read-committed-snapshot

SQL Azure and READ_COMMITTED_SNAPSHOT

那年仲夏 提交于 2019-12-07 04:14:48
问题 I would like to set READ_COMMITTED_SNAPSHOT to ON on my SQL Azure database, but the following code, which works with other versions of SQL Server, is not supported in Azure: ALTER DATABASE [database_name] SET READ_COMMITTED_SNAPSHOT ON GO First question: Is it still a good idea to set READ_COMMITTED_SNAPSHOT to ON in SQL Azure (or whatever achieves the same result)? My intention is not to lock records when they are just being read, in order to improve performance. Second question: If it is a

SQL Azure and READ_COMMITTED_SNAPSHOT

北慕城南 提交于 2019-12-05 10:58:27
I would like to set READ_COMMITTED_SNAPSHOT to ON on my SQL Azure database, but the following code, which works with other versions of SQL Server, is not supported in Azure: ALTER DATABASE [database_name] SET READ_COMMITTED_SNAPSHOT ON GO First question: Is it still a good idea to set READ_COMMITTED_SNAPSHOT to ON in SQL Azure (or whatever achieves the same result)? My intention is not to lock records when they are just being read, in order to improve performance. Second question: If it is a good idea, what's the Azure syntax for doing it? From what I can tell based on this MSDN article the

How programmatically enable READ COMMITTED SNAPSHOT in SQL Server?

∥☆過路亽.° 提交于 2019-12-04 10:13:11
问题 I need to programmatically enable READ COMMITTED SNAPSHOT in SQL Server. How can I do that? 回答1: I recommend switching to single-user mode first. That ensures you're the only connection. Otherwise, the query might be suspended. From: http://msdn.microsoft.com/en-us/library/ms175095.aspx When setting the READ_COMMITTED_SNAPSHOT option, only the connection executing the ALTER DATABASE command is allowed in the database. There must be no other open connection in the database until ALTER DATABASE

How to detect READ_COMMITTED_SNAPSHOT is enabled?

送分小仙女□ 提交于 2019-12-03 00:11:18
问题 In MS SQL Server is there a way to detect whether a database has had its isolation level set via the T-SQL command ALTER DATABASE <database> SET READ_COMMITTED_SNAPSHOT ON; I cannot find a simple way to detect this in either T-SQL or via the Management Studio's GUI. TIA 回答1: SELECT is_read_committed_snapshot_on FROM sys.databases WHERE name= 'YourDatabase' Return value: 1 : READ_COMMITTED_SNAPSHOT option is ON . Read operations under the READ COMMITTED isolation level are based on snapshot

How to detect READ_COMMITTED_SNAPSHOT is enabled?

不想你离开。 提交于 2019-12-02 13:56:29
In MS SQL Server is there a way to detect whether a database has had its isolation level set via the T-SQL command ALTER DATABASE <database> SET READ_COMMITTED_SNAPSHOT ON; I cannot find a simple way to detect this in either T-SQL or via the Management Studio's GUI. TIA Galwegian SELECT is_read_committed_snapshot_on FROM sys.databases WHERE name= 'YourDatabase' Return value: 1 : READ_COMMITTED_SNAPSHOT option is ON . Read operations under the READ COMMITTED isolation level are based on snapshot scans and do not acquire locks. 0 (default): READ_COMMITTED_SNAPSHOT option is OFF . Read operations

Read committed Snapshot VS Snapshot Isolation Level

大兔子大兔子 提交于 2019-11-28 02:58:55
Could some one please help me understand when to use SNAPSHOT isolation level over READ COMMITTED SNAPSHOT in SQL Server? I understand that in most cases READ COMMITTED SNAPSHOT works, but not sure when go for SNAPSHOT isolation. Thanks READ COMMITTED SNAPSHOT does optimistic reads and pessimistic writes. In contrast, SNAPSHOT does optimistic reads and optimistic writes. Microsoft recommends READ COMMITTED SNAPSHOT for most apps that need row versioning. Read this excellent Microsoft article: Choosing Row Versioning-based Isolation Levels . It explains the benefits and costs of both isolation

Read committed Snapshot VS Snapshot Isolation Level

一世执手 提交于 2019-11-26 22:30:48
问题 Could some one please help me understand when to use SNAPSHOT isolation level over READ COMMITTED SNAPSHOT in SQL Server? I understand that in most cases READ COMMITTED SNAPSHOT works, but not sure when go for SNAPSHOT isolation. Thanks 回答1: READ COMMITTED SNAPSHOT does optimistic reads and pessimistic writes. In contrast, SNAPSHOT does optimistic reads and optimistic writes. Microsoft recommends READ COMMITTED SNAPSHOT for most apps that need row versioning. Read this excellent Microsoft

SELECT FOR UPDATE with SQL Server

一曲冷凌霜 提交于 2019-11-26 19:36:40
I'm using a Microsoft SQL Server 2005 database with isolation level READ_COMMITTED and READ_COMMITTED_SNAPSHOT=ON . Now I want to use: SELECT * FROM <tablename> FOR UPDATE ...so that other database connections block when trying to access the same row "FOR UPDATE". I tried: SELECT * FROM <tablename> WITH (updlock) WHERE id=1 ...but this blocks all other connections even for selecting an id other than "1". Which is the correct hint to do a SELECT FOR UPDATE as known for Oracle, DB2, MySql? EDIT 2009-10-03: These are the statements to create the table and the index: CREATE TABLE example ( Id

SELECT FOR UPDATE with SQL Server

…衆ロ難τιáo~ 提交于 2019-11-26 07:22:08
问题 I\'m using a Microsoft SQL Server 2005 database with isolation level READ_COMMITTED and READ_COMMITTED_SNAPSHOT=ON . Now I want to use: SELECT * FROM <tablename> FOR UPDATE ...so that other database connections block when trying to access the same row \"FOR UPDATE\". I tried: SELECT * FROM <tablename> WITH (updlock) WHERE id=1 ...but this blocks all other connections even for selecting an id other than \"1\". Which is the correct hint to do a SELECT FOR UPDATE as known for Oracle, DB2, MySql?