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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3
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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 ...
4
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3answers
372 views

Why is sql server waiting for acknowledgment?

I have an application that often request a big set of rows [about 20K] from a sql view, in the mean time other applications can't update the table from where the data comes from, the update query's ...
4
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1answer
357 views

What is the PREEMPTIVE_REENLIST wait type in Microsoft SQL Server 2008 R2

This is not urgent, just curiosity. QUESTION: I was trying to troubleshoot a slow server today, and I came across a high figure for a wait type called PREEMPTIVE_REENLIST. I'm not able to find this ...
4
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1answer
13k views

resource wait SQLCLR - wait_type CLR_SEMAPHORE by SPID 0

UPDATE In the comments under Aaron's post is an extensive explanation why I want to find this out, please read it if you want to know. The system is running some ETL, reporting services and a ...
1
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2answers
2k views

PAGEIOLATCH_SH and LCK_M_IX wait type

I'm seeking for a resolution into wait types I observe on one of my servers. I've been keeping wait statistics for a long time and can positively say that the top two are PAGEIOLATCH_SH and LCK_M_IX ...
2
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1answer
238 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 ...
4
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2answers
571 views

Can WAITFOR increase CXPACKET waits?

If I have some T-SQL code like this: While @done<1 Begin WAITFOR DELAY '00:00:30'; Set @done=<some select statement> End Is this likely to increase waits for CXPACKET? Presumably the other ...
1
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1answer
965 views

sql server service broker

For the last few days the service broker command which run from master database is consuming much more RESOURCES than before. The Impact on the Database is high (from the bad side), It causes for ...
3
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3answers
3k views

Collecting Wait Stats

We currently use a monitoring tool which shows us our top wait stats either by number of waiting tasks or total wait time. Below are the wait stats by number of tasks waiting and also wait time per ...
3
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2answers
11k views

Ideal values for wait time in SQL server

This is related to my own post here The SQL server starts everyday at 8:30 AM and stops around 9:30 PM.( So wait times will reset everyday) SQL server will be used by around 60 users simultaneously(...
8
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2answers
2k views

Intermittent RESOURCE_SEMAPHORE_QUERY_COMPILE Wait Stats

I'm trying to troubleshoot some intermittent CPU spikes that we're witnessing on one of our production SQL Servers. We're running SQL Server 2008 R2 Standard Edition with 28 GB RAM and 4 CPU cores. ...
8
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2answers
2k views

SQL Server performance: PREEMPTIVE_OS_DELETESECURITYCONTEXT dominant wait type

I received a call yesterday from a customer who was complaining about high CPU usage on their SQL Server. We're using SQL Server 2012 64 bit SE. Server is running Windows Server 2008 R2 Standard, 2.20 ...
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 ...
4
votes
1answer
614 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 ...
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 ...
6
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1answer
2k views

What does the wait type PREEMPTIVE_XE_CALLBACKEXECUTE mean?

I have two instances in the last week where a DROP command for an Extended Events session has taken over a day to complete, sitting with the wait: PREEMPTIVE_XE_CALLBACKEXECUTE. Can anyone explain ...
13
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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 ...
10
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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 ...
7
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3answers
17k views

Investigating high SQL waits, especically LCK_M_U

Recently I have been struggling with SQL server performance and although we have fixed a huge multitude of basic errors in the config it is still performing badly. To clarify it is not overall ...
2
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4answers
8k views

Select from linked server to local server causing waits on both sides

The queries in question are here: http://pastie.org/4833351 Run individually, each of these queries runs through (albeit slow). Run as a group, it just sits there, showing either OLEDB waits on the ...
5
votes
1answer
2k views

Is the SQLTRACE_FILE_BUFFER wait type documented? What does it indicate?

We run a background task on one of our servers which polls sys.dm_exec_requests for long-running queries, gathering diagnostic information when it finds them, including wait type. I'm seeing a number ...
6
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1answer
908 views

Attempting to tune a Sharepoint site using SQL Server Waits and Queues

I'm pretty new to this performance tuning with Waits and Queues thing - fascinating, but also not always all that intuitive... Right now, a customer of mine has a SQL Server 2008 64-bit Enterprise ...
9
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3answers
66k 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 ...
4
votes
3answers
6k views

PageIOLatch_Sh waits noticed after tuning an index

Lately, a lot of queries to the database are timing out. While investigating I found that queries are in the suspended state with wait_type as PageIOLatch_Sh. I have not noticed so many queries being ...
3
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1answer
2k views

async_network_io issues with BIDS

This is related to my previous question drastically different runtimes in BIDS and the SSRS Web Portal. I am struggling with refreshing some reports in BIDS because they run forever. I have now ...
33
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1answer
31k views

SLEEP_TASK Wait Type in SQL Server - What does it indicate?

I haven't seen the SLEEP_TASK wait type before, and today I seem to be getting a ton of them. I'm not the official DBA, just a SQL Server developer who knows some DBA stuff. We upgraded our servers ...