I have a stored procedure that updates a table. I also have an UDF that allows dirty reads (nolock).
What's the precedence level in SQL server? If I add xlock,rowlock to the update statement, will the dirty read wait for the update transaction to commit, or will it perform a dirty read regardless of the locking scheme in the update statement?
Hello,I need to lock only one row with exclusive lock (nobody else can see ormodify this row), but when I use "with (xlock, rowlock)" it doesn't work.XLOCK always locks whole table.Can anybody help me?Thanks in advance.Magda
View 1 Replies View RelatedI have a SSIS package that is run from one job, nowhere else. The package has TransactionOption NotSupported.
In the SSIS package I first have a sequence container that has TransactionOption Required (Serializable). The sequence container contains several Execute SQL tasks that access the same SQL Server 2005 database. The Execute SQL tasks have TransactionOption supported / Serializable. The first SQL statement is:
select p.column_name
from table_name p with (XLOCK, ROWLOCK)
where p.second_column_name = 'COLUMN_VALUE'
After this there are a couple of SQL tasks, and finally a task containing the following SQL:
select p.third_column_name
from table_name p
where p.second_colomn_name = 'COLUNM_NAME'
The idea is that the first query exclusively locks the row in the table_name-table for mutual exclusion purposes, i.e. so that if for some reason the SSIS package would be executed simultaneously two or more times, only one package execution could lock the row and proceed and the other executions will have to wait. There's an index on column second_column_name in the table to avoid the select locking other rows in addition to the required row.
Some questions:
1) Is it so in my setup that when SSIS runtime executes the sequence container it creates a transaction in the beginning of the sequence container and commits the transaction in the end of the sequence container? And in my setup the Execute SQL tasks in the sequence containar are executed under the same transaction?
2) I have a problem that the second query sometimes gives this error:"ErrorCode: -1073548784. ErrorDescription: Executing the query "XXXXX" failed with the following error: "Transaction (Process ID 73) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly."
The 1st query has locked the row for the transaction. How can the second query be deadlocked, shouldn't the transaction have a lock on the row? I'd understand if the 1st query failed sometimes, but don't understand how the 2nd quey can fail.
r,
JM
Hello all.
I'm a litle confused about what's best to use, either isolation levels or locking per table.
Cause there are some queries in the stored procedures where I don't need locking i.e. when I check the status of client, but other queries where I do need locking like when I check the existence of a product.
What's best to use, can I combine both? Could you explain it thecnically?
lots of thanks in advance
Reading about avoiding deadlocks in SQL, I have found different opnions about whether using or not NOLOCK/ROWLOCK hints on SELECT/UPDATE/DELETE statements. I have several applications executing transactions on the same databases and tables, including inserts, updates and deletes. I wonder if by using NOLOCK/ROWLOCK I could decrease the chances of having deadlocks. At least using ROWLOCK on my update statements?. I just need some advice here.
Regards.
I am inserting updating few tables from snapshot and reading same bunch of tables from reporting using readcommitted . It is showing some deadlocks i think it is write in this situation as " x" is not compitable with "s" ,"is".
View 4 Replies View RelatedHi Sql gurus :))I've got a question that I couldn't find a satisfying answer on the net.What is the difference between:1) running sql query (select from sth with nolock) with no transaction2) running sql query (select from sth) withing a TransactionScope with option Read Uncommitted dataBasically, both should do the same work. However is anyone aware of any potential problems using any of both approaches ?We use 1) to improve our web application scalability since the system works in such a way that any selects and updates on that table (sth) do not interfere with one another.However, updates are done in a TransactionScope. And when having simultaneous select with nolock and update in a Transaction scope (the select statement has a where clause and returns records that are not updated by the update statement). However sometimes ( we still cannot figure it out when) the select statement returns some records twice.For example, the select should return 1000 records , but (sometimes) it returns 1002 records ( the extra 2 records are copies of some of the original 1000 records).Removing the nolock, makes the problem does not appear - but i want to be 100% sure that nolock is our troublemaker. And if it is - why ?We also have a problem that this particular nolock select sometimes return even less records than it should.I know it sounds impossible but it happens.So anyone who has experience with select with nolock, please share :)Thanks in advance, Yani
View 4 Replies View RelatedHere is the situation i am stuck with, see the example first and below explained the problem:
-- 'SESSION A
create table foo (
id integer,
pid integer,
data varchar(10)
);
begin transaction
insert into foo values ( 1, 1, 'foo' )
insert into foo values ( 2, 1, 'bar' )
insert into foo values ( 3, 1, 'bozo' )
insert into foo values ( 4, 2, 'snafu' )
insert into foo values ( 5, 2, 'rimrom' )
insert into foo values ( 6, 2, 'blark' )
insert into foo values ( 7, 3, 'smeg' )
commit transaction
create index foo_id_idx on foo ( id )
create index foo_pid_idx on foo ( pid )
begin transaction
insert into foo values ( 9, 3, 'blamo' )
-- 'SESSION B
begin transaction
select id, data from foo with ( updlock, rowlock ) where id = 5;
-- Problem:
-- Uncommitted transaction in session A, with insert into table FOO, aquires lock on index foo_pid_idx which BLOCKS select with ( updlock, rowlock ) in session B.
-- Insert should aquire only exclusive rowlock. Why does insert block select with ( updlock, rowlock )?
Appreciate your help,
Rajesh.
I'm in a project to replicate a database from the production environment to another sql server.
The idea is use it for some biggest querys because in the production database we had experimenting various problems. What is the best way for do it? Transactional replication? Log Shipping? I'm reading absolutely everything but I can not get decide.
Both servers are SQL Server 2008 R2 and they are in the same LAN.
I have a file 'c:extrasiadt1.xml' the content is:
<?xml version="1.0" encoding="UTF-8"?>
<FlsAssDom_1 xmlns="http://flussi.mds.it/flsassdom_1">
<Assistenza >
<Trasmissione tipo="I"/>
<Assistito>
<IdentificativoUnivoco>XYZZYX66P17G920L</IdentificativoUnivoco>
[code]....
how to read the data to view the content like recordset (rows end columns).
How would I find the last read/write dates for all the tables within a database.
View 6 Replies View RelatedI was given a 2 GB XML file without an XSD. I need to find the element names. I know how to do that using openxml but it takes forever on a file this large. Is there a faster way to do it using xquery?
View 0 Replies View RelatedI have a requirement to read a value from table and increment it by 1. There can be multi-threads doing the same operation and would need a ROW LOCK so that read and write both are atomic. How can i put an exclusive lock on the row before I read the value from the table.
CREATE TABLE [dbo].[tblOnboardingSequence](
[OnboardingSequenceID] [uniqueidentifier] NOT NULL,
[Name] [nvarchar](255) NOT NULL,
[NextNumber] [bigint] NOT NULL,
CONSTRAINT [PK_OnboardingSequence] PRIMARY KEY CLUSTERED(
[OnboardingSequenceID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
My Stored Procedure has below logic
DECLARE @NextNumber BIGINT
----------- Acquire row lock here
SELECT @NextNumber = NextNumber FROM tblOnboardingSequence WHERE Name = 'TPO'
UPDATE tblOnboardingSequence SET NextNumber = @NextNumber + 1 WHERE Name = 'TPO'
----------- Release row lock here
I would like to have a row lock for the row having Name "TPO" before SELECT query and release after UPDATE query.
What si the best way to deal with this?
The below query will read the data in XML format but any query to read from each column of XML tags easily?
SELECT CAST(record AS XML), record
FROM sys.dm_os_ring_buffers
WHERE ring_buffer_type = 'RING_BUFFER_CONNECTIVITY'
way to read data from database already stored as question marks .that because by mistake i insert the data "arabic" from the VS as sqltext but the field in the database is nvarchar now i want to get the data back.
View 4 Replies View RelatedWe have many users with a mobile application running SQL Mobile and using merge replication to get data back to the SQL 2008 R2 database. This has worked very well for many years.
We now have a requirement to have this data reported on using Reporting Services. This is where it gets messy.
Due to a limitation of Report Builder(see this blog) we cannot provide access to users for creating their own reports. The report database is remote from the host and there is no VPN.
We hit upon the idea of creating an almost identical publication but the articles as read-only. It was only after this was done that we started having trouble with our existing mobile users.
It seems that a published article is EITHER Bi-directional OR Read-only even if they are in separate publications.
I then thought of using Transactional Publication but this too is blocked on creation with "automatic identity range support is useful only for publications that allow updating subscribers"(Merge and Transactional publication are mutually exclusive)
So in the final analysis is there a way for me to have merge replication AND some other form of SQL replication/data transfer that can have the same data transmitted readonly to a separate full SQL server database?
If I have a table with 1 or more Nullable fields and I want to make sure that when an INSERT or UPDATE occurs and one or more of these fields are left to NULL either explicitly or implicitly is there I can set these to non-null values without interfering with the INSERT or UPDATE in as far as the other fields in the table?
EXAMPLE:
CREATE TABLE dbo.MYTABLE(
ID NUMERIC(18,0) IDENTITY(1,1) NOT NULL,
FirstName VARCHAR(50) NULL,
LastName VARCHAR(50) NULL,
[Code] ....
If an INSERT looks like any of the following what can I do to change the NULL being assigned to DateAdded to a real date, preferable the value of GetDate() at the time of the insert? I've heard of INSTEAD of Triggers but I'm not trying tto over rise the entire INSERT or update just the on (maybe 2) fields that are being left as null or explicitly set to null. The same would apply for any UPDATE where DateModified is not specified or explicitly set to NULL. I would want to change it so that DateModified is not null on any UPDATE.
INSERT INTO dbo.MYTABLE( FirstName, LastName, DateAdded)
VALUES('John','Smith',NULL)
INSERT INTO dbo.MYTABLE( FirstName, LastName)
VALUES('John','Smith')
INSERT INTO dbo.MYTABLE( FirstName, LastName, DateAdded)
SELECT FirstName, LastName, NULL
FROM MYOTHERTABLE
I have the following query:
Select p.Id [SenderId], p.Username, up.PhotoId,
CASE
WHEN mr.ReadDate is null then 1 -- New message
ELSE 0 -- Message has been read
END AS NewMessage,
p.LastLoggedIn, p.LoggedIn
[Code] ....
The above query returns me all messages (inbox functionality) that have been sent to mr.ReceipientId, the issue I have is when I send another email to the recipient the readdate field will be null, and the other emails linked to the recipient which have also been sent via me will have a readdate date. This causes duplicate rows to appear due to the case statement, I'm trying to figure out if / how it is possible to only display the one row per conversation and set newmessage to 1 if there is an un-read message otherwise show 0 ?
So instead of showing this:
2Person102015-07-26 17:07:24.9370
2Person112015-07-26 17:07:24.9370
I'm trying to get it to look like this:
2Person112015-07-26 17:07:24.9370
Or if we have no new mail (read date is not null) then it will appear like this, and I can confirm when there is no new mail it works as expected.
2Person102015-07-26 17:07:24.9370
How can I create a SQL authentication account with read-write access to only 1 table in a SQL database.
View 1 Replies View RelatedLength specified in network packet payload did not match number of bytes read; the connection has been closed. Please contact the vendor of the client library. [CLIENT: xxx.xx.xxx.xx]
Client IP address is same as the server its producing the error on. I get these messages around 12pm everyday.
I have run into a perplexing issue with how to UPDATE some rows in my table correctly.I have a Appointment table which has Appointment Times and a Appointment Names. However the Name is only showing on the Appt start Time line. I need it to show for its duration. So for example in my DDL Morning Appt only shows on at 8:00 I need it to show one each line until the next Appt Starts and so on. In this case Morning Appt should show at 8:00,8:15, 8:30.
CREATE TABLE #TEST ( ApptTime TIME, ApptName VARCHAR (20), DURATION TINYINT)
INSERT INTO #TEST VALUES ('8:00', 'Morning Appt', 45), ('8:15', NULL, NULL),('8:30', NULL,NULL),('8:45', 'Brunch Appt', 45),('9:00', NULL,NULL),('9:15', NULL,NULL),
('9:30', 'Afternoon Appt', 30),('9:45', NULL,NULL),('10:00', NULL,NULL).
I have a query, I am trying to update a certain column in my query you can see that is hard coded. The column that I am trying to update is "O_Test" I used a select statement trying to figure out how many records that accounts for with the entire database of all the tables. I got 643 records. So I am wondering if there is a way I can update all the columns without looking up each table and updating each one. This Update statement wont work because I am accounting for all records in the DB of all tables associated of what I hard coded
SELECT t.name AS table_name,
SCHEMA_NAME(schema_id) AS schema_name,
c.name AS column_name
FROM sys.tables AS t
INNER JOIN sys.columns c ON t.OBJECT_ID = c.OBJECT_ID
WHERE c.name LIKE '%O_Test%'
ORDER BY schema_name, table_name;
The last two columns in one table is [StarText](varchar(20)) and [Star] (binary). It stored data like below:
StarTest---Star
***
**
Null
*****
How to write a update code to insert star image at column [Star]?
For example, at column [Star]
row1 insert 3 stars
row2 insert 2 stars
row3 keep null
row4 insert 5 stars
I'm getting the following error message 'An aggregate may not appear in the set list of an UPDATE statement' What is the proper way to carry out an update on aggregates?
My code is below:
t1.TotalTest1 = coalesce(Sum(t2.AmountTest1), 0.00),
t1.TotalTest2 = coalesce(Sum(t2.AmountTest2), 0.00),
t1.TotalTest3 = coalesce(Sum(t2.AmountTest3), 0.00),
t1.TotalTest4 = coalesce(Sum(t2.AmountTest4), 0.00),
from #tbl_CHA t1
inner join
[Code] ....
I need to update the Denominator column in one row with the value from the Numerator column in a different row. For example the last row in the table is
c010A92NULL
I need to update the Denominator, which is currently NULL, with the value from the Numerator where the MeasureID=c001 and GroupID=A.
This value is 668 so, the row should look like
c010A92668
create table dbo.TEST
(
MeasureID varchar(10),
GroupID char(1),
Numerator float,
Denominator float
)
[Code] .....
I have a table and a specific column inside this table. I know this table is being updated, by using sys.dm_db_index_usage_stats, I was able to determine this, by some process (stored procedure / SQL Job / etc), but the problem is, I am not sure what process is doing it.
How would I search our SQL Server 2008 database to find any process that manipulates this table / column (I only care about Inserts / Updates and Deletes, but do not really care for SELECT).
The Delete-Insert update happens for key columns of Indexes and that makes sense.
But I am confused that why Delete-Insert update happens for Included columns of nonclustered indexes, where I expected them to be InPlace updates ???
Currently our database size is around 350G. It will grow up to 1.5 TB
We have the
Auto create statistics option :True,
auto update statistics option :True,
auto update statistics asynchronously option : False
at database level
we have a weekly job, update statistics running very long time. It is created through maintenance plan using the option full scan.
Previously they tested with sampling but instead of full scan running with the sampling effected the queries.
Is there option to avoid the long time job duration.
If we didn't run the statistics manually what will happen? How do you maintain statistics with large databases
I ran a db update script to update the datatype for a column from a tinyint to a smallint:
ALTER TABLE MyTable
ALTER COLUMN Age smallint
Then I ran another db update script to update the value in these 2 columns:
update MyTable
set Age = Age * 12,
However, the second db update script returns the following error:
Msg 220, Level 16, State 2, Line 1
Arithmetic overflow error for data type tinyint, value = 1440.
The statement has been terminated.
SSMS shows the column with the new data type of smallint. I even restarted SSMS but I still get the error above. 1440 is out of range for a tiny int but should be in range for a smallint. Both scripts need to be executed together in sequence by the release manager.
I have a table where I would like to update the document number row for 3k rows. The problem I have is that the documents come in sets of two (version 1 and 2) but both have different numbers. Picture it like this below:
DOCNUM: 4445787 Version 1
DOCNUM: 4445790 Version 2
It should be the same docnum (ie 4445787 Version 1, 4445787 Version 2).
The challenge is how can we assign the new docnum for version 1 to be also for version 2 as well. Basically in SQL we need a way to
1. Find a way to distinguish the pair of documents in the target db that are the same even though they have different docnums.
2. Update them so that the docnums match.
I have a new production server with about 100 jobs on it. These are ETL jobs about half of which are in SSIS packages and half call stored procedures directly. For those calling stored procedures directly, might there be a way to use the system catalog to link the schedule of the job to the table being updated by the procedure? The result is a list of tables (those updated by jobs) and the schedule of when they are updated.
SQL 2012 Standard VPS Windows 2012 Server Standard
I am experimenting with using CDC to track user changes in our application database. So far I've done the following:
-- ENABLE CDC ON DV_WRP_TEST
USE dv_wrp_test
GO
EXEC sys.sp_cdc_enable_db
GO
-- ENABLE CDC TRACKING ON THE AVA TABLE IN DV_WRP_TEST
USE dv_wrp_test
[Code] ....
The results shown above are what I expect to see. My problem occurs when I use our application to update the same column in the same table. The vb.net application passes a Table Valued Parameter to a stored procedure which updates the table. Below is the creation script for the stored proc:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
if exists (select * from sysobjects where id = object_id('dbo.spdv_AVAUpdate') and sysstat & 0xf = 4)
drop procedure dbo.spdv_AVAUpdate
[Code] ....
When I look at the results of CDC, instead of operations 3 and 4, I see 1 (DELETE) and 2 (INSERT) for the change that was initiated from the stored procedure:
-- GET CDC RESULTS FOR CHANGES TO AVA TABLE
USE dv_wrp_test
GO
SELECT *
FROM cdc.dbo_AVA_CT
GO
--RESULTS SHOW OPERATION 1 (DELETE) AND 2 (INSERT) INSTEAD OF 3 AND 4
--__$start_lsn__$end_lsn__$seqval__$operation__$update_maskAvaKeyAvaDescAvaArrKeyAvaSAPAppellationID
--0x0031E84F000000740008NULL0x0031E84F00000074000230x02119Test26NULL
--0x0031E84F000000740008NULL0x0031E84F00000074000240x02119Test36NULL
--0x0031E84F00000098000ANULL0x0031E84F00000098000310x0F119Test36NULL
--0x0031E84F00000098000ANULL0x0031E84F00000098000420x0F119Test46NULL
Why this might be happening, and if so, what can be done to correct it? Also, is there any way to get the user id associated with the CDC?
this directory is over 2gb
Program FilesMicrosoft SQL Server100Setup BootstrapUpdate Cache
can you delete the contents safely?