultSet() error {
 // QuoteIdentifier quotes an "identifier" (e.g. a table or a column name) to be
 // used as part of an SQL statement.  For example:
 //
-//    tblname := "my_table"
-//    data := "my_data"
-//    quoted := pq.QuoteIdentifier(tblname)
-//    err := db.Exec(fmt.Sprintf("INSERT INTO %s VALUES ($1)", quoted), data)
+//	tblname := "my_table"
+//	data := "my_data"
+//	quoted := pq.QuoteIdentifier(tblname)
+//	err := db.Exec(fmt.Sprintf("INSERT INTO %s VALUES ($1)", quoted), data)
 //
 // Any double quotes in name will be escaped.  The quoted identifier will be
 // case sensitive when used in a query.  If the input string contains a zero
@@ -1647,12 +1648,24 @@ func QuoteIdentifier(name string) string {
 	return `"` + strings.Replace(name, `"`, `""`, -1) + `"`
 }
 
+// BufferQuoteIdentifier satisfies the same purpose as QuoteIdentifier, but backed by a
+// byte buffer.
+func BufferQuoteIdentifier(name string, buffer *bytes.Buffer) {
+	end := strings.IndexRune(name, 0)
+	if end > -1 {
+		name = name[:end]
+	}
+	buffer.WriteRune('"')
+	buffer.WriteString(strings.Replace(name, `"`, `""`, -1))
+	buffer.WriteRune('"')
+}
+
 // QuoteLiteral quotes a 'literal' (e.g. a parameter, often used to pass literal
 // to DDL and other statements that do not accept parameters) to be used as part
 // of an SQL statement.  For example:
 //
-//    exp_date := pq.QuoteLiteral("2023-01-05 15:00:00Z")
-//    err := db.Exec(fmt.Sprintf("CREATE ROLE my_user VALID UNTIL %s", exp_date))
+//	exp_date := pq.QuoteLiteral("2023-01-05 15:00:00Z")
+//	err := db.Exec(fmt.Sprintf("CREATE ROLE my_user VALID UNTIL %s", exp_date))
 //
 // Any single quotes in name will be escaped. Any backslashes (i.e. "\") will be
 // replaced by two backslashes (i.e. "\\") and the C-style escape identifier

copy.go

@@ -1,6 +1,7 @@
 package pq
 
 import (
+	"bytes"
 	"context"
 	"database/sql/driver"
 	"encoding/binary"
@@ -20,29 +21,35 @@ var (
 // CopyIn creates a COPY FROM statement which can be prepared with
 // Tx.Prepare().  The target table should be visible in search_path.
 func CopyIn(table string, columns ...string) string {
-	stmt := "COPY " + QuoteIdentifier(table) + " ("
+	buffer := bytes.NewBufferString("COPY ")
+	BufferQuoteIdentifier(table, buffer)
+	buffer.WriteString(" (")
+	makeStmt(buffer, columns...)
+	return buffer.String()
+}
+
+// MakeStmt makes the stmt string for CopyIn and CopyInSchema.
+func makeStmt(buffer *bytes.Buffer, columns ...string) {
+	//s := bytes.NewBufferString()
 	for i, col := range columns {
 		if i != 0 {
-			stmt += ", "
+			buffer.WriteString(", ")
 		}
-		stmt += QuoteIdentifier(col)
+		BufferQuoteIdentifier(col, buffer)
 	}
-	stmt += ") FROM STDIN"
-	return stmt
+	buffer.WriteString(") FROM STDIN")
 }
 
 // CopyInSchema creates a COPY FROM statement which can be prepared with
 // Tx.Prepare().
 func CopyInSchema(schema, table string, columns ...string) string {
-	stmt := "COPY " + QuoteIdentifier(schema) + "." + QuoteIdentifier(table) + " ("
-	for i, col := range columns {
-		if i != 0 {
-			stmt += ", "
-		}
-		stmt += QuoteIdentifier(col)
-	}
-	stmt += ") FROM STDIN"
-	return stmt
+	buffer := bytes.NewBufferString("COPY ")
+	BufferQuoteIdentifier(schema, buffer)
+	buffer.WriteRune('.')
+	BufferQuoteIdentifier(table, buffer)
+	buffer.WriteString(" (")
+	makeStmt(buffer, columns...)
+	return buffer.String()
 }
 
 type copyin struct {

copy_test.go

@@ -500,3 +500,11 @@ func BenchmarkCopyIn(b *testing.B) {
 		b.Fatalf("expected %d items, not %d", b.N, num)
 	}
 }
+
+var bigTableColumns = []string{"ABIOGENETICALLY", "ABORIGINALITIES", "ABSORBABILITIES", "ABSORBEFACIENTS", "ABSORPTIOMETERS", "ABSTRACTIONISMS", "ABSTRACTIONISTS", "ACANTHOCEPHALAN", "ACCEPTABILITIES", "ACCEPTINGNESSES", "ACCESSARINESSES", "ACCESSIBILITIES", "ACCESSORINESSES", "ACCIDENTALITIES", "ACCIDENTOLOGIES", "ACCLIMATISATION", "ACCLIMATIZATION", "ACCOMMODATINGLY", "ACCOMMODATIONAL", "ACCOMPLISHMENTS", "ACCOUNTABLENESS", "ACCOUNTANTSHIPS", "ACCULTURATIONAL", "ACETOPHENETIDIN", "ACETYLSALICYLIC", "ACHONDROPLASIAS", "ACHONDROPLASTIC", "ACHROMATICITIES", "ACHROMATISATION", "ACHROMATIZATION", "ACIDIMETRICALLY", "ACKNOWLEDGEABLE", "ACKNOWLEDGEABLY", "ACKNOWLEDGEMENT", "ACKNOWLEDGMENTS", "ACQUIRABILITIES", "ACQUISITIVENESS", "ACRIMONIOUSNESS", "ACROPARESTHESIA", "ACTINOBIOLOGIES", "ACTINOCHEMISTRY", "ACTINOTHERAPIES", "ADAPTABLENESSES", "ADDITIONALITIES", "ADENOCARCINOMAS", "ADENOHYPOPHYSES", "ADENOHYPOPHYSIS", "ADENOIDECTOMIES", "ADIATHERMANCIES", "ADJUSTABILITIES", "ADMINISTRATIONS", "ADMIRABLENESSES", "ADMISSIBILITIES", "ADRENALECTOMIES", "ADSORBABILITIES", "ADVENTUROUSNESS", "ADVERSARINESSES", "ADVISABLENESSES", "AERODYNAMICALLY", "AERODYNAMICISTS", "AEROELASTICIANS", "AEROHYDROPLANES", "AEROLITHOLOGIES", "AEROSOLISATIONS", "AEROSOLIZATIONS", "AFFECTABILITIES", "AFFECTIVENESSES", "AFFORDABILITIES", "AFFRANCHISEMENT", "AFTERSENSATIONS", "AGGLUTINABILITY", "AGGRANDISEMENTS", "AGGRANDIZEMENTS", "AGGREGATENESSES", "AGRANULOCYTOSES", "AGRANULOCYTOSIS", "AGREEABLENESSES", "AGRIBUSINESSMAN", "AGRIBUSINESSMEN", "AGRICULTURALIST", "AIRWORTHINESSES", "ALCOHOLISATIONS", "ALCOHOLIZATIONS", "ALCOHOLOMETRIES", "ALEXIPHARMAKONS", "ALGORITHMICALLY", "ALKALINISATIONS", "ALKALINIZATIONS", "ALLEGORICALNESS", "ALLEGORISATIONS", "ALLEGORIZATIONS", "ALLELOMORPHISMS", "ALLERGENICITIES", "ALLOTETRAPLOIDS", "ALLOTETRAPLOIDY", "ALLOTRIOMORPHIC", "ALLOWABLENESSES", "ALPHABETISATION", "ALPHABETIZATION", "ALTERNATIVENESS", "ALTITUDINARIANS", "ALUMINOSILICATE", "ALUMINOTHERMIES", "AMARYLLIDACEOUS", "AMBASSADORSHIPS", "AMBIDEXTERITIES", "AMBIGUOUSNESSES", "AMBISEXUALITIES", "AMBITIOUSNESSES", "AMINOPEPTIDASES", "AMINOPHENAZONES", "AMMONIFICATIONS", "AMORPHOUSNESSES", "AMPHIDIPLOIDIES", "AMPHITHEATRICAL", "ANACOLUTHICALLY", "ANACREONTICALLY", "ANAESTHESIOLOGY", "ANAESTHETICALLY", "ANAGRAMMATISING", "ANAGRAMMATIZING", "ANALOGOUSNESSES", "ANALYZABILITIES", "ANAMORPHOSCOPES", "ANCYLOSTOMIASES", "ANCYLOSTOMIASIS", "ANDROGYNOPHORES", "ANDROMEDOTOXINS", "ANDROMONOECIOUS", "ANDROMONOECISMS", "ANESTHETIZATION", "ANFRACTUOSITIES", "ANGUSTIROSTRATE", "ANIMATRONICALLY", "ANISOTROPICALLY", "ANKYLOSTOMIASES", "ANKYLOSTOMIASIS", "ANNIHILATIONISM", "ANOMALISTICALLY", "ANOMALOUSNESSES", "ANONYMOUSNESSES", "ANSWERABILITIES", "ANTAGONISATIONS", "ANTAGONIZATIONS", "ANTAPHRODISIACS", "ANTEPENULTIMATE", "ANTHROPOBIOLOGY", "ANTHROPOCENTRIC", "ANTHROPOGENESES", "ANTHROPOGENESIS", "ANTHROPOGENETIC", "ANTHROPOLATRIES", "ANTHROPOLOGICAL", "ANTHROPOLOGISTS", "ANTHROPOMETRIES", "ANTHROPOMETRIST", "ANTHROPOMORPHIC", "ANTHROPOPATHIES", "ANTHROPOPATHISM", "ANTHROPOPHAGIES", "ANTHROPOPHAGITE", "ANTHROPOPHAGOUS", "ANTHROPOPHOBIAS", "ANTHROPOPHOBICS", "ANTHROPOPHUISMS", "ANTHROPOPSYCHIC", "ANTHROPOSOPHIES", "ANTHROPOSOPHIST", "ANTIABORTIONIST", "ANTIALCOHOLISMS", "ANTIAPHRODISIAC", "ANTIARRHYTHMICS", "ANTICAPITALISMS", "ANTICAPITALISTS", "ANTICARCINOGENS", "ANTICHOLESTEROL", "ANTICHOLINERGIC", "ANTICHRISTIANLY", "ANTICLERICALISM", "ANTICLIMACTICAL", "ANTICOINCIDENCE", "ANTICOLONIALISM", "ANTICOLONIALIST", "ANTICOMPETITIVE", "ANTICONVULSANTS", "ANTICONVULSIVES", "ANTIDEPRESSANTS", "ANTIDERIVATIVES", "ANTIDEVELOPMENT", "ANTIEDUCATIONAL", "ANTIEGALITARIAN", "ANTIFASHIONABLE", "ANTIFEDERALISTS", "ANTIFERROMAGNET", "ANTIFORECLOSURE", "ANTIHELMINTHICS", "ANTIHISTAMINICS", "ANTILIBERALISMS", "ANTILIBERTARIAN", "ANTILOGARITHMIC", "ANTIMATERIALISM", "ANTIMATERIALIST", "ANTIMETABOLITES", "ANTIMILITARISMS", "ANTIMILITARISTS", "ANTIMONARCHICAL", "ANTIMONARCHISTS", "ANTIMONOPOLISTS", "ANTINATIONALIST", "ANTINUCLEARISTS", "ANTIODONTALGICS", "ANTIPERISTALSES", "ANTIPERISTALSIS", "ANTIPERISTALTIC", "ANTIPERSPIRANTS", "ANTIPHLOGISTICS", "ANTIPORNOGRAPHY", "ANTIPROGRESSIVE", "ANTIQUARIANISMS", "ANTIRADICALISMS", "ANTIRATIONALISM", "ANTIRATIONALIST", "ANTIRATIONALITY", "ANTIREPUBLICANS", "ANTIROMANTICISM", "ANTISEGREGATION", "ANTISENTIMENTAL", "ANTISEPARATISTS", "ANTISEPTICISING", "ANTISEPTICIZING", "ANTISEXUALITIES", "ANTISHOPLIFTING", "ANTISOCIALITIES", "ANTISPECULATION", "ANTISPECULATIVE", "ANTISYPHILITICS", "ANTITHEORETICAL", "ANTITHROMBOTICS", "ANTITRADITIONAL", "ANTITRANSPIRANT", "ANTITRINITARIAN", "ANTITUBERCULOUS", "ANTIVIVISECTION", "APHELIOTROPISMS", "APOCALYPTICALLY", "APOCALYPTICISMS", "APOLIPOPROTEINS", "APOLITICALITIES", "APOPHTHEGMATISE", "APOPHTHEGMATIST", "APOPHTHEGMATIZE", "APOTHEGMATISING", "APOTHEGMATIZING", "APPEALABILITIES", "APPEALINGNESSES", "APPENDICULARIAN", "APPLICABILITIES", "APPRENTICEHOODS", "APPRENTICEMENTS", "APPRENTICESHIPS", "APPROACHABILITY", "APPROPINQUATING", "APPROPINQUATION", "APPROPINQUITIES", "APPROPRIATENESS", "ARACHNOIDITISES", "ARBITRARINESSES", "ARBORICULTURIST", "ARCHAEBACTERIUM", "ARCHAEOBOTANIES", "ARCHAEOBOTANIST", "ARCHAEOMETRISTS", "ARCHAEOPTERYXES", "ARCHAEZOOLOGIES", "ARCHEOASTRONOMY", "ARCHEOBOTANISTS", "ARCHEOLOGICALLY", "ARCHEOMAGNETISM", "ARCHEOZOOLOGIES", "ARCHEOZOOLOGIST", "ARCHGENETHLIACS", "ARCHIDIACONATES", "ARCHIEPISCOPACY", "ARCHIEPISCOPATE", "ARCHITECTURALLY", "ARCHPRIESTHOODS", "ARCHPRIESTSHIPS", "ARGUMENTATIVELY", "ARIBOFLAVINOSES", "ARIBOFLAVINOSIS", "AROMATHERAPISTS", "ARRONDISSEMENTS", "ARTERIALISATION", "ARTERIALIZATION", "ARTERIOGRAPHIES", "ARTIFICIALISING", "ARTIFICIALITIES", "ARTIFICIALIZING", "ASCLEPIADACEOUS", "ASSENTIVENESSES"}
+
+func BenchmarkCopy(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		CopyIn("temp", bigTableColumns...)
+	}
+}