Read replicas have the same lifecycle as a primary DB. If there is no constant traffic for 1-2 minut

Read replicas have the same lifecycle as a primary DB. If there is no constant traffic for 1-2 minutes, they will hibernate. Once the next request comes in they will start their boot process, and until they finish booting requests are forwarded to the primary. Once the replica boots (depends on the DB size how many (milli)seconds it will take), then replicas serve the read traffic in that region.

If your traffic is very low, once every few minutes for example, then you probably won't see any traffic served by replicas.

My database is very quiet just now (but not silent, it's still receiving queries from all over).

This is not concrete. What is quiet, and what is "still receiving queries from all over"?

Is there something that prevents replica creation if the DB isn't getting enough traffic?

No, replicas are always "created" as in ready to start, one in each region. But, the traffic is what keeps them alive. No traffic, and they will shutdown again.

Llambrospetrou Read replicas have the same lifecycle as a primary DB. If there is no constant t...

lambrospetrouOP•9/7/25, 8:18 AM

Each response has fields telling you if it's the primary or a replica handling your request and from which region: https://developers.cloudflare.com/d1/best-practices/read-replication/#check-where-d1-request-was-processed

const result = await env.DB.withSession()
  .prepare(`SELECT * FROM Customers WHERE CompanyName = 'Bs Beverages'`)
  .run();
console.log({
  servedByRegion: result.meta.served_by_region ?? "",
  servedByPrimary: result.meta.served_by_primary ?? "",
});

const result = await env.DB.withSession()
  .prepare(`SELECT * FROM Customers WHERE CompanyName = 'Bs Beverages'`)
  .run();
console.log({
  servedByRegion: result.meta.served_by_region ?? "",
  servedByPrimary: result.meta.served_by_primary ?? "",
});

Llambrospetrou Each response has fields telling you if it's the primary or a replica handling y...

lambrospetrouOP•9/7/25, 8:18 AM

Also, I assume you use the Sessions API. Otherwise, all your requests will go to the primary regardless if you have enabled read replication or not.

Llambrospetrou Also, I assume you use the [Sessions API](https://developers.cloudflare.com/d1/b...

aza547•9/7/25, 8:44 AM

Thank you for the detailed response. That clears it up for me

- It would be awesome if this could be captured in the docs.
- My problem is almost certainly that I'm not using the sessions API.

This is not concrete. What is quiet, and what is "still receiving queries from all over"?

What I was trying to convey is that there is consistent non-zero traffic in every region, and that I expected read replicas in every region to be queried. "Quiet" as in "not enough to overload the primary DB".

The docs to me imply that the sessions API is to guarantee sequential consistency for a set of queries, but the bulk of my traffic is pulling a single field out of the database so I don't actually care about sequential consistency in a lot of cases.

Feel free to point out if I'm missing the obvious, but I don't think the docs make it clear that the sessions API is required for queries to hit a read replica.

I'll go add some

.withSession()

.withSession()

calls to my worker and see what happens. Thanks again.

Aaza547 Thank you for the detailed response. That clears it up for me 🙂 - It would be a...

lambrospetrouOP•9/7/25, 8:45 AM

At the very top:

Your application can use read replicas with D1 Sessions API.

Your application can use read replicas with D1 Sessions API.

We can make it even stronger if that's not clear enough. I will add another clarifying sentence there.

aza547•9/7/25, 8:50 AM

That would be great, I guess I'm still reading that as "you can use the sessions API optionally to get sequential consistency which a read replication enabled DB otherwise doesn't provide"

aza547•9/7/25, 9:13 AM

Happy days

OOr Will enabling read replication cause the primary DB to be locked while the repli...

lambrospetrouOP•9/7/25, 9:42 PM

No, replication is done asynchronously, and there is no blocking time while replicas are being created. As I mentioned above though, in order to get benefits from replicas you would need some continuous traffic, especially since 3GB would need a few seconds to boot.
If you only have a request per minute for example, you will pretty much always go to the primary.

flof.fly•9/7/25, 9:56 PM

Is there a way to Duplicate a D1 (including data) via APICall or CLI?

Fflof.fly Is there a way to Duplicate a D1 (including data) via APICall or CLI?

lambrospetrouOP•9/8/25, 7:13 AM

Not at the moment

Pingo•9/8/25, 2:12 PM

Hi im a noob to d1 and my biggest concern is obviously avoiding something like tea app disaster. So I wanted to know if there is an awesome list with projects using d1 so I can learn how real life applications are configuring d1 with battle tested patterns. I am extremely paranoid about managing user data correctly. Sorry if this is not the place to ask about this.

PPingo Hi im a noob to d1 and my biggest concern is obviously avoiding something like t...

lambrospetrouOP•9/8/25, 2:24 PM

Hi im a noob to d1 and my biggest concern is obviously avoiding something like tea app disaster.

What is the "tea app disaster"?

D1 is durable storage, and provides up to 30 days of Point-in-time-restore for your data to be able to revert to any point in these 30 days.

There are certain limits, about storage (10GB) and fixed resource limits due to being single threaded execution of the queries, but we don't lose your data.

If you have specific concerns or questions, happy to answer. Or anyone in this community for what's worth.

Llambrospetrou > Hi im a noob to d1 and my biggest concern is obviously avoiding something like...

Isaac McFadyen•9/8/25, 2:28 PM

What is the "tea app disaster"?

Recent data breach from an app called Tea: https://www.bbc.com/news/articles/c7vl57n74pqo

IIsaac McFadyen > What is the "tea app disaster"? Recent data breach from an app called Tea: htt...

lambrospetrouOP•9/8/25, 2:55 PM

D1 data is encrypted at rest (built ontop of Durable Objects), but obviously access is authenticated using either your worker binding (so having access to deploying workers) or to the Cloudflare access tokens, so you should protect your access tokens as any other secret. I can't say anything specific about the leaked incident of Tea.

Gab•9/8/25, 3:35 PM

HI guys, how can I aapply drizzle migrations to preview or local d1 database?
im trying with ->
wrangler d1 migrations apply d1_database --local
the CLI say it works well, but when I come to sql editor, there is no schema in the database

Gab•9/8/25, 3:38 PM

when I use wrangler d1 migrations apply d1_database --remote
it workers well on the main d1 database, but --local does not seen to apply

GGab when I use wrangler d1 migrations apply d1_database --remote it workers well on ...

Anes•9/8/25, 3:43 PM

you can apply the migrations using drizzle, your drizzle.config.ts should look like this:

import { defineConfig } from "drizzle-kit";
import { config } from "dotenv";

config({
  path: ".env.stage"
});

export default defineConfig({
  schema: ["./src/app/schema.ts", "./src/app/auth-schema.ts"],
  out: "./drizzle/app",
  dialect: "sqlite",
  driver: "d1-http",
  dbCredentials: {
    accountId: process.env.CF_ACCOUNT_ID,
    databaseId: process.env.CF_DATABASE_ID,
    token: process.env.CF_TOKEN,
    url: ""
  }
});

import { defineConfig } from "drizzle-kit";
import { config } from "dotenv";

config({
  path: ".env.stage"
});

export default defineConfig({
  schema: ["./src/app/schema.ts", "./src/app/auth-schema.ts"],
  out: "./drizzle/app",
  dialect: "sqlite",
  driver: "d1-http",
  dbCredentials: {
    accountId: process.env.CF_ACCOUNT_ID,
    databaseId: process.env.CF_DATABASE_ID,
    token: process.env.CF_TOKEN,
    url: ""
  }
});

eg script:

"db:push": "drizzle-kit push --config=./drizzle.config.ts"

"db:push": "drizzle-kit push --config=./drizzle.config.ts"

Gab•9/8/25, 3:48 PM

ok, do i need to change the CF_DATABASE_ID for the local preview d1 database? (i can add in .dev.vars)

Gab•9/8/25, 4:19 PM

I got working with the old script, It was working, thje problem was at my betterAuth objecta tha was not findind the correct db

csmykay•9/8/25, 6:27 PM

Howdy all. Is there a good "best practices" document for working with D1 databases locally with multiple developers and how best to push updates? I actually have a response from Claude but looking for something to double check.

52Hz•9/8/25, 8:20 PM

Is it currently possible to download the data of a specific time point three days ago from the D1 database without modifying the database?

csmykay•9/8/25, 9:07 PM

On a side note a "best practices" in using drizlle on your docs page would be great.

552Hz Is it currently possible to download the data of a specific time point three day...

lambrospetrouOP•9/9/25, 7:30 AM

No, unfortunately.

52Hz•9/9/25, 7:50 AM

Is it possible to restore to a certain point in time, export the data, and then revert back to the point in time before the operation?

552Hz Is it possible to restore to a certain point in time, export the data, and then ...

lambrospetrouOP•9/9/25, 9:21 AM

Yes, with the caveat that during export your DB won't be able to process queries.

52Hz•9/9/25, 10:19 AM

OK. Thank you.

Dean•9/9/25, 6:27 PM

anyone else seeing D1 issues right now? WNAM region. database won't even load in dashboard

parisholley•9/9/25, 6:27 PM

yes

Dean•9/9/25, 6:28 PM

looks like it's back for me, for some dbs, some are still dead

nullptr•9/9/25, 6:29 PM

D1 is returning errors all over

aza547•9/9/25, 6:29 PM

Also seeing issues

nullptr•9/9/25, 6:30 PM

Guys any help here? Our production stack is on fire it looks like

Iaci•9/9/25, 6:31 PM

yes, same here:
Error: D1_ERROR: Internal error while starting up D1 DB storage caused object to be reset.

thirtyfourdifferentoranges•9/9/25, 6:34 PM

having catastrophic d1 failures here

kafk•9/9/25, 6:34 PM

same

Matthew•9/9/25, 6:34 PM

bunch of errors. had the same last night around 0:30 UTC

Tc001•9/9/25, 6:34 PM

lol just as I was trying to use my app built with it

to all the employees

thirtyfourdifferentoranges•9/9/25, 6:34 PM

oh my god, this is going to be a long day

parisholley•9/9/25, 6:35 PM

https://tenor.com/view/wet-hot-american-summer-group-hug-crying-sad-together-gif-5276724

Tenor

a good group cry

Paul Shriner - Titleless•9/9/25, 6:36 PM

Well this sucks.

kafk•9/9/25, 6:38 PM

I thought some villain hacked and dropped the db, fortunately it's just a global Cloudflare failure :MeowHeartCloudflare:

Hard@Work•9/9/25, 6:38 PM

Team is aware, thanks for the reports!

Tc001•9/9/25, 6:41 PM

Yay it's back for me (edit: nvm)

mrk•9/9/25, 6:43 PM

My production database is down as well! @Hard@Work | R2 do keep us posted

Chaika•9/9/25, 6:44 PM

Should be status page in a bit

Hard@Work•9/9/25, 6:44 PM

Yep, team is working on it

const result = await env.DB.withSession() .prepare(`SELECT * FROM Customers WHERE CompanyName = 'Bs Beverages'`) .run(); console.log({ servedByRegion: result.meta.served_by_region ?? "", servedByPrimary: result.meta.served_by_primary ?? "", });

import { defineConfig } from "drizzle-kit"; import { config } from "dotenv"; config({ path: ".env.stage" }); export default defineConfig({ schema: ["./src/app/schema.ts", "./src/app/auth-schema.ts"], out: "./drizzle/app", dialect: "sqlite", driver: "d1-http", dbCredentials: { accountId: process.env.CF_ACCOUNT_ID, databaseId: process.env.CF_DATABASE_ID, token: process.env.CF_TOKEN, url: "" } });

Read replicas have the same lifecycle as a primary DB. If there is no constant traffic for 1-2 minut

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