Ismael Rodrigues
02/09/2024, 3:45 AMScout
02/09/2024, 3:45 AMis_required
parameter along with yield
syntax to implement this behavior. If the is_required
parameter is set to False
on an output, and your function does not yield
an Output
object for that output, then no asset materialization event will be created, the I/O manager will not be invoked, downstream assets will not be materialized, and asset sensors monitoring the asset will not trigger.
Here's an example from the documentation:
python
import random
from dagster import Output, asset
@asset(output_required=False)
def may_not_materialize():
# to simulate an asset that may not always materialize.
if random.randint(1, 10) < 5:
yield Output([1, 2, 3, 4])
@asset
def downstream(may_not_materialize):
# will not run when may_not_materialize doesn't materialize the asset
return may_not_materialize + [5]
In this example, the may_not_materialize
asset will only materialize if the random condition is met. If it does not materialize, the downstream asset will not run. Don't change the state of Fivetran asset... button Thank you for your feedback!Ismael Rodrigues
02/09/2024, 4:56 AMScout
02/09/2024, 4:57 AMAutoMaterializePolicy
or FreshnessPolicy
on a multi-asset, you can specify these policies on individual assets within the multi-asset. Here's an example from the documentation: python from dagster import multi_asset, AutoMaterializePolicy, AssetOut, FreshnessPolicy @multi_asset( outs={ "asset1": AssetOut(auto_materialize_policy=..., freshness_policy=...), "asset2": AssetOut(auto_materialize_policy=..., freshness_policy=...) } ) def my_function(): ...
In this example, asset1
and asset2
are part of a multi-asset, and each has its own AutoMaterializePolicy
and FreshnessPolicy
specified. You would replace the ellipses (...
) with the actual policy objects that you want to apply to each asset.Ismael Rodrigues
02/09/2024, 1:38 PMschema: public
threads: 1
ra3_node: true
type: redshift
autocommit: true
And these configurations for my model
config:
sort:
- dt
dist: even
schema: some
I having a issue, where when the model runs, it's creating a new schema called public_some and I don't want that. I want it to use the already created schema some instead of a new one public_someScout
02/09/2024, 1:38 PMpublic_some
is being created instead of using the existing schema some
, is likely due to how dbt handles schema names in combination with your profile and model configurations. In dbt, the schema
field in the profile configuration specifies the default schema to use when creating models. However, if you specify a schema
in your model's configuration, dbt treats it as a suffix to the schema specified in the profile, rather than as an absolute schema name. This is why you're seeing a new schema public_some
being created, as dbt is appending the model's schema
value to the profile's schema
value. To resolve this issue, you should adjust your dbt configurations to ensure that the schema
specified in your model's configuration is not treated as a suffix. Here's how you can do it: 1. Remove the schema
field from your model's configuration if you want to use the default schema specified in your profile. 2. If you want to use a different schema than the one specified in your profile, you should override the schema in your dbt project configuration or use a custom schema macro that handles schema names as absolute rather than suffixes. For example, if you want all models to use the some
schema, you can set it in your dbt_project.yml
file like this: yaml models: your_project_name: +schema: some
This will apply the some
schema to all models in your project unless overridden at a lower level (such as within a specific model's configuration). Remember to replace your_project_name
with the actual name of your dbt project. If you have further questions or need assistance with dbt and Dagster configurations, please let me know, and I'll be happy to help!Ismael Rodrigues
02/09/2024, 5:28 PMScout
02/09/2024, 5:28 PM--full-refresh
flag when running the dbt run
command. This flag instructs dbt to treat incremental models as table models, which means it will drop and recreate them, rather than inserting or updating records based on a unique key. Here's how you can use the --full-refresh
flag: shell dbt run --full-refresh
This command will apply the full refresh to all incremental models in your project. If you want to apply it to a specific model, you can use the --select
or -m
flag to specify the model name: shell dbt run --full-refresh --select your_model_name
Replace your_model_name
with the actual name of your model. Keep in mind that using --full-refresh
can be resource-intensive and time-consuming, especially for large datasets, because it involves dropping and recreating the entire table. If you want to enforce this behavior within your dbt project without relying on the command line flag, you can set the +full_refresh
materialization configuration in your model's configuration block. Here's an example of how to do this within your model SQL file: sql -- models/your_model_name.sql {{ config(materialized='incremental', full_refresh=true) }} select ... from ...
By setting full_refresh
to true
in the model's configuration, you're telling dbt to always perform a full refresh on this model, even if the --full-refresh
flag is not provided in the command line. Please note that the full_refresh
configuration is only applicable to incremental models. If your model is not incremental, it will be recreated every time by default. If you have any more questions or need further assistance with dbt, feel free to ask!Ismael Rodrigues
02/09/2024, 5:36 PMScout
02/09/2024, 5:36 PMpg_class
catalog table in PostgreSQL. This table stores information about tables, indexes, sequences, and other relation types, and the relname_nsp_index
index enforces the uniqueness of relation names within a namespace (schema). This error can occur if two concurrent transactions are trying to create or modify relations with the same name in the same schema. In the context of dbt, this might happen if you have multiple dbt jobs trying to create or modify the same model at the same time. Here are some steps you can take to troubleshoot and resolve this issue: 1. Ensure Serial Execution: Make sure that your dbt runs are executed serially and not in parallel if they are trying to modify the same database objects. This can be managed by scheduling your dbt runs in a way that prevents overlap. 2. Check for Long-Running Transactions: Look for any long-running transactions that might be holding locks on the database objects dbt is trying to modify. You can use PostgreSQL's activity monitoring queries to identify such transactions. 3. Review dbt Project Configuration: Ensure that your dbt project is correctly configured and that the full_refresh
flag is being used appropriately. If you're using the full_refresh
flag in a CI/CD pipeline, make sure that concurrent runs are not being triggered. 4. Database Cleanup: If you suspect that a failed dbt run has left behind temporary or orphaned relations, you might need to clean them up manually. Be cautious with this step and make sure to identify the correct objects before dropping them. 5. Retry Logic: Implement retry logic in your dbt run command to handle transient errors that might occur due to temporary conflicts. 6. Database Locks: Investigate any potential issues with database locks that might be causing the conflict. You can query the pg_locks
view to see active locks in the database. 7. Examine dbt Logs: Review the dbt logs for more detailed error messages or stack traces that might provide additional context about the conflict. 8. Database Maintenance: Perform routine database maintenance tasks such as vacuuming and analyzing tables to ensure that the database is operating efficiently. If the issue persists after taking these steps, you may need to look into the specific timing and coordination of your dbt runs, or consider reaching out to the dbt community or support channels for further assistance. It's also important to ensure that your database is properly tuned and configured to handle the workload of your dbt jobs.Scout
02/09/2024, 5:59 PMIsmael Rodrigues
02/09/2024, 6:17 PMScout
02/09/2024, 6:17 PMCREATE TABLE
statement. To work around this limitation, you can consider the following strategies that adhere to dbt's rules and properties configurations: 1. Use Pre-Hooks and Post-Hooks: You can use dbt's pre-hook and post-hook configurations to execute SQL statements before or after a model is run. For example, you could use a post-hook to insert data into a table in a different database after the table has been created in the default database. 2. Materialize as Views: If your database supports cross-database references in views, you could materialize your dbt models as views instead of tables. This way, you can select data from one database and present it in another without physically moving the data. 3. Intermediate Materialization: Create an intermediate table within the same database, and then use a separate process to move the data to the target database. This could be done with a dbt model that materializes as a table in the default database and then a separate dbt run operation or a custom script to transfer the data to the other database. 4. Database-specific Features: Some databases offer features that facilitate cross-database operations. For example, Snowflake allows creating databases and schemas that can reference each other. If your database offers similar features, you can leverage them within your dbt models. 5. Change the Database Configuration: If possible, configure your dbt models to use the same database to avoid cross-database operations. You can specify the database in your dbt_project.yml
file or within individual model files using the {{ config(...) }}
macro. 6. Custom Macros: Write custom dbt macros that handle the logic for cross-database operations. This could involve creating a table in one database, exporting the data, and then importing it into the other database. 7. Staging Data: Use a staging area within the same database to prepare your data before moving it to the final destination. This can help avoid direct cross-database table creation. Remember to check the documentation for your specific database to understand its capabilities and limitations regarding cross-database operations. Each database has its own set of features and restrictions, and the best approach will depend on those details. If you continue to encounter issues, please provide more context about your dbt models, the databases you are using, and the specific operations you are trying to perform. This information will help in suggesting a more tailored solution.Ismael Rodrigues
02/09/2024, 6:21 PMScout
02/09/2024, 6:21 PMUNLOAD
command to export data from one database to Amazon S3, and then use the COPY
command to load the data into another database. This is a two-step process that involves moving data out of Redshift and then back in, but it allows you to transfer data between databases.
3. Federated Query: Redshift supports federated querying, which allows you to query live data in external databases such as Amazon RDS or Amazon Aurora PostgreSQL. If your data resides in one of these supported databases, you can use federated queries to access it from Redshift.
4. Materialize Within a Single Database: If possible, consider restructuring your dbt project to materialize all models within a single Redshift database, even if that means using different schemas to logically separate the data. This would avoid the need for cross-database queries altogether.
5. External Schemas: Redshift allows you to create external schemas that reference data stored in Amazon S3 using Redshift Spectrum. You can create external tables within these schemas and query them as if they were regular Redshift tables. This could be a way to access data across databases, but it requires the data to be in S3.
6. Database Linking (Future Consideration): As of my knowledge cutoff, Redshift does not support database links like some other databases (e.g., Oracle). However, AWS continuously evolves its services, so it's worth checking the latest Redshift documentation or AWS announcements for any new features that might support cross-database queries more directly.
When using any of these strategies, you'll need to adjust your dbt models and configurations accordingly. For example, you might need to write custom macros or scripts to handle the data movement and ensure that your dbt models are compatible with the approach you choose.
If you're facing specific errors or challenges with these strategies, please provide mScout
02/09/2024, 6:22 PMIsmael Rodrigues
02/09/2024, 6:34 PMScout
02/09/2024, 6:34 PMprofiles.yml
file, each corresponding to a different database. You can then specify which target to use when running your dbt commands. Here's an example of how your profiles.yml
might look with multiple targets: yaml my_project: target: dev outputs: dev: type: redshift host: my-redshift-cluster user: myuser pass: mypass port: 5439 dbname: dev_db schema: public prod: type: redshift host: my-redshift-cluster user: myuser pass: mypass port: 5439 dbname: prod_db schema: public
Then, when running dbt, you can specify the target: shell dbt run --target prod
2. Use Custom Schema in the Model Config: If you want to keep the same database but change the schema, you can override the schema in your model's configuration. This is done using the {{ config() }}
macro within your model SQL file. Here's an example of how to set a custom schema for a model: sql -- models/my_model.sql {{ config(schema='my_schema') }} select ...
This will instruct dbt to use my_schema
instead of the default schema defined in the profile when creating the model. 3. Database-Specific Functionality: Some databases support cross-database queries within the same database cluster or instance. If your database supports this, you can write your SQL to reference the fully qualified table name, including the database name. For example, in Redshift, you might write: sql select * from other_database.public.my_table
However, as of my knowledge cutoff, Redshift does not support cross-database queries in this manner. If you need to connect to an entirely different database that is not just a different target within the same Redshift cluster, you would typically need to set up a separate dbt profile for that database and run your dbt project with the appropriate profile target for that database. Keep in mind that the ability to switch databases or schemas can depend on the capabilities of the database you are using and the permissions configured for the database user. Always refer to the documentation for your specific database and dbt for the most accurate and up-to-date information.