Implement zlib compression (#1487)

Implemented the SQL compression protocol. This new feature is enabled by:

* Adding `compress=true` in DSN.
* `cfg.Apply(Compress(True))`

Co-authored-by: Brigitte Lamarche <brigitte.lamarche@mongodb.com>
Co-authored-by: Julien Schmidt <julienschmidt@users.noreply.github.com>
Co-authored-by: Jeffrey Charles <jeffreycharles@gmail.com>
Co-authored-by: Jeff Hodges <jeff@somethingsimilar.com>
Co-authored-by: Daniel Montoya <dsmontoyam@gmail.com>
Co-authored-by: Justin Li <jli.justinli@gmail.com>
Co-authored-by: Dave Stubbs <dave@randomjunk.co.uk>
Co-authored-by: Linh Tran Tuan <linxGnu@users.noreply.github.com>
Co-authored-by: Robert R. Russell <robert@rrbrussell.com>
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>
Co-authored-by: Kieron Woodhouse <kieron.woodhouse@yahoo.co.uk>
Co-authored-by: Alexey Palazhchenko <alexey.palazhchenko@gmail.com>
Co-authored-by: Reed Allman <rdallman10@gmail.com>
Co-authored-by: Joe Mann <joe.mann@showpad.com>

.github/workflows/test.yml

@@ -83,7 +83,7 @@ jobs:
           my-cnf: |
             innodb_log_file_size=256MB
             innodb_buffer_pool_size=512MB
-            max_allowed_packet=16MB
+            max_allowed_packet=48MB
             ; TestConcurrent fails if max_connections is too large
             max_connections=50
             local_infile=1

AUTHORS

@@ -21,6 +21,7 @@ Animesh Ray <mail.rayanimesh at gmail.com>
 Arne Hormann <arnehormann at gmail.com>
 Ariel Mashraki <ariel at mashraki.co.il>
 Asta Xie <xiemengjun at gmail.com>
+B Lamarche <blam413 at gmail.com>
 Brian Hendriks <brian at dolthub.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>
 Caine Jette <jette at alum.mit.edu>
@@ -62,6 +63,7 @@ Jennifer Purevsuren <jennifer at dolthub.com>
 Jerome Meyer <jxmeyer at gmail.com>
 Jiajia Zhong <zhong2plus at gmail.com>
 Jian Zhen <zhenjl at gmail.com>
+Joe Mann <contact at joemann.co.uk>
 Joshua Prunier <joshua.prunier at gmail.com>
 Julien Lefevre <julien.lefevr at gmail.com>
 Julien Schmidt <go-sql-driver at julienschmidt.com>

README.md

@@ -38,6 +38,7 @@ A MySQL-Driver for Go's [database/sql](https://golang.org/pkg/database/sql/) pac
   * Secure `LOAD DATA LOCAL INFILE` support with file allowlisting and `io.Reader` support
   * Optional `time.Time` parsing
   * Optional placeholder interpolation
+  * Supports zlib compression.
 
 ## Requirements
 
@@ -267,6 +268,16 @@ SELECT u.id FROM users as u
 
 will return `u.id` instead of just `id` if `columnsWithAlias=true`.
 
+##### `compress`
+
+```
+Type:           bool
+Valid Values:   true, false
+Default:        false
+```
+
+Toggles zlib compression. false by default.
+
 ##### `interpolateParams`
 
 ```

benchmark_test.go

@@ -46,9 +46,13 @@ func (tb *TB) checkStmt(stmt *sql.Stmt, err error) *sql.Stmt {
 	return stmt
 }
 
-func initDB(b *testing.B, queries ...string) *sql.DB {
+func initDB(b *testing.B, useCompression bool, queries ...string) *sql.DB {
 	tb := (*TB)(b)
-	db := tb.checkDB(sql.Open(driverNameTest, dsn))
+	comprStr := ""
+	if useCompression {
+		comprStr = "&compress=1"
+	}
+	db := tb.checkDB(sql.Open(driverNameTest, dsn+comprStr))
 	for _, query := range queries {
 		if _, err := db.Exec(query); err != nil {
 			b.Fatalf("error on %q: %v", query, err)
@@ -60,10 +64,18 @@ func initDB(b *testing.B, queries ...string) *sql.DB {
 const concurrencyLevel = 10
 
 func BenchmarkQuery(b *testing.B) {
+	benchmarkQueryHelper(b, false)
+}
+
+func BenchmarkQueryCompression(b *testing.B) {
+	benchmarkQueryHelper(b, true)
+}
+
+func benchmarkQueryHelper(b *testing.B, compr bool) {
 	tb := (*TB)(b)
 	b.StopTimer()
 	b.ReportAllocs()
-	db := initDB(b,
+	db := initDB(b, compr,
 		"DROP TABLE IF EXISTS foo",
 		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
 		`INSERT INTO foo VALUES (1, "one")`,
@@ -222,7 +234,7 @@ func BenchmarkInterpolation(b *testing.B) {
 		},
 		maxAllowedPacket: maxPacketSize,
 		maxWriteSize:     maxPacketSize - 1,
-		buf:              newBuffer(nil),
+		buf:              newBuffer(),
 	}
 
 	args := []driver.Value{
@@ -269,7 +281,7 @@ func benchmarkQueryContext(b *testing.B, db *sql.DB, p int) {
 }
 
 func BenchmarkQueryContext(b *testing.B) {
-	db := initDB(b,
+	db := initDB(b, false,
 		"DROP TABLE IF EXISTS foo",
 		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
 		`INSERT INTO foo VALUES (1, "one")`,
@@ -305,7 +317,7 @@ func benchmarkExecContext(b *testing.B, db *sql.DB, p int) {
 }
 
 func BenchmarkExecContext(b *testing.B) {
-	db := initDB(b,
+	db := initDB(b, false,
 		"DROP TABLE IF EXISTS foo",
 		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
 		`INSERT INTO foo VALUES (1, "one")`,
@@ -323,7 +335,7 @@ func BenchmarkExecContext(b *testing.B) {
 // "size=" means size of each blobs.
 func BenchmarkQueryRawBytes(b *testing.B) {
 	var sizes []int = []int{100, 1000, 2000, 4000, 8000, 12000, 16000, 32000, 64000, 256000}
-	db := initDB(b,
+	db := initDB(b, false,
 		"DROP TABLE IF EXISTS bench_rawbytes",
 		"CREATE TABLE bench_rawbytes (id INT PRIMARY KEY, val LONGBLOB)",
 	)
@@ -376,7 +388,7 @@ func BenchmarkQueryRawBytes(b *testing.B) {
 // BenchmarkReceiveMassiveRows measures performance of receiving large number of rows.
 func BenchmarkReceiveMassiveRows(b *testing.B) {
 	// Setup -- prepare 10000 rows.
-	db := initDB(b,
+	db := initDB(b, false,
 		"DROP TABLE IF EXISTS foo",
 		"CREATE TABLE foo (id INT PRIMARY KEY, val TEXT)")
 	defer db.Close()

buffer.go

@@ -10,13 +10,16 @@ package mysql
 
 import (
 	"io"
-	"net"
-	"time"
 )
 
 const defaultBufSize = 4096
 const maxCachedBufSize = 256 * 1024
 
+// readerFunc is a function that compatible with io.Reader.
+// We use this function type instead of io.Reader because we want to
+// just pass mc.readWithTimeout.
+type readerFunc func([]byte) (int, error)
+
 // A buffer which is used for both reading and writing.
 // This is possible since communication on each connection is synchronous.
 // In other words, we can't write and read simultaneously on the same connection.
@@ -25,15 +28,12 @@ const maxCachedBufSize = 256 * 1024
 type buffer struct {
 	buf       []byte // read buffer.
 	cachedBuf []byte // buffer that will be reused. len(cachedBuf) <= maxCachedBufSize.
-	nc        net.Conn
-	timeout   time.Duration
 }
 
 // newBuffer allocates and returns a new buffer.
-func newBuffer(nc net.Conn) buffer {
+func newBuffer() buffer {
 	return buffer{
 		cachedBuf: make([]byte, defaultBufSize),
-		nc:        nc,
 	}
 }
 
@@ -43,7 +43,7 @@ func (b *buffer) busy() bool {
 }
 
 // fill reads into the read buffer until at least _need_ bytes are in it.
-func (b *buffer) fill(need int) error {
+func (b *buffer) fill(need int, r readerFunc) error {
 	// we'll move the contents of the current buffer to dest before filling it.
 	dest := b.cachedBuf
 
@@ -64,13 +64,7 @@ func (b *buffer) fill(need int) error {
 	copy(dest[:n], b.buf)
 
 	for {
-		if b.timeout > 0 {
-			if err := b.nc.SetReadDeadline(time.Now().Add(b.timeout)); err != nil {
-				return err
-			}
-		}
-
-		nn, err := b.nc.Read(dest[n:])
+		nn, err := r(dest[n:])
 		n += nn
 
 		if err == nil && n < need {
@@ -92,10 +86,10 @@ func (b *buffer) fill(need int) error {
 
 // returns next N bytes from buffer.
 // The returned slice is only guaranteed to be valid until the next read
-func (b *buffer) readNext(need int) ([]byte, error) {
+func (b *buffer) readNext(need int, r readerFunc) ([]byte, error) {
 	if len(b.buf) < need {
 		// refill
-		if err := b.fill(need); err != nil {
+		if err := b.fill(need, r); err != nil {
 			return nil, err
 		}
 	}