Questions tagged [wait-types]

Whenever the server is running queries, it’s tracking how much time it spends waiting on bottlenecks. These wait statistics are the easiest way to identify your bottleneck.

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1answer
64 views

Sp_BlitzWho can get blocked…?

I was playing around with sp_BlitzWho and got blocked by another session. The session was from the DB were sp_BlitzWho is... I was planning to automate it and save the results to a table, so I could ...
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1answer
99 views

Is this an excessively large 'Lock' time and is it indicative of a problem?

Given: Production environment Application Servers using Hibernate SQL Server Studio Manager v17.5 SQL Server 2016 in a clustered HAG setup SQL Servers do NOT have the Query Store feature enabled The ...
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1answer
80 views

High Latch Wait time with Logon trigger enabled while full backups are running

I have 14 production servers with SQL 2016 standard version, 128 gb of RAM, 16 CPU and SSD drives. Microsoft SQL Server 2016 (SP2-CU15-GDR) (KB4583461) - 13.0.5865.1 (X64) Oct 31 2020 02:43:57 ...
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3answers
181 views

Instance performance variations around SOS_SCHEDULER_YIELD behavior during single-row INSERT statements

I have a shared SQL Server 2016 dev instance in a VM which has poor INSERT performance compared to a shared SQL Server 2012 dev instance on an (supposed to be) identical VM. It also compares poorly ...
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1answer
69 views

Job waiting for resources - is it better to kill it or let it wait

Our server is very busy sometimes and I can see my jobs are waiting for resources. Is it better to kill it and start it after e.g. one hour or let it wait until it finishes? Right now there is a rule ...
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1answer
48 views

High PREEMPTIVE_OS Wait Stats [duplicate]

How to reduce PREEMPTIVE_OS_AUTHENTICATIONOPS wait type stats in SQL Server, any advice on it would be greatly appreciated. Thanks
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0answers
66 views

What would cause slow disk access on an AWS EBS SQL Server? (PAGEIOLATCH_SH)

I have an EC2 instance (r5a.4xlarge) which should be able to do 2Gbps+ in EBS access. This machine has a 7TB mounted gp2 volume, with 16,000 IOPS, which is mounted and contains a SQL Server database ...
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0answers
72 views

SQL server 2016 (13.0.5026.0) Standard. High CPU ussage even without user queries

So SQL server CPU ussage is around 20% even when no users are making queries I query the sysprocesses, and i can see some internal spid's: select * from master.dbo.sysprocesses order by cpu desc Any ...
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0answers
65 views

Reduce file header block

I'm in the middle of my first Statspack analysis, and one of the most time consuming events is Buffer Busy Waits (around 30% time). I checked out the Buffer Wait statistics, and it seems like the most ...
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1answer
210 views

What is the difference between ASYNC_IO_COMPLETION and IO_COMPLETION wait types?

Could someone explain what is the main difference between these two wait types?
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1answer
428 views

Prevent THREADPOOL waits due to idle worker thread trimming

After reading Unusual THREADPOOL Waits by Josh Darnell, a Twitter user mentioned there is an undocumented trace flag to prevent trimming idle workers: The idea is that once SQL Server has created ...
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1answer
160 views

Why do I have THREADPOOL waits even though I have threads available?

We are seeing application time outs and with help of the First Responder Kit, I have captured details. One of the things that caught my attention was: Poison wait detected: Thread Pool So I ran ...
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1answer
40 views

How to dig deeper into ASYNC_NETWORK_IO waits

I've been handed a graph that comes from SolarWinds showing top wait events broken down by day. The last 2 days there's a part of the daily color coded bar representing a total of 3 hours for ...
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21 views

Upgraded DB Driver SRVSQL High Waits PREEMPTIVE_OS_NETVALIDATEPASSWORDPOLICY

Upgraded our PHP SQL driver and now the Top 3 waits are below? Wait_Type Wait_Time_Seconds Waiting_Tasks_Count Percentage_WaitTime PREEMPTIVE_OS_NETVALIDATEPASSWORDPOLICY 5.551000 53732 21....
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1answer
675 views

What steps can I take to determine if my server is under-provisioned for memory?

My server is running SQL Server 2016. The environment is fairly high workload with a lot of write transactions and reading of the data throughout the day. I have a hunch the server isn't provisioned ...
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2answers
91 views

What is the difference between PAGEIOLATCH_* and IO_COMPLETION?

according to this blog: SQL Server Books online defines IO_COMPLETION as “Occurs while waiting for I/O operations to complete. This wait type generally represents non-data page I/Os. Data page I/O ...
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1answer
44 views

Impacts of a change to the Page Verify option

There's no doubt about importance of doing regular integrity checks on production databases. I'm testing the impact of changing the maintenance plans and changing how databases are backed up. First of ...
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1answer
634 views

Job waiting on CXCONSUMER

We have got a procedure on SQL Server agent jobs and this job started to hang on transaction for many hours with wait stats CXCONSUMER and never complete. The problem is after we noticed that it was ...
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2answers
227 views

SQL Server experiencing THREADPOOL waits while still having plenty of available workers

I recently took a look at my production SQL Server's cumulative threadpool waits, and it's literally days worth of waits. So I started doing some digging. I'm on a 32 core, 64 bit server (running on ...
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1answer
164 views

What is non-page data structure in SQL Server

I was monitoring one of the SQL Server in my client evnironment and I can see there is momentary blocking on SQL Server sessions with wait type as LATCH_EX and with wait resource as ...
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0answers
63 views

How do I troubleshoot FILESTREAM_WORKITEM_QUEUE waits in SQL Server 2014?

Env: SQL Server 2014 SP2 on Windows Server 2012 R2. I am seeing our top wait as FILESTREAM_WORKITEM_QUEUE, with average waits near 1s and over 5000 waits during a 2-hour period of time. I haven't ...
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2answers
949 views

SQL Server RAM usage is increasing and query executions is slowing down with time

I'm using SQL server on a server with 48 GB of RAM. When I start the SQL Server service, it's using 12% of the RAM at first, but after 24 hours it's reaching 90% and query executions begin slowing ...
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1answer
1k views

Restore stuck in ASYNC_IO_COMPLETION

Very frequently when I restore databases the restore operation gets stuck and the wait type is ASYNC_IO_COMPLETION. It can be in such state for 10-20-30 minutes untill it proceeds to ...
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1answer
1k views

how does CXPACKETS relates to CXCONSUMER wait types?

when running a delete query to a table that has many foreign keys I get the following waits. I noticed that I have both CXPACKETS and CXCONSUMER wait types at the same time during of the execution ...
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1answer
555 views

Strange blocking on readable secondary after reboot

We are running an SQL Server 2014 Availability Group with 3 replicas, one synchronous (SQL2 for this matter) and one asynchronous secondary replica. We also configured read-only routing to the ...
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1answer
143 views

Where/When is the use of RBAR buffering related to ASYNC_NETWORK_IO waits negotiated between the Client/SQL Server [closed]

Where/When is the use of RBAR buffering related to ASYNC_NETWORK_IO waits negotiated between the Client/SQL Server, or Is it always utilized as in that is just how SQL Server spools data to the client?...
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2answers
499 views

CXPACKET wait on SQL Server

Recently I am experiencing performance issue on a SQL Server database and I have two queries that show me the wait as shown below, one of the databases on this server is a member of Always On replica, ...
4
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2answers
465 views

Help with wait type CHECK_TABLES_THREAD_BARRIER

I have a 2016 SQL Server freshly built - 13.0.5149.0 - OS 2016 (Microsoft Windows NT 6.3 (14393)). The environment is VMWare. No SQL Server HA configuration. It has a problem where CheckDB "stops" ...
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1answer
57 views

Why does a query on a local instance with local database files cause NETWORK_IO waits?

I have followed this tutorial to get the wait stats of a particular query while it is 'in flight' using extended events. Whilst the tutorial refers to an index rebuild, I just did a select statement ...
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1answer
661 views

Slow Query with RESOURCE_SEMAPHORE wait info [closed]

Hi I see lot of RESOURCE_SEMAPHORE as wait_info when i run sp_whoisactive in my sql database server.I see few CXCONSUMER as well.I learned that CXCONSUMER is because of parallel query execution.How to ...
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0answers
948 views

PAGEIOLATCH_EX Wait on Target table of insert..select query

We are running SQL Server 2012 on Windows 2008 R2 with 256GB RAM and 90% memory allocated to SQL Server. No other Apps run on the server. I have a scenario where I’ve to copy a Source (staging) table ...
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1answer
33 views

Wait Stats on Microsoft Azure test

On a particular test we're doing with Microsoft Azure, we are seeing a wait_category called: PAGE LATCH (non-I/O) that we're unfamiliar with. In our test, CaptureSeconds = 1595 and for PAGE LATCH (...
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1answer
2k views

Why is my SQL Server reporting CLR_AUTO_EVENT waits when I don't even use SQL CLR?

When I run this query, I see high wait time for CLR_AUTO_EVENT: SELECT * FROM sys.dm_os_wait_stats WHERE wait_type IN ( 'CLR_AUTO_EVENT', 'CLR_CRST', 'CLR_JOIN'...
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0answers
107 views

MySQL wait events start and end time

How to get wait events exact start and exact end time in MySQL 5.7 version ? Any help will be helpful to us
5
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1answer
379 views

Does sys.dm_os_waiting_tasks include RUNNABLE threads?

From MSDN: Returns information about the wait queue of tasks that are waiting on some resource. Is CPU considered a resource in this definition? I initially thought it's not, but what made me ...
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1answer
3k views

Oracle wait type enq: TM - contention

I’m administrating an Oracle 12c database which shows the wait type: enq: TM – contention in certain time periods (up to 30% of total waits). During this periods the applications does not allow new ...
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2answers
609 views

Why would I get PREEMPTIVE_OS_AUTHORIZATIONOPS using tSQLt when Working at Home?

I have an SSDT project containing tSQLt unit tests. I always find when working at home that publishing this and running all tests (from a post deploy script) is problematic (against both localdb and ...
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0answers
153 views

Negative values for Wait Time per Core per Sec in sp_BlitzFirst

I'm a developer in a firm that doesn't want to spend money on a DBA so i'm on my own with keeping the SQL servers healty. I checked some of Brent's videos and decided to check how hard the SQL servers ...
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2answers
7k views

Identify Queries causing High Average Wait time (SQL Server 2008) [closed]

Recently we started to receive many alerts from SCOM : Alert: SQL 2008 DB Average Wait Time is too high. When reviewed the graph for this counter, we found that the alert is always ranging between 1,...
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2answers
18k views

Huge “Network I/O” type resource waits

We have an in-house application, developed in WinDev, that uses a Microsoft SQL Server 2012 SP2 (build 11.0.5058) database running on Windows Server 2008R2. We are experiencing performance issues. At ...
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2answers
832 views

tsql Process running forever… what is it doing

Trying to create a big test DB, I have an SP that I created that uses a predefined list of tables (35 That I'm interested in) and multiplies the data in each one of them. In other words, A table ...
3
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1answer
66 views

Nightly EDW Build Wait Stats

We are trying to determine our best MAXDOP and Cost Threshold settings for an EDW box. I setup a job to clear the wait stats before the build started and then capture the wait stats after the build ...
3
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2answers
975 views

Wait types with queries

I have a query to find the wait types in which my system is suffering from. WITH [Waits] AS (SELECT [wait_type], [wait_time_ms] / 1000.0 AS [WaitS], ([wait_time_ms] - [...
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1answer
5k views

High Log Flush Wait Time and filling Transaction logs [closed]

I have problem with Log Flush Wait Time - as of now, they are averaging at 30000ms (min 0 max 35000); database itself is performing poorly, transaction logs are also growing beyond reasonable ...
5
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1answer
4k views

SQL Server performance issue (CXPACKET wait type)

I have a performance issue with production SQL Server 2012 which has 24 cores and 32 GB of RAM. From wait type I can see CXPACKET is on the top based on the following SQL Server metrics, should I ...
6
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1answer
520 views

SQL Server CLR procedures and SQLCLR_QUANTUM_PUNISHMENT

I have a CLR stored procedure running on SQL Server 2014. This stored procedure gathers some data (generally numbering in the tens-of-thousands of rows range), runs some computations on the data, ...
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2answers
205 views

SQLserver WaitType : EXECUTION_PIPE_EVENT_INTERNAL

One of our production Microsoft SQL Server 2014 (SP1-CU5) experiencing performance issue so I ran the ShortPeriodWaitStats.sql script from Paul S. Randal, SQLskills.com and the top WaitType is ...
3
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1answer
2k views

What is the DPT_ENTRY_LOCK wait type?

We have a SQL Server 2016 Availability Group with 3 servers. Twice in the past 5 days we have had performance issues. 8a is our primary server, and 8b and 8c are the secondaries. We started having ...
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0answers
1k views

LCK_M_S causing blocking with session id < 50

We are experiencing high LCK_M_S wait times conflicting with idle blocking sessions whose ids are less than 50. The waiting session is always a Select statement within a stored procedure. The ...
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0answers
3k views

Troubleshooting Preemptive_Xe_Dispatcher wait type

While looking for a reason behind slowness of the database server I accidentaly came across Preemptive_Xe_Dispatcher wait. Could you please suggest how this type of wait should be troubleshooted? ...