Can we create data warehouse like t-sql table in azure serverless sql pool. means does serverless sql pool supports storage of relational table structures like t-sql
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We have created a SQL Database from our Azure SQL Serverless Pool. We have a table that has over 450 fields.
Whenever we try to extract the table with all the fields the query times out and produces the following error:
Msg 15884, Level 16, State 1, Line 2
Query timeout expired.
However, when I we try to extract just a few fields it successfully gives us all the rows.
Therefore, can someone let me know if there are any limitations on the number fields when extracting tables from Azure SQL Serverless Pool?
Msg 15884, Level 16, State 1, Line 2
Query timeout expired.
This error is because the SQL query takes long time to execute. Unfortunately, timeout settings cannot be modified in Synapse SQL serverless pool. The solution is to either optimize the query or to optimize the data stored in external storage.
Below are some points for better performance.
Try to store data in parquet format than csv or Json file. Parquet files are columnar format and size will be lesser for same data which is stored as csv or Json format.
Do not use the storage account with other workloads during query execution.
In order to query large amount of data, use Azure Data Studio or SQL Server Management Studio than azure synapse studio.
Make sure to have Synapse serverless SQL pool and Storage in the same region.
Refer Microsoft document on Best practices for serverless SQL pool - Azure Synapse Analytics .
I want to insert table from different factory / server in Azure data warehouse. Is it possible to insert by query?
Because it takes a lot of time if I make dataset and pipeline for each table in Azure data factory.
Just from your screenshot, according the icon of the Azure SQL, you're using Azure SQL database, not Azure Data Warehouse.
You could use Elastic Query to do a cross database query in Azure.
Ref the tutorial: Get started with cross-database queries (vertical partitioning) (preview)
Elastic database query (preview) for Azure SQL Database allows you to run T-SQL queries that span multiple databases using a single connection point. This article applies to vertically partitioned databases.
When completed, you will: learn how to configure and use an Azure SQL Database to perform queries that span multiple related databases.
Then you can inset data from external table to current database table.
Note: Azure SQL database already has the master key, you don't need create it again.
Hope this helps.
I am working on a project designed to run on azure platform using Azure database and Locally using local sql server. We have stored procedure that contain cross database calls. However It doesn't works on Azure server.I need cross database queries that capable of working in both azure and local sql server.
We an use Elastic Query which allows us to query across Azure SQL Databases
https://azure.microsoft.com/en-us/documentation/articles/sql-database-elastic-query-overview/
We can setup external data source in azure server Using following code. In this case we can execute cross database calls likes joining tables in a single database.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'yourPassword';
CREATE DATABASE SCOPED CREDENTIAL yourServeradminlogin
WITH IDENTITY = 'yourServeradminlogin',
SECRET = 'yourPassword';
CREATE EXTERNAL DATA SOURCE RefmyDemoDB2
WITH
(
TYPE=RDBMS,
LOCATION='testdbdemoserver.database.windows.net',
DATABASE_NAME='myDemoDB2',
CREDENTIAL= yourServeradminlogin
);
CREATE EXTERNAL TABLE [dbo].[Department](
[DeptId] [int] NOT NULL,
[Name] [varchar](50) NULL
)
WITH
(
DATA_SOURCE = RefmyDemoDB2
);
It doesn't seem possible to use above method on our local SQL server without adding a third party database engine.
Install something called PolyBase to do cross database query in local sql server version 2017 and above.It only supported with external data source of type such as HADOOP rather than referencing another database(or any data storage) within the sql server.
We can accomplish that using following code
CREATE MASTER KEY ENCRYPTION BY PASSWORD='MyP#ssword123secretword';
CREATE DATABASE SCOPED CREDENTIAL mycredential
WITH IDENTITY = 'credential', Secret = 'secretkey'
CREATE EXTERNAL DATA SOURCE mycustomers
WITH (
TYPE = HADOOP,
LOCATION = 'wasbs://azurestorage.blob.core.windows.net/',
CREDENTIAL = mycredential
);
CREATE EXTERNAL FILE FORMAT csvformat
WITH (
FORMAT_TYPE = DELIMITEDTEXT,
FORMAT_OPTIONS (
FIELD_TERMINATOR = ','
)
);
CREATE EXTERNAL TABLE TableName
(
[did] [int] NOT NULL,
[Dname] [varchar] (50) NULL
)
WITH
(
LOCATION = '/',
DATA_SOURCE = mycustomers,
FILE_FORMAT = csvformat
)
Using HADOOP and polybase we can create an external data source in local sql server. But it create external data source of that external data storage. That is External data table located in that external storage.Exactly, my requirement is create an external data source of database within the sql server. So that i can use same corss data base query in both azure and local sql server
Is there any solution to solve this. or any solution to run cross database queries in both azure and local sql server?
You should not assume that using external tables in SQL Azure is remotely similar to doing cross-database queries in SQL Server. They are not the same thing and they have very different performance profiles. External tables is closer to linked servers than cross-database queries in SQL Server.
In SQL Server, cross-database queries are:
- running in the same SQL instance
- run the same basic execution code path to read data vs. single-database SQL Azure
- you have some slightly different transactional semantics vs. single-database operaitons in SQL Server, but the experience is generally similar from your perspective.
In SQL Azure singletons ("traditional") SQL Azure, you generally do not have the databases on the same physical machines. So, you have to cross-server queries (which are exposed using a linked-server like mechanism called external tables which support sharding/fan-out scenarios mostly). Trying to use this feature to simulate cross-database queries may functionally work, but it is not really a great plan due to the performance differences. There are also no real transactional guarantees in this path at all (no DTC).
SQL Azure Managed Instance does support cross-database queries within a single SQL Server instance internally. So, this would be the path that would be most similar for you to use if you really want to use cross-database queries. If you want to use SQL Azure single databases, you generally would not want to do cross-db queries at all for a legacy workload and you would want to rewrite to avoid the dependency. (Otherwise it will just be an ongoing headache due to the performance differences)
Is it possible to create an external table in Azure SQL of the data residing in Azure Table storage?
Answer is no.
I am currently facing similiar issue and this is my research so far:
Azure SQL Database doesn't allow Azure Table Storage as a external data source.
Sources:
https://learn.microsoft.com/en-us/sql/t-sql/statements/create-external-data-source-transact-sql?view=sql-server-2017
https://learn.microsoft.com/en-us/sql/t-sql/statements/create-external-file-format-transact-sql?view=sql-server-2017
https://learn.microsoft.com/en-us/sql/t-sql/statements/create-external-table-transact-sql?view=sql-server-2017
Reason:
The possible data source scenarios are to copy from Hadoop (DataLake/Hive,..), Blob (Text files,csv) or RDBMS (another sql server). The Azure Table Storage is not listed.
The possible external data formats are only variations of text files/hadoop: Delimited Text, Hive RCFile, Hive ORC,Parquet.
Note - even copying from blob in JSON format requires implementing custom data format.
Workaround:
Create a copy pipeline with Azure Data Factory.
Create a copy
function/script with Azure Functions using C# and manually transfer
the data
Yes, there are a couple options. Please see the following:
CREATE EXTERNAL TABLE (Transact-SQL)
APPLIES TO: SQL Server (starting with 2016) Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse
Creates an external table for PolyBase, or Elastic Database queries. Depending on the scenario, the syntax differs significantly. An external table created for PolyBase cannot be used for Elastic Database queries. Similarly, an external table created for Elastic Database queries cannot be used for PolyBase, etc.
CREATE EXTERNAL DATA SOURCE (Transact-SQL)
APPLIES TO: SQL Server (starting with 2016) Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse
Creates an external data source for PolyBase, or Elastic Database queries. Depending on the scenario, the syntax differs significantly. An external data source created for PolyBase cannot be used for Elastic Database queries. Similarly, an external data source created for Elastic Database queries cannot be used for PolyBase, etc.
What is your use case?
What should I do to ensure optimal query performance using transact-SQL in Azure SQL Data Warehouse while combining data sets from SQL and non-relational data in Azure Blob storage? Any inputs would be greatly appreciated.
The best practice is to load data from Azure Blob Storage into SQL Data Warehouse instead of attempting interactive queries over that data.
The reason is that when you run a query against your data residing in Azure Blob Storage (via an external table), SQL Data Warehouse (under-the-covers) imports all the data from Azure Blob Storage into SQL Data Warehouse temporary tables to process the query. So even if you a run SELECT TOP 1 query on your external table, the entire dataset for that table will be imported temporarily to process the query.
As a result, if you know that you will querying the external data frequently, it is recommended that you explicitly load the data into SQL Data Warehouse permanently using a CREATE TABLE AS SELECT command as shown in the document: https://azure.microsoft.com/en-us/documentation/articles/sql-data-warehouse-load-with-polybase/.
As a best practice, break your Azure Storage data into no more than 1GB files when possible for parallel processing with SQL Data Warehouse. More information about how to configure Polybase in SQL Data Warehouse to load data from Azure Storage Blob is here: https://azure.microsoft.com/en-us/documentation/articles/sql-data-warehouse-load-with-polybase/
Let me know if that helps!