kandi X-RAY | scylla Summary
kandi X-RAY | scylla Summary
Scylla is the real-time big data database that is API-compatible with Apache Cassandra and Amazon DynamoDB. Scylla embraces a shared-nothing approach that increases throughput and storage capacity to realize order-of-magnitude performance improvements and reduce hardware costs. For more information, please see the ScyllaDB web site.
Top functions reviewed by kandi - BETA
scylla Key Features
scylla Examples and Code Snippets
Trending Discussions on scylla
I'm using Scylla to save parties created by a users. The method below returns a list of parties created by a user. I currently return all parties without allowing pagination, but I'm trying to implement Pagination for the method below but I still don't quite understand how pagination is handled with Scylla.
My guess would be that a cursor can be passed to a query. Based on this example it looks like the
PageState can be used to pass something similar to a cursor.
I would appreciate a short explanation what
PageState is and if I should use it to accomplish token based pagination. It would also be great if an example could be provided that shows how a new
PageState can be returned to the client and used to fetch a new page on a second request.
ANSWERAnswered 2022-Mar-07 at 10:07
Hi gocqlx author here.
Please take a look at this example https://github.com/scylladb/gocqlx/blob/25d81de30ebcdfa02d3d849b518fc57b839e4399/example_test.go#L482
I have 2 server in difference datacenter.
- First server in DC1 with public IP 10.10.10.1
- Second server in DC2 with public IP 22.214.171.124
docker-compose for first server in DC1 look like this :...
ANSWERAnswered 2022-Jan-06 at 04:22
After research and consultation with product advisor from scylla. i has resolved the problems :
Scylla arsitecture if use node in virtual must be a public cloud source https://www.scylladb.com/product/technology/
So docker-compose.yaml i change map port to public ip like this
Is it guaranteed that rows returned for a token range CQL
SELECT query are ordered by token value?
ScyllaDB orders partitions by a function of the partition key, known as the partitioner, and also as the token function
I'd like to have it confirmed that it's guaranteed (by a specification) because I'd like to implement efficient "group by partitioning key" without having to read the whole result set into memory. I'm using the latest Java driver for Scylla (not for C*) if that makes any difference....
ANSWERAnswered 2022-Jan-05 at 17:18
Yes, it is guaranteed (I am the author of that article).
How to add or remove seed from node scylladb that create with docker run, for example :...
ANSWERAnswered 2021-Dec-13 at 20:24
Since you are running docker (no K8s), all parameters that you use when spinning up your container are saved under
You can edit this file and then use
supervisorctl restart scylla to update the seed list as well as other parameters you wish.
I have a question about query in scylladb. I want to count the rows in a table with:...
ANSWERAnswered 2021-Nov-29 at 13:38
The problem you're running into is inherent in any distributed row store (Cassandra or Scylla). In order for that to work, a coordinator node needs to contact all other nodes, query them, and assemble the result set. That causes a lot of contention which may prevent some replicas from reporting properly.
I recommend (downloading) using DSBulk for this type of operation. It has a
count feature designed just for this purpose.
I use crate scylla that use tokio 1, so i must use crate actix-web 4.0 beta. Now i have problem that use actix_web::client::Client show error :...
ANSWERAnswered 2021-Nov-04 at 02:16
This is mentioned in the
actix_web Changes.md for v4.0:
clientmod was removed. Clients should now use
actix_web::client module has long since largely been a wrapper around the
awc crate ever since the 1.0 release, but it seems they now want to separate them entirely.
The types from
awc should be near identical to those exposed in prior
actix_web releases, however if you're using it with
actix_web:4.0 (currently in beta) then you'll want to use
awc:3.0 (currently in beta) for compatibility.
I have problems implement scylla-rust-driver on Rust Actix. I want just create simple CRUD with scyllaDb.
First i create struct for App Data...
ANSWERAnswered 2021-Nov-01 at 08:45
There is nothing special with Session, as seen here https://github.com/scylladb/scylla-rust-driver/blob/main/examples/parallel-prepared.rs
The solution is to wrap it in an
Arc. We don't necessary need to do so ourselves as
web::Data does this itself. Here is what I got.
I have lots of fast incoming data that is organised thusly;
- Lots of 1D arrays, one per logical object, where the position of each element in the array is important and each element is calculated and produced individually in parallel, and so not necessarily in order.
- The data arrays themselves are not necessarily written in order.
- The length of the arrays may vary.
- The data is either read as an entire array at a time so makes sense to store the entire thing together.
The way I see it, the issue is primarily caused by the way the data is made available for writing. If it was all available together I'd just store the entire lot together at the same time and be done with it.
For smaller data loads I can get away with the postgres array datatype. One row per logical object with a key and an array column. This allows me to scale by having one writer per array, writing the elements in any order without blocking any other writer. This is limited by the rate of a single postgres node.
In Cassandra/Scylla it looks like I have the options of either:
- Storing each element as its own row which would be very fast for writing, reads would be more cumbersome but doable and involve potentially lots of very wide scans,
- or converting the array to json/string, reading the cell, tweaking the value then re-writing it which would be horribly slow and lead to lots of compaction overhead
- or having the writer buffer until it receives all the array values and then writing the array in one go, except the writer won't know how long the array should be and will need a timeout to write down whatever it has by this time which ultimately means I'll need to update it at some point in the future if the late data turns up.
What other options do I have?
ANSWERAnswered 2021-Oct-18 at 17:54
Option 1, seems to be a good match: I assume each logical object have an unique id (or better uuid) In such a case, you can create something like
There is a native map type in Scylla DB https://docs.scylladb.com/getting-started/types/#maps Is it possible to create an index on it? So it would be somewhat like GIN in PostgreSQL....
ANSWERAnswered 2021-Oct-11 at 18:55
maps are a type of collection, I think this GH issue pretty much sums it and what's supported (or not). https://github.com/scylladb/scylla/issues/3654#issuecomment-479639450
Validations req mentioned in the GH issue:
- disallow FULL indexes on non-frozen collections
- disallow non-FULL indexes on frozen collections
- disallow repeated creation of FULL indexes on the same collection
- disallow referencing frozen-map entries in the WHERE clause (only allow complete map values)
What we have:
Non-frozen collections are currently not supported at all with proper error message, non-full indexes on frozen collections are also disallowed, repeated creation is by default forbidden for any index too. Also, I think that referencing frozen-map entries in WHERE clause should be allowed, at least with filtering.
If you find any different behavior, please let us know and file a GH issue.
We have a script which talks to Scylla (a cassandra drop-in replacement). The script is supposed to run for a few thusands systems. The script runs a few thousands queries to get its required data. However, after sometime the script gets crashed throwing this error:...
ANSWERAnswered 2021-Oct-01 at 00:11
The Client session timeout indicates that the driver is timing out before the server does or - should it be overloaded - that Scylla hasn't replied back the timeout to the driver. There are a couple of ways to figure this out:
1 - Ensure that your default_timeout is higher than Scylla enforced timeouts in /etc/scylla/scylla.yaml
2 - Check the Scylla logs for any sign of overload. If there is, consider throttling your requests to find a balanced sweet spot to ensure they no longer fail. If it continues, consider resizing your instances.
In addition to these, it is worth to mention that your sample code is not using PreparedStatements, TokenAwareness and other best practices as mentioned under https://docs.datastax.com/en/developer/python-driver/3.19/api/cassandra/policies/ that will certainly improve your overall throughput down the road.
You can find further information on Scylla docs: https://docs.scylladb.com/using-scylla/drivers/cql-drivers/scylla-python-driver/ and Scylla University https://university.scylladb.com/courses/using-scylla-drivers/lessons/coding-with-python/
No vulnerabilities reported
Reuse Trending Solutions
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page