Add temporaryStorage and cacheSizeKb for op-sqlite.

Author: rkistner

packages/powersync-op-sqlite/src/db/OPSqliteAdapter.ts

@@ -44,19 +44,28 @@ export class OPSQLiteDBAdapter extends BaseObserver<DBAdapterListener> implement
   }
 
   protected async init() {
-    const { lockTimeoutMs, journalMode, journalSizeLimit, synchronous } = this.options.sqliteOptions!;
+    const { lockTimeoutMs, journalMode, journalSizeLimit, synchronous, cacheSizeKb, temporaryStorage } =
+      this.options.sqliteOptions!;
     const dbFilename = this.options.name;
 
     this.writeConnection = await this.openConnection(dbFilename);
 
-    const statements: string[] = [
+    const baseStatements = [
       `PRAGMA busy_timeout = ${lockTimeoutMs}`,
+      `PRAGMA cache_size = -${cacheSizeKb}`,
+      `PRAGMA temp_store = ${temporaryStorage}`
+    ];
+
+    const writeConnectionStatements = [
+      ...baseStatements,
       `PRAGMA journal_mode = ${journalMode}`,
       `PRAGMA journal_size_limit = ${journalSizeLimit}`,
       `PRAGMA synchronous = ${synchronous}`
     ];
 
-    for (const statement of statements) {
+    const readConnectionStatements = [...baseStatements, 'PRAGMA query_only = true'];
+
+    for (const statement of writeConnectionStatements) {
       for (let tries = 0; tries < 30; tries++) {
         try {
           await this.writeConnection!.execute(statement);
@@ -79,7 +88,9 @@ export class OPSQLiteDBAdapter extends BaseObserver<DBAdapterListener> implement
     this.readConnections = [];
     for (let i = 0; i < READ_CONNECTIONS; i++) {
       const conn = await this.openConnection(dbFilename);
-      await conn.execute('PRAGMA query_only = true');
+      for (let statement of readConnectionStatements) {
+        await conn.execute(statement);
+      }
       this.readConnections.push({ busy: false, connection: conn });
     }
   }

packages/powersync-op-sqlite/src/db/SqliteOptions.ts

@@ -30,6 +30,21 @@ export interface SqliteOptions {
    */
   encryptionKey?: string | null;
 
+  /**
+   * Where to store SQLite temporary files. Defaults to 'MEMORY'.
+   * Setting this to `FILESYSTEM` can cause issues with larger queries or datasets.
+   *
+   * For details, see: https://www.sqlite.org/pragma.html#pragma_temp_store
+   */
+  temporaryStorage?: TemporaryStorageOption;
+
+  /**
+   * Maximum SQLite cache size. Defaults to 50MB.
+   *
+   * For details, see: https://www.sqlite.org/pragma.html#pragma_cache_size
+   */
+  cacheSizeKb?: number;
+
   /**
    * Load extensions using the path and entryPoint.
    * More info can be found here https://op-engineering.github.io/op-sqlite/docs/api#loading-extensions.
@@ -40,6 +55,11 @@ export interface SqliteOptions {
   }>;
 }
 
+export enum TemporaryStorageOption {
+  MEMORY = 'memory',
+  FILESYSTEM = 'file'
+}
+
 // SQLite journal mode. Set on the primary connection.
 // This library is written with WAL mode in mind - other modes may cause
 // unexpected locking behavior.
@@ -65,6 +85,8 @@ export const DEFAULT_SQLITE_OPTIONS: Required<SqliteOptions> = {
   journalMode: SqliteJournalMode.wal,
   synchronous: SqliteSynchronous.normal,
   journalSizeLimit: 6 * 1024 * 1024,
+  cacheSizeKb: 50 * 1024,
+  temporaryStorage: TemporaryStorageOption.MEMORY,
   lockTimeoutMs: 30000,
   encryptionKey: null,
   extensions: []

tools/diagnostics-app/src/library/powersync/ConnectionManager.ts

@@ -28,11 +28,11 @@ export const schemaManager = new DynamicSchemaManager();
 export const db = new PowerSyncDatabase({
   database: {
     dbFilename: 'example.db',
-    debugMode: true
+    debugMode: true,
+    cacheSizeKb: 500000
   },
   schema: schemaManager.buildSchema()
 });
-db.execute('PRAGMA cache_size=-500000');
 
 export const connector = new TokenConnector();