Use writeWithoutTransaction when appropriate

.github/workflows/ci.yml

@@ -5,10 +5,11 @@ on: push
 jobs:
   test:
     runs-on: macos-13
-    
+
     steps:
       - uses: actions/checkout@v3
       - name: Select Xcode 15
         run: sudo xcode-select -s /Applications/Xcode_15.0.app
       - name: Test
         run: swift test
+

Sources/SQLite/SQLiteDatabase.swift

@@ -111,6 +111,20 @@ public final class SQLiteDatabase: DatabaseProtocol, @unchecked Sendable {
         )
     }
 
+    public func truncate() throws {
+        switch database {
+        case let .pool(pool):
+            try pool.writeWithoutTransaction { db in
+                _ = try db.execute(raw: "PRAGMA wal_checkpoint(TRUNCATE);")
+            }
+
+        case let .queue(queue):
+            try queue.writeWithoutTransaction { db in
+                _ = try db.execute(raw: "PRAGMA wal_checkpoint(TRUNCATE);")
+            }
+        }
+    }
+
     // NOTE: This function is only really meant to be called in tests.
     public func close() throws {
         changeNotifier.stop()
@@ -275,7 +289,7 @@ public extension SQLiteDatabase {
     @discardableResult
     func execute(raw sql: SQL) async throws -> [SQLiteRow] {
         do {
-            return try await database.writer.write { db in
+            return try await database.writer.writeWithoutTransaction { db in
                 try db.execute(raw: sql)
             }
         } catch {
@@ -339,7 +353,7 @@ public extension SQLiteDatabase {
     @discardableResult
     func execute(raw sql: SQL) throws -> [SQLiteRow] {
         do {
-            return try database.writer.write { db in
+            return try database.writer.writeWithoutTransaction { db in
                 try db.execute(raw: sql)
             }
         } catch {
@@ -644,13 +658,10 @@ private extension SQLiteDatabase {
         config.journalMode = isInMemory ? .default : .wal
         // NOTE: GRDB recommends `defaultTransactionKind` be set
         //       to `.immediate` in order to prevent `SQLITE_BUSY`
-        //       errors. Using `.immediate` appears to disable
-        //       automatic vacuuming.
+        //       errors.
         //
         // https://swiftpackageindex.com/groue/grdb.swift/v6.24.2/documentation/grdb/databasesharing#How-to-limit-the-SQLITEBUSY-error
-        config.defaultTransactionKind = isInMemory
-            ? .deferred
-            : .immediate
+        config.defaultTransactionKind = .immediate
         config.busyMode = .timeout(busyTimeout)
         config.observesSuspensionNotifications = true
         config.maximumReaderCount = max(
@@ -770,7 +781,7 @@ private enum Database {
         arguments: SQLiteArguments = [:]
     ) throws {
         do {
-            try writer.write { db in
+            try writer.writeWithoutTransaction { db in
                 try db.write(sql, arguments: arguments)
             }
         } catch {

Tests/SQLiteTests/SQLiteDatabaseTests.swift

@@ -253,6 +253,27 @@ final class SQLiteDatabaseTests: XCTestCase {
         }
     }
 
+    func testCheckpointUsingTruncate() throws {
+        try Sandbox.execute { directory in
+            let path = directory.appendingPathComponent("test.db").path
+            let db = try SQLiteDatabase(path: path)
+            defer { try? db.close() }
+
+            try db.execute(raw: _createTableWithBlob)
+
+            try db.inTransaction { db in
+                for index in 0 ..< 100 {
+                    let args: SQLiteArguments = [
+                        "id": .integer(Int64(index)), "data": .data(_textData),
+                    ]
+                    try db.write(_insertIDAndData, arguments: args)
+                }
+            }
+
+            try db.truncate()
+        }
+    }
+
     func testCreateTable() throws {
         XCTAssertNoThrow(try database.execute(raw: _createTableWithBlob))
         let tableNames = try database.tables()