caching.md

Caching queries

You can cache results selected by these QueryBuilder methods: getMany, getOne, getRawMany, getRawOne and getCount.

You can also cache results selected by these Repository methods: find, findAndCount, findByIds, and count.

To enable caching you need to explicitly enable it in your connection options:

{
    type: "mysql",
    host: "localhost",
    username: "test",
    ...
    cache: true
}

When you enable cache for the first time, you must synchronize your database schema (using CLI, migrations or the synchronize connection option).

Then in QueryBuilder you can enable query cache for any query:

const users = await connection
    .createQueryBuilder(User, "user")
    .where("user.isAdmin = :isAdmin", { isAdmin: true })
    .cache(true)
    .getMany();

Equivalent Repository query:

const users = await connection
    .getRepository(User)
    .find({
        where: { isAdmin: true },
        cache: true
    });

This will execute a query to fetch all admin users and cache its result. Next time when you execute same code it will get admin users from the cache. Default cache time is equal to 1000 ms, e.g. 1 second. This means cache will be invalid 1 second after you called the query builder code. In practice, it means that if users open user page 150 times within 3 seconds only three queries will be executed during this period. All users inserted during the 1 second of caching won't be returned to the user.

You can change cache time manually via QueryBuilder:

const users = await connection
    .createQueryBuilder(User, "user")
    .where("user.isAdmin = :isAdmin", { isAdmin: true })
    .cache(60000) // 1 minute
    .getMany();

Or via Repository:

const users = await connection
    .getRepository(User)
    .find({
        where: { isAdmin: true },
        cache: 60000
    });

Or globally in connection options:

{
    type: "mysql",
    host: "localhost",
    username: "test",
    ...
    cache: {
        duration: 30000 // 30 seconds
    }
}

Also, you can set a "cache id" via QueryBuilder:

const users = await connection
    .createQueryBuilder(User, "user")
    .where("user.isAdmin = :isAdmin", { isAdmin: true })
    .cache("users_admins", 25000)
    .getMany();

Or with Repository:

const users = await connection
    .getRepository(User)
    .find({
        where: { isAdmin: true },
        cache: { 
            id: "users_admins",
            milisseconds: 25000
        }
    });

It will allow you to granular control your cache, for example, clear cached results when you insert a new user:

await connection.queryResultCache.remove(["users_admins"]);

By default, TypeORM uses a separate table called query-result-cache and stores all queries and results there. If storing cache in a single database table is not effective for you, you can change the cache type to "redis" and TypeORM will store all cached records in redis instead. Example:

{
    type: "mysql",
    host: "localhost",
    username: "test",
    ...
    cache: {
        type: "redis",
        options: {
            host: "localhost",
            port: 6379
        }
    }
}

"options" are redis specific options.

You can use typeorm cache:clear to clear everything stored in the cache.