Use a dedicated write connection for persisting in sqlite and switch pool to read-only

netquery/database.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"strings"
+	"sync"
 	"time"
 
 	"zombiezen.com/go/sqlite"
@@ -48,6 +49,9 @@ type (
 		Schema *orm.TableSchema
 
 		pool *puddle.Pool[*sqlite.Conn]
+
+		l         sync.Mutex
+		writeConn *sqlite.Conn
 	}
 
 	// Conn is a network connection that is stored in a SQLite database and accepted
@@ -111,16 +115,14 @@ func New(path string) (*Database, error) {
 	constructor := func(ctx context.Context) (*sqlite.Conn, error) {
 		c, err := sqlite.OpenConn(
 			path,
-			sqlite.OpenCreate,
-			sqlite.OpenReadWrite,
+			sqlite.OpenReadOnly,
 			sqlite.OpenNoMutex,
-			sqlite.OpenWAL,
 			sqlite.OpenSharedCache,
 			sqlite.OpenMemory,
 			sqlite.OpenURI,
 		)
 		if err != nil {
-			return nil, fmt.Errorf("failed to open sqlite at %s: %w", path, err)
+			return nil, fmt.Errorf("failed to open read-only sqlite connection at %s: %w", path, err)
 		}
 
 		return c, nil
@@ -137,10 +139,24 @@ func New(path string) (*Database, error) {
 		return nil, err
 	}
 
+	writeConn, err := sqlite.OpenConn(
+		path,
+		sqlite.OpenCreate,
+		sqlite.OpenReadWrite,
+		sqlite.OpenNoMutex,
+		sqlite.OpenWAL,
+		sqlite.OpenSharedCache,
+		sqlite.OpenMemory,
+		sqlite.OpenURI,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open sqlite at %s: %w", path, err)
+	}
+
 	return &Database{
-		pool:   pool,
-		Schema: schema,
-		// conn:   c,
+		pool:      pool,
+		Schema:    schema,
+		writeConn: writeConn,
 	}, nil
 }
 
@@ -283,6 +299,9 @@ func (db *Database) dumpTo(ctx context.Context, w io.Writer) error { //nolint:un
 
 // Save inserts the connection conn into the SQLite database. If conn
 // already exists the table row is updated instead.
+//
+// Save uses the database write connection instead of relying on the
+// connection pool.
 func (db *Database) Save(ctx context.Context, conn Conn) error {
 	connMap, err := orm.ToParamMap(ctx, conn, "", orm.DefaultEncodeConfig)
 	if err != nil {
@@ -301,6 +320,9 @@ func (db *Database) Save(ctx context.Context, conn Conn) error {
 		updateSets = append(updateSets, fmt.Sprintf("%s = :%s", key, key))
 	}
 
+	db.l.Lock()
+	defer db.l.Unlock()
+
 	// TODO(ppacher): make sure this one can be cached to speed up inserting
 	// and save some CPU cycles for the user
 	sql := fmt.Sprintf(
@@ -314,14 +336,12 @@ func (db *Database) Save(ctx context.Context, conn Conn) error {
 		strings.Join(updateSets, ", "),
 	)
 
-	if err := db.withConn(ctx, func(conn *sqlite.Conn) error {
-		return sqlitex.ExecuteTransient(conn, sql, &sqlitex.ExecOptions{
-			Named: values,
-			ResultFunc: func(stmt *sqlite.Stmt) error {
-				log.Errorf("netquery: got result statement with %d columns", stmt.ColumnCount())
-				return nil
-			},
-		})
+	if err := sqlitex.Execute(db.writeConn, sql, &sqlitex.ExecOptions{
+		Named: values,
+		ResultFunc: func(stmt *sqlite.Stmt) error {
+			log.Errorf("netquery: got result statement with %d columns", stmt.ColumnCount())
+			return nil
+		},
 	}); err != nil {
 		log.Errorf("netquery: failed to execute:\n\t%q\n\treturned error was: %s\n\tparameters: %+v", sql, err, values)
 		return err
@@ -333,7 +353,5 @@ func (db *Database) Save(ctx context.Context, conn Conn) error {
 // Close closes the underlying database connection. db should and cannot be
 // used after Close() has returned.
 func (db *Database) Close() error {
-	return nil
-
-	//return db.conn.Close()
+	return db.writeConn.Close()
 }