All versions of Microsoft SQL Server (not MySQL). Please also add a version-specific tag like sql-server-2016 if that is relevant to the question.

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6
votes
2answers
33k views

Copy a large data from sql query result

In my sql server 2008, after running the query the data return is very huge say in millions. I tried copying but it gives an exception sql memory error. Can you let us know how can i copy the entire ...
5
votes
2answers
7k views

Issues with TempDB mdf file ever increasing

I have a tempdb growth issue. Let me preface everything by giving my tempdb settings. Even with no queries running on the database/server tempdb keeps on increasing in size, at first rapidly and ...
4
votes
2answers
1k views

How can I find databases with a large number of virtual log files?

I have several databases on a production server that are in the hundreds of gigabytes, and have many thousands of transactions running through them on a daily basis. Almost all these databases are ...
4
votes
1answer
228 views

MS SQL Server CPU load goes up dramatically when turning on 2014 features by setting compatibility level

I'm running some Microsoft SQL Server 2014 load testing on a decently spec'ed machine. I'm certainly not an expert on the SQL Server tuning specifics, but with the bits an pieces I've gathered from ...
4
votes
3answers
4k views

NULLs in a composite primary key - SQL Server

I'm trying to work out the best way of creating SQL Server primary keys, foreign keys and constraints to accurately represent my data model in LINQ / Entity Data Objects. Let's assume - for the ...
4
votes
1answer
2k views

Running queries with SQLCMD vs. Running queries with SSMS

I've noticed something which i'm not sure about. can it be that running queries directly with SSMS is much faster than running queries with SQLCMD? I've noticed that the results of queries that ran ...
3
votes
1answer
2k views

Is SQL Server Backup single or multi-threaded?

If you perform a... BACKUP DATABASE [DB_Name] TO DISK=N'c:\backups\db_name.bak' WITH STATS=10 Will that perform a single or multi-threaded write? Our Server support company advised us that if we ...
3
votes
2answers
181 views

Unable to restore database backup because it is accessed by other connection

--first command use master Go -- second command ALTER DATABASE MyDB SET SINGLE_USER WITH ROLLBACK IMMEDIATE Go -- Third command RESTORE DATABASE [MyDB] FROM DISK = N'D:\Restore_Backup\...
3
votes
1answer
148 views

Should all queries where you expect a specific order, include an ORDER BY clause?

In order to better understand the SQL Server query processor, I've been thinking about how the ORDER BY clause works, and how SQL Server provides results. It appears SQL Server will provide results ...
3
votes
1answer
628 views

SQL Server DMV to show if database is used

What is the best indicator in finding out whether a database is utilized or accessed? I tried index statistics and based on I/O utilization but none seem to be a good indicator. Problem: I have a ...
3
votes
1answer
440 views

Shrinking log file

Some of the sql log files (idf) are hugh like 5gb. Found a article (http://extended64.com/blogs/rhoffman/archive/2009/06/11/shrink-sql-server-2008-database-log-file-script.aspx) but not sure why he ...
3
votes
1answer
2k views

How does Log shipping knows to keep track

I have set up log shipping between 2 SQL Servers (SQL Server 2008 and SQL Server 2012). At first i took a full backup of the first one and restored it on the other one and than i set up the log ...
3
votes
3answers
3k views

Query to find GUID's “not in” null containing subquery returns no results

When I have a query that checks if a column of type uniqueidentifer does not exist in a table that has a null value then I get no results back. If the subquery does not return a null it works fine and ...
2
votes
2answers
317 views

how to find the T-SQL of a sleeping session that is blocking some other process?

I have a stored procedure called sp_radhe that I put on my servers and it has been helping me to "see" what is happening internally. here is the code of this stored procedure: USE [master] GO SET ...
2
votes
3answers
5k views

Multiple Transaction Log files and performance impact

So I've gotten into an argument with several people regarding the number of transaction log files a give databases should have. I've seen several post saying you should only have 1 transaction log ...
2
votes
1answer
117 views

What is the most efficient way to concatenate strings in SQL Server?

I have this code: DECLARE @MyTable AS TABLE ( [Month] INT, Salary INT ); INSERT INTO @MyTable VALUES (1,2000), (1,3100); SELECT [Month], Salary FROM @MyTable; Output: I want to concat ...
1
vote
2answers
129 views

Managing logins with Availabilty Groups

I have created a user on my primary node that has access to all of the databases in Availability Group AG1. How do I ensure that same user has the same rights on all the other replicas in AG1? ...
1
vote
1answer
325 views

Restoring a differential backup in SQL server 2005

I have created a full back up of my database by executing the line below in my application: Dim Query As String = "backup database Ari to disk='G:\Documents and Settings\i\Desktop\BKAR\" & MyTime....
1
vote
1answer
2k views

Partial restore to a different database

I have a database with 3 filegroups: PRIMARY, AP, and GL. I did a full database backup. I did a partial restore of just the PRIMARY and AP files successfully using this command: -- Partial Backup (...
-2
votes
2answers
9k views

Microsoft recommends using Rowversion over timestamp , but i can not find “rowversion” data type inside my sql server 2008 R2 [closed]

MS on this link http://msdn.microsoft.com/en-us/library/ms182776.aspx mentioned that we should use rowversion data type over Timestamps. Now inside my sql server 2008 R2 I want to create a column with ...
67
votes
5answers
32k views

When to use TINYINT over INT?

In general, I always use Ints. I know that in theory this is not the best practice, though, since you should use the smallest data type that will be guaranteed to store the data. For example, it's ...
47
votes
4answers
37k views

What risks are there if we enable read committed snapshot in sql-server?

I have read here that some extra data will be stored per row so we might see a performance degradation but what other risks are there? eg. Will this affect recovery of the database? Is there anything ...
52
votes
2answers
128k views

How to the get current date without the time part

In SQL Server 2005 how do I get the current date without the time part? I have been using GETDATE() but would like it to have a time of 00:00:00.0
17
votes
2answers
13k views

What are the best practices for running SQL Server in a Virtual Machine?

What are the best practices for running SQL Server in a Virtual Machine? My on-line transaction activities are very low, but there is a high amount of data processing for the purpose of providing ...
27
votes
4answers
44k views

How do I assign an entire Active Directory group security access in SQL Server 2008?

I would like to use integrated security with my internal application which is all on a domain. Unfortunately, I've never been able to get this to work well. I would like to assign an entire Exchange ...
23
votes
3answers
11k views

Running total with count?

As the title suggests I need some help getting a running total in T-SQL. The problem is that the sum I need to do is the sum of a count: sum(count (distinct (customers))) Say if I ran the count ...
16
votes
1answer
13k views

Trigger in combination with transaction

Suppose we have the following situation: We have a table (let's say Table_A), wich has a trigger on INSERT. The trigger job is to update some rows in table_B based on the inserted values in table_A. ...
36
votes
11answers
6k views

How can I track database dependencies?

As internal applications evolve over a number of years, you occasionally find there are a number of tables that people believe are no longer relevant and want to cull. What are the practical methods ...
14
votes
2answers
53k views

High Disk I/O from sql server or is High disk I/O slowing sql server?

I've been arguing with a DBA and a couple hardware guys about performance issues on our SQL server. Normally everything is fine, however over the past few weeks we have been having huge lag spikes in ...
11
votes
2answers
9k views

SQL Server database design for “archived but available” data

We have this large database (>1TB) that we intend to "shrink". The database revolves around one main entity, let's call it "Visit". For discussion, let's say it is a database for a medical practice. ...
11
votes
1answer
232 views

SQL Server: How to track progress of CREATE INDEX command?

SQL Server 2014, Std Ed I have read that percent_complete in dm_exec_requests does not work for CREATE INDEX, and in practice, percent_complete sticks at 0. So that doesn't help. I currently use the ...
26
votes
1answer
8k views

Why is using a table variable more than twice as fast as a #temp table in this specific case?

I was looking at the article here Temporary Tables vs. Table Variables and Their Effect on SQL Server Performance and on SQL Server 2008 was able to reproduce similar results to those shown there for ...
21
votes
3answers
7k views

Managing concurrency when using SELECT-UPDATE pattern

Let's say you have the following code (please ignore that it's awful): BEGIN TRAN; DECLARE @id int SELECT @id = id + 1 FROM TableA; UPDATE TableA SET id = @id; --TableA must have only one row, ...
16
votes
1answer
12k views

SQL query for combinations without repetition

I need a query which can be used in (or as) a function and retrieves all combinations of n values. And I need all combinations of length k where k = 1..n. Extended sample input and result so input ...
8
votes
2answers
7k views

Most Efficient Way to Retrieve Date Ranges

What's the most efficient way to retrieve date ranges with a table structure like this? create table SomeDateTable ( id int identity(1, 1) not null, StartDate datetime not null, EndDate ...
18
votes
3answers
4k views

What are valid usage scenarios for HEAP tables?

I am currently doing some data imports into a legacy system and discovered that this system does not use a single clustered index. A quick Google search introduced me to the concept of HEAP tables and ...
17
votes
1answer
17k views

Connection pools being reset with Error: 18056, Severity: 20, State: 46. & Perfmon Counters not showing

We are using SQL authentication & .net 4.0 Connection strings to connect to an Enterprise Edition 2012 SP1 SQL Server on a windows 2008r2 Enterprise Server. We use about 50 Servers split into 8 ...
7
votes
4answers
8k views

SQL Server - Separating data, log, and TempDB files on a SAN

I have a SQL Server connected to a SAN. Our new storage vendor recommends that all LUNs span the entire disk array, which is RAID5. I would normally request 3 separate LUNs (data, log, and TempDB) ...
24
votes
2answers
4k views

Why does query error with empty result set in SQL Server 2012?

When running the following queries in MS SQL Server 2012 the second query fails but not the first. Also, when run without the where clauses both queries will fail. I am at a loss why either would fail ...
16
votes
2answers
3k views

Why does DELETE leave a lingering effect on performance?

At the end is a test script for comparing the performance between a @table variable and a #temp table. I think I've set it up correctly - the performance timings are taken outside of the DELETE/...
16
votes
3answers
34k views

After moving database (backup, restore), I have to re-add user

I occasionally move a database (SQL Express 2012) from a development machine to a server, or vice versa, using database backup and restore in SQL Server Management Studio. Whenever I do this, the ...
16
votes
2answers
29k views

How To Profile Stored Procedures

I am using SQL Server 2012 and was wondering how to profile stored procedures For instance can profiler capture each individual SQL statement in a stored procedure, what it is, and how long it takes ...
14
votes
2answers
8k views

What is a Clustered Index?

I need a short explaining of clustered index. What is a clustered index? What are best practices for using the clustered index?
13
votes
2answers
12k views

What is blocking and how does it happen?

I tried to find some information about blocking in SQL Server, but I could not find a concise explanation for what it is and how it happens. Could you please enlighten me?
12
votes
3answers
19k views

How can I backup a large SQL Server database without impacting performance?

We've had reports of queries running slowly or timing out early in the morning, and the only job I see running that I think could affect this is our database backup job. The database itself is about ...
11
votes
3answers
5k views

Comparing Columns that can contain NULLS - is there a more elegant way?

I know that you can't compare a value to NULL and expect a result without adding something like in the following code... SELECT * FROM A INNER JOIN B ON A.ID = B.ID WHERE A.STRING &...
9
votes
2answers
8k views

why is io_stall_writes_ms so much higher for tempdb?

We have the user and system data files on the same disk drive. The ( io_stall_write_ms / ( 1.0 + num_of_writes ) ) is below 2 for the user files but the tempdb files are typically over 400. I see ...
8
votes
4answers
80k views

Combine column from multiple rows into single row

I've got some customer_comments split out into multiple rows due to database design, and for a report I need to combine the comments from each unique id into one row. I previously tried something ...
7
votes
2answers
6k views

Is there a better option than Union All for multiple selects from the same row?

Example Schema: CREATE TABLE [dbo].[Base]( [ID] [int] IDENTITY(1,1) NOT NULL, [Option1ID] [int] NULL, [Option2ID] [int] NULL, [Option3ID] [int] NULL, [Option1Name] [varchar] NULL, [Option2Name] [...
7
votes
2answers
6k views

SQL Server 2012 memory consumption outside the buffer pool

I've got an instance of SQL Server 2012 SP2 Enterprise Edition consuming ~20GB of memory higher than the max. memory limit. The instance is limited to 65GB but the physical memory in use from the ...