sql - 插入和删除的伪表存储在哪里？

Question

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Answer 1

在 SQL Server 2005 之前的版本中，这些表 were read from the transaction log when needed .

自 SQL Server 2005 以来，构成后触发器的插入和删除伪表的行都存储在 the version store 中。 (总是在 tempdb 的页面中——这些页面可能存在也可能不存在于内存中)。

您可以从下面清楚地看到这一点(在快照隔离和 RCSI 关闭的数据库中运行)

CREATE TABLE T1 (X BINARY(10));

GO

--B = Before
INSERT INTO T1
VALUES     (0xBBBBBBBBBBBBBBBBBBBB); 

GO

CREATE TRIGGER TR ON T1 AFTER UPDATE
AS
    PRINT 'Trigger called'

GO

DECLARE @mtsn INT = ISNULL(MAX(transaction_sequence_num), 0)
FROM   sys.dm_tran_version_store
WHERE  database_id = DB_ID();    

UPDATE T1
SET    X = 0xAAAAAAAAAAAAAAAAAAAA;    --A = After

SELECT transaction_sequence_num,
       version_sequence_num,
       record_image_first_part,
       CASE
         WHEN CHARINDEX(0xBBBBBBBBBBBBBBBBBBBB, record_image_first_part) > 0
           THEN 'Before'
         WHEN CHARINDEX(0xAAAAAAAAAAAAAAAAAAAA, record_image_first_part) > 0
           THEN 'After'
       END
FROM   sys.dm_tran_version_store
WHERE  database_id = DB_ID()
       AND transaction_sequence_num > @mtsn;


DROP TABLE T1 

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