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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14
votes
2answers
30k views

Rebuilding the transaction log

We have a very large database (~6TB), whose transaction log file was deleted (while SQL Server was shut down. We have tried: Detaching and reattaching the database; and Undeleting the transaction ...
13
votes
2answers
904 views

Understanding MS SQL Server encryption and backups

So I was asking in chat about how secure SQL Server backup files are. I'm told that if an attacker has access to the .bak file unencrypted that they can have access to the data. So lets look at ...
12
votes
1answer
3k views

Why is Clustered Index Scan Number of Executions so high?

I have two similar queries that generate the same query plan, except that one query plan executes a Clustered Index Scan 1316 times, while the other executes it 1 time. The only difference between ...
11
votes
2answers
150 views

Queries without Good Enough Plan Found

I have a SQL Server 2012 database. I noticed value of Reason for early termination of statement optimization for some queries and all gave Good Enough Plan Found. Now my questions are: What are all ...
11
votes
5answers
2k views

Backing up & restoring 10-20 SQL Server databases to a ~synchronous state?

I need to backup up 10-20 SQL Server 2008 R2 databases with sizes between 10-50 GB, while they are online and used simultaneously by a single enterprise app. I also need to restore them to a state ...
11
votes
1answer
2k views

Does sys.sql_logins.is_policy_checked mean that the policy has been checked?

When I look in sys.sql_logins, I see a column called is_policy_checked. Can I trust that my password policy has been checked for all of the logins where this column value is 1?
11
votes
1answer
648 views

Visualizing SQL Server Extended Events data

Lately I've been exploring using Extended Events in SQL Server to help me benchmark and optimize various queries. So far, to view the event data I have been using the "Watch Live Data" feature in ...
11
votes
3answers
484 views

How To Strip Hebrew Accent Marks

I need a Char Encoding Trick to Strip Hebrew Accent Marks. Sample Before בְּרֵאשִׁ֖ית בָּרָ֣א אֱלֹהִ֑ים אֵ֥ת הַשָּׁמַ֖יִם וְאֵ֥ת הָאָֽרֶץ Sample After בראשית ברא אלהים את השמים ואת הארץ
11
votes
1answer
4k views

AlwaysOn AG, DTC with failover

Problem: How can I run Distributed Transaction Coordinator (DTC) on all servers in an AlwaysOn Availability Group (AG)? I do NOT need to maintain transactions over failover/switchover events. Setup: ...
11
votes
5answers
4k views

Does it make sense to use SQL Server's bracket notation in hand written code?

Code generators tend to be simpler when they generate output using the new Microsoft bracket notation ([]) for nearly everything. When I first saw it, I though wow a reincarnation of the somewhat ...
10
votes
4answers
679 views

Why does my query search datetime not match?

select * from A where posted_date >= '2015-07-27 00:00:00.000' and posted_date <= '2015-07-27 23:59:59.999' But the result contains a record that has posted_date today: 2015-07-28. My ...
10
votes
2answers
13k views

What are Measures and Dimensions in Cubes

I'm very new to Microsoft Sql Server Business Intelligence and Analysis Service(but I'm programming for years with SQL Server).Can any one describe Measures and Dimensions in Cubes in Simple words(If ...
10
votes
1answer
20k views

How to control the excessive use of ram by SQL Server?

The database server that I am using is running 6 different SQL Server instances. It has 48 GB RAM. And one of them is consuming more than 10 GB of RAM, total consumption is 20 GB for now. The RAM ...
9
votes
2answers
9k views

Why are non-digits LIKE [0-9]?

My server's default collation is Latin1_General_CI_AS, as determined by this query: SELECT SERVERPROPERTY('Collation') AS Collation; I was surprised to discover that with this collation I can match ...
9
votes
1answer
20k views

Give permission to select from system tables

I have a database Microsoft SQL Server 2008 r2. A user called marie is defined, who can access tables on the main database; this works well. Now, I would like marie to be able to perform this query: ...
9
votes
3answers
2k views

How to control the order of servers listed in the SSMS connection dialog?

My current project involves a lot of database shuffling as we upgrade from SQL 2008 -> 2012, re-task hardware, repeat. One minor annoyance is the connection dialog in SSMS re-shuffling the server ...
9
votes
4answers
30k views

Read XML file in SQL Server 2008

How can I read an XML file and store the data in XML to our table in SQL Server 2008?
8
votes
2answers
193 views

How many backup devices is recommended to improve backup performance?

In order to improve performance of our SQL Server backups we backup to multiple backup files. On most blog posts about this topic they say to use multiple backup files but, is there a point where ...
8
votes
2answers
14k views

Outer Apply vs Left Join Performance

I am Using SQL SERVER 2008 R2 I just came across APPLY in SQL and loved how it solves query problems for so many cases, Many of the tables I was using 2 left join to get the result, I was able to ...
8
votes
1answer
3k views

Database design for handling 1 billion rows and counting

We receive real-time GPS data at a rate of around 5000 pr. minute (from 4 TCP servers). Each server uses a single connection to insert the data, and buffers data in between inserts. Every 15 minutes ...
8
votes
1answer
6k views

How to improve Procedure Cache Hit Ratio?

From what I can tell Procedure Cache Hit Ratio below 95% is a problem. On my box, the values hover from 85 to 95%. How do I fix this issue? The server seems to have plenty of RAM so that ...
8
votes
2answers
7k views

In SQL Server, how do read locks work?

Suppose I have the following long-running query UPDATE [Table1] SET [Col1] = 'some value' WHERE [Col2] -- some clause which selects thousands of rows and suppose the following query is executed ...
8
votes
1answer
858 views

Equality query on NVARCHAR column yields multiple results in SQL Server 2012

I am in the process of moving a pet project from PostgreSQL (9.2.2) to SQL Server (2012 Standard). I've noticed an interesting phenomenon when querying unicode words. Given the definition: CREATE ...
8
votes
2answers
10k views

Transaction and Try-catch in SQL Server Job

We have DML operations in each step of a SQL Server job. To ensure the update/insert will be rolled back in case something goes wrong, I have wrapped the data modifications of each step in TRY CATCH ...
8
votes
3answers
798 views

Create function in central database or repeat in each database?

One of my developers has written a SQL function that works like the VB.Net function (LastIndexOf) and wants to publish it. My question is what would be the reason to put this in a central database ...
8
votes
1answer
726 views

Why is the page life expectancy 0 (zero) on SQL Server 2005

We have been wanting to know the page life expectancy for our SQL Server. So we look at the counter using Perform. The value is ZERO and never changes. I thought there must be some bug, so I checked ...
8
votes
3answers
8k views

Performance Hit using CAST() in TSQL (SQL Server)?

We have a SQL generator that emits SQL conditional statements generically for specified fields (which for the sake of discussion: we will label as myField). So, if myField is of type NVARCHAR, we ...
8
votes
5answers
1k views

Does SQL Sentry Plan Explorer work?

Does SQL Sentry Plan Explorer work as advertised and is it legitimate? Are there any gotchas or something to be concerned about? It looks like it shows the hot path in color commpared to SSMS's ...
8
votes
5answers
14k views

User Permissions Messed Up following a Backup -> Restore Operation

I had to move several SQL Server 2008 databases to our new db server so I backed them all up (to .bak files), copied these files over to the new box and restored them (all done using SQL Management ...
8
votes
6answers
5k views

Pros and Cons of SQL Server back up strategies and their appropriate usage scenarios

From what I can tell, there are three possible ways of backing up your SQL Server database Full backup Differential backup Log Shipping What are the pros and cons of each strategy and in what ...
7
votes
2answers
377 views

Average of last 4 runs of a product

I need to show the average weight of a product over its last 4 production runs. I'm not sure how best to describe it other than an example: Let's imagine I have the following table that lists a ...
7
votes
6answers
922 views

Fast reads without paying the price on writes

We have a large append-only table containing financial transactions. On average 1000 transactions are inserted per minute. Since there are now more and more usecases where we actually want to read, ...
7
votes
2answers
5k views

An efficient way to compare two large data sets in SQL

Currently, I'm comparing two data sets, that contain unique StoreKey/ProductKey combinations. The 1st data set has the unique StoreKey/ProductKey combinations for sales between begin January 2012 and ...
7
votes
2answers
243 views

'Cleanse' a SQL Server database file created with Instant File Initialization enabled?

I have Instant File Initialization enabled on our SQL Server, so the 'empty' part of the database file is not zeroed before being allocated. My understanding is that this means that the file could ...
7
votes
1answer
494 views

Strange behaviour DBCC Shrinkfile

I am attempting to run a dbcc shrinkfile in chunks of 1GB against a database where 95% of the data has been archived and deleted. I'm leaft with a 235GB file where 9GB is data/indexes. I want to ...
7
votes
1answer
12k views

Why does CREATE INDEX … WITH ONLINE=ON block access to the table over a period of minutes?

I have an existing table: CREATE TABLE dbo.ProofDetails ( ProofDetailsID int NOT NULL CONSTRAINT PK_ProofDetails PRIMARY KEY CLUSTERED IDENTITY(1,1) , ProofID int NULL , ...
7
votes
1answer
782 views

How much memory is a table taking up?

Is there a way to find out how much memory a table is taking up in SQL Server (2005 and greater)? For example, suppose I have a table with 30 million records. I'd like to know how many pages ...
7
votes
2answers
12k views

SQL 2008 R2 creates user/schema when Windows user creates tables

We added a server login and database user that map a Windows Group to a SQL 2008 R2 instance using the following script, with the names changed for anonymity: USE master go CREATE LOGIN ...
7
votes
4answers
2k views

Slow temp table drops in sql 2005

I've run into a problem on our production sql server where temp table objects take a long time to drop (obvious when small and synchronous drop is used). I can't reproduce this on other sql servers ...
6
votes
2answers
352 views

Insert only deadlocks

We have an application inserting data into a table. Unfortunately, we are getting deadlocks and the deadlocks are coming from inserts only. We are seeing the inserts take key locks in a different ...
6
votes
3answers
12k views

How to export all the security-related information from a SQL Server database

As you guys probably know, SQL Server does not provide an out-of-the-box solution to export all the security related statements that are declared for each element in the database (both at the database ...
6
votes
2answers
3k views

Linked Server Risks

I'm implementing a new feature which requires data from databases on multiple servers. I just need to union data from all these servers and sort it. The two options that come to mind are: Use linked ...
6
votes
2answers
38k views

Primary filegroup is full SQL Server 2008

I have a large table (~50 million rows) I'm trying to bulk insert into SQL Server and I get the error: Could not allocate space for object 'myDB' in database 'I 3 Stroke' because the 'PRIMARY' ...
6
votes
3answers
4k views

Can I get SSMS to show me the Actual query costs in the Execution plan pane?

I'm fixing performance issues on a multistatement stored procedure in SQL Server. I want to know which part(s) I should spend time on. I understand from How do I read Query Cost, and is it always a ...
6
votes
2answers
1k views

Parameter Sniffing: Why Does This Become An Issue?

Today, I had an issue with a SPROC Timing Out (took longer than 30 seconds) when it was run from an ASP.NET webpage, but executed quickly when run from SSMS (took 5 seconds). After suspecting ...
6
votes
1answer
9k views

How can I monitor the call count per stored procedure per timespan?

In order to diagnose some performance issues I would like to get a better understanding of the number of times certain procedures are called compared to the system performance. Is there a way to get ...
5
votes
2answers
472 views

Should we create a schema per “project”?

This is a database where users create a 'project' and work on it. We have a table for project and various other tables that contain different attributes for project (multiple rows for each project ...
5
votes
2answers
305 views

Copy data from multiple databases to a central database for reporting and analysis

I have more than 8 databases and all are in a SQL Server environment. I need to extract data from specific tables (more than 50 tables) of each database and dump into a central database for reporting ...
5
votes
4answers
29k views

Displaying the list of all tables in all database

How can I display a list containing all the tables of all the database in a SQL Server 2008 R2 server?
5
votes
1answer
41k views

IF NOT NULL then UPDATE else keep the value of the field

I think I am somehow close to get it work, but for some reason I still get errors. I have the following UPDATE query: UPDATE DeviceAttribute SET Details = CASE Name WHEN 'Accessories' THEN ...