guys, is there something like "migrations" (schemas which will automatically applied when a worker i

guys, is there something like "migrations" (schemas which will automatically applied when a worker is deployed)?
I'm fairly new to D1 but I have worked with durable objects before.

LLukeZ guys, is there something like "migrations" (schemas which will automatically app...

Isaac McFadyen•11/5/25, 5:27 PM

https://developers.cloudflare.com/d1/reference/migrations/ not automatic but yes.

LukeZOP•11/5/25, 5:31 PM

ah, thx

IIsaac McFadyen https://developers.cloudflare.com/d1/reference/migrations/ not automatic but yes...

lambrospetrou•11/5/25, 5:57 PM

I mentioned it before but just to point out that this the built-in way of doing things, but not the only way. You could literally use a similar flow as to what you were doing with DOs, but instead of running the queries in the local SQLite you would run them in the remote D1 DB.

LukeZOP•11/5/25, 5:58 PM

I got another question. Since D1 uses SQlite dialect, can I store a column of type

TIMESTAMP

TIMESTAMP

LukeZOP•11/5/25, 6:00 PM

because if not, I gotta store ISO timestamps in text format

LukeZOP•11/5/25, 6:01 PM

uuuh, what?

LLukeZ I got another question. Since D1 uses SQlite dialect, can I store a column of ty...

lambrospetrou•11/5/25, 6:01 PM

See https://developers.cloudflare.com/d1/worker-api/#type-conversion for details on some types specific gotchas as well.

Supported SQLite types are in https://www.sqlite.org/datatype3.html (I don't see TIMESTAMP)

LLukeZ uuuh, what?

Isaac McFadyen•11/5/25, 6:02 PM

They mean that D1 actually runs SQLite itself, it's not a custom SQLite compatible engine.

LukeZOP•11/5/25, 6:02 PM

LukeZOP•11/5/25, 6:03 PM

makes sense

LukeZOP•11/5/25, 6:03 PM

I'm storing as iso timestamps now

David.Stanton•11/5/25, 7:57 PM

does the replication when enabled actually show any metrics for it, I have it turned on, can see the X-D1-Bookmark: responce header etc but there seems to be no metrics in the D1 Ui, the dropbox also says eplicas 0 ?

1534980751438970153470891543•11/5/25, 8:21 PM

d1 jurisdiction is huge

1534980751438970153470891543•11/5/25, 8:21 PM

and it maintains replicas within the jurisdiction which is also huge

1534980751438970153470891543•11/5/25, 8:44 PM

???? only happens on the jurisdiction table not sure why its throwing a r2 bucket error lol

1534980751438970153470891543•11/5/25, 8:51 PM

recreated a bunch of databases and this error only occurs for jurisdiction created databases, not for normal location hint creations both in the same EEUR region

11534980751438970153470891543 ???? only happens on the jurisdiction *table* not sure why its throwing a r2 buc...

Florent•11/5/25, 9:13 PM

I have been able to reproduce it on my end. I'm forwarding it internally.

DDavid.Stanton does the replication when enabled actually show any metrics for it, I have it tu...

lambrospetrou•11/5/25, 10:28 PM

You will see metrics for each region serving queries, yes. But, replicas are used only on-demand for queries inside each region, they don't run all the time. For example, if you have traffic in ENAM and EEUR, you should see the primary and the replicas in those two regions being in your metrics.

Samantas5855•11/6/25, 10:49 AM

is d1 down?

Samantas5855•11/6/25, 10:49 AM

my workers endpoints using it take forever to load

Samantas5855•11/6/25, 10:49 AM

also I cannot use cloudflare's endpoints to make changes externally

Samantas5855•11/6/25, 10:50 AM

504, {"result":null,"success":false,"errors":[{"code":7009,"message":"Upstream service unavailable"}],"messages":[]}

Samantas5855•11/6/25, 10:50 AM

keep getting these

11534980751438970153470891543 ???? only happens on the jurisdiction *table* not sure why its throwing a r2 buc...

lambrospetrou•11/6/25, 3:11 PM

The fix for this should be out now everywhere. Thank you for reporting.

jLynx•11/6/25, 10:45 PM

@Visal .In not sure if you are the correct one to ping, but I am having really bad D1 performance. I have a simple query

SELECT * FROM visits WHERE token_hash='MTc2MjQ2ODczO....EVCRT0=';

SELECT * FROM visits WHERE token_hash='MTc2MjQ2ODczO....EVCRT0=';

where

token_hash

token_hash

is an indexed column in the table, but that query took 16.59 seconds to complete in a table that has

64,360

64,360

items in it

jLynx•11/6/25, 11:21 PM

Scratch that. was a bad index I had taking up too much index space

amanzad•11/8/25, 11:38 AM

Is d1 suitable for web apps with say thousands of daily users? It feels complicated to setup multiple d1s so I would prefer to just have like one for all users like a ”normal” database

Aamanzad Is d1 suitable for web apps with say thousands of daily users? It feels complica...

aza547•11/8/25, 1:35 PM

I'm using it for this, just keep in mind it's single threaded so there are limits to scalability. But I'm using replication and it's working great since enabling that for my few thousand users.

amanzad•11/8/25, 4:24 PM

Oh okay, could you point me to guides or docs on how to achieve this? Also how well does this structure handle many writes and limits of like 10gb storage or the 128mb memory limit?

blyedev•11/8/25, 7:45 PM

Hi I don't know if this is known but maybe someone from Cloudflare decides to push on this. Sadly because cloudflare uses PRAGMA defer_foreign_keys not the simple turn on or off the migrations generated by drizzle are invalid and often broken. This means if we want to use drizzle with cloudflare we need to hand edit migrations

Aamanzad Is d1 suitable for web apps with say thousands of daily users? It feels complica...

lambrospetrou•11/8/25, 8:17 PM

I am hoping to merge this docs update on Monday, and it contains some guidance on D1 performance: https://github.com/cloudflare/cloudflare-docs/pull/26369

If you have thousands of active users at the same time, which will translate to high hundreds or thousands of queries to D1 at the same time (e.g. per second), then you will hit performance limitations and overload the single database.
You will definitely need to shard across several databases.

If you are going to have many thousands of queries per second and would need tens of D1 DBs, then using SQLite Durable Objects would be preferable and my suggestion. You can create thousands of Durable Objects dynamically in your code without having to mess with bindings, and it's the same underlying SQLite engine.

tobystr•11/9/25, 4:33 AM

Before I test, how many rows per second can D1 / DO with SQL scan per second? any unofficial data around it?

Ttobystr Before I test, how many rows per second can D1 / DO with SQL scan per second? an...

lambrospetrou•11/9/25, 8:40 AM

I have seen high hundreds of thousands or single digit millions reads per second. Obviously it's different if your rows are 10 bytes vs 2MB!
Also, with such high number of reads per second, if you are doing that constantly you need to be careful of hitting CPU limits, or overload limits since a DO is single threaded.

Cemal•11/9/25, 9:19 AM

Hi, I have a question about D1. I'm using it together with Drizzle ORM. I have a table that stores user balances, and each request deducts from the balance. The issue is that a simple query like

amount -= 100

amount -= 100

might cause a problem known as a race condition (I think). It seems D1 doesn't support transactions, so could async operations cause issues here?

Larry•11/9/25, 10:29 AM

I have seen high hundreds of thousands or single digit millions reads per second.

Wait! How is that possible? I've been using no more 1,000 request/messages per second as design ceiling for DOs, eventhough, I've seen as high as 5,000. Even assuming 5,000, you'd need 200 read replicas to hit 1M. Does D1 go to that level?

tobystr•11/9/25, 12:16 PM

@Larry if think we are discussing different things, I was asking how many rows per second can be scanned, so if you have a table with 100k rows, how long would it take to scan it, vs request per second which would be how many queries can run in a second

Ttobystr @Larry if think we are discussing different things, I was asking how many rows p...

Larry•11/9/25, 12:21 PM

Duh, I should read more carefully. Thanks for the clarification! That makes a lot more sense.

tobystr•11/9/25, 12:22 PM

No problems

CCemal Hi, I have a question about D1. I'm using it together with Drizzle ORM. I have a...

Cemal•11/9/25, 2:47 PM

Would an atomic update be sufficient?

UPDATE account SET amount = amount - ? WHERE id = ?

UPDATE account SET amount = amount - ? WHERE id = ?

Or using durable objects.

CCemal Would an atomic update be sufficient? ```sql UPDATE account SET amount = amount ...

James•11/9/25, 5:56 PM

I like using DOs for transactions more simply because you control the thread of processing. Run a bunch of SQL in synchronous code with the right error handling in place and you have transactions.

Another approach I use when coordinating changes async across D1/DO other resources in a saga pattern.

blyedev•11/9/25, 9:59 PM

I saw the post about the rollout of data jurisdictions. Love it! Will it be possible to enable retroactively for existing DBs? I've got a project in staging that's about to go live and I really don't want to recreate the DB

Zetax•11/10/25, 2:41 AM

There should definitely be something like development branches for D1. This would be a great addition as it would compliment preview deployments from git repositories. That way, developers could test database changes in a staging enviroment without modifying the prod database.

CCemal Hi, I have a question about D1. I'm using it together with Drizzle ORM. I have a...

lambrospetrou•11/10/25, 9:27 AM

If you can build all the queries you want to run in a transaction before hand, you can send them all in a single

batch()

batch()

query and they will all run within the same transaction.
So, for example, if you want to update two tables, or two different rows but with separate queries, you can prepare both of them and send them together.
https://developers.cloudflare.com/d1/worker-api/d1-database/#batch

Cloudflare Docs

D1 Database

To interact with your D1 database from your Worker, you need to access it through the environment bindings provided to the Worker (env).

Llambrospetrou If you can build all the queries you want to run in a transaction before hand, y...

Cemal•11/10/25, 9:35 AM

This is great — but could it still lead to a race condition issue?

CCemal This is great — but could it still lead to a race condition issue?

lambrospetrou•11/10/25, 9:40 AM

You can always add race conditions if you split something that should be a single transaction across multiple requests.
I am just mentioning that there is the

batch()

batch()

method for running independent queries in a transaction.

If you need to intervleave JS code with SQL queries, then D1 cannot do that, and your best bet would be SQLite DOs.

Cemal•11/10/25, 9:55 AM

I got it, thanks.

Mitya•11/10/25, 10:12 AM

In both the CF dash and via the D1 REST API's list DBs endpoint, it says my database has zero tables. This isn't true; it has 2, and I can successfully query data. These tables have existed for several days. Why would this be happening?

MMitya In both the CF dash and via the D1 REST API's list DBs endpoint, it says my data...

lambrospetrou•11/10/25, 11:06 AM

I believe the GET database details should give you the correct information.
The list endpoint I think returns stale data due to a control plane change few weeks ago. I will report it internally to be fixed.

thipperz•11/10/25, 3:35 PM

About database scaling limits, is there a way I can check my current usage?

Tthipperz About database scaling limits, is there a way I can check my current usage?

lambrospetrou•11/10/25, 3:46 PM

The graphql API returns rows read/written and db sizes per database. The dashboard also shows that data in the metrics tab.