Microsoft's SQL Server is a relational database management system (RDBMS) that runs as a server providing multi-user access to a number of databases. It originated from the Sybase SQL Server codebase, which is why both products use the extension of SQL called Transact-SQL (T-SQL).

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14
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6answers
13k views

Optimal drive configuration for SQL Server 2008R2

I have a fairly busy database server running SQL Server 2008 R2 that has the following setup: SATA RAID 1 (2 Drives) - OS / Programs SAS RAID 10 (4 Drives) - Sql Database Files (data and logs) SAS ...
14
votes
1answer
8k 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 ...
11
votes
3answers
709 views

What is a deterministic method for evaluating a sensible buffer pool size?

I'm trying to come up with a sane way to understand if the max server memory (mb) setting is appropriate (either should be lower, or higher, or stay the way it is). I am aware that max server memory ...
18
votes
5answers
4k views

Why use an int as a lookup table's primary key?

I want to know why I should use an int as a lookup table's primary key instead of just using the lookup value as the primary key (which in most cases would be a string). I understand that using a ...
13
votes
3answers
1k views

Why are queries parsed in such a way that disallows the use of column aliases in most clauses?

While trying to write a query, I found out (the hard way) that SQL Server parses WHEREs in a query long before parsing the SELECTs when executing a query. The MSDN docs say that the general logical ...
15
votes
2answers
4k views

How (and why) does TOP impact an execution plan?

For a moderately complex query I am trying to optimize, I noticed that removing the TOP n clause changes the execution plan. I would have guessed that when a query includes TOP n the database engine ...
14
votes
4answers
42k views

How to add sysadmin to user in SQL Server 2008 when no sysadmin accounts exist

I have a SQL server 2008 instance running. Unfortunately during testing I deselected the sysadmin rights for my login and now can't readd it (because I don't have sysadmin rights). There are no other ...
3
votes
4answers
39k views

List all permissions for a given role?

I've searched around all over and haven't found a conclusive answer to this question. I need a script that can give ALL permissions for an associated role. Any thoughts, or is it even possible? ...
39
votes
5answers
21k views

Why does ALTER COLUMN to NOT NULL cause massive log file growth?

I have a table with 64m rows taking 4.3 GB on disk for its data. Each row is about 30 bytes of integer columns, plus a variable NVARCHAR(255) column for text. I added a a NULLABLE column with ...
8
votes
2answers
9k views

For absolute performance, is SUM faster or COUNT?

This relates to counting the number of records that match a certain condition, e.g. invoice amount > $100. I tend to prefer COUNT(CASE WHEN invoice_amount > 100 THEN 1 END) However, this is ...
3
votes
1answer
2k views

SQL Server Many-to-One replication

I have 8 individual SQL Server 2008 R2 machines, each hosting 1 database. Each database has an identical table structure and schema, and entirely unique data. I would like to establish a reporting ...
12
votes
3answers
4k views

Is it possible to backup and restore part of a database in sql-server?

We have a sql-server 2005 database that we regularly transfer from our client site to ours. This takes a long time because we don't have a direct connection and have to transfer the file over their ...
5
votes
1answer
5k views

SQL Server - How to determine ideal memory for instance?

We have some virtual machines that have X memory allocated to them. This amount of memory is somewhat random. It was allocated to the machine because that was the amount of memory the physical ...
5
votes
1answer
2k views

Find transactions that are filling up the version store

we have enabled the "READ_COMMITTED_SNAPSHOT" for some of our SQL Server 2005 databases. Now from time to time we see that our TempDB is filling up the harddisk and we suspect the version store to be ...
4
votes
2answers
987 views

Run a PowerShell script on a different server - from inside a SQL Server job

I have a procedure to backup SSAS Databases. That is working as a charm. Now my server is filling up with SSAS backups and I would like to delete the backup files that are older than 2 days. to ...
5
votes
1answer
3k views

Kerberos authentication not working with Linked Servers in SQL Server 2012

I am setting up a DEV/TEST environment using 2 SQL Servers running SQL Server 2012 on Windows Server 2012. We are moving from SQL Server 2005 on Windows Server 2008, where we already have this ...
1
vote
1answer
456 views

Why is CDC capture failing due to a missing dbo principal

I am having a problem running the CDC change capture job against some of my test databases. The error message I'm getting is the following: Executed as user: NT AUTHORITY\NETWORK SERVICE. Cannot ...
75
votes
8answers
49k views

What's the difference between a CTE and a Temp Table?

What is the difference between a Common Table Expression (CTE) and a temp table? And when should I use one over the other? CTE WITH cte (Column1, Column2, Column3) AS ( SELECT Column1, Column2, ...
71
votes
4answers
14k views

Why use both TRUNCATE and DROP?

In the system I work on there are a lot of stored procedures and SQL scripts that make use of temporary tables. After using these tables it's good practice to drop them. Many of my colleagues (almost ...
54
votes
5answers
21k 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 ...
39
votes
6answers
3k views

Retrieving n rows per group

I often need to select a number of rows from each group in a result set. For example, I might want to list the 'n' highest or lowest recent order values per customer. In more complex cases, the ...
47
votes
4answers
25k views

Why would SET ARITHABORT ON dramatically speed up a query?

The query is a single select containing a lot of grouping levels and aggragate operations. With SET ARITHABORT ON is takes less than a second, otherwise it takes several minutes. We have seen this ...
18
votes
2answers
4k views

Handling growing number of Tenants in Multi-tenant Database Architecture

Handling a modest number of customers (tenants) in a common server with separate databases for each tenant's instance of the application is relatively straightforward and is normally the correct way ...
21
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4answers
89k views

Restore SQL Server 2012 backup to a SQL Server 2008 database?

Is there a way to restore a SQL Server 2012 database backup to a SQL Server 2008? I tried to attach file, it does not work.
17
votes
2answers
7k views

Stored procedures vs. inline SQL

I know stored procedures are more efficient through the execution path (than the inline sql in applications). However, when pressed, I'm not super knowlegeable about why. I'd like to know the ...
13
votes
3answers
7k views

SQL Server Agent Jobs and Availability Groups

I'm looking for best practice in dealing with scheduled SQL Server Agent jobs in SQL Server 2012 availability groups. Maybe I missed something, however at the current state I feel that SQL Server ...
13
votes
3answers
13k views

What can cause a mirroring session to timeout then failover? SQL Server 2005

We have two production SQL Servers running SQL Server 2005 SP4 with cumulative update 3. Both servers run on physical machines that are identical. DELL PowerEdge R815 with 4 x 12 core CPUs and 512GB ...
17
votes
2answers
29k views

How to find the SQL statements that caused tempdb growth?

The tempdb of a server (SQL Server 2008) increases to 500GB+ several times every month. Is it possible to find out which SQL statements caused this problem? The problem is usually not caused by create ...
7
votes
5answers
1k views

Over use/correct use of schemas?

Having asked This question on Stackoverflow, I wondered where what I have done is correct/best practise. Basically, every object that I create is going into a schema with the schema name reflecting a ...
18
votes
1answer
7k views

GO After every T-SQL statement

What is the reasoning behind using the GO statement after every SQL statement? I understand that GO signals the end of batch and/or allows the reputation of statements but what advantage does it have ...
13
votes
4answers
21k views

Methods of speeding up a huge DELETE FROM <table> with no clauses

Using SQL Server 2005. I am performing a huge DELETE FROM with no where clauses. It's basically equivalent to a TRUNCATE TABLE statement - except I'm not allowed to use TRUNCATE. The problem is ...
10
votes
4answers
4k views

Help me choose a RAID level combination for a SQL Server 2008 instance

I am going to rebuild one IBM 3400 server from scratch. This server is dedicated to a SQL Server 2008 instance running on Windows 2008 R2. I am going to make new RAID configuration. I have 6 SCSI ...
8
votes
1answer
21k views

Login failed for user - Error 18456 - Severity 14, State 38

Message that SQL Server Log File Viewer shows: Login failed for user [User] Error: 18456, Severity: 14, State 38 What it actually means: Failed to open the explicitly specified database My ...
8
votes
3answers
29k views

Copy complete structure of a table

Using some methods, when you create a copy of a table you lose indexes, PK, FK, etc. For example in SQL Server I can say: select * into dbo.table2 from dbo.table1; This is just a simple copy of the ...
7
votes
1answer
28k views

Setting user permissions for different SQL Server schemas

I need to limit access to a particular user, but they still need to be able to see the data in tables owned by dbo. I'm trying to do the following: dbo schema functions as it would normally, has ...
3
votes
1answer
387 views

VLDB with large quantity of data file imports

I am a little out of my league with this scenario and hope this community can help get me on the right direction. I have recently been tasked with re-designing and implementing a database application ...
8
votes
1answer
5k views

SQL Server 2012: Generate Scripts from command line

I am running SQL Server 2012. The SQL Server Management Studio has the option to right click on a database then select Tasks and Generate Scripts. Is there a way to automate that via command line ...
7
votes
2answers
13k views

SQL Server gets slow over time until we have to restart it

We have a database with a mixed OLAP/OLTP workload. The queries are quite ad-hoc and are dynamically created in the mid-tier application server. When we start the server, the performance is quite ...
7
votes
2answers
13k views

Quick look at how much RAM is allocated to SQL Server?

With SQL Server 2005, you could look at the Task Manager and, at least, get a cursory look at how much memory is allocated to SQL Server. With SQL Server 2008, the Working Set or Commit Size never ...
5
votes
1answer
644 views

The use of NOT logic in relation to indexes

According to Microsoft's book on database development Exam 70-433: Microsoft SQL Server 2008 Database Development: Neither leading wildcard characters not NOT logic allow the query optimizer to ...
18
votes
3answers
3k views

Justify NOT using (nolock) hint in every query

Have you ever had to justify NOT using a query hint? I am seeing WITH (NOLOCK) in every single query that hits a very busy server. It is to the point that the developers think it should just be on ...
10
votes
1answer
1k views

SQL Server 2012 Page Life Expectancy resets to 0 after about 50 days

I've noticed an odd behavior on a 2-server HA cluster and I was hoping someone could confirm my suspicion, or maybe offer some other explanation... Here is my setup: A 2-server SQL 2012 SP1 ...
10
votes
2answers
9k views

Need to understand parallel query execution error

Today we experienced a degradation in performance on our production sql server. Durring the time this occurred we logged several "The query processor could not start the necessary thread resources ...
10
votes
2answers
645 views

Setting READ UNCOMMITTED when reading DMVs

I've seen several people call SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED before reading system DMVs. Is there ever any reason to do this, assuming you aren't mixing calls to DMVs and tables in ...
8
votes
1answer
3k views

Trouble With Database Permissions for sp_send_mail

I am trying to send database mail but I am getting EXECUTE permission denied on the object 'sp_send_dbmail' database 'msdb', schema 'dbo'.. I code I am running is as follows: SELECT SUSER_NAME(), ...
7
votes
3answers
19k views

Reset IDENTITY value

I have a table with an IDENTITY column. While developing I delete the rows from time to time and add them again. But the IDENTITY values always kept increasing and didn't start from 1 when I added ...
5
votes
5answers
31k views

Why is SQL Server consuming more server memory?

Sqlserver is consuming 87.5 % of my server Ram. This recently causes alot of performance bottleneck such as slowness.I Research on this issue. One common solution i could find on the internet is to ...
5
votes
5answers
7k views

SQL Server 2012 AlwaysOn: need to automatically add databases by script- T-sql or PowerShell

I've installed and successfully configured our SQL Server 2012 AlwaysOn 2-node servers for our new "Intranet" that is coming out. I've gotten AlwaysOn working great, and our Front End servers for the ...
5
votes
1answer
3k views

SQL Server: hierarchy of permissions for schema?

We have several databases under development and I would like to start using SQL Server schemas for permission management and logical grouping of database objects. Under Schema Properties there is ...
3
votes
1answer
459 views

Limiting database security

A number of texts signify that the most important aspects offered by a DBMS are availability, integrity and secrecy. As part of a homework assignment I have been tasked with mentioning attacks which ...