Prepared statements in D1 are only a client side thing so that you can bind values to the statement.

Prepared statements in D1 are only a client side thing so that you can bind values to the statement. It doesn't change the actual query execution, or duration, at all.

Llambrospetrou Prepared statements in D1 are only a client side thing so that you can bind valu...

onewug•8/6/25, 10:52 AM

then should the docs be updated to not reference performance?

Oonewug then should the docs be updated to not reference performance?

lambrospetrouOP•8/6/25, 11:29 AM

What that might mean is that if someone just inlines all their data in the SQL itself it might be slower. So, it does have a small benefit in that way. What I meant above is that D1 prepared statements are not like in other databases that you compile a query and avoid overhead by reusing it.
In the current version of D1 since you make a remote call for every query SQLite is given the query SQL string and the params, and does its thing. The prepared statements are not reused across requests at the SQLite engine level.

I will see how we can make that note clearer.

onewug•8/6/25, 1:36 PM

i see, thanks for explaining!

Jun•8/6/25, 2:01 PM

The text has been updated FYI

JJun The text has been updated FYI 😄

Larry•8/6/25, 2:53 PM

That was fast! That's one thing I really love about being a developer on the Cloudflare platform! Thanks Jun!!!

lmsqqt•8/6/25, 4:13 PM

I'm a newcomer. I want to ask if there is a security problem if the ID of the d1 database is directly put on Github?

Llmsqqt I'm a newcomer. I want to ask if there is a security problem if the ID of the d1...

Isaac McFadyen•8/6/25, 4:21 PM

No security issue, it's fine. All binding IDs can be posted in public settings, they only work on your own account.

lmsqqt•8/6/25, 4:28 PM

thank

ryan•8/7/25, 2:08 AM

CeeJay•8/7/25, 9:59 AM

I don't think Cloudflare did a great job choosing the region for my D1, I should have put a location hint in (if that was available when I created it?).

Anyhow, now I am in a position that the DB (and likely the workers) are resident in Western North America and all my workload originates in UK.

Apart from exporting the whole thing, importing into a Western Europe resident DB are there any tools or patterns for transitioning and ensuring consistency / syncing?

TIA

CCeeJay I don't think Cloudflare did a great job choosing the region for my D1, I should...

lambrospetrouOP•8/7/25, 10:51 AM

Unfortunately, we don't provide any tooling to transfer databases at the moment, and we cannot move them after creation. I suggest creating a new DB providing a location hint to ~~EEUR~~ WEUR (includes UK), and copy your data there.

Llambrospetrou Unfortunately, we don't provide any tooling to transfer databases at the moment,...

CeeJay•8/7/25, 10:54 AM

Thanks for coming back to me

- Can you confirm that UK is in/closest to Eastern Europe, it's usually categorised as Western Europe?

CCeeJay Thanks for coming back to me 🙏 - Can you confirm that UK is in/closest to Easte...

lambrospetrouOP•8/7/25, 10:58 AM

Yeah sorry, I meant WEUR, see also https://where.durableobjects.live/colo/LHR to see latencies across all location hints.
Your DB will end up in the UK or Amsterdam probably but depending on datacenter issues might move into other WEUR locations.

Where Durable Objects Live

London, England, United Kingdom (colo)

Tracking where Durable Objects are created, wherever you are in the world.

Billy•8/7/25, 8:27 PM

In this doc: https://developers.cloudflare.com/d1/best-practices/import-export-data/#known-limitations, the statement "A running export will block other database requests." really only applies to

CREATE

CREATE

INSERT

INSERT

, and

DELETE

DELETE

requests, correct? If so, it would've helped assure me that

READ

READ

would not be blocked during an export (if that's true). Thanks

Cloudflare Docs

Import and export data

D1 allows you to import existing SQLite tables and their data directly, enabling you to migrate existing data into D1 quickly and easily. This can be useful when migrating applications to use Workers and D1, or when you want to prototype a schema locally before importing it to your D1 database(s).

gruntlord6•8/7/25, 8:32 PM

reads are blocked

BBilly In this doc: https://developers.cloudflare.com/d1/best-practices/import-export-...

gruntlord6•8/7/25, 8:32 PM

the whole thing is not accessible while its dumping the database

Ggruntlord6 reads are blocked

Billy•8/7/25, 9:10 PM

yikes, ok... but that blocking limitation is about to be eliminated, correct?

gruntlord6•8/7/25, 9:15 PM

I mean they want to eliminate it, they haven't given a timeline of any kind. You can always just copy the data directly instead of using that tool

ldo•8/8/25, 8:32 AM

Is there a page or dashboard where I can check the server health/status of D1? One of my D1 services has been returning timeouts or 500 errors for about two hours, and I would like to know when this issue is expected to be resolved.

Lldo Is there a page or dashboard where I can check the server health/status of D1? O...

lambrospetrouOP•8/8/25, 10:00 AM

There isn't any widespread D1 service issue or individual DBs with startup issues. If you continue having 5xx please send us more details. DB/Account IDs, and any timeranges you can specify to help us investigate.

Llambrospetrou There isn't any widespread D1 service issue or individual DBs with startup issue...

ldo•8/8/25, 10:21 AM

It was not a 100% failure, but the connection was very unstable.
The UUID of the problematic D1 is e6cdb51a-42e0-4a40-a342-bf1852204a87, and the following issues occurred:

D1_ERROR: Network connection lost.
D1_ERROR: D1 DB is overloaded. Requests queued for too long.
Timeout (30s)
When attempting to access the DB via the console, it would load indefinitely.

Currently, the situation has somewhat stabilized and console access is possible.
However, timeouts or response times exceeding 10 seconds still remain.

Lldo It was not a 100% failure, but the connection was very unstable. The UUID of the...

lambrospetrouOP•8/8/25, 11:10 AM

OK, these errors are not from the D1 service itself, so that's good at least

Network connection lost errors are indeed internal errors from the runtime, usually due to the underlying Durable Object connectivity issues. Some amount of these is to be expected but should be very transient and not ongoing, feel free to retry these if your query allows. If you see these continuously please let me/us know, since sometimes a database might be in a faulty location for a few minutes before it gets taken out of the network or might need something manual on our side.

The overloaded error indicates that either you send too many requests and they are slow being processed, so the queue is growing and at some point extra reqs will be rejected with that error.

I will take a glance on your DB, if you DM me your account ID too.

lambrospetrouOP•8/8/25, 11:12 AM

As a side note to everyone, it makes it faster for us to investigate issues in your accounts if you connect the account info to your Discord profile, otherwise we would need to ask you all the time about it, meaning more back and forth comms before we can do anything.

Run

/link

/link

and fill the info, so that we can figure out your account by your profile.

JJun The text has been updated FYI 😄

cortopy•8/8/25, 5:48 PM

This is so much clearer!! Would it be possible to maybe clarify the same for durable objects sql api? I’ve been trying to figure out if sql methods protect against sql injection

https://developers.cloudflare.com/durable-objects/api/storage-api/#returns

Cloudflare Docs

Durable Object Storage

The Durable Object Storage API allows Durable Objects to access transactional and strongly consistent storage. A Durable Object's attached storage is private to its unique instance and cannot be accessed by other objects.

Llambrospetrou As long as you use the D1 Binding from your worker, or Pages function, it should...

Dean•8/11/25, 6:19 AM

i enabled it and haven't been able to have a single instance where it's used the replicated db. served_by_region: "WNAM",served_by_primary: true. does it take a few days for it to start serving from different regions?

DDean i enabled it and haven't been able to have a single instance where it's used the...

lambrospetrouOP•8/11/25, 6:39 AM

No, creating the replicas is immediate, although the couple first requests per location will go to the primary until the replica boots. The most common case of not using replicas is when the request rate is not high enough, for example if you do a request every few minutes in each region then most likely all of them will go to the primary.

We know a small bug on our side for the "enabling" itself which we plan on fixing soon, so if you send constant traffic to your DB and still get no replicas, try disabling it and re-enabling it, and if you still get no replicas DM me your details to take a look.

Llambrospetrou No, creating the replicas is immediate, although the couple first requests per l...

Dean•8/11/25, 6:41 AM

thx - let me try that and if not ill send you db ids. edit disable/reenable fixed it.

can•8/11/25, 10:05 AM

Hello y'all, i ran

d1 export

d1 export

for one of my databases and now it says

Error in worker: Error: D1_ERROR: Currently processing a long-running export.

Error in worker: Error: D1_ERROR: Currently processing a long-running export.

and i'm not sure it's currently processing because it errored out on my terminal. Is there a way to cancel this process?

can•8/11/25, 10:11 AM

how am i suppose to stop polling for that process?

ToonyGen•8/11/25, 7:09 PM

I just found a fancy repo to manage d1. https://github.com/earth-app/CollegeDB.git

GitHub

GitHub - earth-app/CollegeDB: Cloudflare D1 Sharding Router for Hor...

Cloudflare D1 Sharding Router for Horizontal Scaling - earth-app/CollegeDB

red2green•8/12/25, 3:05 AM

are there any case stuides/examples of cloudflare customers that have thousands of dbs? Curious what its like to actually have to manage that many databases in production.

TToonyGen I just found a fancy repo to manage d1. https://github.com/earth-app/CollegeDB.g...

lambrospetrouOP•8/12/25, 9:41 AM

Really cool. I like the simplicity of using an explicitly provided "shard/hash key". It makes the routing much simpler. This is similar approach to how I shard across SQLite DOs.

I wonder how this was developed, was it a work project, college project (hint in the name), or just a side project? Majority of the logic seems to have been added in a single commit.

Either way, very nice to read through. Haven't checked the code yet. This is not an endorsement to use this in production, BTW.

Rred2green are there any case stuides/examples of cloudflare customers that have thousands ...

lambrospetrouOP•8/12/25, 9:44 AM

Unfortunately, I am not aware of publicly documented cases. We do have a few users that are like agencies developing apps for other companies and use thousands of D1 DBs. They mostly manage them through the REST API. Most of these cases are not attaching thousands of DBs to a single worker, as far as I know, although some did and use the Workers Patch API to update the bindings on their worker dynamically.

My suggestion, if you have a single worker project and want thousands of DBs using SQLite DOs will give you a much nicer experience. Now, if you are a platform creating thousands of projects and each one needs a small D1 DB that's a great use-case for D1 and managing the DBs through the API.

Llambrospetrou Unfortunately, I am not aware of publicly documented cases. We do have a few use...

Levi•8/12/25, 12:25 PM

I essentially came here to ask about dynamically creating and binding of D1 databases, but it seems like using Durable Objects would work better.

My goal is to have a database per user, org, or tenant for my one app.

Llambrospetrou Really cool. I like the simplicity of using an explicitly provided "shard/hash k...

ToonyGen•8/12/25, 1:25 PM

I think the author is using as the backend for its own social media project.

LLevi I essentially came here to ask about dynamically creating and binding of D1 data...

cloudkite•8/12/25, 8:27 PM

We are building a db per customer architecture and were holding out for dynamic bindings. However decided to bite the bullet and currently migrating from d1 to durable objects. Was initially reluctant but have to say it gives you a lot more flexibility and as a bonus has opened up some nice opportunities for performance optimisations.

Ccloudkite We are building a db per customer architecture and were holding out for dynamic ...

red2green•8/12/25, 8:43 PM

with a durable object, backed by sqlite, does it act just like a sqlite db? you can create many tables etc? DO is a little confusing.

red2green•8/12/25, 8:44 PM

with DO, you will have to migrate the schema using code ?

Rred2green with DO, you will have to migrate the schema using code ?

James•8/12/25, 8:50 PM

yeah, just plain jane sqlite, but only accessible via the DO runtime, no backdoor, file based access. Treat the DO as a web server running in the same process as the sqlite process and you're only way to run bindings/sql console. Which it literally just is that.

JJames yeah, just plain jane sqlite, but only accessible via the DO runtime, no backdoo...

Larry•8/12/25, 9:10 PM

I went straight to DOs so I don't know much about D1, but is there a backdoor to D1's SQLite file?

LLarry I went straight to DOs so I don't know much about D1, but is there a backdoor to...

James•8/12/25, 9:24 PM

no, but some people get the impression DO sqlite is something they get more 'native' sqlite access to the file system or extensions if they don't know otherwise

red2green•8/12/25, 9:27 PM

You can connect to D1 using wrangler

red2green•8/12/25, 9:27 PM

so that's a "backdoor"

Rred2green You can connect to D1 using wrangler

Larry•8/12/25, 9:33 PM

I was aware of that for D1 and DO, but it sounded like James was hinting at it being available for D1 but not DO for files in the Cloudflare cloud.

red2green•8/13/25, 4:12 PM

generally speaking, other than the limits of db size, query size, etc. Are there any requests per second limits?

Rred2green generally speaking, other than the limits of db size, query size, etc. Are th...

lambrospetrouOP•8/13/25, 4:22 PM

Each database is backed by a Durable Object, which is single threaded SQLite under the hood, so the limit depends on how fast/slow your queries are. If your queries execute at 1ms, you can do 1K of them at most, etc.
Rough guideline is that for most cases we see SELECTs with proper indexes usually finish in less than 1ms, and writes are a few milliseconds, so depends on your case.
My ballpark generic guideline is about 300-900 queries per second.

We have users doing more, and we have users doing less.

Llambrospetrou Each database is backed by a Durable Object, which is single threaded SQLite und...

red2green•8/13/25, 4:46 PM

great thanks. ok I didn't realize D1 uses Durable objects... I really need to understand DO b/c I'm a little confused now

I thought DO were backed by sqlite, but didn't realize d1 has DO "in front" of it.

red2green•8/13/25, 4:46 PM

so I should create multiple d1's based o the rough threshold of 300-900 qps.

Rred2green great thanks. ok I didn't realize D1 uses Durable objects... I really need to...

lambrospetrouOP•8/13/25, 4:48 PM

D1 is essentially a layer ontop of SQLite DOs. The underlying sqlite engine is the same, since D1 uses a DO for each database.

red2green•8/13/25, 4:48 PM

got it thanks.

Prepared statements in D1 are only a client side thing so that you can bind values to the statement.

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