4.django缓存优化课件-iczt441解析

1、Lesson4: Database缓存解析讲师：Cynthia课程内容Database缓存配置源码解析配置与使用演示Database缓存配置BACKEND:django.core.cache.backends.db.DatabaseCacheLOCATION: 数据库表名CACHES = default: BACKEND: django.core.cache.backends.db.DatabaseCache, LOCATION: my_cache_table, Database缓存配置创建缓存表使用数据库缓存之前，需要创建缓存表：python manage.py createcachetab

2、le创建的表名为缓存配置中的LOCATION值思考：Cache表创建到哪里去了呢？Database缓存配置创建缓存表配置好数据库缓存之前还需要配置数据库:DATABASES = default: NAME: app_data, ENGINE: django.db.backends.postgresql_psycopg2, USER: postgres_user, PASSWORD: password 只会创建不存在的表，如果表已经存在，不操作Database缓存配置创建缓存表疑问？可否将cache分类存储到不同的表？可否将cache分别存储到不同数据库？YESDatabase缓存配置创建缓存表

3、Mutiple Database Caches: createcachetable会为每个 Cache 创建一张缓存表Mutiple Databases: createcachetable会去查找数据库routers中的allow_migrate()方法，检查是否允许migrate。默认使用default数据库，要使用其它数据库，需要用-database参数。Multi Database CachesCACHES = default: BACKEND: django.core.cache.backends.db.DatabaseCache, LOCATION: api_cache_table,

4、 ，# 必须配置default apps: BACKEND: django.core.cache.backends.db.DatabaseCache, LOCATION: apps_cache_table, Multiple Databasesclass CacheRouter(object): A router to control all database cache operations def db_for_read(self, model, *hints): All cache read operations go to the replica def db_for_write(se

5、lf, model, *hints): All cache write operations go to primary def allow_migrate(self, db, app_label, model_name=None, *hints): Only install the cache model on primary Multiple Databases读 def db_for_read(self, model, *hints): All cache read operations go to the replica if model._meta.app_label = djang

6、o_cache: return cache_replica return None所有DB缓存的读操作指向 cache_replica DBMultiple Databases写def db_for_write(self, model, *hints): All cache write operations go to primary if model._meta.app_label = django_cache: return cache_primary return None def db_for_write(self, model, *hints): All cache write op

7、erations go to primary if model._meta.app_label = django_cache: return cache_primary return None所有DB缓存的写操作指向 cache_primary DBMultiple Databasesmigrationdef allow_migrate(self, db, app_label, model_name=None, *hints): Only install the cache model on primary if app_label = django_cache: return db = cache_primary return None允许在 cache_primary DB 上执行 migration源码解析Cache接口：getset (会调用_cull)addhas_keydeleteclear演示环境说明操作系统Ubuntu数据库MySQLDjango 版本 1.8IDE PyCharm， VIMDatabase配置与使用演示DB Cache 配置与使用Multiple DB Caches 配置与使用基于 Multiple DBs 缓存配置与使用DB router 配置与使用参考资料Djangos cache framwork Multiple dat