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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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95 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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8 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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1answer
217 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 ...
14
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1answer
11k views

Troubleshooting SOS_SCHEDULER_YIELD wait

Running our corporate ERP (Dynamics AX 2012), I noticed our production environment seemed much slower than our development systems. After performing the same activities in both the development and ...
5
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1answer
111 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 ...
5
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1answer
109 views

Different Disk Drive Same Backend Storage

I have a database running on a VM which is getting hammered during a large load, in particular I can see waits of WRITELOG happening. My initial thought is to split the files out on to their own ...
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1answer
106 views

Scalability of concurrent log restore for different databases on SQL Server

Are there any locks or resource blocking/contention (beyond IO capacity) between two sessions, which restore logs for two different databases with norecovery? Same about restore logs with recovery? ...
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1answer
131 views

Large Sleep counts causing THREADPOOL wait?

When I run sp_whoisactive throughout the day, I usually see we have around 500-700 connections on our server. We are occasionally getting threadpool waits and high signal wait ratios (so we are thread ...
2
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1answer
256 views

How can I reduce OLEDB wait type in a SSAS linked server connection?

I have recently created a linked server to one of my SSAS servers. when I go ahead and open the catalogs, to see which ssas databases I have there, I use the following procedure: create procedure ...
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3answers
67k views

How to troubleshoot enq: TX - row lock contention?

I have the following situation. I have RAC. On both nodes there are the locks. On the First Node SID EVENT USERNAME BLOCKING_SESSION ROW_WAIT_OBJ# OBJECT_NAME ...
6
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1answer
429 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, ...
6
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1answer
268 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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2answers
2k views

LATCH_EX Waits on Resource METADATA_SEQUENCE_GENERATOR

We have a process that generates an inventory report. On the client side, the process splits of a configurable number of worker threads to build a chunk of data for the report that corresponds to one ...
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1answer
94 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?...
4
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2answers
242 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
231 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
43 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
2k 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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1answer
317 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
353 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
22 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
763 views

ACCESS_METHODS_DATASET_PARENT Problem

We had an AlwaysOn Async replica we had some problems so we deleted the availability group After that the database and CPU seem to work abnormally It's very slow and we have waittype = LATCH_EX , ...
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1answer
1k 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
101 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
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1answer
261 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 ...
2
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1answer
2k views

Clarification on signal wait percent

I'm experiencing high Signal Wait percent while CPU utilisation is very low at one of our servers. I have gone through numerous articles online about Signal Waits and understand that it is the time ...
4
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1answer
3k 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 ...
6
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2answers
414 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
100 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 ...
3
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1answer
2k 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 ...
0
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2answers
4k 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,...
13
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3answers
32k views

High CXPACKET and LATCH_EX waits

I am having some performance issues with a data processing system which I am working on. I have gathered wait stats from a one hour peroid which show a large amount of CXPACKET and LATCH_EX wait ...
6
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2answers
11k 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 ...
4
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2answers
1k views

PAGEIOLATCH wait type

I'm trying to get a better understanding of how serious this wait type is. I'm using sp_WhoIsActive stored procedure. Our DBAs don't seem to know much about this wait type. But I often see it when I ...
3
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2answers
667 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 ...
4
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1answer
628 views

Why is there ASYNC_NETWORK_IO wait type on Shared Memory connections?

I have an app (windows service) local to the SQL Server box. It calls a stored procedure on the SQL Server box that returns a ton of data and thus causes ASYNC_NETWORK_IO wait. The database ...
4
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3answers
1k views

Reading ASYNC_NETWORK_IO wait stats

I was troubleshooting some bad performance for a client yesterday and identified that there was a missing index for a particular set of queries that were heavily used (this was for an ERP applicaton: ...
3
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2answers
702 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] - [...
3
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1answer
63 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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1answer
1k 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 ...
1
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2answers
156 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 ...
16
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1answer
21k views

Is ASYNC_NETWORK_IO wait type anything to worry about?

In looking at the list of stored procedures that take long time to execute, one stands out as causing the most wait. However, most of that wait (81%) is ASYNC_NETWORK_IO and I know why: the stored ...
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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 ...
2
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0answers
2k 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? ...
2
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1answer
241 views

Wait Stats, Server Up Time and CXPACKET

I have been looking at the following post and using the query to look at my top wait stats: http://www.sqlskills.com/blogs/paul/wait-statistics-or-please-tell-me-where-it-hurts/ My top wait stat is ...
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2answers
9k views

CXPACKET SUSPENDED and NULL wait type

I was was running the query in this article: http://sqlity.net/en/708/why-cxpacket-waits-are-not-your-performance-problem/ To see what my threads were waiting on in regards to a suspended query with ...
9
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1answer
527 views

Blocked sessions waiting with PAGELATCH_* wait types?

Edited : Why are sessions reporting being blocked but waiting with PAGELATCH_*, and not LCK_M_ related wait types? I previously assumed that SQL server would only report blocking sessions in the ...
3
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1answer
563 views

DIRTY_PAGE_POLL without activated Indirect Checkpoint

Since I encounter some performance issues on my SQL Server 2014 (12.0.2370.0 (X64)) I'm dealing with enormes amounts of different wait types. One of the top 5 wait type is "DIRTY_PAGE_POLL". I've ...
2
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2answers
377 views

SOS_SCHEDULER_YIELD - Prevent a Proc from giving up the Processor Time

I've got a process which about once a month at times unrelated (or as far as we can tell) goes into SOS_SCHEDULER_YIELD State. This process blocks our main data entry pipeline and brings the entire ...
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0answers
55 views

How to identify a process that has been cancelled?

How can you identify a process that has been cancelled? for example: I was running this dynamic sql - via a linked server: declare @sql nvarchar(max) declare @i int declare @z int DECLARE @vCrlf ...