I'm migrating a DW that has external tables, however they point to the original data lake instead of the copy I created. Is there any easy/efficient way to repoint the data source without having to drop/recreate all the external tables? I found that the ALTER EXTERNAL DATA SOURCE is only compatible with SQL Server 2016.
Any insights are appreciated!
Thanks!
Deleting and recreating external definitions is currently the only method supported for Azure SQL Data Warehouse.
Assuming that your credentials have not changed, you'll have to follow this sequence:
Drop external tables
Drop external data source
Create external data source
Create external tables
How are you loading your DW? You might avoid this problem if you're using the Azure SQL Data Warehouse loaders from ADF V2 or Databricks. These components create and drop their external definitions for each run.
The one feature you'll lose from the ADF / Databricks approach is if you're using views over external tables to add metadata such as load datetime, hashes, etc., at the point of ingestion.
I've just created a request for this feature, please add your vote and supporting comments.
https://feedback.azure.com/forums/307516-sql-data-warehouse/suggestions/35957506-alter-external-data-source
Related
I am moving from SSIS to Azure.
we have 100's of files and MSSQL tables that we want to push into a Gen2 data lake
using 3 zones then SQL Data Lake
Zones being Raw, Staging & Presentation (Change names as you wish)
What is the best process to automate this as much as possible
for example build a table with files / folders / tables to bring into Raw zone
then have Synapse bring these objects either full or incremental load
then process the them into the next 2 zones I guess more custom code as we progress.
Your requirement can be accomplished using multiple activities in Azure Data Factory.
To migrate SSIS packages, you need to use SSIS Integrated Runtime (IR). ADF supports SSIS Integration which can be configured by creating a new SSIS Integration runtime. To create the same, click on the Configure SSIS Integration, provide the basic details and create a new runtime.
Refer below image to create new SSIS IR.
Refer this third-party tutorial by SQLShack to Move local SSIS packages to Azure Data Factory.
Now, to copy the data to different zones using copy activity. You can make as much copy of your data as your requirement using copy activity. Refer Copy data between Azure data stores using Azure Data Factory.
ADF also supports Incrementally load data using Change Data Capture (CDC).
Note: Both Azure SQL MI and SQL Server support the Change Data Capture technology.
Tumbling window trigger and CDC window parameters need to be configured to make the incremental load automated. Check this official tutorial.
The last part:
then process them into the next 2 zones
This you need to manage programmatically as there is no such feature available in ADF which can update the other copies of the data based on CDC. You need to either create a separate CDC for those zones or do it logically.
I read a few threads on this but noticed most are outdated, with excel becoming an integration in 2020.
I have a few excel files stored in Drobox, I would like to automate the extraction of that data into azure data factory, perform some ETL functions with data coming from other sources, and finally push the final, complete table to Azure SQL.
I would like to ask what is the most efficient way of doing so?
Would it be on the basis of automating a logic app to extract the xlsx files into Azure Blob, use data factory for ETL, join with other SQL tables, and finally push the final table to Azure SQL?
Appreciate it!
Before using Logic app to extract excel file Know Issues and Limitations with respect to excel connectors.
If you are importing large files using logic app depending on size of files you are importing consider this thread once - logic apps vs azure functions for large files
Just to summarize approach, I have mentioned below steps:
Step1: Use Azure Logic app to upload excel files from Dropbox to blob storage
Step2: Create data factory pipeline with copy data activity
Step3: Use blob storage service as a source dataset.
Step4: Create SQL database with required schema.
Step5: Do schema mapping
Step6: Finally Use SQL database table as sink
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
I need to export a multi terabyte dataset processed via Azure Data Lake Analytics(ADLA) onto a SQL Server database.
Based on my research so far, I know that I can write the result of (ADLA) output to a Data Lake store or WASB using built-in outputters, and then read the output data from SQL server using Polybase.
However, creating the result of ADLA processing as an ADLA table seems pretty enticing to us. It is a clean solution (no files to manage), multiple readers, built-in partitioning, distribution keys and the potential for allowing other processes to access the tables.
If we use ADLA tables, can I access ADLA tables via SQL Polybase? If not, is there any way to access the files underlying the ADLA tables directly from Polybase?
I know that I can probably do this using ADF, but at this point I want to avoid ADF to the extent possible - to minimize costs, and to keep the process simple.
Unfortunately, Polybase support for ADLA Tables is still on the roadmap and not yet available. Please file a feature request through the SQL Data Warehouse User voice page.
The suggested work-around is to produce the information as Csv in ADLA and then create the partitioned and distributed table in SQL DW and use Polybase to read the data and fill the SQL DW managed table.
Migration of on-premise SSIS packages to Azure SQL Data Warehouse.
Can someone suggest references or ideas/steps involved in modifying existing SSIS packages that loads a on-premise sql data warehouse to populate a SQL Data Warehouse?
Is this possible?
Regards,
KK
If you would like to just use your existing SSIS package without changing much, it can be as simple as re-configuring the OLEDB destination to connect to Azure Data Warehouse endpoint.
But then, the right way to go about loading data to Azure DW depends on the amount of data involved and what intervals. If you are exporting large amounts of data at regular intervals, then you might want to edit your SSIS package to first stage the data in Azure blob storage flat files. Next, use execute SQL task to create external tables via Polybase and then use CREATE TABLE AS dbo.InternalTable AS SELECT * FROM blob.ExternalTable.
Please check this guidance from Microsoft
If you use the latest feature pack you can go (via blob storage) into the destination table.
https://msdn.microsoft.com/en-US/library/mt146770.aspx