Support EXECUTE IMMEDIATE

Use EXECUTE IMMEDIATE sent in the HTTP request body, instead of putting
the query text in HTTP headers. This should allow sending large query
text. It can be enabled by setting the `explicitPrepare` option to
false in the connection string.

trino/etc/config.properties

@@ -12,3 +12,5 @@ http-server.https.port=8443
 http-server.authentication.allow-insecure-over-http=true
 http-server.https.keystore.path=/etc/trino/secrets/certificate_with_key.pem
 internal-communication.shared-secret=gotrino
+
+query.max-length=5000043

trino/etc/jvm.config

@@ -1,4 +1,4 @@
--Xmx1G
+-Xmx4G
 -XX:+UseG1GC
 -XX:G1HeapRegionSize=32M
 -XX:+UseGCOverheadLimit

trino/integration_test.go

@@ -34,6 +34,7 @@ import (
 	"math/big"
 	"net/http"
 	"os"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -75,6 +76,9 @@ func TestMain(m *testing.M) {
 	flag.Parse()
 	DefaultQueryTimeout = *integrationServerQueryTimeout
 	DefaultCancelQueryTimeout = *integrationServerQueryTimeout
+	if *trinoImageTagFlag == "" {
+		*trinoImageTagFlag = "latest"
+	}
 
 	var err error
 	if *integrationServerFlag == "" && !testing.Short() {
@@ -97,9 +101,6 @@ func TestMain(m *testing.M) {
 			if err != nil {
 				log.Fatalf("Could not generate TLS certificates: %s", err)
 			}
-			if *trinoImageTagFlag == "" {
-				*trinoImageTagFlag = "latest"
-			}
 			resource, err = pool.RunWithOptions(&dt.RunOptions{
 				Name:       name,
 				Repository: "trinodb/trino",
@@ -1112,3 +1113,29 @@ func TestIntegrationDayToHourIntervalMilliPrecision(t *testing.T) {
 		})
 	}
 }
+
+func TestIntegrationLargeQuery(t *testing.T) {
+	version, err := strconv.Atoi(*trinoImageTagFlag)
+	if (err != nil && *trinoImageTagFlag != "latest") || (err == nil && version < 418) {
+		t.Skip("Skipping test when not using Trino 418 or later.")
+	}
+	dsn := *integrationServerFlag
+	dsn += "?explicitPrepare=false"
+	db := integrationOpen(t, dsn)
+	defer db.Close()
+	rows, err := db.Query("SELECT ?, '"+strings.Repeat("a", 5000000)+"'", 42)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rows.Close()
+	count := 0
+	for rows.Next() {
+		count++
+	}
+	if rows.Err() != nil {
+		t.Fatal(err)
+	}
+	if count != 1 {
+		t.Fatal("not enough rows returned:", count)
+	}
+}

trino/trino.go

@@ -141,6 +141,7 @@ const (
 	sslCertPathConfig               = "SSLCertPath"
 	sslCertConfig                   = "SSLCert"
 	accessTokenConfig               = "accessToken"
+	explicitPrepareConfig           = "explicitPrepare"
 )
 
 var (
@@ -282,6 +283,7 @@ type Conn struct {
 	kerberosRemoteServiceName string
 	progressUpdater           ProgressUpdater
 	progressUpdaterPeriod     queryProgressCallbackPeriod
+	useExplicitPrepare        bool
 }
 
 var (
@@ -298,6 +300,10 @@ func newConn(dsn string) (*Conn, error) {
 	query := serverURL.Query()
 
 	kerberosEnabled, _ := strconv.ParseBool(query.Get(kerberosEnabledConfig))
+	useExplicitPrepare := true
+	if query.Get(explicitPrepareConfig) != "" {
+		useExplicitPrepare, _ = strconv.ParseBool(query.Get(explicitPrepareConfig))
+	}
 
 	var kerberosClient *client.Client
 
@@ -356,6 +362,7 @@ func newConn(dsn string) (*Conn, error) {
 		kerberosClient:            kerberosClient,
 		kerberosEnabled:           kerberosEnabled,
 		kerberosRemoteServiceName: query.Get(kerberosRemoteServiceNameConfig),
+		useExplicitPrepare:        useExplicitPrepare,
 	}
 
 	var user string
@@ -867,7 +874,7 @@ func (st *driverStmt) exec(ctx context.Context, args []driver.NamedValue) (*stmt
 
 				hs.Add(arg.Name, headerValue)
 			} else {
-				if hs.Get(preparedStatementHeader) == "" {
+				if st.conn.useExplicitPrepare && hs.Get(preparedStatementHeader) == "" {
 					for _, v := range st.conn.httpHeaders.Values(preparedStatementHeader) {
 						hs.Add(preparedStatementHeader, v)
 					}
@@ -880,7 +887,11 @@ func (st *driverStmt) exec(ctx context.Context, args []driver.NamedValue) (*stmt
 			return nil, ErrInvalidProgressCallbackHeader
 		}
 		if len(ss) > 0 {
-			query = "EXECUTE " + preparedStatementName + " USING " + strings.Join(ss, ", ")
+			if st.conn.useExplicitPrepare {
+				query = "EXECUTE " + preparedStatementName + " USING " + strings.Join(ss, ", ")
+			} else {
+				query = "EXECUTE IMMEDIATE " + formatStringLiteral(st.query) + " USING " + strings.Join(ss, ", ")
+			}
 		}
 	}
 
@@ -1028,6 +1039,10 @@ func (st *driverStmt) exec(ctx context.Context, args []driver.NamedValue) (*stmt
 	return &sr, handleResponseError(resp.StatusCode, sr.Error)
 }
 
+func formatStringLiteral(query string) string {
+	return "'" + strings.ReplaceAll(query, "'", "''") + "'"
+}
+
 type driverRows struct {
 	ctx     context.Context
 	stmt    *driverStmt