Snippet Name: SQL_Server_Warnings_Diagnosis
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Created Date: 2025-06-16 13:12:40
Last Modified Date: 2025-05-31 10:31:42
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Title: SQL Server Warnings Diagnosis
Author: user
in SQL server, i am getting thousands of the warnings below in the error log; can you tell me what is the cause?
Author: ChatGPT
Certainly! To diagnose the cause of the warnings in your SQL Server error log, I'll need to see the specific warning messages you're receiving. The error log messages typically provide details about the type of issue, the affected components, and sometimes even hints towards resolution.
Could you please share a sample of the warning messages? This will help in identifying the underlying issue and provide a more precise solution.
Author: user
WARNING Long asynchronous API Call: The scheduling fairness of scheduler can be impacted by an asynchronous API invocation unexpectedly exceeding 453274979 ms.
Author: ChatGPT
The warning message you're encountering is related to the SQL Server scheduler and indicates that an asynchronous API call is taking an unusually long time to complete. This can impact the fairness of task scheduling on the SQL Server instance.
Here are a few potential causes and steps to troubleshoot:
1. **Long-running queries or transactions**: Investigate if there are any long-running queries or transactions that might be causing the delay.
- Check the running queries using the following SQL statement:
```sql
SELECT
session_id,
start_time,
status,
command,
wait_type,
wait_time,
last_wait_type,
blocking_session_id,
wait_resource,
db_name(database_id) AS database_name,
text
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle);
```
2. **Blocking and Deadlocks**: Check for any blocking or deadlocks that might be contributing to the issue.
- Use the following queries to identify blocking sessions:
```sql
SELECT
blocking_session_id,
session_id,
wait_type,
wait_time,
wait_resource,
db_name(database_id) AS database_name,
text
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle)
WHERE blocking_session_id <> 0;
```
3. **Resource Contention**: High CPU or I/O contention can cause delays. Monitor the server's resource usage to identify any bottlenecks.
- Use SQL Server's Dynamic Management Views (DMVs) to check for high resource usage:
```sql
SELECT
r.session_id,
r.cpu_time,
r.reads,
r.writes,
r.logical_reads,
r.total_elapsed_time,
s.program_name,
s.login_name,
s.host_name
FROM sys.dm_exec_requests r
JOIN sys.dm_exec_sessions s
ON r.session_id = s.session_id
WHERE r.status = 'running';
```
4. **Hardware Issues**: Issues with hardware, such as slow disks or network problems, could also cause such delays. Check the health and performance of your hardware components.
5. **Configuration Settings**: Verify that your SQL Server configuration settings are optimized for your workload. For instance, ensure that the `max degree of parallelism` and `cost threshold for parallelism` settings are appropriately configured.
6. **SQL Server Version and Patches**: Ensure that your SQL Server is up to date with the latest service packs and cumulative updates. Sometimes, bugs in SQL Server can cause such issues, and these are often resolved in newer updates.
7. **Asynchronous Operations**: Specifically investigate any application code or jobs that might be making asynchronous API calls to SQL Server. Review the implementation to ensure that these calls are optimized and not causing excessive delays.
By systematically reviewing these potential causes, you should be able to identify and resolve the issue leading to the long asynchronous API calls. If the problem persists, consider consulting SQL Server logs in more detail or using a SQL Server performance monitoring tool to gain deeper insights.
Author: user
how can i identify asynchronous operaitons
Author: ChatGPT
To identify asynchronous operations in SQL Server that might be causing the warning messages, you can use a combination of SQL Server's Dynamic Management Views (DMVs) and Extended Events. Here are some steps to help you identify these operations:
### Step 1: Check for Asynchronous Operations with DMVs
SQL Server DMVs can provide valuable insights into the currently running operations and their status. While DMVs don't directly show asynchronous operations, they can help you identify long-running queries and sessions that might be involved in asynchronous processing.
1. **Identify Long-Running Queries**:
```sql
SELECT
session_id,
start_time,
status,
command,
wait_type,
wait_time,
last_wait_type,
blocking_session_id,
wait_resource,
db_name(database_id) AS database_name,
text
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle)
WHERE status = 'running' AND total_elapsed_time > 60000; -- Adjust the time threshold as needed
```
2. **Check for Wait Types Indicative of Asynchronous Operations**:
Some wait types are associated with asynchronous operations, such as `ASYNC_NETWORK_IO` or `PREEMPTIVE_OS_*` waits.
```sql
SELECT
session_id,
wait_type,
wait_time,
wait_resource,
blocking_session_id,
db_name(database_id) AS database_name,
text
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle)
WHERE wait_type LIKE 'ASYNC%' OR wait_type LIKE 'PREEMPTIVE_OS%';
```
### Step 2: Use Extended Events to Track Asynchronous Operations
Extended Events in SQL Server provide a powerful way to capture detailed information about various events, including asynchronous operations.
1. **Create an Extended Events Session**:
```sql
CREATE EVENT SESSION &#91;TrackAsyncOperations] ON SERVER
ADD EVENT sqlserver.async_io_requested
ADD EVENT sqlserver.async_io_completed
ADD EVENT sqlserver.wait_info
ADD EVENT sqlserver.sql_statement_completed
ADD EVENT sqlserver.rpc_completed
ADD EVENT sqlserver.batch_completed
ADD EVENT sqlserver.error_reported
ADD TARGET package0.event_file (SET filename=N'C:\temp\AsyncOps.xel')
WITH (STARTUP_STATE=ON);
```
2. **Start the Extended Events Session**:
```sql
ALTER EVENT SESSION &#91;TrackAsyncOperations] ON SERVER STATE = START;
```
3. **Analyze the Captured Data**:
After the Extended Events session has been running for a while, you can analyze the captured events to identify any long-running asynchronous operations.
```sql
-- Read the event file
SELECT
event_data.value('(event&#91;@name="async_io_requested"]/@timestamp)&#91;1]', 'datetime2') AS &#91;Timestamp],
event_data.value('(event/data&#91;@name="duration"]/value)&#91;1]', 'int') AS &#91;Duration],
event_data.value('(event/data&#91;@name="file_id"]/value)&#91;1]', 'int') AS &#91;FileID],
event_data.value('(event/data&#91;@name="io_handle"]/value)&#91;1]', 'bigint') AS &#91;IOHandle]
FROM sys.fn_xe_file_target_read_file('C:\temp\AsyncOps*.xel', NULL, NULL, NULL)
CROSS APPLY (SELECT CAST(event_data AS XML) FROM (SELECT CONVERT(XML, event_data) AS event_data) AS T(event_data)) AS X(event_data);
```
### Step 3: Review Application Code and Jobs
1. **Review Application Code**:
- Check the application code for any asynchronous operations (e.g., asynchronous calls to the database, background tasks, etc.).
- Look for async methods in your application, especially in .NET applications where async/await patterns are common.
2. **Check SQL Server Jobs**:
- Review the jobs running on your SQL Server instance. Some jobs might be running asynchronous operations or external processes that take a long time to complete.
```sql
SELECT
sj.name AS &#91;JobName],
sja.start_execution_date,
sja.stop_execution_date,
sja.run_requested_date,
sja.run_status
FROM msdb.dbo.sysjobs sj
JOIN msdb.dbo.sysjobactivity sja
ON sj.job_id = sja.job_id
WHERE sja.run_requested_date IS NOT NULL
AND sja.stop_execution_date IS NULL;
```
By following these steps, you should be able to identify the asynchronous operations that are causing the warnings in your SQL Server error log. If you need further assistance, you might also consider consulting the SQL Server documentation or reaching out to a database administrator with expertise in performance tuning and troubleshooting.
Author: user
in Powershell I have a variable named $ADUserName that ahs a value of 'US1\izaguirrel' how can i remove the string slash and all preceding characters
Author: ChatGPT
You can use PowerShell to manipulate strings easily with the help of string methods or regular expressions. In this case, to remove the slash and all preceding characters from the string, you can use the `Split` method or a regular expression. Here's how you can do it:
### Using the `Split` Method
The `Split` method splits a string into an array based on a delimiter. You can then select the last element of the resulting array to get the desired part of the string.
```powershell
$ADUserName = 'US1\izaguirrel'
$UserName = $ADUserName.Split('\')&#91;-1]
Write-Output $UserName
```
### Using Regular Expressions
You can also use a regular expression to remove everything up to and including the slash:
```powershell
$ADUserName = 'US1\izaguirrel'
$UserName = $ADUserName -replace '.*\\', ''
Write-Output $UserName
```
Both methods will give you the result:
```
izaguirrel
```
Choose the method that you find more intuitive and suitable for your needs. The `Split` method is straightforward for simple delimiters, while regular expressions offer more flexibility for complex patterns.