FAQs
Yes, the Workers Free plan will always include the ability to prototype and experiment with D1 for free.
What happens if I exceed the daily limits on reads and writes, or the total storage limit, on the Free plan?
When your account hits the daily read and/or write limits, you will not be able to run queries against D1. D1 API will return errors to your client indicating that your daily limits have been exceeded. Once you have reached your included storage limit, you will need to delete unused databases or clean up stale data before you can insert new data, create or alter tables or create indexes and triggers.
Upgrading to the Workers Paid plan will remove these limits, typically within minutes.
You will be billed for the additional reads, writes and storage according to D1's pricing metrics.
Every query returns a meta object that contains a total count of the rows read (rows_read) and rows written (rows_written) by that query. For example, a query that performs a full table scan (for instance, SELECT * FROM users) from a table with 5000 rows would return a rows_read value of 5000:
"meta": { "duration": 0.20472300052642825, "size_after": 45137920, "rows_read": 5000, "rows_written": 0}These are also included in the D1 Cloudflare dashboard ↗ and the analytics API, allowing you to attribute read and write volumes to specific databases, time periods, or both.
No.
D1 itself does not charge for additional compute. Workers querying D1 and computing results: for example, serializing results into JSON and/or running queries, are billed per Workers pricing, in addition to your D1 specific usage.
Yes, any queries you run against your database, including inserting (INSERT) existing data into a new database, table scans (SELECT * FROM table), or creating indexes count as either reads or writes.
Yes, you can use an index to reduce the number of rows read by a query. Creating indexes for your most queried tables and filtered columns reduces how much data is scanned and improves query performance at the same time. If you have a read-heavy workload (most common), this can be particularly advantageous. Writing to columns referenced in an index will add at least one (1) additional row written to account for updating the index, but this is typically offset by the reduction in rows read due to the benefits of an index.
Yes, although minimal. An empty table consumes at least a few kilobytes, based on the number of columns (table width) in the table. An empty database consumes approximately 12 KB of storage.
D1 is designed for horizontal scale out across multiple, smaller (10 GB) databases, such as per-user, per-tenant or per-entity databases. D1 allows you to build applications with thousands of databases at no extra cost for isolating with multiple databases, as the pricing is based only on query and storage costs.
- Each D1 database can store up to 10 GB of data, and you can create up to thousands of separate D1 databases. This allows you to split a single monolithic database into multiple, smaller databases, thereby isolating application data by user, customer, or tenant.
- SQL queries over a smaller working data set can be more efficient and performant while improving data isolation.
You can open up to six connections (to D1) simultaneously for each invocation of your Worker.
For more information on a Worker's simultaneous connections, refer to Simultaneous open connections.
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