server: support compressed MySQL protocol

- https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_basic_compression.html
- https://dev.mysql.com/worklog/task/?id=12039
- #22605

go.mod

@@ -59,7 +59,7 @@ require (
 	github.com/jingyugao/rowserrcheck v1.1.1
 	github.com/joho/sqltocsv v0.0.0-20210428211105-a6d6801d59df
 	github.com/kisielk/errcheck v1.6.3
-	github.com/klauspost/compress v1.15.13
+	github.com/klauspost/compress v1.16.5
 	github.com/kyoh86/exportloopref v0.1.11
 	github.com/lestrrat-go/jwx/v2 v2.0.6
 	github.com/mgechev/revive v1.3.1

go.sum

@@ -604,8 +604,8 @@ github.com/klauspost/compress v1.9.7/go.mod h1:RyIbtBH6LamlWaDj8nUwkbUhJ87Yi3uG0
 github.com/klauspost/compress v1.10.5/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.11.7/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.12.2/go.mod h1:8dP1Hq4DHOhN9w426knH3Rhby4rFm6D8eO+e+Dq5Gzg=
-github.com/klauspost/compress v1.15.13 h1:NFn1Wr8cfnenSJSA46lLq4wHCcBzKTSjnBIexDMMOV0=
-github.com/klauspost/compress v1.15.13/go.mod h1:QPwzmACJjUTFsnSHH934V6woptycfrDDJnH7hvFVbGM=
+github.com/klauspost/compress v1.16.5 h1:IFV2oUNUzZaz+XyusxpLzpzS8Pt5rh0Z16For/djlyI=
+github.com/klauspost/compress v1.16.5/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
 github.com/klauspost/cpuid v1.2.1/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/klauspost/cpuid v1.3.1 h1:5JNjFYYQrZeKRJ0734q51WCEEn2huer72Dc7K+R/b6s=
 github.com/klauspost/cpuid v1.3.1/go.mod h1:bYW4mA6ZgKPob1/Dlai2LviZJO7KGI3uoWLd42rAQw4=

parser/mysql/const.go

@@ -140,7 +140,7 @@ const (
 	ClientLongFlag                                      // CLIENT_LONG_FLAG
 	ClientConnectWithDB                                 // CLIENT_CONNECT_WITH_DB
 	ClientNoSchema                                      // CLIENT_NO_SCHEMA
-	ClientCompress                                      // CLIENT_COMPRESS, Not supported: https://github.com/pingcap/tidb/issues/22605
+	ClientCompress                                      // CLIENT_COMPRESS
 	ClientODBC                                          // CLIENT_ODBC
 	ClientLocalFiles                                    // CLIENT_LOCAL_FILES
 	ClientIgnoreSpace                                   // CLIENT_IGNORE_SPACE
@@ -160,8 +160,8 @@ const (
 	ClientHandleExpiredPasswords                        // CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS, Not supported: https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_basic_expired_passwords.html
 	ClientSessionTrack                                  // CLIENT_SESSION_TRACK, Not supported: https://github.com/pingcap/tidb/issues/35309
 	ClientDeprecateEOF                                  // CLIENT_DEPRECATE_EOF
-	// 1 << 25 == CLIENT_OPTIONAL_RESULTSET_METADATA
-	// 1 << 26 == CLIENT_ZSTD_COMPRESSION_ALGORITHM
+	ClientOptionalResultsetMetadata                     // CLIENT_OPTIONAL_RESULTSET_METADATA, Not supported: https://dev.mysql.com/doc/c-api/8.0/en/c-api-optional-metadata.html
+	ClientZstdCompressionAlgorithm                      // CLIENT_ZSTD_COMPRESSION_ALGORITHM
 	// 1 << 27 == CLIENT_QUERY_ATTRIBUTES
 	// 1 << 28 == MULTI_FACTOR_AUTHENTICATION
 	// 1 << 29 == CLIENT_CAPABILITY_EXTENSION
@@ -629,3 +629,12 @@ const (
 	CursorTypeForUpdate
 	CursorTypeScrollable
 )
+
+const (
+	// CompressionNone is no compression in use
+	CompressionNone = iota
+	// CompressionZlib is zlib/deflate
+	CompressionZlib
+	// CompressionZstd is Facebook's Zstandard
+	CompressionZstd
+)

server/conn.go

@@ -54,6 +54,7 @@ import (
 	"time"
 	"unsafe"
 
+	"github.com/klauspost/compress/zstd"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/tidb/config"
@@ -279,6 +280,14 @@ func (cc *clientConn) handshake(ctx context.Context) error {
 		logutil.Logger(ctx).Debug("flush response to client failed", zap.Error(err))
 		return err
 	}
+
+	// With mysql --compression-algorithms=zlib,zstd both flags are set, the result is Zlib
+	if cc.capability&mysql.ClientCompress > 0 {
+		cc.pkt.SetCompressionAlgorithm(mysql.CompressionZlib)
+	} else if cc.capability&mysql.ClientZstdCompressionAlgorithm > 0 {
+		cc.pkt.SetCompressionAlgorithm(mysql.CompressionZstd)
+	}
+
 	return err
 }
 
@@ -414,6 +423,7 @@ type handshakeResponse41 struct {
 	Auth       []byte
 	AuthPlugin string
 	Attrs      map[string]string
+	ZstdLevel  zstd.EncoderLevel
 }
 
 // parseHandshakeResponseHeader parses the common header of SSLRequest and HandshakeResponse41.
@@ -502,18 +512,23 @@ func parseHandshakeResponseBody(ctx context.Context, packet *handshakeResponse41
 			// Defend some ill-formated packet, connection attribute is not important and can be ignored.
 			return nil
 		}
-		if num, null, off := parseLengthEncodedInt(data[offset:]); !null {
-			offset += off
+		if num, null, intOff := parseLengthEncodedInt(data[offset:]); !null {
+			offset += intOff // Length of variable length encoded integer itself in bytes
 			row := data[offset : offset+int(num)]
 			attrs, err := parseAttrs(row)
 			if err != nil {
 				logutil.Logger(ctx).Warn("parse attrs failed", zap.Error(err))
 				return nil
 			}
 			packet.Attrs = attrs
+			offset += int(num) // Length of attributes
 		}
 	}
 
+	if packet.Capability&mysql.ClientZstdCompressionAlgorithm > 0 {
+		packet.ZstdLevel = zstd.EncoderLevelFromZstd(int(data[offset]))
+	}
+
 	return nil
 }
 
@@ -625,6 +640,7 @@ func (cc *clientConn) readOptionalSSLRequestAndHandshakeResponse(ctx context.Con
 	cc.dbname = resp.DBName
 	cc.collation = resp.Collation
 	cc.attrs = resp.Attrs
+	cc.pkt.zstdLevel = resp.ZstdLevel
 
 	err = cc.handleAuthPlugin(ctx, &resp)
 	if err != nil {
@@ -1163,6 +1179,7 @@ func (cc *clientConn) Run(ctx context.Context) {
 		}
 		cc.addMetrics(data[0], startTime, err)
 		cc.pkt.sequence = 0
+		cc.pkt.compressedSequence = 0
 	}
 }