I have questions about ways to automate data transformation process.
What I normally do is that I transform data using python or postgresql and then export the processed data as csv. After that, I connect the csv file to Tableau.
I have done some research and found that ETL can help. However, I've watched some ETL tools' demo videos, and I'm not sure whether these tools' transform features would meet my need or not. For example, I have written 100+ sql lines for one of my data transforming task; it's better if I can use postgresql to run the query instead of using ETL tools.
The problem is that I don't know what's the proper way to automate the data transforming process and then push the data to Tableau. The csv files will be updated on a daily basis, so I'll need to refresh the data.
Data transformation can be done in various ways. It depends on your nature of data to figure out what can be the right fit.
If you have huge volume of data and you are comfortable in python/java and you can automate your transformation logic using spark and write it to a hive table and then connect tableau to read data from hive.
Most of the next gen ETL tools like pentaho and talend can be used but that erodes the flexibility and portability what a framework like spark or beam can give.
If you want to know , how can you achieve this using cloud provider services like GCP or AWS , please let me know
Prep is the Tableau tool for preparing data. It can be used for joining, appending, cleaning, pivoting, filtering and other data cleansing activities.
Tableau Prep is available:
for free if you have a Tableau Creator license
in desktop and Online/ Tableau server versions
Scheduling Prep flows is available in Tableau Online/ Server. To schedule flows you will need to acquire the Tableau Prep Conductor add-on.
Related
I am looking for the recommended way of streaming database change from cloud SQL (postgres) to bigQuery ? I am seeing that CDC streaming does not seems available for postgres, does anyone know the timeline of this feature ?
Thanks a lot for you help.
Jonathan.
With Datastream for BigQuery, you can now replicate data and schema updates from operational databases directly into BigQuery.
Datastream reads and delivers every change—insert, update, and delete—from your MySQL, PostgreSQL, AlloyDB, and Oracle databases into BigQuery with minimal latency. The source database can be hosted on-premises, on Google Cloud services such as Cloud SQL or Bare Metal Solution for Oracle, or anywhere else on any cloud.
https://cloud.google.com/datastream-for-bigquery
You have to create an ETL process. That will allow you to automatically transform data from Postgres into BigQuery. You can do that using many ways, but I will point you to the two main approaches that I've already implemented:
Way 1:
Set Up the ETL Process manually:
Create your ETL using open source tools...
This method involves the use of the COPY command to migrate data from PostgreSQL tables and standard file-system files. It can be used as a normal SQL statement with SQL functions or PL/pgSQL procedures which gives a lot of flexibility to extract data as a full dump or incrementally. You need to know that it is a time-consuming process and would need you to invest in engineering bandwidth!
Also, you could try different tech stacks to implement the above, and I recommended this one Java Spring Data Flow
Way 2:
Using DataFlow
You can automate the ETL process using GCP's DataFlow without coding your own solution. It is faster and it cost, of course.
DataFlow is Unified stream and batch data processing that's
serverless, fast, and cost-effective.
Check more details and learn in a minute here
Also check this
I've had a look at this SO post but it's three years old and I think GCP has changed since then.
What I'm trying to do is set up a data pipeline using DataFlow jobs to copy/transform data from one GBQ project into another GBQ project.
To create a DataFlow job, you need to choose a template and there is no template that matches my needs i.e. no BQ to BQ template.
There is an option to use a custom template (which I imagine would be a python script or something along those lines), but it seems odd that there is no BQ to BQ template. Is DataFlow not the right tool for this job? Should I just use scheduled queries?
Thanks in advance
There is a way which is not very straight forward if you really want to use Dataflow template, you can use BigQuery to cloud storage template to store data in GCS and then cloud storage to BigQuery template to bring the data to destination project. However make sure you gave proper permission that is required to access the cloud storage buckets from the destination project.
If the transformations you want are not possible using SQL or not practical to use SQL, you can use Cloud Data fusion -> Integration studio. Here you can choose both source and sink as BigQuery and there are a number of options available for transformation component. It is similar to ETL tool. Data Fusion Quickstart documentation.
Otherwise, you can simply execute or schedule a query as per your requirement in BigQuery itself and save the result of the query in another table Saving query results in destination table.
I'm very new to Snowflake, so forgive me if the answer is obvious.
I am loading the data from on-prem into Azure using Data Factory, and then ingesting into Snowflake using COPY INTO. However, I need to enable access for some of the transformed data to other platforms, meaning that if I perform transformation in Snowflake, I'll need to create an external table in Azure (essentially pushing this data back to Azure so other platforms can access it).
As we don't particularly want to introduce a new tool, I have two options for our fairly basic transformation:
do the transformation in ADF
do the transformation in Snowflake in SQL scripts and then create an external table so other teams can access the data using other tools (these platforms don't integrate with Snowflake)
Are there any major drawbacks to option 2 apart from increased storage costs?
I'm trying to weigh up the following: maintenance effort (our team's skills lie in SQL not ADF), cost, and performance.
Any advice would be appreciated.
As stated in the question, there are many possible answers for this scenario - with my favorite being the second one ("do the transformation in Snowflake in SQL scripts and then create an external table so other teams can access the data using other tools").
If you need to make the results of these transformations available on Azure storage, Azure Data Factory supports this natively:
Copy data from Snowflake that utilizes Snowflake's COPY into [location] command to achieve the best performance. https://learn.microsoft.com/en-us/azure/data-factory/connector-snowflake#supported-capabilities
Or you could manage this inside Snowflake using the same COPY INTO that ADF uses.
Let me add a couple screenshots from the Snowflake webinar "Data Warehouse or Data Lake? How You Can Have Both in a Single Platform":
https://resources.snowflake.com/webinars-thought-leadership/data-warehouse-or-data-lake-how-you-can-have-both-in-a-single-platform-3
My requirement is to migrate data from teradata database to Google bigquery database where table structure and schema remains unchanged. Later, using the bigquery database, I want to generate reports.
Can anyone suggest how I can achieve this?
I think you should try TDCH to export data to Google Cloud Storage in Avro format. TDCH runs on top of hadoop and exports data in parallel. You can then import data from avro files into BigQuery.
I was part of a team that addressed this issue in a Whitepaper.
The white paper documents the process of migrating data from Teradata Database to Google BigQuery. It highlights several key areas to consider when planning a migration of this nature, including the rationale for Apache NiFi as the preferred data flow technology, pre-migration considerations, details of the migration phase, and post-migration best practices.
Link: How To Migrate From Teradata To Google BigQuery
I think you can also try to use cloud composer(apache airflow) or install apache airflow in instance.
If you can open the ports from Teradata DB then you can run 'gsutil' command from there and schedule it via airflow/composer to run the jobs on daily basis. Its quick and you can leverage the scheduling capabilities of airflow.
BigQuery introduced Migration Service which is a comprehensive solution for migrating the data warehouse to BigQuery. It includes free to use tools that help with each phase of migration including assessment and planning to execution and verification.
Reference:
https://cloud.google.com/bigquery/docs/migration-intro
We are very pleased with the combination BigQuery <-> Tableau Server with live connection. However, we now want to work with a data extract (500MB) on Tableau Server (since this datasource is not too big and is used very frequently). This takes too much time to refresh (1.5h+). We noticed that only 0.1% is query time and the rest is data export. Since the Tableau Server is on the same platform and location, latency should not be a problem.
This is similar to the slow export of a BigQuery table to a single file, which can be solved by using "daisy chain" option (wildcards). Unfortunately we can't use similar logic with a Google BigQuery data extract refresh in Tableau...
We have identified some approaches, but are not pleased with our current ideas:
Working with incremental refresh: our existing BigQuery table rows can change: these changes can only be applied in Tableau if you do a full refresh
Exporting the BigQuery table to GCS using the daisy chain option and making a Tableau data extract using the Tableau SDK: this would result in quite some overhead...
Writing a Dataflow job using a custom sink for Tableau Server (data extracts).
Experimenting with a Tableau web connector that communicates directly with the BigQuery API: I don't think this will be faster? I didn't see anything about parallelizing calls with the Tableau web connecector, but I didn't try this approach yet.
We would prefer a non-technical option, to limit maintenance... Is there a way to modify the Tableau connector to make use of the "daisy chain" option for BigQuery?
You've uploaded the data in BigQuery. Can't you just use the input for that load job (a CSV perhaps) as input for Tableau?
When we use Tableau and BigQuery we also notice that extracts are slow but we generally don't do that because you lose BigQuery's power. We start with a live data connection at first, and then (if needed) convert this into a custom query that aggregates that data into a much smaller datasets which extracts in just a few seconds.
Another way to achieve higher performance with BigQuery and Tableau is aggregating or joining tables on beforehand. JOINs on huge tables can be slow, so if you use a lot of those you might consider generating a denormalised dataset which does all of the JOIN-ing first. You will get a dataset with a lot of duplicates and a lot of columns. But if you select only what you need in Tableau (hide unused fields!) then these columns won't count in your query cost.
One recommendation I have seen is similar to your point 2 where you export the BQ table to Google Cloud Storage and then use the Tableau Extract API to create a .tde from the flat files in GCS.
This was from an article on the Google Cloud site so I'd assume it would be best practice:
https://cloud.google.com/blog/products/gcp/the-switch-to-self-service-marketing-analytics-at-zulily-best-practices-for-using-tableau-with-bigquery
There is an article here which provides a step by step guide to achieving the above.
https://community.tableau.com/docs/DOC-23161
It would be nice if Tableau optimised the BQ connector for extract refresh using the BigQuery Storage API. We too have our Tableau Server environment in the same GCP zone as our BQ datasets and experience slow refresh times.