Cloudflare Developers•2y ago

It's pretty much just a dummy value.

Kkian It's pretty much just a dummy value.

x03•3/13/24, 5:52 AM

Ok I appreciate the explanation. Does R2 and D1 work similarly?

x03•3/13/24, 5:53 AM

I haven't tried to set those up yet, but am planning to

kianOP•3/13/24, 5:55 AM

Yep

x03•3/13/24, 5:56 AM

Alright, thanks

kianOP•3/13/24, 5:56 AM

id = "abc"id = "abc" and id = "cba"id = "cba" will be different namespaces locally, but they don't have to be the same as an actual ID.

Kkian `id = "abc"` and `id = "cba"` will be different namespaces locally, but they don...

x03•3/13/24, 5:56 AM

Thanks for clarifying, this makes sense now.

x03•3/13/24, 6:02 AM

@kian one last question, does the preview option even matter for pages?

x03•3/13/24, 6:02 AM

Would it be used if I have a dev branch set up or something?

x03•3/13/24, 6:04 AM

Ohh I see now, so any non-main branch that's deployed will use those. Got it

anirudh•3/15/24, 4:42 AM

I have a use case like the following - we have a language learning app and users can tap on any word and listen to how its pronounced. We are using Google Text to Speech API for this. To save costs, we want to cache the response from the API. These are mostly short audio of one or two words. Would KV be a good fit for this compared to CF Cache API?

Aanirudh I have a use case like the following - we have a language learning app and users...

Matt Silverlock•3/15/24, 2:14 PM

It really depends - the Cache API is best effort. There is no guarantee that — especially low frequency requests — stay in cache for long. KV is persistent, or persistent up until the ttlttl you set if you want an expiring key.

anirudh•3/15/24, 3:58 PM

Ok got it. Thanks

Bobakanoosh•3/16/24, 12:09 AM

Is it inadvisable to cache entire static + dynamic html pages via KV? I want to edge cache these pages so they’re closer to the user, and then the backend isn’t hit per request.

Right now I have a proxy worker which adds the page to KV before returning it, or returns the one stored in KV if it exists. I know when the dynamic content changes, so I was planning on using the KV API to clear those keys from cache when they update.

James•3/16/24, 12:39 AM

That seems perfectly fine to me. Pages stores assets in KV too, as does the previous Workers Sites and it works really well.

Bobakanoosh•3/16/24, 1:25 AM

thanks for the response! follow up question, does a KV delete request only count if a matching key is found?

realizing I have a lot of dynamic page updates per month and would probably put me way past the 1m included quota

BBobakanoosh thanks for the response! follow up question, does a KV delete request only count...

Isaac McFadyen•3/16/24, 1:58 AM

Delete counts regardless (consistent with other KV providers, because it's still CPU/load the on the providers' servers and so they need to charge you)

Bobakanoosh•3/16/24, 2:01 AM

Makes sense just hoped it wasn’t the case haha

MMatt Silverlock It really depends - the Cache API is best effort. There is no guarantee that — e...

anirudh•3/16/24, 2:20 PM

Are cached KV values in local DCs evicted earlier than the specified TTL if they are infrequently read?

Aanirudh Are cached KV values in local DCs evicted earlier than the specified TTL if they...

Matt Silverlock•3/16/24, 2:21 PM

The TTL is not for the cache. It’s for the key-value pair itself (after which it is deleted).

anirudh•3/16/24, 2:29 PM

Yes I’m aware, but in the docs its says that values are stored in central servers and then cached in regional tiers and finally in local DCs closest to the workers. I was asking about the eviction behavior of these caches.

Aanirudh Yes I’m aware, but in the docs its says that values are stored in central server...

Hello, I’m Allie!•3/16/24, 2:30 PM

If you are referring to the cacheTtlcacheTtl parameter, then yes. It is best effort, which means that it will, at the most, be cached for the specified amount of time

anirudh•3/16/24, 2:36 PM

The eviction behavior of these caches

Aanirudh The eviction behavior of these caches

Hello, I’m Allie!•3/16/24, 2:45 PM

Yes. Values cached in local datacenters may be evicted earlier than the cacheTtlcacheTtl, based on demand/other factors

anirudh•3/16/24, 2:46 PM

Got it, thanks for the clarification

AnotherAlex•3/18/24, 11:56 AM

Can you use cacheTtl on a list command? I think I understand how values are cached for individual keys but not sure about the list of keys in a namespace. Thanks.

AAnotherAlex Can you use cacheTtl on a list command? I think I understand how values are cach...

anirudh•3/19/24, 4:47 AM

The cache is for each key, the list command will only list all keys

anirudh•3/19/24, 4:48 AM

if a key has expired, it won't appear in the list

Marc•3/22/24, 2:12 PM

Anyone have any idea how we could possibly be hitting timeout errors accessing KV over the HTTP api? Is that a symptom of being rate limited or something? Our timeout is set to 15 seconds right now. Seems like a crazy long time for KV to respond. Anyone ever deal with something similar?

MMarc Anyone have any idea how we could possibly be hitting timeout errors accessing K...

Matt Silverlock•3/22/24, 3:49 PM

The HTTP API has a rate limit, but you should see a HTTP 429 when you hit it: https://developers.cloudflare.com/fundamentals/api/reference/limits/#:~:text=The%20global%20rate%20limit%20for,API%20key%2C%20or%20API%20token.

Cloudflare Docs

Limits · Cloudflare Fundamentals docs

The global rate limit for the Cloudflare API is 1200 requests per five minutes per user, and applies cumulatively regardless of whether the request is …

MMatt Silverlock The HTTP API has a rate limit, but you should see a HTTP 429 when you hit it: ht...

Marc•3/22/24, 4:50 PM

Yeah we've hit that a couple times. This is seemingly different since it's just timeouts? Also is there a better way I should interface with kv or is that just the rate limit I have to deal with?

MMarc Yeah we've hit that a couple times. This is seemingly different since it's just ...

Matt Silverlock•3/22/24, 5:20 PM

You won't have this issue via a Worker. There's a plan to improve how we do rate limits via the HTTP API, but a larger project.

squareclamp•3/22/24, 6:41 PM

I'm a bit confused on what should go in cache api vs kv? I've run some simple numbers and the numbers for read seem comparable. The specific use case, I'm looking at is caching database responses which seem to be ~ 100ms from my laptop.

squareclamp•3/22/24, 6:43 PM

I would really appreciate some help on how to better think about latencies between cache api, kv and d1.

Ssquareclamp I'm a bit confused on what should go in cache api vs kv? I've run some simple nu...

Chaika•3/22/24, 6:49 PM

cache api -> free but not guaranteed, no replication, always fast though

kv -> always cost money, but replicates, potentially cold/slow hits if that location hasn't pulled it before

d1 -> right now just a single durable object in a single location, cheaper then kv at access

Chaika•3/22/24, 6:50 PM

kv has two central stores (one in us, one in eu)

Chaika•3/22/24, 6:51 PM

I would probably say if your goal is just to cache d1 responses, use normal cache api instead of KV, as KV costs money and potentially has cold hits from one of the two stores, unless the query is very slow/its critical to be cached for most users

squareclamp•3/22/24, 6:53 PM

Between cache and kv, are the latencies expected to be similar if the data is present in pop? I'm assuming locations for KV are same as cache and D1 locations are lot fewer.

Ssquareclamp Between cache and kv, are the latencies expected to be similar if the data is pr...

Chaika•3/22/24, 7:02 PM

I think KV is just a bit slower for cached hits, but generally the same. I just tested and they're about the same with KV being maybe a few ms slower on average for cached hits.

I'm assuming locations for KV are same as cache and D1 locations are lot fewer.

KV has two central stores and can be cached in every location.
D1 is only in a few places (https://where.durableobjects.live/), where Durable Objects are, and once you create it, it's only in that single location. They're working on read replicas but nothing at the moment

Chaika•3/22/24, 7:06 PM

There's no rule saying you can't use all 3 either. If you have a really expensive query, could have a Worker on cron pushing it into KV, and then use BetterKV (https://flareutils.pages.dev/betterkv/old), which uses local Cache API + KV to bring your bill down.

Mmare arcis Does this pull immediately upon expiry, or upon a worker request when expired?

Isaac McFadyen•3/24/24, 2:56 AM

Worker request when expired.

Tony Leung•3/24/24, 8:52 AM

hi guys, is there any API to list KV Item with values or an API which is similar to BatchGetItem API in Dynamo? Currently I have to use list API to get keys and sequentially get their values which is really inconvenient. My current workaround is putting the item into

metadata

metadata

so it could be fetched during the list operation when the item data is small otherwise I still have to manually get each item out of KV.

x03•3/24/24, 5:41 PM

I want to store user sessions in KV, but am not sure how to approach it.

I need each session entry to have a unique UUID, but also have the user's ID as part of the key so that I can list a user's sessions.

doing UID:SIDUID:SID as the key lets me use prefix to list a user's sessions, but I cant query a session by just having the session ID (without the user id)

just doing SIDSID as the key lets me query sessions with just a session ID, but I dont know how to list a user's sessions.

x03•3/24/24, 5:45 PM

The only solution I see at the moment is just using SIDSID key and UIDUID value, and if I need to list a user's sessions I just list every session and filter it in the code itself. This seems a bit weird though cause if I have thousands of sessions this may slow things down

Xx03 I want to store user sessions in KV, but am not sure how to approach it. I need...

Hello, I’m Allie!•3/24/24, 6:15 PM

You could also use a Durable Object for each user?

HHello, I’m Allie!You could also use a Durable Object for each user?

x03•3/24/24, 6:21 PM

Wouldn't that be expensive?

x03•3/24/24, 6:21 PM

I need some efficient way of storing users and sessions. My current approach is D1 database for users and KV for sessions

Xx03 Wouldn't that be expensive?

Hello, I’m Allie!•3/24/24, 6:23 PM

It shouldn't be? DO compute is slightly more expensive than Workers on Standard, but if you are just using it for storage, then compute shouldn't be much of an issue

HHello, I’m Allie!It shouldn't be? DO compute is slightly more expensive than Workers on Standard,...

x03•3/24/24, 6:23 PM

Where would sessions be stored though?

It's pretty much just a dummy value.

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