0
votes
0answers
16 views

How to increase sql server performance? denormalization (making cascade delete off) vs making duplicate data

I have a database with following related table ( sql server enterptise edtion 2014) each state have many citites which each city has may municpalArea and so on State => Cities = > ...
3
votes
1answer
118 views

Why does my query end up with two seeks instead of one and how do I fix that?

I have these two tables: CREATE TABLE [TaskItems] ( [ItemId] UNIQUEIDENTIFIER NOT NULL UNIQUE PRIMARY KEY, [LastOperationTime] DATETIME NULL DEFAULT GETUTCDATE(), [OwnerId] ...
1
vote
2answers
36 views

Changing compatibility level of database causes performance improvement of stored procedure

We have a Web Application in a Windows Server 2012 Datacenter (IIS 8), running under .NET Framework 4.0, which connects to another Windows Server 2012 Datacenter with SQL Server 2012. My Database has ...
0
votes
1answer
38 views

If a query contains two identical subqueries, will they both run?

Say I have a SELECT query that contains two identical subqueries, like the below: SELECT (SELECT SUM(Price) FROM Product p WHERE p.GroupID = g.GroupID) AS 'TotalCost', (SELECT SUM(Price) ...
3
votes
2answers
194 views

Can I update every datetime in bulk?

The current database assumes all times are local to the user. Now we're changing this so the database stores everything in UTC and our application converts the UTC time in the database to the correct ...
2
votes
1answer
73 views

If an INNER JOIN in a query returns no rows, do additional INNER JOINS add a significant performance overhead?

If I make a query as follows: SELECT * FROM TableA A INNER JOIN TableB B ON A.AID = B.AID INNER JOIN TableC C ON B.BID = C.BID Does the INNER JOIN with TableC add significantly to the performance ...
0
votes
1answer
45 views

Does it make sense to order condition in where query?

We have a clustered index in table Tbl with order of A,B,C. Does it make senses to write a query to have WHERE A = @a, B = @b, C = @c or it'll be as same as WHERE C = @c, B = @b, A = @a Does the ...
2
votes
1answer
89 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
0
votes
1answer
44 views

Migration query taking time

I'm doing a migration from Oracle to SQL Server and, for one of the tables where we have 3 million records, it is taking a lot of time to complete. When I check the activity monitor, I can see the a ...
1
vote
2answers
184 views

SQL 2008 Server - performance loss possibly connected with a very large table

Migrated from http://serverfault.com/questions/615129/sql-2008-server-performance-loss-possibly-connected-with-a-very-large-table We have SQL Server 2008 with 3 active databases running on it. DB1 ...
6
votes
2answers
398 views

Explanation requested for slow DELETE with SQL Server

I would like to get some extra insights/reasoning for SQL Server delete behavior. We have a fairly large database of over 1800 GB. In there are some very shallow tables (only a few integer columns) ...
0
votes
0answers
41 views

Database design for large incoming data

I've been tasked to design a database to handle a large volume of incoming traffic from sensor readings, possibly 1,000s an hour when it's at full strength. Each reading will be relatively short - ...
0
votes
0answers
58 views

A working view now starts timing out

I have 2 identical databases (one larger, one smaller) with identical views. Recently a view on the smaller DB started timing out. Google searches seems to point to deadlocking of some sorts. If I ...
0
votes
2answers
44 views

Does leaving a connection open for a matter of seconds cause deadlocks?

I have been testing a system application and have noticed that it is slow when it connects to the database overseas. This is to be expected to some extent, but there is a big difference with the ...
0
votes
1answer
88 views

How to deal with async calls to a stored procedure that updates data

I have asynchronous calls from Entity Framework to a stored procedure. The stored procedure selects data to a temp table and later on, it updates the real table. This works fine for sync calls. The ...
6
votes
5answers
543 views

Performance tuning a Great Circle distance calculation

I have a query that I am using to find locations that are within 1km of a known point. To do this, I am using the Spherical Law of Cosines formula with my latitude and longitudes. Currently, the ...
1
vote
0answers
28 views

Extended Events missing documentation

I have been looking pretty hard for the documentation regarding the RingBufferTarget <RingBufferTarget truncated="0" eventsPerSec="1370714" processingTime="7" totalEventsProcessed="9595" ...
1
vote
0answers
22 views

Database slowdown at random times using mirroing

Our web application suffers DB query timeouts a few times a day at random times. Can you help to work out the cause, e.g. deadlocks, mirroring (disk or network), etc? We have two identical database ...
1
vote
2answers
308 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 ...
1
vote
1answer
355 views

SQL Server 2008 R2 Express single CPU core usage and need of upgrade to SQL Server 2014 Express

In our office we are using SQL Server 2008R2 Express which is installed in Windows server 2012. The SQL Server database is accessed by more than 60 users in network simultaneously. In recent days we ...
1
vote
1answer
135 views

Slow delete caused by many foreign keys

My DB has about 90 tables. Most of the tables have an UpdatedBy and AddedBy column that have foreign keys pointing back to the user table. With even moderate amounts of data spread throughout the ...
1
vote
2answers
49 views

SQL Server Backup and Query Execution

Is SQL Server Backup affects the query execution performance? Is there an effect while running the SQL Server backup in remote query execution? Thanks.
3
votes
1answer
214 views

SQL Server “TOP 101” much slower than “TOP 100”

SQL Server shows huge decrease in performance when query is written like: select top 101 name from Dogs order by name compared to select top 100. As far as I know, this happens for the reason that ...
1
vote
1answer
161 views

SQL Server 2012 performance degradation

We are running SQL Server 2012 SP1 on Windows Server 2012. The issue we have is that after some time the server automatically reboots. Checking the logs did not show any errors. When looking into ...
1
vote
0answers
72 views

Why is this query stuck if there are no waits?

I am working with a vendor's activity logging system. One of the tables has 70+ million records and is constantly increasing at several hundred records per minute. They have a utility to delete old ...
2
votes
2answers
108 views

DBCC CheckDB causing high values for resource_semaphore wait type

On one of our production server, where SQL Server 2008R2 (Service Pack 2) is installed with 24 GB memory and 24 CPU cores grouped into two NUMA nodes, we are facing high counts for resource_semaphore ...
0
votes
2answers
86 views

Disk I/O Activity

Resource Monitor on our SQL Server DB server shows very high fluctuating disk activity that I cannot understand. I then check Activity Monitor and the Database I/O looks ok. Any ideas why I am seeing ...
1
vote
1answer
361 views

Does SQL Server allow INSERTs into tables and indexes to be written in parallel?

If I have a table that has many indexes, and I run a statement that inserts rows into the table, will SQL Server insert rows one-at-a-time, or will the rows be inserted using parallelism?
6
votes
1answer
449 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 ...
2
votes
1answer
565 views

SQL Server PerfMon: Compilations/sec > Batch Requests/sec

I've been looking at various PerfMon metrics on one of our client's SQL Server instances trying to get a good gauge of where our database (or server) could use improvements. One measure that has me ...
2
votes
2answers
229 views

SQL server query is slow *without* including execution plan

I have just set up fresh installation of SQL Server 2012 on a new server and I'm experiencing very strange performance problems. Long story short, for some reason not including execution plan makes my ...
6
votes
2answers
262 views

Major Discrepancy Between SQLIO IOPS/Throughput Stats and DBCC CHECKDB Operations

I'm conducting time trials on a new SSD array running both SQLIO tests and a real-world workload of DB restores and DBCC CHECKDB calls. I'm seeing a major discrepancy between the IOPS and throughput ...
-2
votes
2answers
66 views

Index is not used with same Query on two Servers [closed]

I have two notebooks with same specs (same model, only ram is 24GB/32GB, same ssd) and exact same database and same sql server version. SQLIO is 3300 and 3600. Now I run a query on one notebook and ...
1
vote
1answer
138 views

Optimistic Paging and separate query for COUNT?

I am using SQL SERVER 2012 FETCH/OFFSET after searching a lot that this will give me the best performance. But for paging to work, I need a Total count. There are 2 ways to achieve this. 1) Paging ...
0
votes
4answers
97 views

SQL Where Clause Efficiency

Say I have a SQL statement: SELECT * FROM MyTable WHERE KeyColumn1 = 1 OR KeyColumn1 = 2 OR KeyColumn1 =3 OR ... KeyColumn1 = 10 And another: SELECT * FROM MyTable ...
3
votes
2answers
146 views

Enhance performance of update query

I have a query that is running against a table with 50 million rows. The phone number is stored as a CHAR(10) and an ETL process is changing the phone number if it has certain values. We are seeing ...
2
votes
2answers
106 views

SQL Server 2008 R2 Missing Index

I am performing index maintenance on a database. I have run SQL script that uses DMVs to provides a list of indexes SQL Server believes should be created. I am not creating indexes just because the ...
1
vote
3answers
104 views

Is bulk-logged recovery model ever a good choice if point-in-time restore is not needed?

Is the Bulk-Logged recovery model in SQL Server ever preferable to Simple if point-in-time restore is never needed? I have read many articles about transaction log models, but cannot find a clear ...
7
votes
3answers
1k views

How do I best measure the query performance?

I have 2 stored procedures, where the second stored procedure is an improvement of the first one. I'm trying to measure by exactly how much that is an improvement. 1/ Measuring clock time doesn't ...
2
votes
1answer
206 views

Disk Latency vs Throughput

I've searched the web for a little while and haven't found an answer I'm confortable with. I am testing a SQL Server on a VM that was presented new disc. If disk latency is reduced, shouldn't ...
3
votes
1answer
135 views

Frequent Delete & Insert, impact on performance

In my application, we have very few updates. Most of the data gets deleted and inserted. My question is, how this will impact the performance? We are using SQL Server 2012. Table statistics (will ...
3
votes
2answers
2k 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 ...
9
votes
3answers
2k views

When a previously-fast SQL query starts running slow, where do I look to find the source of the issue?

Background I have a query running against SQL Server 2008 R2 that joins and/or left-joins about 12 different "tables". The database is fairly large with many tables over 50 million rows and about 300 ...
11
votes
1answer
1k 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 ...
4
votes
1answer
73 views

How can a connection for one DB block a connection to another DB in SQL Server?

We have an interesting scenario. For weeks, we have been experiencing 'outages' on SQL Server 2008 -- where our websites have slowed to a crawl and mass timeouts for all customers who have DB's ...
6
votes
1answer
233 views

Estimating IO Requirements for Bursty Usage

We have an application that queries a SQL database periodically throughout the day. There are periods of zero or only light activity, interspersed with individual requests for relatively large ...
2
votes
1answer
94 views

Avoiding Deadlocks

We currently have a trigger-based system in place that does the following: When records in certain tables are modified, a trigger fires that makes a field NULL in a varying number of records in ...
0
votes
0answers
50 views

TempDB causing high IO writes - dependent on server's max memory setting [duplicate]

I have a mirrored SQL Server 2012 database. The first server has a hugh tempdb write IO load when the maximum memory limit is set above 8192 mb. These 8192 where the original setting for both the ...
0
votes
1answer
62 views

RAID0 vs multiple files in file group

I have a server that gets updated and backed up once a day and processes queries the rest of the day (selects). I'm trying to improve performance of the update process and the selects. I'm not worried ...
6
votes
2answers
2k views

What is the fastest way to insert large numbers of rows?

I have a database where I load files into a staging table, from this staging table i have 1-2 joins to resolve some foreign keys and then insert this rows into the final table (which has one partition ...