Troubleshoot dedicated SQL pool (formerly SQL DW) in Azure Synapse Analytics
Artikkeli
This article lists common troubleshooting issues in dedicated SQL pool (formerly SQL DW) in Azure Synapse Analytics.
Connect
Issue
Resolution
Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. (Microsoft SQL Server, Error: 18456)
This error occurs when a Microsoft Entra user tries to connect to the master database, but does not have a user in master. To correct this issue, either specify the dedicated SQL pool (formerly SQL DW) you wish to connect to at connection time or add the user to the master database. For more information, see Security overview.
The server principal "MyUserName" is not able to access the database master under the current security context. Cannot open user default database. Login failed. Login failed for user 'MyUserName'. (Microsoft SQL Server, Error: 916)
This error occurs when a Microsoft Entra user tries to connect to the master database, but does not have a user in master. To correct this issue, either specify the dedicated SQL pool (formerly SQL DW) you wish to connect to at connection time or add the user to the master database. For more information, see Security overview.
CTAIP error
This error can occur when a login has been created on the SQL Database master database, but not in the specific SQL database. If you encounter this error, take a look at the Security overview article. This article explains how to create a login and user in the master database, and then how to create a user in a SQL database.
Blocked by Firewall
Dedicated SQL pools (formerly SQL DW) are protected by firewalls to ensure only known IP addresses have access to a database. The firewalls are secure by default, which means that you must explicitly enable and IP address or range of addresses before you can connect. To configure your firewall for access, follow the steps in Configure server firewall access for your client IP in the Provisioning instructions.
Manual scripting, using the scripting wizard, or connecting via SSMS is slow, not responding, or producing errors
Ensure that users have been created in the master database. In scripting options, also make sure that the engine edition is set as "Microsoft Azure Synapse Analytics Edition" and engine type is "Microsoft Azure SQL Database".
Generate scripts fails in SSMS
Generating a script for dedicated SQL pool (formerly SQL DW) fails if the option "Generate script for dependent objects" option is set to "True." As a workaround, users must manually go to Tools -> Options ->SQL Server Object Explorer -> Generate script for dependent options and set to false
Data ingestion and preparation
Issue
Resolution
Exporting empty strings using CETAS will result in NULL values in Parquet and ORC files. Note if you are exporting empty strings from columns with NOT NULL constraints, CETAS will result in rejected records and the export can potentially fail.
Remove empty strings or the offending column in the SELECT statement of your CETAS.
Loading a value outside the range of 0-127 into a tinyint column for Parquet and ORC file format is not supported.
Specify a larger data type for the target column.
Msg 105208, Level 16, State 1, Line 1 COPY statement failed with the following error when validating value of option 'FROM': '105200;COPY statement failed because the value for option 'FROM' is invalid.'
Currently, ingesting data using the COPY command into an Azure Storage account that is using the new DNS partitioning feature results in an error. DNS partition feature enables customers to create up to 5000 storage accounts per subscription. To resolve, provision a storage account in a subscription that does not use the new Azure Storage DNS partition feature (currently in Public Preview).
Monitor TempDB space usage. Common causes for running out of tempdb space are: - Not enough resources allocated to the query causing data to spill to tempdb. See Workload management - Statistics are missing or out of date causing excessive data movement. See Maintaining table statistics for details on how to create statistics - tempdb space is allocated per service level. Scaling your dedicated SQL pool (formerly SQL DW) to a higher DWU setting allocates more tempdb space.
Poor query performance and plans often is a result of missing statistics
The most common cause of poor performance is lack of statistics on your tables. See Maintaining table statistics for details on how to create statistics and why they are critical to your performance.
Low concurrency / queries queued
Understanding Workload management is important in order to understand how to balance memory allocation with concurrency.