Merge pull request #3091 from NoelDeMartin/MOBILE-3977

MOBILE-3977: Database optimization strategies

.eslintrc.js

@@ -271,6 +271,7 @@ testsConfig['rules']['padded-blocks'] = [
         switches: 'never',
     },
 ];
+testsConfig['rules']['jest/expect-expect'] = 'off';
 testsConfig['plugins'].push('jest');
 testsConfig['extends'].push('plugin:jest/recommended');
 

scripts/print-performance-measures.js

@@ -75,5 +75,13 @@ for (const [name, { duration, scripting, styling, blocking, longTasks, database,
     };
 }
 
+// Sort tests
+const tests = Object.keys(performanceMeasures).sort();
+const sortedPerformanceMeasures = {};
+
+for (const test of tests) {
+    sortedPerformanceMeasures[test] = performanceMeasures[test];
+}
+
 // Display data
-console.table(performanceMeasures);
+console.table(sortedPerformanceMeasures);

src/core/classes/database-table.ts

@@ -1,194 +0,0 @@
-// (C) Copyright 2015 Moodle Pty Ltd.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-import { SQLiteDB, SQLiteDBRecordValues } from './sqlitedb';
-
-/**
- * Database table wrapper used to improve performance by caching all data in memory
- * for faster read operations.
- */
-export abstract class CoreDatabaseTable<
-    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
-    PrimaryKeyColumns extends keyof DBRecord = 'id',
-    PrimaryKey extends GetPrimaryKey<DBRecord, PrimaryKeyColumns> = GetPrimaryKey<DBRecord, PrimaryKeyColumns>
-> {
-
-    /**
-     * Create an instance.
-     *
-     * @param db Database connection.
-     * @returns Instance.
-     */
-    static async create<This extends AnyCoreDatabaseTable>(this: CoreDatabaseTableConstructor<This>, db: SQLiteDB): Promise<This> {
-        const instance = new this(db);
-
-        await instance.initialize();
-
-        return instance;
-    }
-
-    protected db: SQLiteDB;
-    protected data: Record<string, DBRecord>;
-    protected primaryKeys: string[] = ['id'];
-
-    constructor(db: SQLiteDB) {
-        this.db = db;
-        this.data = {};
-    }
-
-    /**
-     * Find a record matching the given conditions.
-     *
-     * @param conditions Matching conditions.
-     * @returns Database record.
-     */
-    find(conditions: Partial<DBRecord>): DBRecord | null  {
-        return Object.values(this.data).find(record => this.recordMatches(record, conditions)) ?? null;
-    }
-
-    /**
-     * Find a record by its primary key.
-     *
-     * @param primaryKey Primary key.
-     * @returns Database record.
-     */
-    findByPrimaryKey(primaryKey: PrimaryKey): DBRecord | null {
-        return this.data[this.serializePrimaryKey(primaryKey)] ?? null;
-    }
-
-    /**
-     * Insert a new record.
-     *
-     * @param record Database record.
-     */
-    async insert(record: DBRecord): Promise<void> {
-        await this.db.insertRecord(this.table, record);
-
-        const primaryKey = this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record));
-
-        this.data[primaryKey] = record;
-    }
-
-    /**
-     * Delete records matching the given conditions.
-     *
-     * @param conditions Matching conditions. If this argument is missing, all records will be deleted.
-     */
-    async delete(conditions?: Partial<DBRecord>): Promise<void> {
-        if (!conditions) {
-            await this.db.deleteRecords(this.table);
-
-            this.data = {};
-
-            return;
-        }
-
-        await this.db.deleteRecords(this.table, conditions);
-
-        Object.entries(this.data).forEach(([id, record]) => {
-            if (!this.recordMatches(record, conditions)) {
-                return;
-            }
-
-            delete this.data[id];
-        });
-    }
-
-    /**
-     * Delete a single record identified by its primary key.
-     *
-     * @param primaryKey Record primary key.
-     */
-    async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
-        await this.db.deleteRecords(this.table, primaryKey);
-
-        delete this.data[this.serializePrimaryKey(primaryKey)];
-    }
-
-    /**
-     * Database table name.
-     */
-    protected abstract get table(): string;
-
-    /**
-     * Initialize object by getting the current state of the database table.
-     */
-    protected async initialize(): Promise<void> {
-        const records = await this.db.getRecords<DBRecord>(this.table);
-
-        this.data = records.reduce((data, record) => {
-            const primaryKey = this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record));
-
-            data[primaryKey] = record;
-
-            return data;
-        }, {});
-    }
-
-    /**
-     * Get an object with the columns representing the primary key of a database record.
-     *
-     * @param record Database record.
-     * @returns Primary key column-value pairs.
-     */
-    protected getPrimaryKeyFromRecord(record: DBRecord): PrimaryKey {
-        return this.primaryKeys.reduce((primaryKey, column) => {
-            primaryKey[column] = record[column];
-
-            return primaryKey;
-        }, {} as Record<PrimaryKeyColumns, unknown>) as PrimaryKey;
-    }
-
-    /**
-     * Serialize a primary key with a string representation.
-     *
-     * @param primaryKey Database record primary key.
-     * @returns Serialized primary key.
-     */
-    protected serializePrimaryKey(primaryKey: PrimaryKey): string {
-        return Object.values(primaryKey).map(value => String(value)).join('-');
-    }
-
-    /**
-     * Check whether a given record matches the given conditions.
-     *
-     * @param record Database record.
-     * @param conditions Conditions.
-     * @returns Whether the record matches the conditions.
-     */
-    protected recordMatches(record: DBRecord, conditions: Partial<DBRecord>): boolean {
-        return !Object.entries(conditions).some(([column, value]) => record[column] !== value);
-    }
-
-}
-
-/**
- * Generic type to match against any concrete database table type.
- */
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-type AnyCoreDatabaseTable = CoreDatabaseTable<SQLiteDBRecordValues, string, Record<string, any>>;
-
-/**
- * Database table constructor.
- */
-type CoreDatabaseTableConstructor<T extends AnyCoreDatabaseTable> = {
-    new (db: SQLiteDB): T;
-};
-
-/**
- * Infer primary key type from database record and columns types.
- */
-type GetPrimaryKey<DBRecord extends SQLiteDBRecordValues, PrimaryKeyColumns extends keyof DBRecord> = {
-    [column in PrimaryKeyColumns]: DBRecord[column];
-};

src/core/classes/database/database-table-proxy.ts

@@ -0,0 +1,219 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { CoreConstants } from '@/core/constants';
+import { asyncInstance } from '@/core/utils/async-instance';
+import { SQLiteDB, SQLiteDBRecordValues } from '@classes/sqlitedb';
+import { CoreConfigProvider } from '@services/config';
+import { CoreEventObserver, CoreEvents } from '@singletons/events';
+import { CoreDatabaseReducer, CoreDatabaseTable, CoreDatabaseConditions, GetDBRecordPrimaryKey } from './database-table';
+import { CoreDebugDatabaseTable } from './debug-database-table';
+import { CoreEagerDatabaseTable } from './eager-database-table';
+import { CoreLazyDatabaseTable } from './lazy-database-table';
+
+/**
+ * Database table proxy used to route database interactions through different implementations.
+ *
+ * This class allows using a database wrapper with different optimization strategies that can be changed at runtime.
+ */
+export class CoreDatabaseTableProxy<
+    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
+    PrimaryKeyColumn extends keyof DBRecord = 'id',
+    PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
+> extends CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey> {
+
+    protected config: CoreDatabaseConfiguration;
+    protected target = asyncInstance<CoreDatabaseTable<DBRecord, PrimaryKeyColumn>>();
+    protected environmentObserver?: CoreEventObserver;
+
+    constructor(
+        config: Partial<CoreDatabaseConfiguration>,
+        database: SQLiteDB,
+        tableName: string,
+        primaryKeyColumns?: PrimaryKeyColumn[],
+    ) {
+        super(database, tableName, primaryKeyColumns);
+
+        this.config = { ...this.getConfigDefaults(), ...config };
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async initialize(): Promise<void> {
+        this.environmentObserver = CoreEvents.on(CoreConfigProvider.ENVIRONMENT_UPDATED, () => this.updateTarget());
+
+        await this.updateTarget();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async destroy(): Promise<void> {
+        this.environmentObserver?.off();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getMany(conditions?: Partial<DBRecord>): Promise<DBRecord[]> {
+        return this.target.getMany(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getOne(conditions: Partial<DBRecord>): Promise<DBRecord> {
+        return this.target.getOne(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
+        return this.target.getOneByPrimaryKey(primaryKey);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async reduce<T>(reducer: CoreDatabaseReducer<DBRecord, T>, conditions?: CoreDatabaseConditions<DBRecord>): Promise<T> {
+        return this.target.reduce<T>(reducer, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async insert(record: DBRecord): Promise<void> {
+        return this.target.insert(record);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
+        return this.target.update(updates, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
+        return this.target.updateWhere(updates, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async delete(conditions?: Partial<DBRecord>): Promise<void> {
+        return this.target.delete(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
+        return this.target.deleteByPrimaryKey(primaryKey);
+    }
+
+    /**
+     * Get default configuration values.
+     *
+     * @returns Config defaults.
+     */
+    protected getConfigDefaults(): CoreDatabaseConfiguration {
+        return {
+            cachingStrategy: CoreDatabaseCachingStrategy.None,
+            debug: false,
+        };
+    }
+
+    /**
+     * Get database configuration to use at runtime.
+     *
+     * @returns Database configuration.
+     */
+    protected getRuntimeConfig(): CoreDatabaseConfiguration {
+        return {
+            ...this.config,
+            ...CoreConstants.CONFIG.databaseOptimizations,
+            ...CoreConstants.CONFIG.databaseTableOptimizations?.[this.tableName],
+        };
+    }
+
+    /**
+     * Update underlying target instance.
+     */
+    protected async updateTarget(): Promise<void> {
+        const oldTarget = this.target.instance;
+        const newTarget = this.createTarget();
+
+        if (oldTarget) {
+            await oldTarget.destroy();
+
+            this.target.resetInstance();
+        }
+
+        await newTarget.initialize();
+
+        this.target.setInstance(newTarget);
+    }
+
+    /**
+     * Create proxy target.
+     *
+     * @returns Target instance.
+     */
+    protected createTarget(): CoreDatabaseTable<DBRecord, PrimaryKeyColumn> {
+        const config = this.getRuntimeConfig();
+        const table = this.createTable(config.cachingStrategy);
+
+        return config.debug ? new CoreDebugDatabaseTable(table) : table;
+    }
+
+    /**
+     * Create a database table using the given caching strategy.
+     *
+     * @param cachingStrategy Caching strategy.
+     * @returns Database table.
+     */
+    protected createTable(cachingStrategy: CoreDatabaseCachingStrategy): CoreDatabaseTable<DBRecord, PrimaryKeyColumn> {
+        switch (cachingStrategy) {
+            case CoreDatabaseCachingStrategy.Eager:
+                return new CoreEagerDatabaseTable(this.database, this.tableName, this.primaryKeyColumns);
+            case CoreDatabaseCachingStrategy.Lazy:
+                return new CoreLazyDatabaseTable(this.database, this.tableName, this.primaryKeyColumns);
+            case CoreDatabaseCachingStrategy.None:
+                return new CoreDatabaseTable(this.database, this.tableName, this.primaryKeyColumns);
+        }
+    }
+
+}
+
+/**
+ * Database proxy configuration.
+ */
+export interface CoreDatabaseConfiguration {
+    cachingStrategy: CoreDatabaseCachingStrategy;
+    debug: boolean;
+}
+
+/**
+ * Database caching strategies.
+ */
+export enum CoreDatabaseCachingStrategy {
+    Eager = 'eager',
+    Lazy = 'lazy',
+    None = 'none',
+}

src/core/classes/database/database-table.ts

@@ -0,0 +1,240 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { SQLiteDB, SQLiteDBRecordValue, SQLiteDBRecordValues } from '@classes/sqlitedb';
+
+/**
+ * Wrapper used to interact with a database table.
+ */
+export class CoreDatabaseTable<
+    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
+    PrimaryKeyColumn extends keyof DBRecord = 'id',
+    PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
+> {
+
+    protected database: SQLiteDB;
+    protected tableName: string;
+    protected primaryKeyColumns: PrimaryKeyColumn[];
+
+    constructor(database: SQLiteDB, tableName: string, primaryKeyColumns?: PrimaryKeyColumn[]) {
+        this.database = database;
+        this.tableName = tableName;
+        this.primaryKeyColumns = primaryKeyColumns ?? ['id'] as PrimaryKeyColumn[];
+    }
+
+    /**
+     * Get database connection.
+     *
+     * @returns Database connection.
+     */
+    getDatabase(): SQLiteDB {
+        return this.database;
+    }
+
+    /**
+     * Get table name.
+     *
+     * @returns Table name.
+     */
+    getTableName(): string {
+        return this.tableName;
+    }
+
+    /**
+     * Get primary key columns.
+     *
+     * @returns Primary key columns.
+     */
+    getPrimaryKeyColumns(): PrimaryKeyColumn[] {
+        return this.primaryKeyColumns.slice(0);
+    }
+
+    /**
+     * Initialize.
+     */
+    async initialize(): Promise<void> {
+        // Nothing to initialize by default, override this method if necessary.
+    }
+
+    /**
+     * Destroy.
+     */
+    async destroy(): Promise<void> {
+        // Nothing to destroy by default, override this method if necessary.
+    }
+
+    /**
+     * Get records matching the given conditions.
+     *
+     * @param conditions Matching conditions. If this argument is missing, all records in the table will be returned.
+     * @returns Database records.
+     */
+    getMany(conditions?: Partial<DBRecord>): Promise<DBRecord[]> {
+        return conditions
+            ? this.database.getRecords(this.tableName, conditions)
+            : this.database.getAllRecords(this.tableName);
+    }
+
+    /**
+     * Find one record matching the given conditions.
+     *
+     * @param conditions Matching conditions.
+     * @returns Database record.
+     */
+    getOne(conditions: Partial<DBRecord>): Promise<DBRecord> {
+        return this.database.getRecord<DBRecord>(this.tableName, conditions);
+    }
+
+    /**
+     * Find one record by its primary key.
+     *
+     * @param primaryKey Primary key.
+     * @returns Database record.
+     */
+    getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
+        return this.database.getRecord<DBRecord>(this.tableName, primaryKey);
+    }
+
+    /**
+     * Reduce some records into a single value.
+     *
+     * @param reducer Reducer functions in SQL and JavaScript.
+     * @param conditions Matching conditions in SQL and JavaScript. If this argument is missing, all records in the table
+     *                   will be used.
+     * @returns Reduced value.
+     */
+    reduce<T>(reducer: CoreDatabaseReducer<DBRecord, T>, conditions?: CoreDatabaseConditions<DBRecord>): Promise<T> {
+        return this.database.getFieldSql(
+            `SELECT ${reducer.sql} FROM ${this.tableName} ${conditions?.sql ?? ''}`,
+            conditions?.sqlParams,
+        ) as unknown as Promise<T>;
+    }
+
+    /**
+     * Insert a new record.
+     *
+     * @param record Database record.
+     */
+    async insert(record: DBRecord): Promise<void> {
+        await this.database.insertRecord(this.tableName, record);
+    }
+
+    /**
+     * Update records matching the given conditions.
+     *
+     * @param updates Record updates.
+     * @param conditions Matching conditions. If this argument is missing, all records will be updated.
+     */
+    async update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
+        await this.database.updateRecords(this.tableName, updates, conditions);
+    }
+
+    /**
+     * Update records matching the given conditions.
+     *
+     * This method should be used when it's necessary to apply complex conditions; the simple `update`
+     * method should be favored otherwise for better performance.
+     *
+     * @param updates Record updates.
+     * @param conditions Matching conditions in SQL and JavaScript.
+     */
+    async updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
+        await this.database.updateRecordsWhere(this.tableName, updates, conditions.sql, conditions.sqlParams);
+    }
+
+    /**
+     * Delete records matching the given conditions.
+     *
+     * @param conditions Matching conditions. If this argument is missing, all records will be deleted.
+     */
+    async delete(conditions?: Partial<DBRecord>): Promise<void> {
+        conditions
+            ? await this.database.deleteRecords(this.tableName, conditions)
+            : await this.database.deleteRecords(this.tableName);
+    }
+
+    /**
+     * Delete a single record identified by its primary key.
+     *
+     * @param primaryKey Record primary key.
+     */
+    async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
+        await this.database.deleteRecords(this.tableName, primaryKey);
+    }
+
+    /**
+     * Get the primary key from a database record.
+     *
+     * @param record Database record.
+     * @returns Primary key.
+     */
+    protected getPrimaryKeyFromRecord(record: DBRecord): PrimaryKey {
+        return this.primaryKeyColumns.reduce((primaryKey, column) => {
+            primaryKey[column] = record[column];
+
+            return primaryKey;
+        }, {} as Record<PrimaryKeyColumn, unknown>) as PrimaryKey;
+    }
+
+    /**
+     * Serialize a primary key with a string representation.
+     *
+     * @param primaryKey Primary key.
+     * @returns Serialized primary key.
+     */
+    protected serializePrimaryKey(primaryKey: PrimaryKey): string {
+        return Object.values(primaryKey).map(value => String(value)).join('-');
+    }
+
+    /**
+     * Check whether a given record matches the given conditions.
+     *
+     * @param record Database record.
+     * @param conditions Matching conditions.
+     * @returns Whether the record matches the conditions.
+     */
+    protected recordMatches(record: DBRecord, conditions: Partial<DBRecord>): boolean {
+        return !Object.entries(conditions).some(([column, value]) => record[column] !== value);
+    }
+
+}
+
+/**
+ * Infer primary key type from database record and primary key column types.
+ */
+export type GetDBRecordPrimaryKey<DBRecord extends SQLiteDBRecordValues, PrimaryKeyColumn extends keyof DBRecord> = {
+    [column in PrimaryKeyColumn]: DBRecord[column];
+};
+
+/**
+ * Reducer used to accumulate a value from multiple records both in SQL and JavaScript.
+ *
+ * Both operations should be equivalent.
+ */
+export type CoreDatabaseReducer<DBRecord, T> = {
+    sql: string;
+    js: (previousValue: T, record: DBRecord) => T;
+    jsInitialValue: T;
+};
+
+/**
+ * Conditions to match database records both in SQL and JavaScript.
+ *
+ * Both conditions should be equivalent.
+ */
+export type CoreDatabaseConditions<DBRecord> = {
+    sql: string;
+    sqlParams?: SQLiteDBRecordValue[];
+    js: (record: DBRecord) => boolean;
+};

src/core/classes/database/debug-database-table.ts

@@ -0,0 +1,139 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { SQLiteDBRecordValues } from '@classes/sqlitedb';
+import { CoreLogger } from '@singletons/logger';
+import { CoreDatabaseTable, CoreDatabaseConditions, GetDBRecordPrimaryKey, CoreDatabaseReducer } from './database-table';
+
+/**
+ * Database table proxy used to debug runtime operations.
+ *
+ * This proxy should only be used for development purposes.
+ */
+export class CoreDebugDatabaseTable<
+    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
+    PrimaryKeyColumn extends keyof DBRecord = 'id',
+    PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
+> extends CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey> {
+
+    protected target: CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey>;
+    protected logger: CoreLogger;
+
+    constructor(target: CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey>) {
+        super(target.getDatabase(), target.getTableName(), target.getPrimaryKeyColumns());
+
+        this.target = target;
+        this.logger = CoreLogger.getInstance(`CoreDatabase[${this.tableName}]`);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    initialize(): Promise<void> {
+        this.logger.log('initialize');
+
+        return this.target.initialize();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    destroy(): Promise<void> {
+        this.logger.log('destroy');
+
+        return this.target.destroy();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    getMany(conditions?: Partial<DBRecord>): Promise<DBRecord[]> {
+        this.logger.log('getMany', conditions);
+
+        return this.target.getMany(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    getOne(conditions: Partial<DBRecord>): Promise<DBRecord> {
+        this.logger.log('getOne', conditions);
+
+        return this.target.getOne(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
+        this.logger.log('findByPrimaryKey', primaryKey);
+
+        return this.target.getOneByPrimaryKey(primaryKey);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    reduce<T>(reducer: CoreDatabaseReducer<DBRecord, T>, conditions?: CoreDatabaseConditions<DBRecord>): Promise<T> {
+        this.logger.log('reduce', reducer, conditions);
+
+        return this.target.reduce<T>(reducer, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    insert(record: DBRecord): Promise<void> {
+        this.logger.log('insert', record);
+
+        return this.target.insert(record);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
+        this.logger.log('update', updates, conditions);
+
+        return this.target.update(updates, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
+        this.logger.log('updateWhere', updates, conditions);
+
+        return this.target.updateWhere(updates, conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    delete(conditions?: Partial<DBRecord>): Promise<void> {
+        this.logger.log('delete', conditions);
+
+        return this.target.delete(conditions);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
+        this.logger.log('deleteByPrimaryKey', primaryKey);
+
+        return this.target.deleteByPrimaryKey(primaryKey);
+    }
+
+}

src/core/classes/database/eager-database-table.ts

@@ -0,0 +1,168 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { CoreError } from '@classes/errors/error';
+import { SQLiteDBRecordValues } from '@classes/sqlitedb';
+import { CoreDatabaseTable, CoreDatabaseConditions, GetDBRecordPrimaryKey, CoreDatabaseReducer } from './database-table';
+
+/**
+ * Wrapper used to improve performance by caching all the records for faster read operations.
+ *
+ * This implementation works best for tables that don't have a lot of records and are read often; for tables with too many
+ * records use CoreLazyDatabaseTable instead.
+ */
+export class CoreEagerDatabaseTable<
+    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
+    PrimaryKeyColumn extends keyof DBRecord = 'id',
+    PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
+> extends CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey> {
+
+    protected records: Record<string, DBRecord> = {};
+
+    /**
+     * @inheritdoc
+     */
+    async initialize(): Promise<void> {
+        const records = await super.getMany();
+
+        this.records = records.reduce((data, record) => {
+            const primaryKey = this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record));
+
+            data[primaryKey] = record;
+
+            return data;
+        }, {});
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getMany(conditions?: Partial<DBRecord>): Promise<DBRecord[]> {
+        const records = Object.values(this.records);
+
+        return conditions
+            ? records.filter(record => this.recordMatches(record, conditions))
+            : records;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getOne(conditions: Partial<DBRecord>): Promise<DBRecord> {
+        const record = Object.values(this.records).find(record => this.recordMatches(record, conditions)) ?? null;
+
+        if (record === null) {
+            throw new CoreError('No records found.');
+        }
+
+        return record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
+        const record = this.records[this.serializePrimaryKey(primaryKey)] ?? null;
+
+        if (record === null) {
+            throw new CoreError('No records found.');
+        }
+
+        return record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async reduce<T>(reducer: CoreDatabaseReducer<DBRecord, T>, conditions?: CoreDatabaseConditions<DBRecord>): Promise<T> {
+        return Object
+            .values(this.records)
+            .reduce(
+                (result, record) => (!conditions || conditions.js(record)) ? reducer.js(result, record) : result,
+                reducer.jsInitialValue,
+            );
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async insert(record: DBRecord): Promise<void> {
+        await super.insert(record);
+
+        const primaryKey = this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record));
+
+        this.records[primaryKey] = record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
+        await super.update(updates, conditions);
+
+        for (const record of Object.values(this.records)) {
+            if (conditions && !this.recordMatches(record, conditions)) {
+                continue;
+            }
+
+            Object.assign(record, updates);
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
+        await super.updateWhere(updates, conditions);
+
+        for (const record of Object.values(this.records)) {
+            if (!conditions.js(record)) {
+                continue;
+            }
+
+            Object.assign(record, updates);
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async delete(conditions?: Partial<DBRecord>): Promise<void> {
+        await super.delete(conditions);
+
+        if (!conditions) {
+            this.records = {};
+
+            return;
+        }
+
+        Object.entries(this.records).forEach(([id, record]) => {
+            if (!this.recordMatches(record, conditions)) {
+                return;
+            }
+
+            delete this.records[id];
+        });
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
+        await super.deleteByPrimaryKey(primaryKey);
+
+        delete this.records[this.serializePrimaryKey(primaryKey)];
+    }
+
+}

src/core/classes/database/lazy-database-table.ts

@@ -0,0 +1,141 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { CoreError } from '@classes/errors/error';
+import { SQLiteDBRecordValues } from '@classes/sqlitedb';
+import { CoreDatabaseTable, CoreDatabaseConditions, GetDBRecordPrimaryKey } from './database-table';
+
+/**
+ * Wrapper used to improve performance by caching records that are used often for faster read operations.
+ *
+ * This implementation works best for tables that have a lot of records and are read often; for tables with a few records use
+ * CoreEagerDatabaseTable instead.
+ */
+export class CoreLazyDatabaseTable<
+    DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
+    PrimaryKeyColumn extends keyof DBRecord = 'id',
+    PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
+> extends CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey> {
+
+    protected records: Record<string, DBRecord | null> = {};
+
+    /**
+     * @inheritdoc
+     */
+    async getOne(conditions: Partial<DBRecord>): Promise<DBRecord> {
+        let record: DBRecord | null =
+            Object.values(this.records).find(record => record && this.recordMatches(record, conditions)) ?? null;
+
+        if (!record) {
+            record = await super.getOne(conditions);
+
+            this.records[this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record))] = record;
+        }
+
+        return record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
+        const serializePrimaryKey = this.serializePrimaryKey(primaryKey);
+
+        if (!(serializePrimaryKey in this.records)) {
+            try {
+                const record = await super.getOneByPrimaryKey(primaryKey);
+
+                this.records[serializePrimaryKey] = record;
+
+                return record;
+            } catch (error) {
+                this.records[serializePrimaryKey] = null;
+
+                throw error;
+            }
+        }
+
+        const record = this.records[serializePrimaryKey];
+
+        if (!record) {
+            throw new CoreError('No records found.');
+        }
+
+        return record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async insert(record: DBRecord): Promise<void> {
+        await super.insert(record);
+
+        this.records[this.serializePrimaryKey(this.getPrimaryKeyFromRecord(record))] = record;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
+        await super.update(updates, conditions);
+
+        for (const record of Object.values(this.records)) {
+            if (!record || (conditions && !this.recordMatches(record, conditions))) {
+                continue;
+            }
+
+            Object.assign(record, updates);
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
+        await super.updateWhere(updates, conditions);
+
+        for (const record of Object.values(this.records)) {
+            if (!record || !conditions.js(record)) {
+                continue;
+            }
+
+            Object.assign(record, updates);
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async delete(conditions?: Partial<DBRecord>): Promise<void> {
+        await super.delete(conditions);
+
+        for (const [primaryKey, record] of Object.entries(this.records)) {
+            if (!record || (conditions && !this.recordMatches(record, conditions))) {
+                continue;
+            }
+
+            this.records[primaryKey] = null;
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
+        await super.deleteByPrimaryKey(primaryKey);
+
+        this.records[this.serializePrimaryKey(primaryKey)] = null;
+    }
+
+}

src/core/classes/promised-value.ts

@@ -134,6 +134,16 @@ export class CorePromisedValue<T = unknown> implements Promise<T> {
         this._reject(reason);
     }
 
+    /**
+     * Reset status and value.
+     */
+    reset(): void {
+        delete this._resolvedValue;
+        delete this._rejectedReason;
+
+        this.initPromise();
+    }
+
     /**
      * Initialize the promise and the callbacks.
      */

src/core/classes/site.ts

@@ -41,6 +41,10 @@ import { CoreLogger } from '@singletons/logger';
 import { Translate } from '@singletons';
 import { CoreIonLoadingElement } from './ion-loading';
 import { CoreLang } from '@services/lang';
+import { CoreSites } from '@services/sites';
+import { asyncInstance, AsyncInstance } from '../utils/async-instance';
+import { CoreDatabaseTable } from './database/database-table';
+import { CoreDatabaseCachingStrategy } from './database/database-table-proxy';
 
 /**
  * QR Code type enumeration.
@@ -103,6 +107,7 @@ export class CoreSite {
     // Rest of variables.
     protected logger: CoreLogger;
     protected db?: SQLiteDB;
+    protected cacheTable: AsyncInstance<CoreDatabaseTable<CoreSiteWSCacheRecord>>;
     protected cleanUnicode = false;
     protected lastAutoLogin = 0;
     protected offlineDisabled = false;
@@ -136,6 +141,11 @@ export class CoreSite {
     ) {
         this.logger = CoreLogger.getInstance('CoreSite');
         this.siteUrl = CoreUrlUtils.removeUrlParams(this.siteUrl); // Make sure the URL doesn't have params.
+        this.cacheTable = asyncInstance(() => CoreSites.getSiteTable(CoreSite.WS_CACHE_TABLE, {
+            siteId: this.getId(),
+            database: this.getDb(),
+            config: { cachingStrategy: CoreDatabaseCachingStrategy.None },
+        }));
         this.setInfo(infos);
         this.calculateOfflineDisabled();
 
@@ -920,8 +930,7 @@ export class CoreSite {
         preSets: CoreSiteWSPreSets,
         emergency?: boolean,
     ): Promise<T> {
-        const db = this.db;
+        if (!this.db || !preSets.getFromCache) {
-        if (!db || !preSets.getFromCache) {
             throw new CoreError('Get from cache is disabled.');
         }
 
@@ -929,11 +938,11 @@ export class CoreSite {
         let entry: CoreSiteWSCacheRecord | undefined;
 
         if (preSets.getCacheUsingCacheKey || (emergency && preSets.getEmergencyCacheUsingCacheKey)) {
-            const entries = await db.getRecords<CoreSiteWSCacheRecord>(CoreSite.WS_CACHE_TABLE, { key: preSets.cacheKey });
+            const entries = await this.cacheTable.getMany({ key: preSets.cacheKey });
 
             if (!entries.length) {
                 // Cache key not found, get by params sent.
-                entry = await db.getRecord(CoreSite.WS_CACHE_TABLE, { id });
+                entry = await this.cacheTable.getOneByPrimaryKey({ id });
             } else {
                 if (entries.length > 1) {
                     // More than one entry found. Search the one with same ID as this call.
@@ -945,7 +954,7 @@ export class CoreSite {
                 }
             }
         } else {
-            entry = await db.getRecord(CoreSite.WS_CACHE_TABLE, { id });
+            entry = await this.cacheTable.getOneByPrimaryKey({ id });
         }
 
         if (entry === undefined) {
@@ -996,12 +1005,18 @@ export class CoreSite {
             extraClause = ' AND componentId = ?';
         }
 
-        const size = <number> await this.getDb().getFieldSql(
+        return this.cacheTable.reduce(
-            'SELECT SUM(length(data)) FROM ' + CoreSite.WS_CACHE_TABLE + ' WHERE component = ?' + extraClause,
+            {
-            params,
+                sql: 'SUM(length(data))',
+                js: (size, record) => size + record.data.length,
+                jsInitialValue: 0,
+            },
+            {
+                sql: 'WHERE component = ?' + extraClause,
+                sqlParams: params,
+                js: record => record.component === component && (params.length === 1 || record.componentId === componentId),
+            },
         );
-
-        return size;
     }
 
     /**
@@ -1015,10 +1030,6 @@ export class CoreSite {
      */
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     protected async saveToCache(method: string, data: any, response: any, preSets: CoreSiteWSPreSets): Promise<void> {
-        if (!this.db) {
-            throw new CoreError('Site DB not initialized.');
-        }
-
         if (preSets.uniqueCacheKey) {
             // Cache key must be unique, delete all entries with same cache key.
             await CoreUtils.ignoreErrors(this.deleteFromCache(method, data, preSets, true));
@@ -1044,7 +1055,7 @@ export class CoreSite {
             }
         }
 
-        await this.db.insertRecord(CoreSite.WS_CACHE_TABLE, entry);
+        await this.cacheTable.insert(entry);
     }
 
     /**
@@ -1058,16 +1069,12 @@ export class CoreSite {
      */
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     protected async deleteFromCache(method: string, data: any, preSets: CoreSiteWSPreSets, allCacheKey?: boolean): Promise<void> {
-        if (!this.db) {
-            throw new CoreError('Site DB not initialized.');
-        }
-
         const id = this.getCacheId(method, data);
 
         if (allCacheKey) {
-            await this.db.deleteRecords(CoreSite.WS_CACHE_TABLE, { key: preSets.cacheKey });
+            await this.cacheTable.delete({ key: preSets.cacheKey });
         } else {
-            await this.db.deleteRecords(CoreSite.WS_CACHE_TABLE, { id });
+            await this.cacheTable.deleteByPrimaryKey({ id });
         }
     }
 
@@ -1084,18 +1091,13 @@ export class CoreSite {
             return;
         }
 
-        if (!this.db) {
+        const params = { component };
-            throw new CoreError('Site DB not initialized');
-        }
 
-        const params = {
-            component,
-        };
         if (componentId) {
             params['componentId'] = componentId;
         }
 
-        await this.db.deleteRecords(CoreSite.WS_CACHE_TABLE, params);
+        await this.cacheTable.delete(params);
     }
 
     /*
@@ -1127,14 +1129,10 @@ export class CoreSite {
      * @return Promise resolved when the cache entries are invalidated.
      */
     async invalidateWsCache(): Promise<void> {
-        if (!this.db) {
-            throw new CoreError('Site DB not initialized');
-        }
-
         this.logger.debug('Invalidate all the cache for site: ' + this.id);
 
         try {
-            await this.db.updateRecords(CoreSite.WS_CACHE_TABLE, { expirationTime: 0 });
+            await this.cacheTable.update({ expirationTime: 0 });
         } finally {
             CoreEvents.trigger(CoreEvents.WS_CACHE_INVALIDATED, {}, this.getId());
         }
@@ -1147,16 +1145,13 @@ export class CoreSite {
      * @return Promise resolved when the cache entries are invalidated.
      */
     async invalidateWsCacheForKey(key: string): Promise<void> {
-        if (!this.db) {
-            throw new CoreError('Site DB not initialized');
-        }
         if (!key) {
             return;
         }
 
         this.logger.debug('Invalidate cache for key: ' + key);
 
-        await this.db.updateRecords(CoreSite.WS_CACHE_TABLE, { expirationTime: 0 }, { key });
+        await this.cacheTable.update({ expirationTime: 0 }, { key });
     }
 
     /**
@@ -1184,18 +1179,17 @@ export class CoreSite {
      * @return Promise resolved when the cache entries are invalidated.
      */
     async invalidateWsCacheForKeyStartingWith(key: string): Promise<void> {
-        if (!this.db) {
-            throw new CoreError('Site DB not initialized');
-        }
         if (!key) {
             return;
         }
 
         this.logger.debug('Invalidate cache for key starting with: ' + key);
 
-        const sql = 'UPDATE ' + CoreSite.WS_CACHE_TABLE + ' SET expirationTime=0 WHERE key LIKE ?';
+        await this.cacheTable.updateWhere({ expirationTime: 0 }, {
-
+            sql: 'key LIKE ?',
-        await this.db.execute(sql, [key + '%']);
+            sqlParams: [key],
+            js: record => !!record.key?.startsWith(key),
+        });
     }
 
     /**
@@ -1270,9 +1264,11 @@ export class CoreSite {
      * @return Promise resolved with the total size of all data in the cache table (bytes)
      */
     async getCacheUsage(): Promise<number> {
-        const size = <number> await this.getDb().getFieldSql('SELECT SUM(length(data)) FROM ' + CoreSite.WS_CACHE_TABLE);
+        return this.cacheTable.reduce({
-
+            sql: 'SUM(length(data))',
-        return size;
+            js: (size, record) => size + record.data.length,
+            jsInitialValue: 0,
+        });
     }
 
     /**

src/core/classes/sqlitedb.ts

@@ -1206,4 +1206,4 @@ export type SQLiteDBQueryParams = {
     params: SQLiteDBRecordValue[];
 };
 
-type SQLiteDBRecordValue = number | string;
+export type SQLiteDBRecordValue = number | string;

src/core/classes/tests/database-table.test.ts

@@ -13,7 +13,12 @@
 // limitations under the License.
 
 import { mock } from '@/testing/utils';
-import { CoreDatabaseTable } from '@classes/database-table';
+import { CoreDatabaseTable } from '@classes/database/database-table';
+import {
+    CoreDatabaseCachingStrategy,
+    CoreDatabaseConfiguration,
+    CoreDatabaseTableProxy,
+} from '@classes/database/database-table-proxy';
 import { SQLiteDB, SQLiteDBRecordValues } from '@classes/sqlitedb';
 
 interface User extends SQLiteDBRecordValues {
@@ -22,63 +27,79 @@ interface User extends SQLiteDBRecordValues {
     surname: string;
 }
 
-class UsersTable extends CoreDatabaseTable<User> {
+function userMatches(user: User, conditions: Partial<User>) {
-
+    return !Object.entries(conditions).some(([column, value]) => user[column] !== value);
-    protected table = 'users';
-
 }
 
-describe('CoreDatabaseTable', () => {
+function prepareStubs(config: Partial<CoreDatabaseConfiguration> = {}): [User[], SQLiteDB, CoreDatabaseTable<User>] {
+    const records: User[] = [];
+    const database = mock<SQLiteDB>({
+        getRecord: async <T>(_, conditions) => {
+            const record = records.find(record => userMatches(record, conditions));
 
-    let records: User[];
+            if (!record) {
-    let db: SQLiteDB;
+                throw new Error();
+            }
 
-    beforeEach(() => {
+            return record as unknown as T;
-        records = [];
+        },
-        db = mock<SQLiteDB>({
+        getRecords: async <T>(_, conditions) => records.filter(record => userMatches(record, conditions)) as unknown as T[],
-            getRecords: async <T>() => records as unknown as T[],
+        getAllRecords: async <T>() => records as unknown as T[],
-            deleteRecords: async () => 0,
+        deleteRecords: async (_, conditions) => {
-            insertRecord: async () => 0,
+            const usersToDelete: User[] = [];
-        });
+
+            for (const user of records) {
+                if (conditions && !userMatches(user, conditions)) {
+                    continue;
+                }
+
+                usersToDelete.push(user);
+            }
+
+            for (const user of usersToDelete) {
+                records.splice(records.indexOf(user), 1);
+            }
+
+            return usersToDelete.length;
+        },
+        insertRecord: async (_, user: User) => records.push(user) && 1,
     });
+    const table = new CoreDatabaseTableProxy<User>(config, database, 'users');
 
-    it('reads all records on create', async () => {
+    return [records, database, table];
-        await UsersTable.create(db);
+}
 
-        expect(db.getRecords).toHaveBeenCalledWith('users');
+async function testFindItems(records: User[], table: CoreDatabaseTable<User>) {
-    });
-
-    it('finds items', async () => {
     const john = { id: 1, name: 'John', surname: 'Doe' };
     const amy = { id: 2, name: 'Amy', surname: 'Doe' };
 
     records.push(john);
     records.push(amy);
 
-        const table = await UsersTable.create(db);
+    await table.initialize();
 
-        expect(table.findByPrimaryKey({ id: 1 })).toEqual(john);
+    await expect(table.getOneByPrimaryKey({ id: 1 })).resolves.toEqual(john);
-        expect(table.findByPrimaryKey({ id: 2 })).toEqual(amy);
+    await expect(table.getOneByPrimaryKey({ id: 2 })).resolves.toEqual(amy);
-        expect(table.find({ surname: 'Doe', name: 'John' })).toEqual(john);
+    await expect(table.getOne({ surname: 'Doe', name: 'John' })).resolves.toEqual(john);
-        expect(table.find({ surname: 'Doe', name: 'Amy' })).toEqual(amy);
+    await expect(table.getOne({ surname: 'Doe', name: 'Amy' })).resolves.toEqual(amy);
-    });
+}
 
-    it('inserts items', async () => {
+async function testInsertItems(records: User[], database: SQLiteDB, table: CoreDatabaseTable<User>) {
     // Arrange.
     const john = { id: 1, name: 'John', surname: 'Doe' };
 
-        // Act.
+    await table.initialize();
-        const table = await UsersTable.create(db);
 
+    // Act.
     await table.insert(john);
 
     // Assert.
-        expect(db.insertRecord).toHaveBeenCalledWith('users', john);
+    expect(database.insertRecord).toHaveBeenCalledWith('users', john);
 
-        expect(table.findByPrimaryKey({ id: 1 })).toEqual(john);
+    await expect(table.getOneByPrimaryKey({ id: 1 })).resolves.toEqual(john);
-    });
+}
 
-    it('deletes items', async () => {
+async function testDeleteItems(records: User[], database: SQLiteDB, table: CoreDatabaseTable<User>) {
     // Arrange.
     const john = { id: 1, name: 'John', surname: 'Doe' };
     const amy = { id: 2, name: 'Amy', surname: 'Doe' };
@@ -88,20 +109,20 @@ describe('CoreDatabaseTable', () => {
     records.push(amy);
     records.push(jane);
 
-        // Act.
+    await table.initialize();
-        const table = await UsersTable.create(db);
 
+    // Act.
     await table.delete({ surname: 'Doe' });
 
     // Assert.
-        expect(db.deleteRecords).toHaveBeenCalledWith('users', { surname: 'Doe' });
+    expect(database.deleteRecords).toHaveBeenCalledWith('users', { surname: 'Doe' });
 
-        expect(table.findByPrimaryKey({ id: 1 })).toBeNull();
+    await expect(table.getOneByPrimaryKey({ id: 1 })).rejects.toThrow();
-        expect(table.findByPrimaryKey({ id: 2 })).toBeNull();
+    await expect(table.getOneByPrimaryKey({ id: 2 })).rejects.toThrow();
-        expect(table.findByPrimaryKey({ id: 3 })).toEqual(jane);
+    await expect(table.getOneByPrimaryKey({ id: 3 })).resolves.toEqual(jane);
-    });
+}
 
-    it('deletes items by primary key', async () => {
+async function testDeleteItemsByPrimaryKey(records: User[], database: SQLiteDB, table: CoreDatabaseTable<User>) {
     // Arrange.
     const john = { id: 1, name: 'John', surname: 'Doe' };
     const amy = { id: 2, name: 'Amy', surname: 'Doe' };
@@ -109,16 +130,94 @@ describe('CoreDatabaseTable', () => {
     records.push(john);
     records.push(amy);
 
-        // Act.
+    await table.initialize();
-        const table = await UsersTable.create(db);
 
+    // Act.
     await table.deleteByPrimaryKey({ id: 1 });
 
     // Assert.
-        expect(db.deleteRecords).toHaveBeenCalledWith('users', { id: 1 });
+    expect(database.deleteRecords).toHaveBeenCalledWith('users', { id: 1 });
 
-        expect(table.findByPrimaryKey({ id: 1 })).toBeNull();
+    await expect(table.getOneByPrimaryKey({ id: 1 })).rejects.toThrow();
-        expect(table.findByPrimaryKey({ id: 2 })).toEqual(amy);
+    await expect(table.getOneByPrimaryKey({ id: 2 })).resolves.toEqual(amy);
+}
+
+describe('CoreDatabaseTable with eager caching', () => {
+
+    let records: User[];
+    let database: SQLiteDB;
+    let table: CoreDatabaseTable<User>;
+
+    beforeEach(() => [records, database, table] = prepareStubs({ cachingStrategy: CoreDatabaseCachingStrategy.Eager }));
+
+    it('reads all records on initialization', async () => {
+        await table.initialize();
+
+        expect(database.getAllRecords).toHaveBeenCalledWith('users');
     });
 
+    it('finds items', async () => {
+        await testFindItems(records, table);
+
+        expect(database.getRecord).not.toHaveBeenCalled();
+    });
+
+    it('inserts items', () => testInsertItems(records, database, table));
+    it('deletes items', () => testDeleteItems(records, database, table));
+    it('deletes items by primary key', () => testDeleteItemsByPrimaryKey(records, database, table));
+
+});
+
+describe('CoreDatabaseTable with lazy caching', () => {
+
+    let records: User[];
+    let database: SQLiteDB;
+    let table: CoreDatabaseTable<User>;
+
+    beforeEach(() => [records, database, table] = prepareStubs({ cachingStrategy: CoreDatabaseCachingStrategy.Lazy }));
+
+    it('reads no records on initialization', async () => {
+        await table.initialize();
+
+        expect(database.getRecords).not.toHaveBeenCalled();
+        expect(database.getAllRecords).not.toHaveBeenCalled();
+    });
+
+    it('finds items', async () => {
+        await testFindItems(records, table);
+
+        expect(database.getRecord).toHaveBeenCalledTimes(2);
+    });
+
+    it('inserts items', () => testInsertItems(records, database, table));
+    it('deletes items', () => testDeleteItems(records, database, table));
+    it('deletes items by primary key', () => testDeleteItemsByPrimaryKey(records, database, table));
+
+});
+
+describe('CoreDatabaseTable with no caching', () => {
+
+    let records: User[];
+    let database: SQLiteDB;
+    let table: CoreDatabaseTable<User>;
+
+    beforeEach(() => [records, database, table] = prepareStubs({ cachingStrategy: CoreDatabaseCachingStrategy.None }));
+
+    it('reads no records on initialization', async () => {
+        await table.initialize();
+
+        expect(database.getRecords).not.toHaveBeenCalled();
+        expect(database.getAllRecords).not.toHaveBeenCalled();
+    });
+
+    it('finds items', async () => {
+        await testFindItems(records, table);
+
+        expect(database.getRecord).toHaveBeenCalledTimes(4);
+    });
+
+    it('inserts items', () => testInsertItems(records, database, table));
+    it('deletes items', () => testDeleteItems(records, database, table));
+    it('deletes items by primary key', () => testDeleteItemsByPrimaryKey(records, database, table));
+
 });

src/core/constants.ts

@@ -145,23 +145,6 @@ export class CoreConstants {
     static readonly CONFIG = { ...envJson.config } as unknown as EnvironmentConfig; // Data parsed from config.json files.
     static readonly BUILD = envJson.build as unknown as EnvironmentBuild; // Build info.
 
-    /**
-     * Update config with the given values.
-     *
-     * @param config Config updates.
-     */
-    static patchConfig(config: Partial<EnvironmentConfig>): void {
-        Object.assign(this.CONFIG, config);
-    }
-
-    /**
-     * Reset config values to its original state.
-     */
-    static resetConfig(): void {
-        Object.keys(this.CONFIG).forEach(key => delete this.CONFIG[key]);
-        Object.assign(this.CONFIG, envJson.config);
-    }
-
 }
 
 interface EnvironmentBuild {

src/core/initializers/initialize-services.ts

@@ -15,11 +15,13 @@
 import { CoreFilepool } from '@services/filepool';
 import { CoreLang } from '@services/lang';
 import { CoreLocalNotifications } from '@services/local-notifications';
+import { CoreSites } from '@services/sites';
 import { CoreUpdateManager } from '@services/update-manager';
 
 export default async function(): Promise<void> {
     await Promise.all([
         CoreFilepool.initialize(),
+        CoreSites.initialize(),
         CoreLang.initialize(),
         CoreLocalNotifications.initialize(),
         CoreUpdateManager.initialize(),

src/core/services/config.ts

@@ -12,13 +12,29 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import { EnvironmentConfig } from '@/types/config';
 import { Injectable } from '@angular/core';
-
+import { CoreDatabaseCachingStrategy, CoreDatabaseTableProxy } from '@classes/database/database-table-proxy';
 import { CoreApp } from '@services/app';
+import { APP_SCHEMA, ConfigDBEntry, CONFIG_TABLE_NAME } from '@services/database/config';
 import { makeSingleton } from '@singletons';
-import { CONFIG_TABLE_NAME, APP_SCHEMA, ConfigDBEntry } from '@services/database/config';
+import { CoreConstants } from '../constants';
-import { CoreDatabaseTable } from '@classes/database-table';
+import { CoreEvents } from '@singletons/events';
-import { CorePromisedValue } from '@classes/promised-value';
+import { CoreDatabaseTable } from '@classes/database/database-table';
+import { asyncInstance } from '../utils/async-instance';
+
+declare module '@singletons/events' {
+
+    /**
+     * Augment CoreEventsData interface with events specific to this service.
+     *
+     * @see https://www.typescriptlang.org/docs/handbook/declaration-merging.html#module-augmentation
+     */
+    export interface CoreEventsData {
+        [CoreConfigProvider.ENVIRONMENT_UPDATED]: EnvironmentConfig;
+    }
+
+}
 
 /**
  * Factory to provide access to dynamic and permanent config and settings.
@@ -27,11 +43,10 @@ import { CorePromisedValue } from '@classes/promised-value';
 @Injectable({ providedIn: 'root' })
 export class CoreConfigProvider {
 
-    protected dbTable: CorePromisedValue<CoreConfigTable>;
+    static readonly ENVIRONMENT_UPDATED = 'environment_updated';
 
-    constructor() {
+    protected table = asyncInstance<CoreDatabaseTable<ConfigDBEntry, 'name'>>();
-        this.dbTable = new CorePromisedValue();
+    protected defaultEnvironment?: EnvironmentConfig;
-    }
 
     /**
      * Initialize database.
@@ -43,10 +58,16 @@ export class CoreConfigProvider {
             // Ignore errors.
         }
 
-        const db = CoreApp.getDB();
+        const table = new CoreDatabaseTableProxy<ConfigDBEntry, 'name'>(
-        const table = await CoreConfigTable.create(db);
+            { cachingStrategy: CoreDatabaseCachingStrategy.Eager },
+            CoreApp.getDB(),
+            CONFIG_TABLE_NAME,
+            ['name'],
+        );
 
-        this.dbTable.resolve(table);
+        await table.initialize();
+
+        this.table.setInstance(table);
     }
 
     /**
@@ -56,9 +77,7 @@ export class CoreConfigProvider {
      * @return Promise resolved when done.
      */
     async delete(name: string): Promise<void> {
-        const table = await this.dbTable;
+        await this.table.deleteByPrimaryKey({ name });
-
-        await table.deleteByPrimaryKey({ name });
     }
 
     /**
@@ -69,18 +88,17 @@ export class CoreConfigProvider {
      * @return Resolves upon success along with the config data. Reject on failure.
      */
     async get<T>(name: string, defaultValue?: T): Promise<T> {
-        const table = await this.dbTable;
+        try {
-        const record = table.findByPrimaryKey({ name });
+            const record = await this.table.getOneByPrimaryKey({ name });
 
-        if (record !== null) {
             return record.value;
-        }
+        } catch (error) {
-
             if (defaultValue !== undefined) {
                 return defaultValue;
             }
 
-        throw new Error(`Couldn't get config with name '${name}'`);
+            throw error;
+        }
     }
 
     /**
@@ -91,21 +109,36 @@ export class CoreConfigProvider {
      * @return Promise resolved when done.
      */
     async set(name: string, value: number | string): Promise<void> {
-        const table = await this.dbTable;
+        await this.table.insert({ name, value });
+    }
 
-        await table.insert({ name, value });
+    /**
+     * Update config with the given values.
+     *
+     * @param config Config updates.
+     */
+    patchEnvironment(config: Partial<EnvironmentConfig>): void {
+        this.defaultEnvironment = this.defaultEnvironment ?? CoreConstants.CONFIG;
+
+        Object.assign(CoreConstants.CONFIG, config);
+        CoreEvents.trigger(CoreConfigProvider.ENVIRONMENT_UPDATED, CoreConstants.CONFIG);
+    }
+
+    /**
+     * Reset config values to its original state.
+     */
+    resetEnvironment(): void {
+        if (!this.defaultEnvironment) {
+            // The environment config hasn't been modified; there's not need to reset.
+
+            return;
+        }
+
+        Object.keys(CoreConstants.CONFIG).forEach(key => delete CoreConstants.CONFIG[key]);
+        Object.assign(CoreConstants.CONFIG, this.defaultEnvironment);
+        CoreEvents.trigger(CoreConfigProvider.ENVIRONMENT_UPDATED, CoreConstants.CONFIG);
     }
 
 }
 
 export const CoreConfig = makeSingleton(CoreConfigProvider);
-
-/**
- * Config database table.
- */
-class CoreConfigTable extends CoreDatabaseTable<ConfigDBEntry, 'name'> {
-
-    protected table = CONFIG_TABLE_NAME;
-    protected primaryKeys = ['name'];
-
-}

src/core/services/db.ts

@@ -38,6 +38,17 @@ export class CoreDbProvider {
         return CoreAppProvider.isAutomated();
     }
 
+    /**
+     * Print query history in console.
+     */
+    printHistory(): void {
+        const substituteParams = ({ sql, params }: CoreDbQueryLog) =>
+            Object.values(params ?? []).reduce((sql: string, param: string) => sql.replace('?', param), sql);
+
+        // eslint-disable-next-line no-console
+        console.log(this.queryLogs.map(substituteParams).join('\n'));
+    }
+
     /**
      * Log a query.
      *

src/core/services/filepool.ts

@@ -48,6 +48,10 @@ import {
 } from '@services/database/filepool';
 import { CoreFileHelper } from './file-helper';
 import { CoreUrl } from '@singletons/url';
+import { CoreDatabaseTable } from '@classes/database/database-table';
+import { CoreDatabaseCachingStrategy } from '@classes/database/database-table-proxy';
+import { lazyMap, LazyMap } from '../utils/lazy-map';
+import { asyncInstance, AsyncInstance } from '../utils/async-instance';
 
 /*
  * Factory for handling downloading files and retrieve downloaded files.
@@ -72,9 +76,13 @@ export class CoreFilepoolProvider {
     protected static readonly ERR_FS_OR_NETWORK_UNAVAILABLE = 'CoreFilepoolError:ERR_FS_OR_NETWORK_UNAVAILABLE';
     protected static readonly ERR_QUEUE_ON_PAUSE = 'CoreFilepoolError:ERR_QUEUE_ON_PAUSE';
 
-    protected static readonly FILE_UPDATE_UNKNOWN_WHERE_CLAUSE =
+    protected static readonly FILE_IS_UNKNOWN_SQL =
         'isexternalfile = 1 OR ((revision IS NULL OR revision = 0) AND (timemodified IS NULL OR timemodified = 0))';
 
+    protected static readonly FILE_IS_UNKNOWN_JS =
+        ({ isexternalfile, revision, timemodified }: CoreFilepoolFileEntry): boolean =>
+            isexternalfile === 1 || ((revision === null || revision === 0) && (timemodified === null || timemodified === 0));
+
     protected logger: CoreLogger;
     protected queueState = CoreFilepoolProvider.QUEUE_PAUSED;
     protected urlAttributes: RegExp[] = [
@@ -94,10 +102,20 @@ export class CoreFilepoolProvider {
     // Variables for DB.
     protected appDB: Promise<SQLiteDB>;
     protected resolveAppDB!: (appDB: SQLiteDB) => void;
+    protected filesTables: LazyMap<AsyncInstance<CoreDatabaseTable<CoreFilepoolFileEntry, 'fileId'>>>;
 
     constructor() {
         this.appDB = new Promise(resolve => this.resolveAppDB = resolve);
         this.logger = CoreLogger.getInstance('CoreFilepoolProvider');
+        this.filesTables = lazyMap(
+            siteId => asyncInstance(
+                () => CoreSites.getSiteTable<CoreFilepoolFileEntry, 'fileId'>(FILES_TABLE_NAME, {
+                    siteId,
+                    config: { cachingStrategy: CoreDatabaseCachingStrategy.Lazy },
+                    primaryKeyColumns: ['fileId'],
+                }),
+            ),
+        );
     }
 
     /**
@@ -114,6 +132,16 @@ export class CoreFilepoolProvider {
                 NgZone.run(() => this.checkQueueProcessing());
             });
         });
+
+        CoreEvents.on(CoreEvents.SITE_DELETED, async ({ siteId }) => {
+            if (!siteId || !(siteId in this.filesTables)) {
+                return;
+            }
+
+            await this.filesTables[siteId].destroy();
+
+            delete this.filesTables[siteId];
+        });
     }
 
     /**
@@ -215,9 +243,7 @@ export class CoreFilepoolProvider {
             ...data,
         };
 
-        const db = await CoreSites.getSiteDb(siteId);
+        await this.filesTables[siteId].insert(record);
-
-        await db.insertRecord(FILES_TABLE_NAME, record);
     }
 
     /**
@@ -560,11 +586,11 @@ export class CoreFilepoolProvider {
         const db = await CoreSites.getSiteDb(siteId);
 
         // Read the data first to be able to notify the deletions.
-        const filesEntries = await db.getAllRecords<CoreFilepoolFileEntry>(FILES_TABLE_NAME);
+        const filesEntries = await this.filesTables[siteId].getMany();
         const filesLinks = await db.getAllRecords<CoreFilepoolLinksRecord>(LINKS_TABLE_NAME);
 
         await Promise.all([
-            db.deleteRecords(FILES_TABLE_NAME),
+            this.filesTables[siteId].delete(),
             db.deleteRecords(LINKS_TABLE_NAME),
         ]);
 
@@ -1125,7 +1151,7 @@ export class CoreFilepoolProvider {
             // Minor problem: file will remain in the filesystem once downloaded again.
             this.logger.debug('Staled file with no extension ' + entry.fileId);
 
-            await db.updateRecords(FILES_TABLE_NAME, { stale: 1 }, { fileId: entry.fileId });
+            await this.filesTables[siteId].update({ stale: 1 }, { fileId: entry.fileId });
 
             return;
         }
@@ -1135,7 +1161,7 @@ export class CoreFilepoolProvider {
         entry.fileId = CoreMimetypeUtils.removeExtension(fileId);
         entry.extension = extension;
 
-        await db.updateRecords(FILES_TABLE_NAME, entry, { fileId });
+        await this.filesTables[siteId].update(entry, { fileId });
         if (entry.fileId == fileId) {
             // File ID hasn't changed, we're done.
             this.logger.debug('Removed extesion ' + extension + ' from file ' + entry.fileId);
@@ -1401,10 +1427,7 @@ export class CoreFilepoolProvider {
 
         await Promise.all(items.map(async (item) => {
             try {
-                const fileEntry = await db.getRecord<CoreFilepoolFileEntry>(
+                const fileEntry = await this.filesTables[siteId].getOneByPrimaryKey({ fileId: item.fileId });
-                    FILES_TABLE_NAME,
-                    { fileId: item.fileId },
-                );
 
                 if (!fileEntry) {
                     return;
@@ -2137,14 +2160,7 @@ export class CoreFilepoolProvider {
      * @return Resolved with file object from DB on success, rejected otherwise.
      */
     protected async hasFileInPool(siteId: string, fileId: string): Promise<CoreFilepoolFileEntry> {
-        const db = await CoreSites.getSiteDb(siteId);
+        return this.filesTables[siteId].getOneByPrimaryKey({ fileId });
-        const entry = await db.getRecord<CoreFilepoolFileEntry>(FILES_TABLE_NAME, { fileId });
-
-        if (entry === undefined) {
-            throw new CoreError('File not found in filepool.');
-        }
-
-        return entry;
     }
 
     /**
@@ -2176,11 +2192,15 @@ export class CoreFilepoolProvider {
      * @return Resolved on success.
      */
     async invalidateAllFiles(siteId: string, onlyUnknown: boolean = true): Promise<void> {
-        const db = await CoreSites.getSiteDb(siteId);
+        onlyUnknown
-
+            ? await this.filesTables[siteId].updateWhere(
-        const where = onlyUnknown ? CoreFilepoolProvider.FILE_UPDATE_UNKNOWN_WHERE_CLAUSE : undefined;
+                { stale: 1 },
-
+                {
-        await db.updateRecordsWhere(FILES_TABLE_NAME, { stale: 1 }, where);
+                    sql: CoreFilepoolProvider.FILE_IS_UNKNOWN_SQL,
+                    js: CoreFilepoolProvider.FILE_IS_UNKNOWN_JS,
+                },
+            )
+            : await this.filesTables[siteId].update({ stale: 1 });
     }
 
     /**
@@ -2199,9 +2219,7 @@ export class CoreFilepoolProvider {
         const file = await this.fixPluginfileURL(siteId, fileUrl);
         const fileId = this.getFileIdByUrl(CoreFileHelper.getFileUrl(file));
 
-        const db = await CoreSites.getSiteDb(siteId);
+        await this.filesTables[siteId].update({ stale: 1 }, { fileId });
-
-        await db.updateRecords(FILES_TABLE_NAME, { stale: 1 }, { fileId });
     }
 
     /**
@@ -2221,7 +2239,6 @@ export class CoreFilepoolProvider {
         onlyUnknown: boolean = true,
     ): Promise<void> {
         const db = await CoreSites.getSiteDb(siteId);
-
         const items = await this.getComponentFiles(db, component, componentId);
 
         if (!items.length) {
@@ -2229,6 +2246,8 @@ export class CoreFilepoolProvider {
             return;
         }
 
+        siteId = siteId ?? CoreSites.getCurrentSiteId();
+
         const fileIds = items.map((item) => item.fileId);
 
         const whereAndParams = db.getInOrEqual(fileIds);
@@ -2236,10 +2255,19 @@ export class CoreFilepoolProvider {
         whereAndParams.sql = 'fileId ' + whereAndParams.sql;
 
         if (onlyUnknown) {
-            whereAndParams.sql += ' AND (' + CoreFilepoolProvider.FILE_UPDATE_UNKNOWN_WHERE_CLAUSE + ')';
+            whereAndParams.sql += ' AND (' + CoreFilepoolProvider.FILE_IS_UNKNOWN_SQL + ')';
         }
 
-        await db.updateRecordsWhere(FILES_TABLE_NAME, { stale: 1 }, whereAndParams.sql, whereAndParams.params);
+        await this.filesTables[siteId].updateWhere(
+            { stale: 1 },
+            {
+                sql: whereAndParams.sql,
+                sqlParams: whereAndParams.params,
+                js: record => fileIds.includes(record.fileId) && (
+                    !onlyUnknown || CoreFilepoolProvider.FILE_IS_UNKNOWN_JS(record)
+                ),
+            },
+        );
     }
 
     /**
@@ -2657,6 +2685,7 @@ export class CoreFilepoolProvider {
      */
     protected async removeFileById(siteId: string, fileId: string): Promise<void> {
         const db = await CoreSites.getSiteDb(siteId);
+
         // Get the path to the file first since it relies on the file object stored in the pool.
         // Don't use getFilePath to prevent performing 2 DB requests.
         let path = this.getFilepoolFolderPath(siteId) + '/' + fileId;
@@ -2682,7 +2711,7 @@ export class CoreFilepoolProvider {
         const promises: Promise<unknown>[] = [];
 
         // Remove entry from filepool store.
-        promises.push(db.deleteRecords(FILES_TABLE_NAME, conditions));
+        promises.push(this.filesTables[siteId].delete(conditions));
 
         // Remove links.
         promises.push(db.deleteRecords(LINKS_TABLE_NAME, conditions));

src/core/services/sites.ts

@@ -32,7 +32,7 @@ import {
     CoreSitePublicConfigResponse,
     CoreSiteInfoResponse,
 } from '@classes/site';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB, SQLiteDBRecordValues, SQLiteDBTableSchema } from '@classes/sqlitedb';
 import { CoreError } from '@classes/errors/error';
 import { CoreSiteError } from '@classes/errors/siteerror';
 import { makeSingleton, Translate, Http } from '@singletons';
@@ -57,6 +57,9 @@ import { CoreErrorWithTitle } from '@classes/errors/errorwithtitle';
 import { CoreAjaxError } from '@classes/errors/ajaxerror';
 import { CoreAjaxWSError } from '@classes/errors/ajaxwserror';
 import { CoreSitePlugins } from '@features/siteplugins/services/siteplugins';
+import { CorePromisedValue } from '@classes/promised-value';
+import { CoreDatabaseTable } from '@classes/database/database-table';
+import { CoreDatabaseConfiguration, CoreDatabaseTableProxy } from '@classes/database/database-table-proxy';
 
 export const CORE_SITE_SCHEMAS = new InjectionToken<CoreSiteSchema[]>('CORE_SITE_SCHEMAS');
 
@@ -85,6 +88,7 @@ export class CoreSitesProvider {
     // Variables for DB.
     protected appDB: Promise<SQLiteDB>;
     protected resolveAppDB!: (appDB: SQLiteDB) => void;
+    protected siteTables: Record<string, Record<string, CorePromisedValue<CoreDatabaseTable>>> = {};
 
     constructor(@Optional() @Inject(CORE_SITE_SCHEMAS) siteSchemas: CoreSiteSchema[][] = []) {
         this.appDB = new Promise(resolve => this.resolveAppDB = resolve);
@@ -99,6 +103,25 @@ export class CoreSitesProvider {
         );
     }
 
+    /**
+     * Initialize.
+     */
+    initialize(): void {
+        CoreEvents.on(CoreEvents.SITE_DELETED, async ({ siteId }) => {
+            if (!siteId || !(siteId in this.siteTables)) {
+                return;
+            }
+
+            await Promise.all(
+                Object
+                    .values(this.siteTables[siteId])
+                    .map(promisedTable => promisedTable.then(table => table.destroy())),
+            );
+
+            delete this.siteTables[siteId];
+        });
+    }
+
     /**
      * Initialize database.
      */
@@ -112,6 +135,49 @@ export class CoreSitesProvider {
         this.resolveAppDB(CoreApp.getDB());
     }
 
+    /**
+     * Get site table.
+     *
+     * @param tableName Site table name.
+     * @param options Options to configure table initialization.
+     * @returns Site table.
+     */
+    async getSiteTable<
+        DBRecord extends SQLiteDBRecordValues,
+        PrimaryKeyColumn extends keyof DBRecord
+    >(
+        tableName: string,
+        options: Partial<{
+            siteId: string;
+            config: Partial<CoreDatabaseConfiguration>;
+            database: SQLiteDB;
+            primaryKeyColumns: PrimaryKeyColumn[];
+        }> = {},
+    ): Promise<CoreDatabaseTable<DBRecord, PrimaryKeyColumn>> {
+        const siteId = options.siteId ?? this.getCurrentSiteId();
+
+        if (!(siteId in this.siteTables)) {
+            this.siteTables[siteId] = {};
+        }
+
+        if (!(tableName in this.siteTables[siteId])) {
+            const promisedTable = this.siteTables[siteId][tableName] = new CorePromisedValue();
+            const database = options.database ?? await this.getSiteDb(siteId);
+            const table = new CoreDatabaseTableProxy<DBRecord, PrimaryKeyColumn>(
+                options.config ?? {},
+                database,
+                tableName,
+                options.primaryKeyColumns,
+            );
+
+            await table.initialize();
+
+            promisedTable.resolve(table as unknown as CoreDatabaseTable);
+        }
+
+        return this.siteTables[siteId][tableName] as unknown as Promise<CoreDatabaseTable<DBRecord, PrimaryKeyColumn>>;
+    }
+
     /**
      * Get the demo data for a certain "name" if it is a demo site.
      *

src/core/utils/async-instance.ts

@@ -0,0 +1,122 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { CorePromisedValue } from '@classes/promised-value';
+
+/**
+ * Create a wrapper to hold an asynchronous instance.
+ *
+ * @param lazyConstructor Constructor to use the first time the instance is needed.
+ * @returns Asynchronous instance wrapper.
+ */
+function createAsyncInstanceWrapper<T>(lazyConstructor?: () => T | Promise<T>): AsyncInstanceWrapper<T> {
+    let promisedInstance: CorePromisedValue<T> | null = null;
+
+    return {
+        get instance() {
+            return promisedInstance?.value ?? undefined;
+        },
+        async getInstance() {
+            if (!promisedInstance) {
+                promisedInstance = new CorePromisedValue();
+
+                if (lazyConstructor) {
+                    const instance = await lazyConstructor();
+
+                    promisedInstance.resolve(instance);
+                }
+            }
+
+            return promisedInstance;
+        },
+        async getProperty(property) {
+            const instance = await this.getInstance();
+
+            return instance[property];
+        },
+        setInstance(instance) {
+            if (!promisedInstance) {
+                promisedInstance = new CorePromisedValue();
+            } else if (promisedInstance.isSettled()) {
+                promisedInstance.reset();
+            }
+
+            promisedInstance.resolve(instance);
+        },
+        resetInstance() {
+            if (!promisedInstance) {
+                return;
+            }
+
+            promisedInstance.reset();
+        },
+    };
+}
+
+/**
+ * Asynchronous instance wrapper.
+ */
+export interface AsyncInstanceWrapper<T> {
+    instance?: T;
+    getInstance(): Promise<T>;
+    getProperty<P extends keyof T>(property: P): Promise<T[P]>;
+    setInstance(instance: T): void;
+    resetInstance(): void;
+}
+
+/**
+ * Asynchronous version of a method.
+ */
+export type AsyncMethod<T> =
+    T extends (...args: infer Params) => infer Return
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        ? T extends (...args: Params) => Promise<any>
+            ? T
+            : (...args: Params) => Promise<Return>
+        : never;
+
+/**
+ * Asynchronous instance.
+ *
+ * All methods are converted to their asynchronous version, and properties are available asynchronously using
+ * the getProperty method.
+ */
+export type AsyncInstance<T> = AsyncInstanceWrapper<T> & {
+    [k in keyof T]: AsyncMethod<T[k]>;
+};
+
+/**
+ * Create an asynchronous instance proxy, where all methods will be callable directly but will become asynchronous. If the
+ * underlying instance hasn't been set, methods will be resolved once it is.
+ *
+ * @param lazyConstructor Constructor to use the first time the instance is needed.
+ * @returns Asynchronous instance.
+ */
+export function asyncInstance<T>(lazyConstructor?: () => T | Promise<T>): AsyncInstance<T> {
+    const wrapper = createAsyncInstanceWrapper<T>(lazyConstructor);
+
+    return new Proxy(wrapper, {
+        get: (target, property, receiver) => {
+            if (property in target) {
+                return Reflect.get(target, property, receiver);
+            }
+
+            return async (...args: unknown[]) => {
+                const instance = await wrapper.getInstance();
+
+                return instance[property](...args);
+            };
+        },
+    }) as AsyncInstance<T>;
+}

src/core/utils/lazy-map.ts

@@ -0,0 +1,40 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * Lazy map.
+ *
+ * Lazy maps are empty by default, but entries are generated lazily when accessed.
+ */
+export type LazyMap<T> = Record<string, T>;
+
+/**
+ * Create a map that will initialize entries lazily with the given constructor.
+ *
+ * @param lazyConstructor Constructor to use the first time an entry is accessed.
+ * @returns Lazy map.
+ */
+export function lazyMap<T>(lazyConstructor: (key: string) => T): LazyMap<T> {
+    const instances = {};
+
+    return new Proxy(instances, {
+        get(target, property, receiver) {
+            if (!(property in instances)) {
+                target[property] = lazyConstructor(property.toString());
+            }
+
+            return Reflect.get(target, property, receiver);
+        },
+    });
+}

src/types/config.d.ts

@@ -17,6 +17,7 @@ import { CoreMainMenuLocalizedCustomItem } from '@features/mainmenu/services/mai
 import { CoreSitesDemoSiteData } from '@services/sites';
 import { OpenFileAction } from '@services/utils/utils';
 import { CoreLoginSiteSelectorListMethod } from '@features/login/services/login-helper';
+import { CoreDatabaseConfiguration } from '@classes/database/database-table-proxy';
 
 /* eslint-disable @typescript-eslint/naming-convention */
 
@@ -31,6 +32,8 @@ export interface EnvironmentConfig {
     cache_update_frequency_rarely: number;
     default_lang: string;
     languages: Record<string, string>;
+    databaseOptimizations?: Partial<CoreDatabaseConfiguration>;
+    databaseTableOptimizations?: Record<string, Partial<CoreDatabaseConfiguration>>;
     wsservice: string;
     demo_sites: Record<string, CoreSitesDemoSiteData>;
     zoomlevels: Record<CoreZoomLevel, number>;