Clearer control for busy timeout

db/db.go

@@ -320,6 +320,22 @@ func (db *DB) WALSize() (int64, error) {
 	return 0, err
 }
 
+// SetBusyTimeout sets the busy timeout for the database.
+func (db *DB) SetBusyTimeout(ms int) error {
+	_, err := db.rwDB.Exec(fmt.Sprintf("PRAGMA busy_timeout=%d", ms))
+	return err
+}
+
+// BusyTimeout returns the current busy timeout value.
+func (db *DB) BusyTimeout() (int, error) {
+	var rwN int
+	err := db.rwDB.QueryRow("PRAGMA busy_timeout").Scan(&rwN)
+	if err != nil {
+		return 0, err
+	}
+	return rwN, err
+}
+
 // Checkpoint checkpoints the WAL file. If the WAL file is not enabled, this
 // function is a no-op.
 func (db *DB) Checkpoint(mode CheckpointMode) error {
@@ -342,11 +358,16 @@ func (db *DB) CheckpointWithTimeout(mode CheckpointMode, dur time.Duration) (err
 	}()
 
 	if dur > 0 {
-		if _, err := db.rwDB.Exec(fmt.Sprintf("PRAGMA busy_timeout=%d", dur.Milliseconds())); err != nil {
+		bt, err := db.BusyTimeout()
+		if err != nil {
+			return fmt.Errorf("failed to get busy_timeout on checkpointing connection: %s", err.Error())
+		}
+		if err := db.SetBusyTimeout(int(dur.Milliseconds())); err != nil {
 			return fmt.Errorf("failed to set busy_timeout on checkpointing connection: %s", err.Error())
 		}
 		defer func() {
-			if _, err := db.rwDB.Exec("PRAGMA busy_timeout=5000"); err != nil {
+			// Reset back to default
+			if _, err := db.rwDB.Exec(fmt.Sprintf("PRAGMA busy_timeout=%d", bt)); err != nil {
 				db.logger.Printf("failed to reset busy_timeout on checkpointing connection: %s", err.Error())
 			}
 		}()

db/db_common_test.go

@@ -2,14 +2,44 @@ package db
 
 import (
 	"errors"
+	"fmt"
 	"os"
 	"strings"
 	"testing"
 
 	command "github.com/rqlite/rqlite/v8/command/proto"
+	"github.com/rqlite/rqlite/v8/random"
 	"github.com/rqlite/rqlite/v8/testdata/chinook"
 )
 
+func testBusyTimeout(t *testing.T, db *DB) {
+	rbt := random.Intn(10000)
+	_, err := db.ExecuteStringStmt(fmt.Sprintf("PRAGMA busy_timeout=%d", rbt))
+	if err != nil {
+		t.Fatalf("failed to set busy_timeout: %s", err.Error())
+	}
+
+	bt, err := db.BusyTimeout()
+	if err != nil {
+		t.Fatalf("failed to get busy_timeout: %s", err.Error())
+	}
+	if exp, got := rbt, bt; exp != got {
+		t.Fatalf("expected busy_timeout %d, got %d", exp, got)
+	}
+
+	rbt2 := random.Intn(10000)
+	if err := db.SetBusyTimeout(rbt2); err != nil {
+		t.Fatalf("failed to set busy_timeout: %s", err.Error())
+	}
+	bt, err = db.BusyTimeout()
+	if err != nil {
+		t.Fatalf("failed to get busy_timeout: %s", err.Error())
+	}
+	if exp, got := rbt2, bt; exp != got {
+		t.Fatalf("expected busy_timeout %d, got %d", exp, got)
+	}
+}
+
 func testCompileOptions(t *testing.T, db *DB) {
 	_, err := db.CompileOptions()
 	if err != nil {
@@ -1529,6 +1559,7 @@ func Test_DatabaseCommonOperations(t *testing.T) {
 		name     string
 		testFunc func(*testing.T, *DB)
 	}{
+		{"BusyTimeout", testBusyTimeout},
 		{"SetSynchronousMode", testSetSynchronousMode},
 		{"CompileOptions", testCompileOptions},
 		{"TableNotExist", testTableNotExist},